2018 IEEE Nuclear Science Symposium and Medical Imaging Conference
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NSS Poster I

Session chair: Charlebois, Serge, A. (Université de Sherbrooke, 3IT, Canada); Le Du, Patrick, (IPNL,IN2P3, France)
 
Shortcut: N-07
Date: Monday, 12 November, 2018, 4:00 PM
Room: Park Side Ballroom
Session type: NSS Session

Contents

Click on an contribution to preview the abstract content.

Poster panel: 1

Poster Number:
N-07-001

XCR4C: A rad-hard full-function CDS ASIC for X-ray CCD Applications (#1022)

B. Lu1, 2, J. Huo1, Y. Chen1, H. Liu2, J. Luo2, B. Li2, Y. Zhou2, 3

1 Chinese Academy of Sicences (CAS), Institute of High Energy Physics, Beijing, China
2 Institute of Microelectronics, Beijing, China
3 University of Chinese Academy of Sciences, Beijing, China

Content

We report in this work the development of a four-channel rad-hard full-function correlated double sampling (CDS) ASIC (XCR4C) targeting the readout of X-ray CCDs for applications in the fields of X-ray spectroscopy, imaging and timing observations. We upgrade the ASIC where both a baseline adjustment circuit and a discriminator are incorporated in the CDS circuit. The ASIC is implemented in a novel differential switched-capacitor architecture, which makes it high linear, low power, immune to commom-mode noise and interferences as well as easy configurable. Particularly, the readout speed is boosted from 100 kHz to 10 MHz. Also, some TID-oriented rad-hard by design techniques are used to combat the harsh low-earth-orbit space environment, among which we describe in detail the even-finger double-side bulk butting (EFBB) layout technique. XCR4C ASIC is fabricated with AMS 0.35 μm 2P4M bulk CMOS with an epitaxial layer and occupies a chip area of 3.47×1.84 mm². The preliminary experimental results show, the ASIC achieves maximum 23 ppm integral nonlinearity (INL) and 5.8 e- equivalent noise charge (ENC) under a typical 1 MHz pixel rate, and only consumes 50 mW approximately from a single 3.3 V supply voltage; After irradiated by 300 krad(Si) TID using 60Co with 50 rad(Si)/s dose rate, the performance degradations are negligible, making it among the analog/mixed-signal ASICs fabricated by 0.35 μm bulk CMOS with state-of-the-art TID tolerance capability.

Keywords: CDS, ASIC
Poster panel: 3

Poster Number:
N-07-003
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Dual Phase-Locked Loop System for TDC Resolution Calibration (#1182)

F. Nolet1, F. Dubois1, N. Roy1, W. Lemaire1, S. A. Charlebois1, R. Fontaine1, J. - F. Pratte1

1 Université de Sherbrooke, Interdisciplinary Institute for Technological Innovation and Department of Electrical and Computer, Sherbrooke, Québec, Canada

Content

Applications such as time-imaging calorimetry and positron emission tomography (PET) would benefit from timing resolution with time-of-flight (ToF) capabilities. In ToF-PET, the annihilation position along the line of response is better circumscribed and contrast-to-noise ratio (CNR) of images can be improved. Our objective is to achieve a coincidence timing resolution (CTR) of ~10 ps FWHM which will open new frontiers in medical imaging. We are actively pursuing the CTR of 10 ps by implementing the photodetector and CMOS readout electronics in a 3D digital silicon photomultiplier (3D dSiPM) structure. The 3D integration enables the implementation of a dedicated readout channel based on an array of a one to one coupling of a time-to-digital converter (TDC) to a single photon avalanche diode (SPAD). A TDC architecture based on a Vernier TDC with two CMOS ring oscillators was previously designed by our group. One of its main concerns is its non-uniformity throughout the array and the non-uniformity between different 3D dSiPM arising from process, voltage and temperature variations (PVT). The ring oscillator frequency of this TDC was measured as a function of voltage and temperature, and showed a dependency to both temperature (∼0.7 ps/◦C) and supply voltage (∼0.5 ps/mV). This paper presents a dual phase-locked loop (PLL) system developed to overcome these variations. Each PLL controls the frequency of one of the ring oscillator to fix the TDC resolution and minimize the impact of PVT variations. The difference between the PLL output and input frequency is below 1 MHz. The PLL total jitter varies between 20 ps rms and 43 ps rms over the range of 0.7 GHz to 2.2 GHz and the TDC timing jitter is 47 ps rms for a TDC resolution of 30 ps.

Keywords: Time-to-Digital Converter, Phase-Locked Loop
Poster panel: 5

Poster Number:
N-07-005
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A Multi-Channel Differential ADC Driver for High-Speed CMOS Image Sensors (#1179)

C. R. Grace1, T. Stezelberger1, P. Denes1

1 Lawrence Berkeley National Laboratory (LBNL), Berkeley, California, United States of America

Content

A 16-channel ADC driver chip that provides single-ended-to-differential conversion and column biasing for high-speed CMOS image sensors is presented. By increasing the level of integration, the number of driver chips and associated number of passives and routing area is reduced, enabling smaller physical cameras. Power dissipation is reduced relative to many commercial approaches by the use of low-voltage CMOS technology and the increased level of integration. The driver chip also supplies programmable bias currents to the sensor, further reducing the number of required components on the camera board. The driver, fabricated in 180 nm CMOS technology, achieves settling to 0.1% in 13 ns with input noise of 89.9 µV-rms. The crosstalk between channels below is –56 dB. The power dissipation is 10.5 mW / channel. When applied to the readout of a high-speed X-ray sensor, the prototype reduced board area by 84% (from 100 mm2 to 16 mm2) and power dissipation by 25%.

Keywords: Mixed-Signal IC Design, Solid-State Imaging
Poster panel: 7

Poster Number:
N-07-007

PMT High-Voltage Bleeder Circuit Studies for in-Beam PET Imaging in Proton Therapy Applications (#1037)

N. Zhang1, M. Bills1, M. Schmand1

1 Siemens Medical Solutions USA, Inc., Molecular Imaging, Rockford, Tennessee, United States of America

Content

Different PMT high-voltage bleeder circuits for in-beam PET imaging in proton therapy applications are discussed in this paper. The design goals of this work is to (1)eliminate the latch-up and hysteresis artifacts in the conventional nMOS-based bleeder circuits; improve high current output capability;(2)add fast on-standby switching function to protect PMTs in the very high radioactive intensities. Compared with the conventional PMT bleeder circuit design, we investigated different architectures, analyzed, simulated, and prototyped different concepts. The finalized bleeder circuits improve the count-rate dynamic ranger over 5 times compared with prior design. The circuits are capable of working properly under extreme conditions like placing a 30mCi Cs-137 point source just in front of the detector windows. This demonstrates that the PMT detectors have good count-rate capabilities in addition to their radiation hardness advantages. So PMT detectors could be suitable in very high count-rate applications like in-beam PET imaging for Proton Therapy.

Keywords: in-Beam PET
Poster panel: 9

Poster Number:
N-07-009
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600MSPS Direct Digital Synthesizer with Amplitude Control for a Cold Atom Gravimeter (#1303)

D. Rivas Marchena1, S. Bell1, M. Clapp1, T. Gardiner1, L. Jones1, Q. Morrissey1, N. Waltham1

1 UK Research and Innovation, Science and Technology Facilities Council, Didcot, United Kingdom

Content

This paper discusses a compressed-ROM 600MSPS dual-branch Direct Digital Synthesizer (DDS) providing sinewaves of <150MHz with 2μHz resolution and SFDR >80dBc. It supports positive chirp slopes up to 40MHz/s with ~1.3kHz/s resolution. The amplitude can be shaped with Gaussian envelopes of FWHM 2μs–2ms and SLRR >85dB. Any other envelope can be generated by pulsing programmable-step increment/decrements through dedicated LVDS inputs. The ASIC delivers two 14-bit 300MSPS LVDS buses to interface with an external DAC using a ping-pong arrangement. The output data is synchronous to a DDR clock coming from the DAC, which can pass through a programmable delay-line to adjust the loop phase. A demonstrator chip is manufactured in 0.18μm CMOS process.

Poster panel: 11

Poster Number:
N-07-011

Shunt Regulator for the Serial Powering of the ATLAS CMOS Pixel Detector Modules (#1574)

A. Habib1, M. Barbero1, T. Kugathasan2, P. Pangaud1, H. Pernegger2, W. J. Snoeys2

1 Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France
2 CERN, Geneva, Switzerland

Content

A shunt regulator was designed to meet the specifications for the serial powering of CMOS pixel detector modules for the operation of the ATLAS experiment at the High Luminosity-LHC upgrade in 2026. Serial powering increases greatly the system’s power efficiency when compared to a parallel power scheme and allows for significant material budget savings in the power cabling. Each module is powered by a shunt regulator that takes in a constant current and produces a regulated output voltage relative to the module’s potential ground. A detailed theoretical model of the regulator has been studied, to guarantee stability for all possible values of load capacitance without an off-chip capacitor. Simulations proved the system to be stable for a load capacitance range up to 10 µF with a damping factor above 0.2 in all cases. In DC, the regulator acts as an ideal voltage source with a series resistance of 175 mΩ. Special design features were implemented to ensure proper functioning in a parallel scheme, as four regulators will be placed in parallel inside one module. Simulations showed that the current mismatch when placing four regulators in parallel is less than 10% for a threshold voltage mismatch up to 100 mV. The regulator is designed in a 0.18 µm CMOS technology and is planned for fabrication in August 2018.

Keywords: Shunt regulator, Serial powering
Poster panel: 13

Poster Number:
N-07-013

FPGA-based Non-Uniform Multi-phase TDC (#1688)

T. Sui1, Z. Zhao2, S. Xie1, Q. Huang2, J. Xu1, Q. Peng3

1 Huazhong University of Science and Technology, Wuhan, China
2 Shanghai Jiaotong University, Shanghai, China
3 Lawrence Berkeley National Laboratory, Berkeley, California, United States of America

Content

We propose a novel Event Latch Shifted Clocks (ELSC) architecture based on what we are calling the Non-Uniform Multi-phase (NUMP) method. A global clock signal is fed into the time delay line (TDL) to generate multiple phase-shifted clocks whose status can be recorded by the hit signal. The TDL can be composed by using combinational logic delay units, carry chains, routing parasitics, and so on.

The NUMP TDC has some general advantages compared to conventional FPGA-based TDCs. First of all, it is resource efficient and robust. Both the rising and falling edges of delayed clocks can be used to fractionize the cycle of the system clock. Secondly, the resolution of a NUMP TDC is not limited by the uniformity and minimum value of the time delays within a delay line. Thirdly, the intrinsic timing resolution of NUMP TDCs is related to the number of delayed clocks. Lastly, there is no need to manually tune, adjust or rearrange the delay lines when migrating NUMP TDC designs from one FPGA to another.

We have constructed 50 identical channels NUMP TDCs in our own designed FPGA board (Cyclone V 5CEFA7F31C6) with a good performance. 320 delay units were used in each TDC to generate 320 delayed 500MHz clocks. The average RMS time resolution is 6.1ps when tested by internal pulses. The RMS measured from the combinations of TDC channel #1 and TDC channel #2~50 with external LVDS signals is 8.3ps.

We also implemented 4 channels NUMP TDCs in a Cyclone 10 development board (EK-10CL025U256). In every single TDC, the length of the TDL is 380 with the clock frequency of 400M. The RMS resolution between the 4 TDC channels is 5.67ps when tested with internal pulses. We conclude that the NUMP method can be utilized to implement multi-channel high-performance TDCs on different FPGAs.

Keywords: FPGA, TDC, Non-Uniform Multi-phase, multi-channel
Poster panel: 15

Poster Number:
N-07-015

HV divider design and optimization for 20-inch MCP-PMT (#1749)

Z. Wang1, F. Luo1, 2, Y. Heng1, 2, P. Wang1, A. Yang1, Z. Qin1, W. Wang3

1 Chinese Academy of Sciences (CAS), Institute of High Energy Physics, Beijing, China
2 University of Chinese Academy of , Beijing, China
3 Sun Ya-Sen University, Guangzhou, China

Content

High detection efficiency and good single photoelectron resolution of photomultiplier tubes are one of the key parameters for the large and high precision neutrino experiments, like JUNO, hyper-K and so on. In this work, we have designed the HV divider for 20-inch MCP-PMT from NNVT, optimized the HV divider ratio to have high collection efficiency, and optimized the HV divider current to improve the peak-to-valley ratio and energy resolution of single photoelectron spectrum. Besides, we have optimized the ringing and overshoot of waveform for MCP-PMT in the positive HV scheme. We have controlled the overshoot to less than ~1% of the signal amplitude.

Poster panel: 17

Poster Number:
N-07-017

TETPIX, A rad-hard pixel chip with a full particle information acquisition capability for the HEPS-TF project (#1840)

W. Wei1, 2, L. Fan1, 2, J. Ren1, 2, J. Zhang1, 2, X. Jiang1, 2, Z. Wang1, 2

1 IHEP, CAS, Beijing, China
2 State Key Laboratory of Particle Detection and Electronics, Beijing, China

Content

A pixel chip based on the Hit-Driven scheme was designed for the HEPS (High Energy Photon Source) project in China. The full information of every photon, including the hit position, arrival time, and photon energy, are detected by the ToT (Time over Threshold) method. Thus a 3D animation of clusters can be rebuild. Priority arbitrary logic was designed to readout all the hit pixels sequentially to the column FIFO (First-in-First-out), and then the chip overall buffer and the output serializer. The beamline gate signal was used as the trigger to make the level 1 data selection. Details of the chip design will be discussed in this paper. A full functional chip with a pixel array of 18*60 pixels was taped out using a CMOS 130nm technology. The test results showed the input noise was 50e- rms and the TOT resolution was 5 bits. The chip was also verified for the radiation hardness. After a dose of over 100 Mrad (Si) X-ray irradiation, it still survived with the performance remained in the normal region.

Keywords: HEPS, pixel chip, hit driven, full information acquisition, rad-hard
Poster panel: 19

Poster Number:
N-07-019

Design and Test of the Analog to Digital Converter Unit for the JUNO Readout Electronics (#1867)

J. Hu1, X. B. Yan1, X. S. Jiang1

1 Institute of High Energy Physics,cAS, Beijing, China

On behalf of the JUNO Collaboration

Content

The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose underground Neutrino experiment with a 20-thousand-ton liquid scintillator detector at 700-meter deep underground. All the signals coming from the almost 18000 Central Detector 20-inch photomultipliers (PMTs), will be digitized thanks to high-speed high-resolution waveform full sampling technique. An Analog to Digital converter Unit (ADU) which will be located very close to the PMTs, inside an underwater box, with large dynamic range, high energy resolution, low noise, low power and high reliability has been designed to digitize the input signal. This paper introduces the details of the ADU design, then describes the ADU test system and the first ADU test results.

Keywords: JUNO, PMT, ADU, reliability
Poster panel: 21

Poster Number:
N-07-021

Hardware Description Language Phase-Locked Loop (HDL-PLL) Open Architecture for FPGAs (#2104)

N. Lusardi1, F. Garzetti1, L. Gatti1, A. Geraci1

1 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milan, Italy

Content

This contribution aims to be a proof of the feasibility of a fully open architecture in Hardware Description Language of a Phase-Locked Loop (HDL-PLL) implemented in Field Programmable Gate Array (FPGA). Main parts of the system are the Phase-Frequency Detector (PFD) based on a Time-to-Digital Converter (TDC) and the Digital-Controlled Oscillator (DCO). Both of them are implemented by means of asynchronous architectures making possible to tune the DCO output period, by means of a feedback loop, with resolution of 78 ps and cycle-cycle jitter below 75.3 ps r.m.s. The dynamic range of the HDL-PLL is set by the user during the implementation and varies from several hundreds of MHz with no practical lower limit.

Preliminary experimental investigations have demonstrated the possibility to get lock in phase in less than 150 ns between the feedback loop signal and an external reference signal, the possibility to synthesize an output frequency based as multiple of the reference one, and the possibility to measure the frequency of an external periodic signal.

With respect to the native PLL built in the FPGA devices, the proposed solution is an open architecture that allows the user configuring the PLL features fully at his own choice, for instance in terms of the minimum frequency not limited by the DCO frequency and of the number of available outputs.

An IP-Core based approach has been used to add flexibility and portability to the HDL-PLL, making it ready to be implemented in Xilinx FPGAs of last generation.

Keywords: PLL, HDL-PLL, FPGA
Poster panel: 23

Poster Number:
N-07-023

Implementation Issues of a High-Performance Multi-Channel Time-to-Digital Converter in Xilinx 20-nm UltraScale FPGAs (#2119)

N. Lusardi1, F. Garzetti1, R. De Marco1, A. Geraci1

1 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milan, Italy

Content

In this contribution we discuss implementation issues of a resource-saving, multi-channels, high-performance, Time-to-Digital Converter (TDC) designed for implementation in Xilinx 20-nm UltraScale Field Programmable Gate Array (FPGA) devices of last generation. Target features are 24 channels with resolution of 100 fs over full-scale range of 419 μs, and single-shot precision below 8.5 ps r.m.s. Moreover, each channel should measure a 32-bit timestamp, by means of the Nutt-interpolation, i.e. merging a coarse with a fine component of the measure. For each channel, the coarse contribution is obtained by sampling an 18-bit counter clocked at 625 MHz, whereas the fine one is returned by the interpolation of 16 Tapped Delay-Lines (TDLs).

The TDLs are implemented using the carry-chains available into the fabric of the FPGA, i.e. the CARRY8 blocks. This choice allows achieving measure resolution in the order of the propagation delay of the technology. However, for reaching resolutions of 100 fs, a sub-interpolation process among the TDLs is mandatory. Moreover, each channel is equipped with a decoder and a calibrator able to compensate at best the non-linearity due to the CARRY8 primitives.

The maximum sustainable rate is 45 MHz per each channel.

The host device is a Xilinx XCKU040-2FFVA1156E (530 kSLICE, 1920 DSP, 21.1 Mb BRAM) 20-nm Kintex UltraScale FPGA installed over a general purpose evaluation board (EVB) KCU105, but the architecture can be easily migrated on different families of Xilinx UltraScale and UltraScale+ FPGAs and System-on-Chips (SoCs). The system is interfaced via USB 3.0 bus.

Keywords: TDC, FPGA, UltraScale
Poster panel: 25

Poster Number:
N-07-025
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PACIFIC: large area Scintillator Fibre (SciFi) tracker readout at LHCb (#2229)

A. Comerma1, B. Leverington1

1 Heidelberg Universitat, Physikalisches Institut , Heidelberg, Baden-Württemberg, Germany

on behalf of the SciFi collaboration

Content

The LHCb detector will undergo a major upgrade during the Long Shutdown 2 (LS2) of the LHC, including the full replacement of the main tracking system.

The new tracker will use scintillating fibres to cover the complete area of the detector. Arrays of silicon photomultipliers (SiPMs) will be used to readout these fibres. Each array has 128 channels and is read out by the low-power ASIC PACIFIC specifically developed for this purpose.

Each of the 64 channels of this ASIC comprise analog processing, digitization, slow control and digital output at a rate of 40 MHz. The analog processing consists of a preamplifier, shaper and integrator. An interleaved double gated integrator avoids dead time as one integrator is in reset while the other collects the signal. The two integrator outputs are merged by a track and hold to provide a continuous measurement. The output voltage is digitized using 3 comparators acting like a non-linear flash ADC.

The three bits output is encoded into two bits and serialized joining four consecutive channels and using a 320MHz clock. The design is complemented by auxil
iary blocks such as voltage and current references, control DACs, power on reset (POR) circuitry and serializers. The slow control digital block consists in a 10 bit addressing I2C slave and a register bank for holding the configuration values.
The PACIFIC ASIC has been designed using a 130 nm technology and several prototypes have been validated. The fith iteration has already been produced in large scale to be installed in the detector.

The talk will summarize latest measurements using electrical characterization and testbeam data. It will also include radiation tests and the latest mass production tests performed in production ASICs.

Keywords: LHCb, SciFi, ASIC, Scintillator, LHC
Poster panel: 27

Poster Number:
N-07-027

Design of a multichannel low-power integrated circuit for microstrip detectors (#2252)

A. Amirkhani1, 2, P. Trigilio3, L. Bombelli3, C. E. Fiorini1, 2, V. Jovanović4, S. J. A. Weijers4

1 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
2 Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milano, Italy
3 XGLab srl, Milano, Italy
4 Malvern Panalytical B.V., Almelo, Netherlands

Content

This work is focused on the development of a 128-channel low-power ASIC for the readout of silicon microstrip detectors with high energy resolution and counting rate efficiency. It is expected that this ASIC would find wider application with other detector solutions as well. Each channel is composed by a charge sensitive preamplifier, a shaping amplifier, two twin discriminators for photon counting within an energy window and one for detection of very small signals, e.g. due to inter-strip charge sharing effect. The chip can accommodate energies ranging between 0 to 30 keV. Several studies have been conducted analytically on different types of real and complex-conjugate pole shapers with respect to their optimum Equivalent Noise Charge (ENC), peaking time and related pulse duration. On these premises, a 5th order complex-conjugate pole shaper has been chosen as filter for the ASIC. To provide both good noise performances and count rate efficiency, four peaking times have been implemented for the shaper: 250 ns, 550 ns, 720 ns and 1.1 us, for diverse applications. Moreover, possibility to operate a local trimming of the gain and offset of each channel has been foreseen, to minimize the spread among the 128 channels. The digital section of the channel consists of a hold logic, to latch the event recognised by the comparators, equipped with storage elements maintaining the data provided by the hold logic until it is transferred to the external electronics; trimming DACs, to compensate for offset and gain mismatches among different channels and channel configuration register, storing specific settings for each channel. This chip is implemented in AMS 0.35 µm CMOS process and its area occupancy is 46.6 mm2. Two version of this chip have been realized, namely nominal one and low-power one, where in the latter an identical shaper with 40% power reduction in comparison to its nominal version has been successfully implemented and tested.  

Keywords: microstrip, ASIC, low-power shaper
Poster panel: 29

Poster Number:
N-07-029
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Algorithm of Cluster Search for CMOS Pixel Sensor with on-chip Artificial Neural Network (#2367)

R. Zhao1, A. Besson1, C. Hu-Guo1, Y. Hu1

1 university of strasbourg, IPHC, strasbourg, France

Content

CMOS Pixel Sensor (CPS) has been used in subatomic physics experiments for tracking devices. In the vertex detector of International Linear Collider (ILC) experiment, there are large quantities of e+/e- particles which come from the beam background impacting parameter resolution and tracking efficiency of the detector and reducing the system bandwidth. Due to the effect of magnetic field in the detector, charged particles in the detector make regular spiral motion, background particles with low momentum (10-100MeV/c) generate large incident angles on CPS compared with particles which come from physics experiments. We propose a CPS with on-chip Artificial Neural Network (ANN) to tag and remove cluster generated by background particles, classify background particles on the basis of cluster shape and charge distribution. In this paper we design an algorithm of cluster search which is used to find out the maximum pixel value in a cluster window as the seed pixel, locate the cluster and collect cluster information. We have verified the feasibility of the algorithm by HDL simulation under the situation of 64 channels pixels and 7×7 cluster window. We have compared synthesis area and power consumption of the algorithm under different system clock or ADC bit with TowerJazz 0.18um process.

Keywords: CMOS pixel sensor, cluster search, algorithm, Artificial Neural network, subatomic physics
Poster panel: 31

Poster Number:
N-07-031

MARS: A new ASIC for multielement detectors (#2423)

D. P. Siddons1, E. Vernon2, A. Kuczewski1, J. Mead2, A. K. Rumaiz1

1 Brookhaven National Laboratory, NSLS-II, Upton, New York, United States of America
2 Brookhaven National Laboratory, Instrumentation Division, Upton, New York, United States of America

Content

We have developed a versatile Application-Specific Integrated Circuit (ASIC) for instrumenting monolithic multi-element X-ray detectors. The chip has a range of gains and shaping times, and can accept either electron or hole signals. It has 32 channels, and under optimal conditions it can achieve an Equivalent Noise Charge (ENC) of 10 electrons rms. We have tested it under a range of conditions with a variety of sensors. We will present data showing its performance and limitations, and suggest possible improvements to be implemented in future revisions.

 

Keywords: Integrated circuit, X-ray spectroscopy, Synchrotron radiation
Poster panel: 33

Poster Number:
N-07-033

Serial Powering for Inner Tracker Detectors at the HL-LHC (#2586)

S. Orfanelli1, D. Koukola1

1 CERN, Geneva, Switzerland

Content

The Large Hadron Collider will be upgraded to deliver peak instantaneous luminosities up to 7.5x1034 cm-2 s-1 and up to 3000 fb-1 during the 10-year High Luminosity phase (HL-LHC). New silicon tracking detector systems will be installed to fully exploit the physics potential of the upgraded machine. Inner tracker systems will be composed entirely of silicon pixel modules and capable of withstanding intense radiation environments while minimizing material in the detector region. Serial power distribution systems offer an attractive approach to fulfill the required granularity, radiation tolerance, and material constraints for these next-generation pixel detectors. This powering scheme is based on the use of Shunt-Low Dropout regulators that will be integrated on the future pixel readout chip designed by the RD53 collaboration. Design choices for powering the inner tracker front-end electronics are discussed along with recent R&D activities in novel serial powering schemes. First results from system tests of serial power chains of pixel readout chips using a prototype power supply are presented.

Keywords: serial powering, pixel detectors, HL-LHC, Shunt-LDO
Poster panel: 37

Poster Number:
N-07-037

AARDVARC: Data Acquisition SOC for Waveform Sampling and Feature Extraction with Picosecond Timing Resolution (#2823)

L. Macchiarulo1, I. Mostafanezhad1, G. Varner2, D. Uehara1, C. Chock1

1 Nalu Scientific, LLC, Honolulu, Hawaii, United States of America
2 University of Hawaii, Physics, Honolulu, Hawaii, United States of America

Content

Abstract: the “AARDVARC” is a novel multichannel waveform digitizing and processing Application Specific Integrated Circuit (ASIC) with fast sampling (at least 10 Gsa/s), deep storage (32K samples or more), and reaching better than 5ps timing resolution. With full waveform sampling, feature extraction and digital signal processing in a single Application Specific Integrated Circuit, AARDVARC can be used as a building block for next generation high luminosity  readout systems that require good radiation hardness, high accuracy, and self-calibration features. Once commercially available, AARDVARC will have significant cost and performance benefits compared to existing state of the art readout devices for SiPM, PMTs and LAPPDs.  A 4 channel prototype chip is currently in fabrication in 130nm CMOS.

Keywords: waveform sampling, picosecond, deep buffer, system-on-chip, feature extraction
Poster panel: 39

Poster Number:
N-07-039

Performance at cryogenic temperatures of an ultra-low noise CMOS front-end for Fano-limited X-ray spectroscopy (#2896)

C. Liu1, 2, G. Bertuccio3, 2, M. Gandola3, 2, M. Sammartini3, 2, F. Mele3, 2, A. Castoldi1, 2

1 Politecnico di Milano, DEIB, Milano, Italy
2 Istituto Nazionale Fisica Nucleare, Sez. Milano, Milano, Italy
3 Politecnico di Milano, Como, Italy

Content

Recently an ultra-low-noise CMOS Charge Sensitive Preamplifier (0.35 µm CMOS), named Sirio, has been specifically designed for low capacitance pixel or silicon drift detectors for high resolution X-ray spectrometry with ultra-low noise performance. On the basis of the known increase of MOSFET channel conductivity with decreasing temperature and cryogenic operation of MOSFET transistors, we qualified the noise performance of Sirio CMOS Charge Sensitive Preamplifier as a function of temperature down to -90 °C. The goal is twofold: i) to achieve an improvement of the ENC and ii) to disentangle the temperature dependence of the individual noise contributions and identify critical design issues in order to extend its ultra-low noise performances at moderate or deeper cryogenic operation. The intrinsic noise of the preamplifier, without connection to any detector, has been measured by injecting charge pulses through a test capacitance with precisely known value. The 3 noise contributions (series white, series flicker, parallel white) have been fitted to the experimental data from which we can estimate the trans-conductance or the gate capacitance of the input MOSFET, the flicker noise coefficient and the detector leakage current, within the tested temperature range. The lowest measured ENC at the optimal peaking time is around 1 el. rms at -90 °C. The obtained results and its implications will be critically discussed.

Keywords: low noise, charge sensitive preamplifier, CMOS front-end, cryogenic operation
Poster panel: 41

Poster Number:
N-07-041

Bonds for detection of very inclined shower due to anti-aliasing filter in the Pierre Auger surface detector data acquisition system (#1056)

Z. P. Szadkowski1

1 University of Lodz, Faculty of Physics and Applied Informatics, Lodz, Poland

Content

At large zenith angles the slant atmospheric depth to the ground level is sufficient to absorb the early part of the shower that follows from the standard cascading interactions, both of electromagnetic and hadronic type. Nucleon induced showers are initiated at the top of the atmosphere. For very inclined showers, due to the large slant depth, only the muons in the shower survive. The fronts of deeply penetrating muon (“old”) showers have only a small longitudinal extension, which leads to short detector signals. Old showers generate short traces of very similar shapes at all core distances.
Inclined showers mainly composed of muons, allow a direct measurement of the muon content at ground level and as a consequence, they can be used to study mass composition and to test high-energy hadronic interaction models.

The Pierre Auger Observatory is particularly well suited for the detection of inclined showers because the water Cherenkov tanks used for the surface detector act like volume detectors. The standard data acquisition system quantizing the analog signals in ADCs, according to the “Golden Rules”, is equipped
with the anti-aliasing filter with the cut-off Nyquist frequency. However, very short pulses, typical for very inclined showers, are significantly suppressed by the anti-aliasing filter and their amplitude may be not enough to generate the 3-fold coincidence trigger.

The paper presents the theoretical analyses of the anti-aliasing Auger filter response as well analyses of measured Auger data.We conclude that for a detection of non-standard rare events maybe it is worth considering non-standard approach and resign with the standard "Golden Rules".

We rather propose to either eliminate the anti-aliasing filter at all, agreeing on some aliasing and higher noise, but being sure that no any crucial rare event would not be lost, or to increase the frequency sampling to 160 MHz with much more soft frequency characteristics: e.g. 2-pole instead of 6-pole Bessel filter.

Keywords: Pierre Auger Observatory, trigger
Poster panel: 43

Poster Number:
N-07-043
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Development of a CsI calorimeter subsystem for the All-Sky Medium-Energy Gamma-ray Observatory (AMEGO) (#1268)

R. S. Woolf1, J. E. Grove1, B. F. Phlips1, E. A. Wulf1

1 U.S. Naval Research Laboratory, Space Science Division, Washington, DC, Washington, United States of America

Content

We report on the development of the thallium-doped cesium iodide (CsI:Tl) calorimeter subsystem for the All-Sky Medium-Energy Gamma-ray Observatory (AMEGO) [1]. The CsI calorimeter is one of the three main subsystems that comprise the AMEGO instrument suite; the others include the double-sided silicon strip detector (DSSD) tracker/converter and a cadmium zinc telluride (CZT) calorimeter. Similar to the LAT instrument on Fermi Gamma-ray Space Telescope, the hodoscopic calorimeter consists of orthogonally layered CsI bars. Unlike the LAT, which uses PIN photodiodes, the scintillation light from each end of the CsI bar is read out with recently developed large-area silicon photomultiplier (SiPM) arrays. We currently have a NASA-APRA program to develop the calorimeter technology for a large space-based gamma-ray observatory. Under this program, we have designed, built and are currently testing a prototype consisting of 24 CsI:Tl bars (each with dimensions of 16.7 mm x 16.7 mm x 100 mm) hodoscopically arranged in 4 layers with 6 bars per layer. The ends of each bar are read out with SensL ArrayJ quad SiPMs. Signal readout and processing is done with the IDEAS SIPHRA (IDE3380) ASIC. Performance testing of this prototype will be done with laboratory sources, a beam test, and a balloon flight in conjunction with the other subsystems led by NASA-GSFC. We will discuss the initial calibration testing, building of the prototype and the most up-to-date results from the laboratory (and accelerator testing) with analog/digital electronics and the SIPHRA DAQ.

[1] https://asd.gsfc.nasa.gov/amego/index.html

Keywords: Calorimeter, Gamma Ray
Poster panel: 45

Poster Number:
N-07-045

Development of an Elpasolite Planetary Science Instrument (#1917)

L. C. Stonehill1, K. E. Mesick1, D. D. S. Coupland1, S. F. Nowicki1, N. A. Dallmann1, W. C. Feldman2, S. A. Storms1

1 Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
2 Planetary Science Institute, Tucson, Arizona, United States of America

Content

Planetary gamma-ray and neutron spectroscopy from orbiting spacecraft has become a standard technique to measure distinctive geochemical composition and volatile abundance signatures for key elements relevant to planetary structure and evolution. Previous instrumentation that has led to the discovery of the concentration of many elements including hydrogen (a strong indicator of water) on planetary bodies, have used separate gamma-ray and neutron spectrometers. Elpasolite scintillators offer an opportunity to combine the gamma-ray and neutron spectrometer into a single instrument, leading to a significant reduction in instrument size, weight, and power (SWaP). The Elpasolite Planetary Ice and Composition Spectrometer (EPICS) instrument under development at Los Alamos National Laboratory utilizes elpasolite scintillator and silicon photomultipliers to offer significantly reduced SWaP with similar neutron and gamma-ray detection efficiency but superior gamma-ray energy resolution compared to current scintillator-based instruments. We will present an overview and motivation for the EPICS instrument, current status of the EPICS development, and discuss the expected sensitivity and performance of EPICS in several potential missions.

Keywords: CLYC, Planetary Science, Space Instrumentation
Poster panel: 47

Poster Number:
N-07-047

Development of Sealed Tube Microchannel Plate Detectors with Cross Strip Readouts. (#1984)

O. Siegmund1, C. D. Ertley1, J. Vallerga1, N. Darling1, J. Hull1

1 University of California, Space Sciences Laboratory, Berkeley, California, United States of America

Content

Cross strip readout anodes provide a novel high spatial resolution image encoding system for microchannel plate sensors. A number of devices in formats from 18 mm to 100 mm have been implemented, however most of these have been open face devices that require vacuum pumping other than one device type with in an 18 mm sealed tube format. We have been developing and implementing cross strip readouts with metal & ceramic layers for larger format (~50 mm) sealed tubes with selected photocathodes covering the UV and optical regimes.  These devices will be important for the next generation of moderate and large NASA astrophysics instruments that are baselining 50 mm to 200 mm format detectors. We have focused on the critical elements of the sensors, high QE, high spatial resolution and large event rate limits, with long lifetimes. Our photocathode work includes investigations of GaN UV photocathodes with >40% QE at 200 nm and 400 nm “solar blind” cutoff. Customizations of bialkali semitransparent cathodes with flat response from 120 nm to 320 nm and a sharp 360 nm cutoff have also been made. We are also evaluating combinations of these semitransparent photocathodes with opaque photocathodes in the same device. New microchannel plate electron multipliers based on atomic layer deposition of resistive and secondary emissive layers on microcapillary arrays are another key element. The borosilicate substrates are more robust than traditional MCPs, allowing them to be produced in large formats (20 × 20 cm) with high open area ratios (≤80%) even with 10 µm pores. These MCPs have very low intrinsic background (<0.05 events/sec/cm2), high gain, and very good lifetime stability (little gain change over 7 C/cm2). With the cross strip readout and encoding electronics we achieve high spatial resolutions (<20 µm FWHM) over both 50 mm and 100 mm formats at event rates exceeding 5 MHz, providing a powerful baseline for future NASA UV/optical instruments.

Keywords: microchannel plate, uv, photosensor, photon counting
Poster panel: 49

Poster Number:
N-07-049

Alpha Particle X-ray Spectrometer onboard Chandrayaan-2 rover (#2254)

A. R. Patel1

1 Physical research Laboratory, Planatary science division, Ahmedabad, India

Content

Alpha Particle X-ray Spectrometer (APXS) is a well proven instrument for quantitative elemental analysis of the planetary surface through in-situ measurements. This technique involves the measurement of X-ray fluorescence by irradiating the lunar surface with Alpha particles and X-rays using radioactive source. The Lander/Rover onboard Chandrayaan-2 gives us first opportunity to explore part of high latitude south polar region of the Moon. Our objective is to determine the elemental composite (Mg, Al, Si, K, Ca, Ti, Fe) of Lunar soil and rocks around the lunar south pole landing site by APXS on-board the Rover in the energy region 1 to 25 keV.

APXS instrument is mounted in the front side of the Rover with motor based mechanism. The motor based mechanism lowers the APXS instrument close to the lunar surface to a height of ~50 mm during the measurement. APXS experiment uses Silicon Drift Detector (SDD) to detect the low energy X-rays, which provides very high energy resolution with active area of 30mm2 and 450μm thickness. The instrument is designed with stack of two PCBs containing sensitive front-end charge readout electronics followed by analog pulse processing electronics, peak detection, A/D conversion with overall noise levels below 20mv. The design also consists of high voltage bias generation and the peltier controller with 0.1°c stability. The Flight model of the APXS instrument is completed and tested for the performance requirement. It is shown that the APXS instrument provides the energy resolution of <150 eV @ 5.9 keV when the SDD operated at -35°C. We have carried out laboratory experiments for measuring fluorescent X-ray spectrum from various known samples irradiated by the six sources of 244Cm with each 5 mCi activity. It is shown that intensities of various characteristic X-ray lines are well correlated with the respective elemental concentrations. The detail about the instrument and experiment results will be presented during conference.

Keywords: APXS, X-ray, SDD
Poster panel: 51

Poster Number:
N-07-051
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In flight performance of the electronics of the High Energy Particle Detector onboard CSES (#2399)

V. Scotti1, G. Osteria1

1 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Napoli, Italy

for the Limadou-CSES Collaboration

Content

In this paper we will present a description of the electronics of the High Energy Particle Detector (HEPD) onboard the China Seismo Electromagnetic Satellite (CSES) and its in flight performance.
CSES is a scientific mission dedicated to monitoring electromagnetic, plasma and particles perturbations of atmosphere and inner Van Allen belts caused by solar and terrestrial phenomena and to the study of the low energy component of the cosmic rays (5 - 100 MeV for electrons and 15 - 300 MeV for protons). The satellite, launched on February 2nd, 2018 from the Jiuquan Satellite Launch Center (Mongolia), hosts several instruments onboard. The HEPD, built by the Italian "Limadou" collaboration, is able to separate electrons and protons and identify nuclei up to Iron. The HEPD comprises the following subsystems: detector, electronics, power supply and mechanics. The electronics can be divided into three blocks: silicon detector, scintillator detectors (trigger, energy and veto detectors) and global control and data managing. The trigger system allows switching between several configurations. Each trigger configuration corresponds to different field of view of the apparatus. It is possible to change the trigger configuration along the orbit to cope with different fluxes encountered.

We will also present an overview of the new electronics we are designing for the CSES-2 satellite, which will be launched in 3 years. The next generation detector foresees improvements both on the silicon tracker and the calorimeter.

Keywords: astroparticle physics, cosmic rays, space instrumentation
Poster panel: 53

Poster Number:
N-07-053
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Study of a new miniaturized radiation monitor based on previous experience with the Space Application of the Timepix Radiation Monitor (SATRAM) (#2534)

S. Gohl1, B. Bergmann1, S. Pospisil1

1 Czech Technical University, Institute of Experimental and Applied Physics, Prague, Czech Republic

Content

A new miniaturised radiation monitor is being developed under a programme of and funded by the European Space Agency. The availability of a radiation monitor on-board any spacecraft is highly desirable to minimize radiation effects on the electronics of the spacecraft. Besides, providing the dose deposited the radiation monitor, it will provide flux estimations for electrons and protons separately. The planned detector will consist of a Timepix (300 μm thick sensor, 256 x 256 pixels, pixel pitch 55 μm) and several diodes for a low power mode and coincidence measurements. Presented are the strategy for the particle-type identification and results from simulations of the detector response for electrons and protons. The strategy as well as the simulation are based on the experience gained from investigation of the data received from the Space Application of the Timepix Radiation Monitor. The simulation is also compared with data measured on Earth.

Keywords: Radiation monitoring, Particle tracking detector, Solid state detectors, dE/dx detectors, On-board space electronics
Poster panel: 55

Poster Number:
N-07-055

Tetrahedral Organ model in Geant4 Based Particle Therapy Simulation Framework (#1190)

T. Aso1, S. Ogasawara2, T. - C. Chao3, H. - C. Chang3, C. - C. Lee3

1 National Institute of Technology, Toyama College, Electronics and Computer Engineering, Toyama, Japan
2 National Institute of Technology, Toyama College, Advanced Course, Toyama, Japan
3 Department of Radiation Oncology, Chang Gung Memorial Hospital, Tao-Yuan, Taiwan

Content

In order to ensure patient’s safety and effectiveness of treatment plan, reliable Monte Carlo simulation is essential for dose calculation in radiation therapy. The simulation needs a computational model of human body for practical studies of patient dose. Because of easy implementation and tolerable computational efficiency, voxel model has been so far employed for this purpose. However, tetrahedral model is more suitable for representing conformal structure of patient organs. In this paper, we report on the implementation of tetrahedral organ model in Geant4 based particle therapy system simulation framework (PTSIM). The implementation has successfully demonstrated to construct several types of organs. The performance of geometry construction was evaluated in terms of computational efficiency and memory usages.

Keywords: Geant4, Tetrahedral geometry
Poster panel: 57

Poster Number:
N-07-057
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Development of Fast Monte Carlo Simulation Code for High Dose Rate Brachytherapy (#1456)

A. Hu1, R. Qiu1, Z. Wu1, C. Li1, H. Zhang1, J. Li1

1 Tsinghua University, Department of Engineering Physics, Beijing, China

Content

Brachytherapy plays an important role in the treatment of various cancers. The TG-43 formalism is widely used in dose calculation for brachytherapy, but it is not accurate as it assumes the patient as homogeneously constituted of water. Monte Carlo simulation can obtain accurate result, but computing time using traditional code is too long to be accepted in clinical application. This work developed a fast Monte Carlo code THUBrachy for high dose rate brachytherapy dose calculation. THUBrachy can simulate photon with energy up to 3MeV for heterogeneous materials and obtain dose, fluence and dose distribution. It applies several accelerators such as Graphics Processing Unit (GPU), Intel Xeon Phi to perform dose calculation with good accuracy and high speed. THUBrachy adopts several parallel programming models to transplant the code onto different hardware accelerators. Voxel geometry based on CT images is used to describe the tissues of patient. A linear track-length estimator is used for dose calculation. In the preliminary accuracy test, a cuboid water model and a heterogeneous-material model were selected as the phantoms. Dose and fluence distributions were calculated by both THUBrachy and FLUKA which is a well-benchmarked Monte Carlo code. A total of 5×108 photons were simulated to make the uncertainty in all area less than 5%. The maxium difference of the results in low dose area is less than 3% and in high dose area is less than 1%, indicating a good agreement. In the performance test, a phantom consisted by 24 types of human tissue materials was chosen to estimate the performance in practical application. Dose distributions with an uncertainty of 2% or less for the target volume were obtained in less than 1 min by simulating 5×107 photons with a GTX 1080Ti, while FLUKA taking several hours to simulate the same number of particles. There is great potential for clinical application in brachytherapy dose planning using this fast Monte Carlo code.

Keywords: brachytherapy, dose calculation, Monte Carlo, hardware accelerator
Poster panel: 59

Poster Number:
N-07-059

An Improved Calculation Software For Coincidence Counting (#1537)

K. Zhong1, K. Z. Song1, Z. G. Ding1, J. C. Liang2, H. Tang2

1 University of Science and Technology of China , Modern Physics Department , Hefei, China
2 National Institute of Metrology, Beijing, China

Content

An improved software developed for absolute radioactivity measurement is developed based on the 4πβ-γ method. The previous software has been applied successfully to the calibration of radioactive source. The improved software is advanced in the following aspects: we improved the computing performance of the software via applying parallel computing technology to the coincidence counting module; we improved the compatibility of the software so that it can be exploited to different measurement system. Some tests on the software indicates that this software can successfully calculate the radioactivity of β-γ decay radionuclides and has good use of prospects.

Keywords: 4πβ-γ coincidence count, absolute radioactivity measurement
Poster panel: 61

Poster Number:
N-07-061
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Estimation of individualized counting efficiency by means of numerical simulation on the assessment of iodine-131 activity in thyroid (#1659)

M. Park1, 2, W. Ha1, T. Kwon1, S. Park1, Y. W. Jin1

1 Korea Institute of Radiological and Medical Sciences, National Radiation Emergency Medical Center, Seoul, Republic of Korea
2 Hanyang University, Department of Nuclear Engineering, Seoul, Republic of Korea

Content

It is necessary to calibrate the thyroid monitoring system to properly assess internal contamination in thyroid. The conventional calibration performed by the neck physical phantom is widely used for calibrating monitoring systems, but the neck physical phantom cannot reflect the individual characteristic such as the size of thyroid, the position of thyroid, and overlay tissue thickness. The physical variations between the neck physical phantom and the human body anatomy can influence on the measurement of radioiodine in thyroid, especially the counting efficiency. Therefore, this study describes the estimation of counting efficiency considering individual characteristics of subject in thyroid measurement for iodine-131 by using the Monte Carlo technique. In this study, the NaI(Tl)-based and high purity germanium-based thyroid monitoring systems in operation at the Korea Institute of Radiological and Medical Sciences were used and embodied with Monte Carlo code. Based on the computational modelling of monitoring systems, simulations were performed using the ICRP adult reference computational phantoms and the UF/NCI pediatric computational phantoms (1, 5, 10, and 15 years) to consider the anatomical variations, including the age and gender of subjects in thyroid measurement. The overlay tissue thickness of subject could be estimated from the counting ratio of two energy peaks at 80.2 and 364 keV of iodine-131 due to the attenuation of gammas. Thus, the overlay tissue thicknesses of each phantom were modified to evaluate the relationships between the above counting ratio and counting efficiency. From these relationships, the equations for estimating the individualized counting efficiencies for each age and gender group were derived. Through these equations, it is possible to estimate the individualized counting efficiencies with considering the age, gender, and overlay tissue thickness of subject in thyroid measurement for iodine-131.

Keywords: computational phantom, counting efficiency, internal contamination, MonteCarlo simulation, thyroid measurement
Poster panel: 63

Poster Number:
N-07-063
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Development of an Educational Tool for Radiation Shielding by Using a Mock Survey Meter   (#2133)

Y. Kunimi1, H. Tenzou1, A. Nagoshi1, K. Yokoyama1, T. Miyatake1, S. Tokutake1

1 National Institute of Technology, Kagawa College, Mitoyo, Japan

Content

The purpose of this study was to develop an educational tool for radiation shielding by using a mock survey meter. The tool was supposed to learn radiation shielding by concrete blocks with no real sources of gamma-rays. The each position of the source, the detector, and the blocks are recognized by image processing and the scattering or absorption of the gamma-rays in the block was calculated approximately by a point source attenuation formula. The tool requires a conventional Windows PC for shielding calculation, a USB camera to recognize the position of materials on the stage and a mock of point source and a detector with a “virtual γ generator” on 120cm × 100 cm stage. The virtual γ generator was built to generate logical pulse according to the count rate at the position of the detector on the stage by an Arduino via serial communication with the PC. The detector was also designed to make alarm sounds proportional to the virtual count rate As the result, it was demonstrated that the learner can watch the count rate on the monitor of the detector and listen to the alarm sounds around the shielding blocks on the stage in real time without manipulating real sources. 

Poster panel: 65

Poster Number:
N-07-065
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Geant4 simulation of a Triple-GEM detector exposed to the CHARM field at CERN (#2334)

I. Vai1, 2

1 Università di Pavia, Department of Physics, Pavia, Italy
2 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia, Italy

On behalf of the CMS Muon Group

Content

The ME0 station has been proposed for the installation in the CMS muon system in the region 2.03 < | eta | < 2.82, with the aim of increasing the detector acceptance for physics with muons. This region, presently not instrumented, is characterized by a very harsh radiation environment, which can reach rates up to 30 kHz/cm2 and an integrated charge of the order of 200 mC/cm2 over ten years of operation. The technology proposed for this station is Triple - Gas Electron Multiplier (Triple-GEM), which has already been qualified for the operation in the CMS muon system. However an additional set of studies focused on the discharge probability is necessary for the ME0 station, due to the characteristic radiation environment mentioned above. A test was carried out in 2017 at CERN's High-Energy-AcceleRator-Mixed (CHARM) facility, with the aim of giving an estimation of the discharge probability of Triple-GEM detectors in a very intense mixed field environment, similar to the one of the CMS muon system. A dedicated stand-alone Geant4 simulation was performed simultaneously, in order to evaluate the behavior of the detector exposed to the CHARM field. The geometry of the detector has been carefully reproduced, as well as the background field present in the facility. This contribution will present the results obtained from the Geant4 simulation, in terms of sensitivity of the detector to the CHARM environment, together with the analysis of the energy deposited in the gaps. The results from simulation will be finally compared with the experimental one obtained from the test.

Keywords: GEM, Geant4, Sensitivity, Disharge probability
Poster panel: 67

Poster Number:
N-07-067

Recent developments of Geant4 for medical physics applications  (#2596)

S. Guatelli1, P. Arce2, M. Bandieramonte3, D. Bolst1, M. - C. Bordage4, J. M. C. Brown5, 1, B. Caccia6, P. Cirrone7, D. Cutajar1, J. A. Davis1, M. Cortés-Giraldo8, G. Cuttone7, P. Dondero9, V. Giacometti10, S. Incerti11, V. Ivanchenko12, I. Kyriakou13, N. Lampe14, A. Mantero1, S. Meylan15, P. Nieminen16, M. Novak3, L. Pandola7, G. Petringa7, S. Pozzi6, F. Romano17, A. B. Rozenfeld1, G. Russo18, D. Sakata1, G. Santin16, N. H. Tran19, C. Villagrasa20

1 University of Wollongong, Centre for Medical Radiation Physics, Wollongong, Australia
2 CIEMAT, Madrid, Spain
3 CERN, Geneva, Switzerland
4 CRCT (INSERM and Paul Sabatier University), Toulouse, France
5 TUDelft, Delft, Netherlands
6 Istituto Superiore di Sanità, Rome, Italy
7 INFN, Catania, Italy
8 Universidad de Sevilla, Sevilla, Spain
9 SWHARD srl, Genova, Italy
10 Queen's Belfast University, Belfast, United Kingdom
11 CENBG, IN2P3, Bordeaux, France
12 Tomsk State University, Tomsk, Russian Federation
13 Ioannina University, Ioannina, Greece
14 Vicinity Centres, Data Science & Insights, Chadstone, Australia
15 SymAlgo Technologies, Paris, France
16 European Space Agency (ESA), Noordwijk, Netherlands
17 NPL, Teddington, United Kingdom
18 CNR-IBFM, Cefalu', Italy
19 Ton Duc Thang University, Ho Chi Minh City, Viet Nam
20 IRSN, Paris, France

Content

Abstract: Geant4 is a particle transport Monte Carlo code in continuous evolution and refinement. Recent developments in terms of physics models, related validations and examples, to address medical physics applications, are presented.

Keywords: Geant4, Medical physics
Poster panel: 69

Poster Number:
N-07-069

Prototype of Integrated Pulse Digitalization and Readout Electronics for CLYC Detector (#1038)

T. Xue1, J. Zhu1, G. Gong1, L. Wei2, J. Li1

1 Tsinghua University, Department of Engineering Physics, Beijing, China
2 Nuctech Company Limited, Beijing, China

Content

For neutron measurement in the CJPL (China Jinping underground laboratory), a detector is built with the Ф25.4 mm × 25.4 mm high CLYC (Cs2LiYCl6:Ce) crystal and R6231-100 PMT from Hamamatsu. A prototype of pulse digitalization and readout electronics is developed and formed as an integrated digital PMT base which can be mounted to the PMT directly. The analog signal from PMT is amplified and digitized by ADC and the data of waveform is buffered in the memory, then will be transmitted to computer with Gigabit Ethernet. This paper will illustrate the architecture of hardware design and software, firmware design. For the n/γ pulse discrimination, five of different ADC is evaluated, including the 8-Bit 1 GSPS ADC, the 12-Bit 500 MSPS ADC, the 12-Bit 1 GSPS ADC, the 12-Bit 2 GSPS ADC, and the 16-Bit 250 MSPS ADC. The performance of diversely ADC is estimated with FoM, the comparison and conclusion will be given in this paper, the result can be used for selection of ADC (including resolution and sample speed) for pulse discrimination of n/γ.

Keywords: CLYC Detector, Pulse Digitalization
Poster panel: 73

Poster Number:
N-07-073

The update of the recording system for the Thomson scattering diagnostic complex on GDT (#1323)

E. A. Puryga1, P. V. Zubarev1, 2, A. N. Kvashnin1, S. V. Ivanenko1, 2, A. D. Khilchenko1, D. V. Moiseev1, A. A. Lizunov1

1 Institute of Nuclear Physics, SB RAS, Novosibirsk, Russian Federation
2 Novosibirsk State Technical University, Novosibirsk, Russian Federation

Content

The current diagnostics of Thomson scattering on the GDT (INP SB RAS, Russia, Novosibirsk) is being modernized. The source of radiation is the Nd: YAG laser at the fundamental harmonic with a wavelength of 1064 nm, pulse energy of 1.7 J and duration of 10 ns. The laser has a pulse-periodic mode of operation with a frequency of 10 Hz. The optical collection system is designed to measure the temperature and electron density in eleven spatial points along the laser beam.

A new recording system is being developed for this diagnostic complex. The 64-channel recording system will ensure the record of the scattered signal in eight spatial points. Each spatial point will be registered by six avalanche photodiode modules and digitized by eight-channel recording module with a sampling rate of 5 GHz and amplitude range of 14 bits. Additional channels of recording module will be used to record the reference signal of a laser pulse.

Keywords: Thomson scattering, Recording system
Poster panel: 75

Poster Number:
N-07-075

Development of PC-based Analysis System for Real-time Classification of Nuclides (#1367)

E. - S. Jung1, H. - G. Lim1, K. W. Seong3, J. S. Suh2, J. Kong1

1 Daegu-Gyeongbuk Medical innovation Foundation, Medical device Development Center, Daegu, Republic of Korea
2 JS TECHWIN, R&D, Daegu, Republic of Korea
3 Kyungpook National Univ. Hospital, Biomedical engineering , Daegu, Republic of Korea

Content

With frequent radioactivity accidents, people are increasingly interested in measuring radiation doses because radiation ionizes molecules that make up the body tissues such as water and organic matter. Most of these radioactive elements are still in the excited state after collapse, and go to the ground state through a transition process that emits gamma rays. And the emitted energy of the gamma rays is different for each nuclide However, to directly identify and distinguish the spectra of gamma nuclides with wavelengths of several hundred nanometers, the pulse train information of the scintillator must be stored and processed on a computer equipped with a high-speed analog-to-digital converter (ADC) module.

In this paper, we developed a pc-based analysis system for real-time classification of radionuclides. This system consisting of a SiPM modules, digitizers, and a computer was programmed based on LabVIEW. For faster and more accurate signal processing, data acquisition and signal processing procedures are separated, and each procedure operates on a different CPU core. In addition, a digitizer (NI PXIe-5160) with 2.5 GHz sampling rate and 500 MHz bandwidth, has been applied in the system. A silicon photomultiplier module (MiniSM, SensL) with CsI(Tl) scintillation crystal has been used for testing the system feasibility. For detecting radiation-induced peak signals, the detecting algorithm based on a thresholding and segmentation had been applied. From the measurements using various radiation sources including 137Cs, 22Na, 60Co and 133Ba, the unique spectrum for each source could be identified.

Keywords: Nuclide spectrum, Gamma-ray, SiPM
Poster panel: 77

Poster Number:
N-07-077

Development of the Fast Front-end Trigger System for COMET Phase-I (#1417)

Y. Fujii1, E. Gillies2, E. Hamada1, M. Ikeno1, M. J. Lee3, S. Mihara1, Y. Miyazaki4, Y. Nakazawa5, M. Shoji1, T. Uchida1, K. Ueno1

1 High Energy Accelerator Research Organization (KEK), Tsukuba, Japan
2 Imperial College London, London, United Kingdom
3 Institute for Basic Science, Daejeon, Republic of Korea
4 Kyushu University, Fukuoka, Japan
5 Osaka University, Toyonaka, Japan

On behalf of the COMET Collaboration

Content

The COMET experiment is designed to search for the muon-to-electron(μ-e) conversion with a sensitivity below 10-14 in the pahse-I.

While this process is forbidden in the standard model, it is predicted in many cases of new physics beyond the standard model within COMET's target sensitivity.

Thus, any signal of μ-e conversion would be a clear evidence of new physics.

To achieve our sensitivity goal, more than 1016 of muons are required. Estimates show that this high intense muons can cause the extremely high hit rate of approximately 1MHz in each detector channel.

These hits are mostly from background particles and can make a trigger rate unacceptably high and lead to severe dead-time in the data acquisition system.

It is critical to reduce these background triggers while maintainig a high sensitivity to signal events.

Besides, the trigger decision should be provided to each readout board within 5μs which is limited by their buffer size.

Finally, the front-end electronics must be radiation tolerant of neutrons and gamma-rays since they will be placed around detectors.

We are developing a dedicated front-end trigger system complete with an online tracking trigger algorithm to fulfill those requirements.

The trigger system is separated into two parts.

First, the hit information from each detector is processed in the front-end electronics and sent to the mother board.

Then, the mother board merges all the information and applies the fast online tracking to suppress backgrounds without any trajectories by a factor of 20.

From the simulation study, the tracking trigger enables us to take a data with a safely low rate such as an O(1)kHz.

The first prototype of the front-end board was produced in 2015, and it passed the baseline performance requirements including the radiation tolerance.

The second prototype will be manufactured before the summer of 2018 and the performance will be reevaluated.

In this talk, we present the existing results from both prototypes and the future prospects.

Keywords: FPGA, CLFV
Poster panel: 79

Poster Number:
N-07-079

A Self-Repairing and Adaptive FPGA-based High-speed Serial Link (#1428)

S. Perrella1, 2, R. Giordano1, 2, D. Barbieri1, 2

1 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Napoli, Italy
2 Università di Napoli, Dipartimento di Fisica, Napoli, Italy

Content

High-speed serial links for trigger and data acquisition (TDAQ) systems in High Energy Physics (HEP) experiments are often implemented by means of Static RAM-based Field Programmable Gate Array (SRAM-based FPGAs). However, due to the sensitivity of SRAM-based FPGA to radiation-induced upsets, their usage is limited to off-detector electronics. In order to benefit of SRAM-based FPGAs re-programmability and high performance in the data transmission, also in a harsh radiation environment, many techniques have been developed: memory configuration correction (memory scrubbing), hardware redundancy (e.g. Triple Modular Redundancy, TMR) and information redundancy (e.g. Forward Error Correcting Code, FEC).

In this paper we describe the architecture of the bidirectional serial link running at 6.25 Gbps we implemented on the Xilinx Kintex-7 SRAM-FPGA devices. We designed the link with a low and deterministic latency for application in HEP TDAQ systems. With the aim of using the link also in a radiation environment, we chose a robust error correction scheme for the line coding, we designed and incorporated a configuration scrubbing in the link architecture and we explored different TMR strategies. We present a link which offers several original features. It can repair itself thanks to the custom embedded scrubber we designed. It is also capable of self-adjusting its line code scheme depending on the measured error faults and transmitted errors. We describe and discuss the different strategies we explored in terms of radiation tolerance versus resources occupation. We present the performance of our serial link carried out in a proton beam irradiation facility. We show the effective Bit Error Ratio as a function of the measured induced upsets. Besides, we present the performance of the link in terms of mean time between failures (MTBF) and mean time between loss of lock. We also present measurements on the transmitter and recovered clock jitter.

Keywords: Serial link, Fixed-latency, TDAQ, FPAG, radiation testing
Poster panel: 81

Poster Number:
N-07-081

Workload Dependent Design and Power Modeling of Pattern Recognition Associative Memories (#1506)

S. Joshi1, S. Ogrenci-Memik1, T. Liu2, J. R. Hoff2

1 Northwestern University, EECS, Evanston, Illinois, United States of America
2 Fermi National Accelerator Laboratory, PPD, Batavia, Illinois, United States of America

Content

In this work, we identify and model the most significant parameters for the power consumption of an associative memory based tracking trigger chip in development for upgrades to the Large Hadron Collider. Content Addressable Memories provide fast lookup operation, which is extremely useful to find and fit the billions of tracks expected every second at the hardware trigger level at high luminosity LHC (HL-LHC). Their high speed comes from their parallel operation which also causes high power consumption. We find that common CAM blocks used in other applications like IP Lookup are not fit for track fitting in high energy particle physics experiments due to the immensely different workload requirements. In this paper, we identify these workload differences which guide the design of the CAM blocks for tracking triggers. We show with tests on our prototype chip the high dependence of power consumption with the workload. We observe that the power consumption in the matchlines is highly dependent on the hit-rate of the workload; whereas the searchline power is influenced by the average Hamming distance between successive input data, and is independent of the hit-rate. Another significant observation is that unlike as in traditional CAMs, the dominant power consumption of associative memories, when used for tracking trigger applications, is in the searchlines instead of matchlines. This is due to the extremely low hit rate expected, and the high density and number of patterns which will have to be stored on a single chip. We develop a power model for these specific CAM blocks which can be used to estimate their power consumption for future chips. We present our power model of these associative memories for use in tracking triggers along with a description of the expected workload to guide future research on associative memory based tracking triggers.

Keywords: Content Addressable Memory, Tracking Trigger, LHC, Power Modeling
Poster panel: 83

Poster Number:
N-07-083

Design of a scalable readout system for GEM detectors (#1615)

A. Abba1, A. Baschirotto2, G. Claps5, G. Corradi5, F. Caponio1, A. Cusimano1, G. Croci2, G. Gorini2, G. Grosso3, L. Mangiagalli2, A. Muraro3, F. Murtas4, 5, E. Perelli3, D. Tagnani5, M. Tardocchi3, R. J. Hall-Wilton6, 7, C. Höglund7, 8, K. Zeitelhack9

1 Nuclear Instruments SRL, Lambrugo, Italy
2 Dipartimento di Fisica, Università degli studi di Milano Bicocca, Milano, Italy
3 IFP-CNR, Milano, Italy
4 CERN, Geneve, Switzerland
5 Laboratori Nazionali di Frascati - INFN , Frascati, Italy
6 European Spallation Source ESS, Lund, Sweden
7 Mid-Sweden University, Sundsvall, Sweden
8 Linköping University, 8 Dept. of Physics, Chemistry and Biology (IFM), Thin Film Physics Division, Linköping, Sweden
9 9 Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Garching, Germany

Content

A read-out system for multiple GEM detectors has been designed. The detection unit is able to measure the position of interaction, the time of flight and the charge released by the particle interactions with the detector. 

In order to read-out the small charge generated by the GEM detector a dedicated ASIC (called GEMINI) has been designed. The FPGA based TDC measures the time of flight and the charge of particles. A complex structure of distributed switches allows to extend the net of readout boards in order to cover very large area detectors.

Data collected by a PCIE DAQ board are processed in realtime on FPGA and store on a raid array as event mode list.

A neutron detector module with 1450 channels and an active area of about 860cm2 have been developed. The detector and its readout system have been validated and successfully collected and reconstructed wavelength resolved images from several neutron scattering samples.The system can be easy scaled up to hundreds of thousands of channels.

Keywords: neutron detector, GEM, TDC, neutron sources
Poster panel: 85

Poster Number:
N-07-085
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Ultrascale+ for the new ATLAS calorimeter trigger board dedicated to jet identification (#1711)

J. Kirk1, J. Vieira De Souza2

1 STFC, Didcot, United Kingdom
2 Johannes Gutenberg, Mainz, Germany

Content

To cope with the expected increase in luminosity at the Large Hadron Collider in 2021, the ATLAS collaboration is planning a major detector upgrade to be installed during Long Shutdown 2. As a part of this, the Level 1 trigger, based on calorimeter data, will be upgraded to exploit the fine granularity readout using a new system of Feature EXtractors (FEXs), which each reconstruct different physics objects for the trigger selection.

The Jet FEX (jFEX) is one of three FEXs and has been conceived to identify small/large area jets, large area tau leptons, missing transverse energy and the total sum of the transverse energy.

The use of the latest generation Xilinx Field Programmable Gate Array (FPGA), the Ultrascale+, was dictated by the physics requirements which include substantial processing power and large input bandwidth, up to ˜3Tb/s, within a tight latency budget <390 ns.

The jFEX board is characterised by a modular design that makes it possible to optimise within the limited space of an ATCA board a large number of high speed signals. To guarantee the signal integrity, the board design has been accompanied by simulation of the power, current and thermal distribution. The printed circuit board has a 24-layer stack-up and uses the MEGTRON6 material, commonly used for signal transmission above 10 Gb/s.

This presentation focuses on the technological aspects of the jFEX board, reporting on the simulation studies and on the design solutions of the board. Two jFEX prototypes have been produced and fully tested in integrated tests at CERN, these test results will be presented.

  1. firmware implemented on the trigger board will be illustrated in connection with the FPGA performance and board power consumption. The jFEX system, consisting of 6 boards, will be produced by end of 2018 to allow the installation and commissioning of the full system in time for the LHC restart at the beginning of 2021.
Keywords: ATLAS, Trigger, L1, Upgrade
Poster panel: 87

Poster Number:
N-07-087

The electronics for the electromagnetic calorimeter of the COMET experiment. (#1768)

D. N. Grigoriev1, 2, Y. V. Yudin1, 2, L. B. Epshteyn1, 2, D. V. Shoukavy3

1 Budker Institute of Nuclear Physics, Novosibirsk, Russian Federation
2 Novosibirsk State University, Novosibirsk, Russian Federation
3 B.I. Stepanov Institute of Physics, Minsk, Belarus

on behalf of the COMET collaboration

Content

The experiments at the Large Hadron Collider discover the Higgs Boson – the last missing particle of the Standard Model (SM). But they still can’t find any robust indication of the new physics beyond the SM. Therefore the searching for new physics in precision experiments become a highlight. One of the such experiments is COMET at J-PARC (Japan). The goal of this experiment is to search for the coherent neutrinoless muon to electron conversion at the field of atomic nuclear. This process is strongly forbidden in the SM at level below 10-50. So any signal will be the hint of new physics beyond the SM. The impact of such evidence for improvement of our knowledge of nature is comparable with the Nobel prize recognized discovery of the neutrino oscillations.

The goal of the COMET experiment is to rich unrivaled sensitivity of 3x10-15 at the first stage and of 3x10-17 at the final experiment. The background rate is extremely high, many megahertz. The electromagnetic calorimeter must to suppress it to the reasonable level of kilohertz trigger rate. It leads to the controversial requirements on the electronics to provide the fast response and low noise performance.

The dedicated electronics for the electromagnetic calorimeter of the COMET experiment has been developed and tested in the lab as well as with the dedicated electron beam. It includes the analog electronics with fast response and low noise performance as well as online signal processing for the trigger, which is implemented in FPGA and provides high energy resolution in real time. The pulse shape of the analog electronics is determinate by decay time of the LYSO scintillator. So a pileup contribution is minimal as possible. The online energy resolution is comparable with OFLLINE one and satisfies the experiment requirement of 5%.

The design and performance of the front-end and trigger electronics of the electromagnetic calorimeter of the COMET experiment will be presented.

Keywords: COMET experiment, electromagnetic calorimeter, frontend electronics, trigger, physics beyond SM
Poster panel: 89

Poster Number:
N-07-089

High-resolution pulse generator based on a fully programmable Digital-to-Time Converter (DTC) IP-Core (#1845)

F. Garzetti1, N. Lusardi1, L. Di Lalla1, M. Gustin2, A. Geraci1

1 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milan, Italy
2 CAEN ELS , Basovizza TS, Italy

Content

We present a novel high-performance Digital-to-Time Converter (DTC) IP-Core, compatible with 28-nm Serie-7 Xilinx Field Programmable Gate Arrays (FPGAs) and System-on-Chips (SoCs), capable of generating multiple digital waveforms, in parallel, characterized by pulse width (duty-cycle) and relative delay with picoseconds resolution.

The proposed DTC IP-Core (DTC-IP) is completely tunable in terms of minimum and maximum pulse width and delay generable, i.e. resolution and full-scale range. Moreover, the user can set the maximum number of parallel digital waveforms available at output that corresponds to the number of channels.

High-performance not only refers to high-resolution over an extensive full-scale range but also means that the system is characterized by high values of precision, rate, linearity, voltage and temperature stability.

The resolution can be tuned up to tens of picoseconds over a maximum full-scale range of order of ms. The number of channels implemented is programmable from 1 to 16 and each channel can sustain a rate of hundreds of MHz. The pulse width and the delay of the waveforms generated can be programmed in real-time.

The DTC IP-Core has been implemented for testing on a 28-nm Artix-7 XC7A200T-1 Xilinx Serie-7 FPGA hosted on a Nexys Video Board. The DTC IP-Core has achieved resolution of 78 ps with time jitter below 16.5 ps r.m.s. over a full-scale range of 1 ms at a maximum pulse rate of 100 MHz per each one of the 16 channels.

Keywords: DTC, FPGA, Soc, Delfino
Poster panel: 91

Poster Number:
N-07-091
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Reliable and reproducible firmware builds in the CMS Level-1 trigger (#1882)

D. Rabady1, J. Fulcher1, T. Reis1, H. Sakulin1

1 CERN, EP-CMD, Geneve, Genève, Switzerland

On behalf of the CMS Collaboration

Content

For Run-2 of the Large Hadron Collider (LHC) the Level-1 Trigger of the Compact Muon Solenoid (CMS) experiment was replaced with an upgraded system. This new system utilises powerful field-programmable gate arrays (FPGAs) with many high-speed optical links and a large amount of logic cells. Their firmware is often developed in teams, partially spanning groups in different timezones or even continents. One part of this upgraded system is the new Global Muon Trigger (µGMT) which receives muon track and calorimeter energy data over 70 optical links at 10 Gb/s and applies duplicate removal, extrapolation, and an isolation algorithm to the tracks while sorting them. It then sends the best eight muon tracks to the upgraded Global Trigger (µGT) over 6x4 optical links at 10 Gb/s. While the algorithm firmware was designed and implemented by a group at CERN, the board infrastructure and support firmware was created by a team comprised of engineers and physicists from Bristol University, Imperial College, and Rutherford-Appleton Laboratory (RAL).

Keywords: Level-1 trigger, CMS, LHC, Muon Trigger, Firmware
Poster panel: 93

Poster Number:
N-07-093

Highly Integrated FPGA-only Signal Digitization Method Using Single-ended Memory Interface Input Receivers (#1996)

J. Y. Won1, 2, J. S. Lee1, 2

1 Seoul National University, Department of Biomedical Sciences, Seoul, Republic of Korea
2 Seoul National University, Department of Nuclear Medicine, Seoul, Republic of Korea

Content

Individual signal readout from time-of-flight (TOF) detectors can draw the best timing performance; however, it requires a large number of signal digitization channels.

In this manuscript, we propose a new highly integrated FPGA-only signal digitization method by configuring an input/output (I/O) port as a single-ended memory interface (SeMI) input receiver. The SeMI is a single-ended voltage-referenced interface that has a common reference voltage per I/O bank, such that each SeMI input receiver can serve as a voltage comparator. The FPGA-only digitizer that uses the single-ended input receivers does not require a separate digitizing integrated chip, and can obtain twice as many signals as that using low-voltage differential signaling (LVDS) input receivers. The energy was measured using a 625-ps binary counter, and the arrival time was measured using a 10-ps time-to-digital converter (TDC) implemented in the same FPGA.

We first measured the intrinsic characteristics of the proposed FPGA-only digitizer by applying test pulses generated using a digital detector emulator. The SeMI input receiver functioned as the voltage comparator without any undesirable offset voltage. The standard deviation value of the arrival time difference measured using two SeMI input receivers with respective TDCs was less than 14.6 ps.

In addition, we fed signals from the TOF detectors to the SeMI input receivers directly and collected the data. The TOF detector consisted of a 3×3×20 mm3 LYSO crystal coupled with a SensL J-series silicon photomultiplier. The energy resolutions were 7.1% and 5.7% for two TOF detectors. The coincidence resolving time was 258 ps FWHM, comparable with those obtained using a 5-GSPS waveform digitizer.

The SeMI digitizer with a high-performance signal digitizer, processor, and high-speed transceivers would provide a compact all-in-one data acquisition system for TOF detectors.

Keywords: FPGA-only digitizer, Individual signal readout
Poster panel: 95

Poster Number:
N-07-095

Liquid Argon Calorimeter Trigger Digitizer Board Development for ATLAS Phase-I upgrade (#2066)

H. Xu1, H. Chen1, K. Chen1, H. Liu1, H. Zhu1, P. Schwemling3, H. Deschamps3, A. Grabas3, M. Citterio2, M. Lazzaroni2, S. Simion2, S. Latorre2

1 BROOKHAVEN NATIONAL LABS, UPTON, New York, United States of America
2 The National Institute for Nuclear Physics (INFN) , Milano, Italy
3 French Atomic Energy Commission (CEA Saclay), SACLAY, France

Content

The LHC is planned to upgrade the instantaneous luminosity to 2-3×10^34 cm^-2s^-1 during Run 3 from 2021 through 2023. A new high granularity trigger readout system of the ATLAS Liquid Argon (LAr) Calorimeter is foreseen to enhance the trigger feature extraction and background rejection. The detector signals will be summed into 34,000 so-called Super Cells, digitized with 12-bit precision at 40 MHz and transferred over optical links to the digital processing system. The LAr Trigger Digitizer Board (LTDB), which is the key element in the readout system, has been developed to process and digitize 320 channels of Super Cell signals, and transmit digitized data to the back end processors via 40 fiber optical links where data are further processed and transmitted to the trigger processors. 5 GBT links are used for timing and slow control on LTDB. Total 124 LTDBs are required for the Phase-I upgrade. Two LTDB pre-production boards have been fully tested and installed on the ATLAS detector for Run 2 data taking in 2018. The preliminary results show that the LTDBs work well on the ATLAS detector.
A test system is designed for LTDB evaluation test and performance measurement. A back-end PCIe card is designed to interface to the ATLAS TTC system, control signal injection for performance test, and communicate with custom ASICs on LTDB via GBT links. A front-end test board for analog signals injection, test baseplane and a custom crate are under development to extend the capability of the test system, which will be used for the LTDB production test.

Keywords: ATLAS, LAr Calorimeter, trigger, readout, GBT
Poster panel: 97

Poster Number:
N-07-097

The Design of BESIII CGEM Detector Control System (#2268)

S. Ma1

1 Chinese Academy of Sciences, Institute of High Energy Physics, Beijing, China

Content

This paper reports the Detector Control System (DCS) of a Cylindrical Gas Electron Multiplier (CGEM) detector, which is the upgrade of the inner tracker detector of BESIII. A dedicated powerful online DCS is required to ensure the safety and correct operation of the CGEM system, which is distributed on several subsystems, including low and high voltage power supplies, front-end electronics, environmental sensors, gas and cooling infrastructure. This paper presents the hardware architecture and software solutions adopted and the evolution along with the results in commissioning phase in the laboratory will also be discussed.

Keywords: Detector Control System, CGEM, BESIII
Poster panel: 99

Poster Number:
N-07-099
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The TOTEM precision clock distribution system. (#2286)

F. S. Cafagna1

1 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Bari, Italy

Content

To further extend the measurement potentialities for the experiment at luminosities where the pile-up and multiple tracks in the proton
detectors make it difficult to identify and disentangle real diffractive events from other event topologies, TOTEM has proposed
to add a timing measurement capability to measure the time-of-flight difference between the two outgoing protons.  
For such a precise timing measurements, a clock distribution system that empowers time information at spatially separate points with picosecond
range precision, is needed.
For the clock distribution task, TOTEM has adopted an adaptation of the
Universal Picosecond Timing System, developed for the FAIR facility at GSI, actually installed as BUTIS system.
In this system an optical network, using dense wavelength division multiplex (DWDM) technique, is used to transmit two reference clock signals from the counting room to a grid of receivers in the tunnel. To these clocks another signal is added that is reflected backand used to continuously measure the delays of every optical transmission line; these delay measurements will be used to correct the time information generated at the detector location.
The usage of the DWDM make it possible to transmit multiple signals generated with different wavelengths, over a common single modefibers. Moreover allows to employ standard telecommunication modules conform to international standards like the ITU (International Telecommunications Union) ones.
The prototype of this system, showed that the influence of the transmission system on the jitter is negligible and that the largest part of the total jitter of the clock transmission, is practically due to the inherent jitter of clock sources and the end user electronics.
The system has been commissioned in the tunnel and in the counting room, and used during the CT-PPS run in 2017. In this contribution details on the system design, installation in the TOTEM and CT-PPS detectors will be given.

Keywords: DAQ, Clock distribution, Timing
Poster panel: 101

Poster Number:
N-07-101

A DIgitizer ReAdout Controller (DIRAC) board for the Mu2e CsI electromagnetic calorimeter data acquisition system (#2326)

E. Pedreschi2, D. Caiulo1, 2, S. Ceravolo3, G. Corradi3, S. Donati1, 2, S. Di Falco2, F. Cervelli2, L. Morescalchi2, F. Spinella2

1 University of Pisa, Physics Department, Pisa, Italy
2 INFN, Sezione di Pisa, Pisa, Italy
3 INFN, LNF, Frascati, Italy

Content

The goal of the Mu2e experiment at Fermilab is the search for the Charged Lepton Flavour Violating (CLFV) coherent neutrino-less muon conversion to an electron in the field of an aluminum nucleus. An experimental observation of CLFV would be an unambiguous signature of new dynamics related to a non-trivial extension of the lepton sector of the Standard Model.  In 3 years of data taking, Mu2e will observe less than one background event mimicking the muon conversion electron. Achieving such a level of background suppression requires an experimental apparatus made of  a straw tube tracker to measure the electron momentum with a resolution of 200 keV/c at 100 MeV/c, a cosmic ray veto system to reject the cosmic ray background, and an electromagnetic calorimeter to measure the time of flight, energy and impact position of the conversion electron. The calorimeter is made of two disks of 1350 un-doped CsI crystals coupled to SiPM arrays. In order to achieve the needed background suppression, the calorimeter provides a time resolution better than 500 ps and an energy resolution of O(5%) @ 100 MeV.To fulfill these requirements a digitizing system, composed of 150 cards which sample the 2700 calorimeter channels at the frequency of 200 MHz, is currently being designed at INFN. The readout electronics is composed of two modules: the Front End module that hosts the shaping amplifier and the high voltage linear regulator, and the Digitizer ReaDout Contoller (DIRAC) board that further amplifies and digitizes the SiPM signal. The DIRAC will be located inside the magnet cryostat on the lateral surface of the calorimeter disks, and will be exposed to a high radiation level and operated in 1 T magnetic field and in a vacuum level of 10-4 Torr. These harsh experimental conditions have made the design extremely challenging. A detailed description of the DIRAC architecture, the complete dataflow, the firmware organization will be provided.

Keywords: Data Acquisition, Trigger, Digital System, FPGA, High Energy Physics
Poster panel: 103

Poster Number:
N-07-103

LAILA: a Compact, High-Dynamic Range Readout for High-Density SiPMs (#2474)

L. Buonanno1, 2, M. Carminati1, 2, D. Di Vita1, 2, C. E. Fiorini1, 2, M. Grandi1, G. L. Montagnani1, 2

1 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
2 Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milano, Italy

Content

The purpose of the LAILA system is to provide a very compact electronic readout of intense, short current pulses from radiation detectors, to exploit the full potential of state-of-the-art scintillators coupled to solid-state photodetectors, while exploiting simplified readout strategy. The current pulses generated in the detectors are processed by the high-dynamic range, high-resolution Gain Adaptive Modulated Multichannel ASIC (GAMMA). Preliminary measurements showed that, coupling a 1”x1” lanthanum bromide (LaBr3) crystal to a NUV-HD SiPM detectors tile, LAILA reaches 3.8% energy resolution at 662 keV. When processing pulses up to many MeV (collecting the signal from only one of the 8 available input channel of the ASIC). It will be shown at the conference the possibility to have a statistical-noise limited readout over a large dynamic range using a 3”x3” LaBr3 crystal.

Keywords: LaBr3, Gamma Spectroscopy, DAQ, ASIC readout
Poster panel: 105

Poster Number:
N-07-105

Data acquisition system based on galvanically isolated ADC (#2500)

S. V. Ivanenko1, 2, E. A. Puryga1, P. V. Zubarev1, 2, A. Kvashnin1, A. D. Khilchenko1

1 Budker Institute of Nuclear Physics, Novosibirsk, Russian Federation
2 Novosibirsk State Technical University, Novosibirsk, Russian Federation

Content

Data acquisition systems  based on galvanically isolated ADC are widely used in probe techniques for plasma research. Such system was development in the Budker Institute of nuclear physics for GDT magnetic mirror device. This system includes eight isolated ADC modules, united by a common data collection node. This node receives data from the ADC modules and is responsible for managing these modules. The received data does not accumulate inside the node itself, but is transmitted in real time via a high-speed optical communication channel to the data processing module. The processing module is a universal device that allows you to receive, store and process data obtained from various diagnostics.

Keywords: galvanically isolated ADC, plasma probe diagnostic
Poster panel: 107

Poster Number:
N-07-107

Design of a Time-to-Digital Converter ASIC for the ATLAS MDT Chambers at HL-LHC (#2585)

H. K. Kroha1, S. Abovyan1, V. Danielyan1, M. Fras1, O. Kortner1, R. Richter1, Y. Zhao1, A. Baschirotto2, M. De Matteis2, A. Pipino2, F. Resta2, J. Zhu3, J. Wang3, Y. Liang3, X. Xiao3

1 Max-Planck-Institut für Physik, HE Physics, München, Bavaria, Germany
2 University of Milan Bicocca, Physics Department, Milan, Italy
3 University of Michigan, Ann-Arbor, Michigan, United States of America

Content

To cope with the high trigger and data rates expected from the high-luminosity upgrade of the LHC (HL-LHC), the readout electronics of the Monitored Drift Tube (MDT) chambers of the ATLAS muon spectrometer has to be replaced. In addition, the data of the MDT detectors will be used for the first-level muon trigger to improve the muon transverse momentum resolution and reduce the overall trigger rate. A new trigger and readout system will be implemented which requires new time-to-digital converter (TDC) ASICs on the front-end boards to digitize the drift time measurements and transmit them in streamed mode to the off-detector first-level muon track trigger processors. For backward compatibility and test purposes, the chip also contains a trigger matching block and corresponding output format. A prototype of the new TDC chip has been designed and fabricated in TSMC 130 nm CMOS technology. The design, simulation and performance test results will be discussed.

 

 

 

Figure 1: Time digitization scheme and implementation.

 

 

Keywords: TDC, MDT trigger, ASIC, CMOS
Poster panel: 109

Poster Number:
N-07-109

ProtoDune Single Phase Detector Data Acquisition Using The SLAC RCE Platform (#2676)

R. T. Herbst1, J. Russell1, L. Ruckman1, M. Graham1, M. Convery1, P. Tsang1

1 SLAC National Accelerator Laboratory, Redwood City, California, United States of America

Content

This paper describes the middle layer DAQ development for the single-phase detector at the ProtoDune experiment at CERN. The single-phase detector DAQ system utilizes the SLAC ATCA based RCE Platform in the middle layer between the front end acquisition board within the detector and the back end data acquisition system. This middle layer DAQ provides data compression and buffering on the incoming data, storing it for later triggered readout. The protoDune experiment, which operates at CERN, is designed to test and validate the two prototype detectors, single-phase and dual-phase, for the upcoming Deep Underground Neutrino Experiment, DUNE. The development of the single-phase DAQ system also serves as a validation of the proposed RCE based DAQ for the larger DUNE experiment. The SLAC ATCA Reconfigurable Cluster Element (RCE) platform provides a cluster of software and firmware resources tightly coupled by a low latency 10G switch fabric. Multiple RCE ATCA cards can be deployed in inter-connected ATCA shelves to form a scalable cluster of computing elements. This cluster can be used as a data acquisition, triggering and data processing platform.

Keywords: ProtoDune, RCE, SLAC
Poster panel: 111

Poster Number:
N-07-111

A Compact 16-channel Waveform Digitizer Assembly for Fast-timing with Single-photon Photodetectors (#2720)

J. Steele1, J. A. Brown1, K. Nishimura2

1 Sandia National Laboratories, Livermore, California, United States of America
2 University of Hawaii, Honolulu, Hawaii, United States of America

Content

Described are the design and performance of a Compact 16-channel Waveform Digitizer assembly made specifically to interface directly with one 16-anode bank of a Photonis XP85012 Planacon 8x8 anode MCP-PMT photodetector. The assembly utilizes two 9-channel Paul Scherrer Institut (PSI) Domino Ring Sampler (DRS4) switched capacitor array (SCA) chips, with 1024 storage cells per channel, to simultaneously sample the 16 anode voltages and the MCP-out sum signal at up to 5 GS/s.  Analog sampling proceeds continuously until a trigger halts it, shortly after which the captured samples are converted using 14-bit ADCs into 18 digital waveforms in parallel to approach minimum deadtime of ~30 us per trigger for the 1024 sample maximum.  A 4-digitizer system required to instrument all 64 anodes of a Planacon delivers ~10k full length waveforms per second via USB 2.0 to PC hard disk.  Selecting fewer samples per waveform reduces deadtime and speeds delivery proportionally.  A Xilinx Artix-7 XC7A50T FPGA controls the SCAs, ADCs, triggering, time and amplitude calibration, and communication electronics.  An assembly measures 130 mm by 54 mm and consumes ~4 W.  We report measurements of bandwidth, noise, linearity, cross-talk, and timing responses of the digitizer assembly alone, as well as single- and multiple-photon amplitude and timing responses of a Planacon/digitizer pair.

Keywords: digitizer, switched-capacitor-array, neutron scatter camera
Poster panel: 113

Poster Number:
N-07-113

Pile-Up Rejection Using Pulse-Shape Discrimination (#2860)

V. T. Jordanov1

1 YANTEL, LLC, Santa Fe, New Mexico, United States of America

Content

An advanced technique for pile-up rejection using real-time pulse-shape discrimination is presented. The pulse-shape discriminator is based on ballistic deficit measurement of digitally synthesized pulse shapes. The digital pulse-shaping system is time-invariant and operates in real time. Two pulse shapers are used - a main shaper, less sensitive to ballistic deficit and a fast shaper with higher sensitivity to ballistic deficit. The fast pulse shape is inverse sawtooth pulse. The pile-up rejection is achieved by measuring the pulse heights of both shapers and calculating their ratio which is an indicator of a pile-up condition. This method is well suited to work as a compliment to the traditional fast discriminator pile-up rejectors as it can detect pile-up within the fast discriminator channel.   

Keywords: pile-up rejection, pulse-shape discrimination, real-time, time-invariant
Poster panel: 115

Poster Number:
N-07-115
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Design of a drift chamber tracking system for the IDEA experiment at FCC-ee (#1333)

N. Alipour Tehrani1

1 CERN, Experimental Physics, Meyrin, Genève, Switzerland

On behalf of the FCC-ee experiment study

Content

The physics aims at the electron-positron option for  the Future Circular Collider FCC-ee, impose high precision requirements on the vertex and tracking detectors.  The detector has also to match the experimental conditions such as the collisions rate and the presence of beam-induced backgrounds.
A light weight tracking detector is under investigation for the IDEA (International Detector for Electron-Positron Accelerator) detector concept and consists of a drift chamber. Simulation studies of the drift chamber using the FCCSW (FCC software) are presented. Full simulations are used to study the effect of beam-induced backgrounds on this detector.

 

Keywords: FCC, Drift chamber, IDEA detector, Gas detector, FCCSW
Poster panel: 117

Poster Number:
N-07-117

Optimization study of the drift field for TPC detector in CEPC (#1425)

Y. Cai1, Y. Li1, H. Qi2, Y. Li1

1 Tsinghua University, Department of Engineering Physics, Beijing, China
2 Chinese Academy of Sciences, Institute of High Energy Physics, Beijing, China

Content

The Time Projection Chamber in Circular Electron Positron Collider brings forward strict requirements including spatial resolution. The drift field determines the drift velocity and diffusion of ionization electrons, so it greatly influences Time Projection Chamber performance. Our aim is to optimize the drift field based on the detector's gas properties and spatial resolution. To make the drift velocity in T2K gas around the plateau region, the drift field should be from 240V/cm to 400V/cm according to the simulation. Analytic formulas of spatial resolution suggest bigger transverse diffusion brings in worse spatial resolution in rφ direction which means there is an upper limit of 220V/cm for the drift field according to the analysis. The formula also indicates the longitude diffusion together with electronics’ time resolution influences the spatial resolution in z direction. There is no overlaps between two ranges perhaps due to the difference between the simulated and actual gas properties, so we are developing a Time Projection Chamber prototype with laser calibration system to study these crucial technical issues. The drift velocity will be measured precisely and the electronics' time resolution will be validated to modify the analytic formula of spatial resolution in z direction to make further efforts to optimize the drift field.

Keywords: Time projection chamber, Drift field, laser calibration system, CEPC
Poster panel: 119

Poster Number:
N-07-119

Outgassing Studies on triple-GEM detectors for CMS GE2/1 and ME0 (#2342)

F. Fallavollita1

1 University of Pavia, Department of Physics, Pavia, Italy

Content

After several years of successful R&D with Gas Electron Multipliers (GEM) based detectors, CMS is going to equip the innermost region of its forward muon system with the triple-GEM technology. Ageing phenomena constitute one of the most complex and potential serious problems which could limit, or severely impair, the use of gaseous detectors in unprecedented radiation environments. As for all gaseous detectors, the triple-GEM technology might be subject to classical aging, i.e. the degradation of their detection performance due to the presence of contaminants in the gas volume when operating in a high-rate particle environment. Most of the contaminants originate from outgassing of some materials used in the detector assembly. Past aging studies had demonstrated the outgassing behavior of some of these materials and related classical aging issues under heavy X-rays and gamma-rays irradiation. Despite the replacement of some critical materials with non-outgassing ones, the experimental data from detectors actually installed in the CMS muon system may indicate some aging effects not expected from laboratory tests. For this reason, a new outgassing test on a triple-GEM prototype is in course. The goal is to understand if there are new outgassing issues and if a correlation with the specific ionization behavior of particles exist, which may induce aging effects not present in the previous X-rays and gamma-rays studies. The prototype is irradiated in two different regions at the same time with two different types of particles, alpha particles from a 5.5 MeV 241-Am source and and 5.9 keV X-rays from a 55-Fe source to investigate if different behaviors in the two areas develop. Also a single wire proportional chamber with polluted gas is irradiated with a X-rays source in order to monitor the effects of the polymerization. Preliminary results on outgassing studies will be presented.

Keywords: GEM, CMS, long-term operation, aging, outgassing
Poster panel: 121

Poster Number:
N-07-121

Experimental ion mobility studies of alternative gas mixtures for the LCTPC (#2515)

M. A. G. Santos1, 2, A. F. V. Cortez1, 2, R. M. Curado da Silva1, 2, P. N. B. Neves3, F. P. Santos1, F. I. G. M. Borges1, 2, C. A. N. Conde2

1 Laboratory of Instrumentation and Experimental Particle Physics, Coimbra, Portugal
2 University of Coimbra, Department of Physics, Coimbra, Portugal
3 Closer Consultoria Lda, Lisboa, Portugal

Content

Data on effective ion mobility for mixtures of two and three gases is important for the improved performance of large volume gaseous detectors, like for example the upcoming LCTPC (Linear Collider TPC) for the International Linear Collider (ILC), where ionization of charge particles created during collisions of 1 ms-long bunch trains produces a large number of electrons and ions. The electron signals are amplified and more ions are produced in the gas amplification stage at the endcaps of the TPC. In order to neutralize these ions, a gating device will be installed at some distance from the gas amplification stage. To optimize this distance, that will ensure a high ion reduction while minimizing the thickness of the endplate, it is important to know the ion mobility for the different gas mixtures of interest. Argon (Ar) has been chosen as the main filling gas for several detectors, while the choice of the quencher is not consensual being determined by different parameters. Recently, carbon tetrafluoride, CF4, has been considered as an additive gas for the LCTPC mixture, eventually also with the addition of isobutane (iC4H10). In the present work, the measurements of the ion mobility in Ar-CF4-CH4, Ar-CF4-C2H6 and Ar-CF4-iC4H10 mixtures were carried out, extending previous studies made for other gases, and since data on ion mobility in these mixtures is scarce or inexistent, the results for low reduced electric fields (from 10 Td to 25 Td), at low pressures and at room temperature are here presented.

Keywords: Gaseous detectors, Ionization and excitation processes, Charge transport and multiplication in gas, Ion sources, Ion mobility
Poster panel: 123

Poster Number:
N-07-123

A Monte Carlo triple-GEM simulation tuned with data (#2687)

R. Farinelli1

1 INFN Ferrara - University of Ferrara, INFN - Ferrara, Ferrara, Micronesia (Federated States of)

Content

Triple-GEM detectors are a well known technology used in high energy physic experiments. In order to use them as subdetectors in big physics experiments, a reliable Monte Carlo simulation has to be developed, to reproduce the performance which have been measured experimentally, for example in test beams, and be able to infer the future behavior in real conditions.  In detail, the software has to simulate the response of the detector to the passage of particles, from the primary ionization, to the amplification and diffusion of the electrons and eventually to the induction of the charge on the anode strips. In the case of gas detectors, existing softwares such as GARFIELD already perform a very detailed simulation of the physical processes but are CPU time consuming. In this presentation a description of a faster simulation is presented. It models the results about the electron production (primary ionization and avalanche) and diffusion in a triple-GEM obtained from GARIFELD and then it reconstructs the signal induced on each anode strip according the the Ramo theorem. The simulation has been tuned on the data collected in several test beam and it can reproduce the real values of time and charge measured by the strip. When the reconstruction algorithms used in the field of Multi Pattern Gas Detectors, such as the Charge Centroid or the micro-Time Projection Chamber readout, are applied on the simulated data, the model shows performance comparable to the experimental one. This provides a validation of this model and allows to extend its usage in different conditions, i.e. geometries, presence of magnetic field, high voltage settings, different direction of the incident particles, to evaluate the expected outcome of the triple-GEM in those cases.


 

Keywords: Monte carlo triple GEM simulatio ngas detector
Poster panel: 125

Poster Number:
N-07-125
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Operational Experience with the CMS Hadron Forward Calorimeters Phase I Upgrade (#1031)

B. Bilki1, 2, Y. Onel1, E. Gülmez3

1 University of Iowa, Department of Physics, Iowa City, Iowa, United States of America
2 Beykent University, Istanbul, Turkey
3 Bogazici University, Department of Physics, Istanbul, Turkey

On behalf of the CMS Collaboration

Content

The Phase I Upgrade of the CMS Hadron Forward Calorimeters was completed during the Extended Year End Technical Stop of 2016 – 2017. In the framework of the upgrade, the front-end electronics were replaced and the PMT boxes were reworked to implement two channel readout in order to exploit the benefits of the multi-anode PMTs. The new PMTs with two channel readout allow background tagging and signal recovery. In addition, the front-end electronics implement a 6-bit TDC to provide additional handles to eliminate the background.

The Hadron Forward Calorimeters were commissioned and operated successfully in 2017 data taking period. Here we describe the details and the components of the upgrade, and discuss the operational experience with the Phase I Upgrade.

Keywords: forward hadron calorimeter
Poster panel: 127

Poster Number:
N-07-127
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Design, Construction and Commissioning of the Upgrade Radiation Damage Monitoring System of the CMS Hadron Forward Calorimeters (#1033)

B. Bilki1, 2, J. - P. Merlo1, A. Mestvirishvili1, M. Miller1, Y. Onel1, I. Schmidt1

1 University of Iowa, Department of Physics, Iowa City, Iowa, United States of America
2 Beykent University, Istanbul, Turkey

On behalf of the CMS Collaboration

Content

The CMS Hadron Forward Calorimeters cover pseudorapidities between 3.0 and 5.0 being exposed to the highest radiation levels in the CMS detector system. The calorimeter consists of quartz fibers as active media inserted into the steel absorber structure. The radiation damage of the quartz fibers is monitored using dedicated data taking by measuring the fraction of laser light intensity after traversing the quartz fibers.

Recently, a new monitoring device was designed, constructed and installed based on solid state laser diode technology. The basic operational integrity was tested extensively prior to installation. The module was integrated into the front-end electronics in a similar way as the Phase I Upgrade LED calibration system.

Here we describe the design and construction phases of this novel radiation monitoring system and present the commissioning and integration phases.

Keywords: hadron calorimeter, calibration system
Poster panel: 129

Poster Number:
N-07-129
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The CMS Tracker Upgrade for the High Luminosity LHC (#1256)

G. Sguazzoni1

1 Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, Sesto Fiorentino, Italy

for the CMS Tracker Group

Content

The LHC machine is planning an upgrade program which will smoothly bring the luminosity to about 7.5x1034cm-2s-1 in 2028, to possibly reach an integrated luminosity of 3000fb-1 by the end of 2037. This High Luminosity LHC scenario, HL-LHC, will require a preparation program of the LHC detectors known as Phase-2 upgrade. The current CMS Outer Tracker, already running beyond design specifications, and CMS Phase1 Pixel Detector will not be able to survive HL-LHC radiation conditions and CMS will need completely new devices, in order to fully exploit the high-demanding operating conditions and the delivered luminosity. The new Outer Tracker should have also trigger capabilities. To achieve these goals, R&D activities are ongoing to explore options for both, the Outer Tracker and the Pixel Inner Tracker. Solutions are being developed that would allow including tracking information at the Level-1 Trigger. The design choices for the Tracker upgrades are discussed along with some highlights of the R&D activities.

Keywords: tracker detectors, silicon sensors, LHC, high luminosity
Poster panel: 131

Poster Number:
N-07-131

Timepix-3 (TPX3) Luminosity Determination of LHC Proton-Proton Collisions at 13 TeV (#1434)

A. Sopczak1, J. Begera1, B. Bergmann1, T. Billoud1, B. Biskup1, P. Burian1, D. Caforio1, E. Heijne1, J. Janecek1, C. Leroy1, P. Manek1, Y. Mora1, S. Pospisil1, T. Seidler1, M. Suk1

1 Czech Technical University in Prague (CTU), Institute of Experiemntal and Applied Physics, Prague, Czech Republic

Content

The Medipix (MPX) and Timepix (TPX) devices installed in the ATLAS cavern have made important contributions to the overall LHC luminosity determinations. We demonstrate for the first time that the Timepix-3 chip (TPX3) as the next generation of X-ray and radiation imaging technology can be used for precision luminosity measurements. Rather than collecting data frame-by-frame the TPX3 device generates a continuous stream of data. Thus, new analysis techniques were applied for the luminosity determination.

The data of a TPX3 device operating d 2017 in a first test phase in the ATLAS cavern was analyzed. For the luminosity determination of the LHC proton-proton collisions, Luminosity Blocks (LBs) of typically 60 seconds were defined. These LBs were used to determine LHC luminosity curves reflecting the luminosity reduction from single-bunch interactions and from beam-beam interactions. From these measurements, the internal long-term time-stability of the TPX3 luminosity was determined. In addition, the linearity of the TPX3 luminosity measurements with respect to other luminosity measurements was determined as a function of the average number of interactions per bunch crossing. Furthermore, the long-term stability of the TPX3 luminosity measurements was determined by comparisons to reference measurements of other luminometers, and good agreement was found. TPX3 with a time precision up to 1.56 ns has the potential to measure the luminosity of individual LHC bunches, rather than bunch-integrated luminosity.

 

Keywords: LHC, Luminosity, pixel detector
Poster panel: 133

Poster Number:
N-07-133
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Aerogel-Based Ring-Imaging Cherenkov counter in the Belle II experiment (#1519)

Y. - T. Lai1

1 KEK, IPNS, Tsukuba, Japan

Belle II Collaboration

Content

In the charged particle identification system of the Belle II experiment, an aerogel-based proximity focusing ring-imaging Cherenkov (ARICH) counter is installed in the forward end-cap region of the Belle II detector. The goal is to enhance the power of separation between kaons and pions up to and above 4σ for momenta up to 4 GeV/c, which is critical to the study of CP violation involved in B decays. The counter is made of aerogel tiles with refractive indices n of 1.045 and 1.055, transmission lengths of 30-40 mm, and dimensions of 18 × 18 × 2 cm3. A 144-channel HAPD (Hybrid Avalanche Photo Detector) is adopted as a photo-detector, and the HAPD signal processing is performed using ASICs (Application Specific Integrated Circuit) to digitize the signal and FPGAs (Field Programmable Gate Array) for data processing.

During Phase II operation of SuperKEKB, the commissioning of ARICH is done both with cosmic rays and beam collisions. The Cherenkov rings are clearly observed, and the performance of the hardware system and identification algorithm is being evaluated. In this presentation, we will report  on the construction of ARICH and on the initial performance of the detector obtained during the commissioning.

Keywords: Cherenkov radiation, detector, Belle II experiment, Particle ID, RICH
Poster panel: 135

Poster Number:
N-07-135

Medipix3RX neutron camera for ambient radiation measurements (#1683)

S. Bheesette1, 5, A. Lokhovitskiy2, 5, S. Mallows3, 5, I. Azhgirey4, 5, I. Kurochkin4, 5, A. Dabrowski5

1 University of Otago, Department of Radiology, Christchurch, New Zealand
2 University of Canterbury, Department of Physics and Astronomy, Christchurch, New Zealand
3 Karlsruhe Institute of Technology, Karlsruhe, Baden-Württemberg, Germany
4 Institute for High Energy Physics, Protvino, Russian Federation
5 CERN, Beam Radiation Instrumentation and Luminosity, Geneva, Genève, Switzerland

and the MARS Collaboration On behalf of the MARS Collaboration: Sikiru A Adebilejec, e, Maya R Ammac, Nigel Andersonc, Marzieh Anjomrouza, Fatemeh Ashariomabadc, Ali Atharifarda, Benjamin Bamfordc, Stephen T Bella, Srinidhi Bheesettec, d, Anthony P H Butlera, b, c, d, e, Philip H Butlera, b, c, d, e, Alexander I Chernoglazova, e, Tara Dalefieldb, Niels J A de Ruitera, b, c, e, Robert M N Doesburga, Neryda Duncanb, Steven P Giesegb, c, Brian P Goultera, Sam Gurneyc, Joseph L Healya, b, Peter J Hiltonb, c, Preveenkumar Kanithib, e, Tracy Kirkbridef, Stuart P Lansleya, Chiara Lowec, V B H Mandalikaa, b, e, Emmanuel Marfoc, Mahdieh Moghiseha, c, David Palmerg, Raj K Pantaa, c, Hannah M Prebblea, b, Aamir Y Rajac, Mohsen Ramyarc, Peter Renaudb, c, Nanette Schleichh, Emily Searleb, Muhammad Shamshada, Jereena S Sheejac, Rayhan Uddinb, Lieza Vanden Broekeb, Vivek V Sa, E Peter Walkerc, Michael F Walsha a MARS Bioimaging Limited, Christchurch, New Zealand b University of Canterbury, Christchurch, New Zealand c University of Otago Christchurch, Christchurch, New Zealand d European Organisation for Nuclear Research (CERN), Geneva, Switzerland e Human Interface Technology Laboratory New Zealand, University of Canterbury, Christchurch, New Zealand f Ara Institute of Canterbury, Christchurch, New Zealand g Lincoln University, Lincoln, New Zealand h University of Otago Wellington, Wellington, New Zealand

Content

We describe a MARS-Medipix3RX neutron camera developed by adapting and modifying detector readout electronics developed at the University of Canterbury. The readout electronics are part of the MARS spectral x-ray scanner and used for biomedical applications. The neutron cameras will be used for precise evaluation of the composition and spectral characteristics of radiation in and around the Compact Muon Solenoid (CMS) of the Large Hadron Collider (LHC) at CERN. This evaluation is necessary to ascertain the performance of various detector sub-systems as well as to predict their useful lifetimes. Medipix3RX detectors can deliver real-time images of fluxes and spectral composition of different particles, including slow and fast neutrons.  In our neutron camera, slow neutrons are detected using a lithium fluoride conversion layer and fast neutrons by a polypropylene layer. These produce charged particles which are then detected by a semiconductor sensor material, silicon. We modelled the mixed-field radiation at seven Medipix detector locations in the cavern by scoring particle tracks using FOCUS (a CMS FLUKA tool), analysing the energy of the neutrons as well as their angular distributions. A good agreement was observed between the average fluxes predicted by standard FLUKA methods and those obtained by FOCUS output data integrated over time. Also, the response function of the Medipix detectors with different neutron conversion layers was simulated using Monte Carlo methods. A post-processing algorithm was developed for track reconstruction and recognition using cluster analysis techniques. This labels and determines the density of clusters formed by groups of particles. The MARS-Medipix detectors with their conversion layers were calibrated in the CERN neutron facility and installed in the CMS cavern during the 2018 run. This paper discusses the calibration of the detector installation and presents early results of radiation measurements from this run.

Keywords: Neutron detectors, Medipix, pattern recognition, neutron flux, Spectral response
Poster panel: 137

Poster Number:
N-07-137

Operational Experience and Performance with the ATLAS Pixel detector at the Large Hadron Collider (#1847)

C. Troncon1, A. Gabrielli2

1 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milano, Italy
2 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Bologna , Italy

On behalf of the ATLAS collaboration

Content

The tracking performance of the ATLAS detector relies critically on its 4-layer Pixel Detector, that has undergone significant hardware and readout upgrades to meet the challenges imposed by the higher collision energy, pileup and luminosity that are being delivered by the Large Hadron Collider (LHC), with record breaking instantaneous luminosities of 2 x 1034 cm-2 s-1 recently surpassed.

The key status and performance metrics of the ATLAS Pixel Detector are summarised, and the operational experience and requirements to ensure optimum data quality and data taking efficiency will be described, with special emphasis to radiation damage experience.

 

Keywords: pixel detector, radiation hardness
Poster panel: 139

Poster Number:
N-07-139
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Design and Characterization of MIC4, the Monolithic Active Pixel Sensor for CEPC Vertex Detector  (#2091)

W. Ren1, P. Yang1, D. Zhang1, X. Sun1, G. Huang1, L. Xiao1, C. Gao1, X. Huang1, W. Zhou1, Y. Li1, J. Liu1, B. You1, L. Zhang1

1 Central China Normal University, PLAC, Key Laboratory of Quark and Lepton Physics, Wuhan, China

Content

The discovery of Higgs makes the Standard Model a complete theory. The Circular Electron Positron Collider (CEPC) is proposed as a Higgs factory to produce adequate events, which is the basis for high precision measurement of Higgs boson. The vertex detector in CEPC should meet the requirement of low material budget, high spatial resolution, fast readout speed and low power consumption. The MIC4 sensor is a CMOS Monolithic Active Pixel Sensor (MAPS) being developed for the R&D activities of CEPC vertex detector. It has been implemented in the TowerJazz 180 nm CMOS Image Sensor (CIS) Process. It measures 3.1 mm * 4.6 mm and features a 128 row * 64 column pixel array with a small pixel pitch of 25 μm. A binary front_end has been designed for a compact pixel combined with a sparsified readout circuitry. Each pixel is composed of an amplification, shaping, discrimination circuit and digital logic. To meet the requirement of high spatial resolution and fast readout speed, a new architecture of an asynchronous zero-suppression data-driven readout circuit is proposed and implemented in MIC4. The readout architecture has applied the traditional OR-gate chain inside a super pixel combined with a priority arbiter tree between the super pixels, which only reads out the hit pixels. The chip periphery contains bandgap, DACs, serializer and LVDS providing bias for the array and transmitting the address data of hit pixels off chip. The test results show that all the blocks of the chip are functional. Preliminary tests show that the front_end features a peaking time below 1 μs, a duration time less than 3 μs, a charge threshold of about 221.5 e- and an Equivalent Noise Charge (ENC) of 5.9 e-. Since the biases of the front_end can be adjusted by DACs, the optimization test of the front_end to get smaller threshold and ENC will continue. Further tests on the mismatch of the pixel and the high speed readout link are under preparation and the full results will be available soon.

Keywords: CMOS Monolithic Active Pixel Sensor, CEPC, Low ENC, Asynchronous zero-suppression data-driven readout, Particle physics
Poster panel: 141

Poster Number:
N-07-141

The ATLAS End-of-Substructure Card for the ITk Strip Tracker Upgrade   (#2269)

P. Göttlicher1, H. Ceslik1, H. Colbow1, M. Stanitzki1, S. Diez-Cornell1, C. Wanotayaroj1, J. P. Wolff1, A. Melnik1, I. - M. Gregor1

1 DESY, Hamburg, Hamburg, Germany

Content

Essential part of the ATLAS Upgrade for the High-Luminosity LHC is the construction of a new inner tracking system. The Inner Tracker (ITk) consists of two major subsystems the Silicon Strip Tracker and the Pixel Detector. The challenge for the ITk in general is to design a robust radiation-hard detector and to increase the granularity of the system while at the same time to significantly reduce the material budget and power consumption. The strip tracker consists of one barrel with four double-sided layers and two end-caps with six doubled-sided disks each. The barrel is made up of so-called staves which hosts on both sides the individual silicon strip detector module on a common mechanical structure and provides all the services (power, data lines, cooling) to the detector modules.For the end-cap the approach is quite similar, however here the wedges-shape building blocks are called petals in this case. At the end of each stave or petal the End-of-Substructure (EoS) cards are located, which act as central interface between the stave/petal and the off-detector electronics.

The EoS card then connects the data, command and the power to the off-detector systems. The EoS hosts the lpGBT chipset currently being developed by CERN, which is a radiation-hard ASIC with a 10 Gigabit/s interface. The challenge here is to provide a high-speed communication with a minimum consumption, a very reliable design with a lifetime of fifteen years, use as little space as possible and make it very radiation hard. We present the experience on the GBTx based prototypes as well as a design-concept using the upcoming lpGBT and VL+ chips. Since the EoS sits at a single-point-of-failure for almost a m2 of silicon strips a dedicated production control is planned and will be presented as well.

Keywords: HL-LHC, ATLAS, ITk
Poster panel: 143

Poster Number:
N-07-143

Lycoris : A large area beam telescope based on hybrid-less strip silicon sensors (#2279)

M. Stanitzki1, M. Wu1, U. Kraemer1, S. Roelofs2, 1, M. Breidenbach3, D. Freytag3, B. Reese3

1 DESY, Hamburg, Hamburg, Germany
2 The Hague University of Applied Sciences, Delft, Netherlands
3 SLAC National Accelerator Laboratory, Menlo Park, California, United States of America

Content

A new Large area x-Y COverage Readout Integrated Strip telescope (LYCORIS) is being constructed
as an improvement of the DESY test beam infrastructure within the Horizon2020 AIDA-2020 project. The LYCORIS telescope consists of six layers of 25 micron pitch strip Si sensor readout by two bump-bonded ASICs (KPiX),
running at a timing resolution as multiples of 80 ns;
its active area is designed to be 10 times 10 cm, extendable to 10 times 20 cm.
It can run either standalone or be mounted inside a 1 T solenoid magnet,
providing a spatial resolution better than 10 micronsalong the bending direction,
and a resolution better than 1 mm along the magnetic field.
The full readout system was tested with a hexagonal pixel sensor designed for the SiD ECAL in the lab with a 90Sr source,
and later tested in the electron beam at DESY in May and October 2017. The first assembled modules with the final strip were tested in spring 2018.
First results of the LYCORIS prototype will be presented with a comparison to simulation,besides, the characterization of sensor and readout system are also included.

Keywords: Test Beam, Beam Telescope, Silicon Sensor;
Poster panel: 145

Poster Number:
N-07-145
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The Phase-II ATLAS Pixel Tracker Upgrade: layout and mechanics (#2299)

R. Bates1

1 University of Glasgow, School of Physics & Astronomy, Glasgow, United Kingdom

ATLAS ITk

Content

The ATLAS experiment will upgrade its tracking detector during the Phase-II LHC shutdown, to efficiently take advantage of the increased luminosity of the HL-LHC. The upgraded tracker will consist of silicon-strip modules surrounding a pixel detector, and will hermetically cover up to | eta | < 4.0. It is critical that the high-precision silicon pixel modules are held in position to exacting specifications under all expected environmental conditions, and that they are maintained at optimal temperatures. To achieve this, the supporting structures will be based on stiff, lightweight, highly-thermally-conductive carbon-based materials and will be cooled by evaporative carbon dioxide. The full pixel detector will consist of three broad regions based on geometries designed to keep the silicon sensors as nearly orthogonal as possible to the track direction: an outer barrel, two endcap, and an integrated inner system which will be replaced once during the lifetime of the project. The layouts of the three sections will be described and a description of the supporting structures will be presented, along with results from testing of prototypes and an overview of the expected production timelines.

Keywords: ATLAS, tracker, upgrade, structures
Poster panel: 147

Poster Number:
N-07-147
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FANGS, a FE-I4-based module for radiation monitoring during the commissioning phase of the Belle II detector (#2363)

P. Ahlburg1

1 University of Bonn, Bonn, Germany

Content

The High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan, performs research in high-energy physics with its main installation, the electron-positron accelerator SuperKEKB. From 2010 to 2017, the accelerator was upgraded with the goal of an instantaneous luminosity 40 times higher than for the previous accelerator KEKB.
At an asymmetric energy of colliding electrons and positrons, the new Belle II detector will record the resulting events. Before the installation of the Belle II inner detector, the BEAST II (Beam Exorcisms for A Stable Experiment) experiment was developed to study the machine-induced background radiation during the commissioning phase of the SuperKEKB machine.
The FANGS (FE-I4 ATLAS Near Gamma Sensors) detector is one of the radiation sensors specifically developed for the BEAST II experiment.
It is based on hybrid pixel detector modules used in the ATLAS pixel detector (FE-I4), which are sensitive to low-keV X-rays and can cope with high particle rates. The FANGS detector consists of 15 FE-I4 with 26880 pixels each and a pixel size of 50 x 250 µm² .
The scope of this presentation revolves around the production of the FANGS detector, the energy calibration of the modules using radioactive sources and the recent installation in the BEAST II experiment in November 2017.

 

Keywords: FANGS, FE-I4, SuperKEKB, Belle II, BEAST II
Poster panel: 149

Poster Number:
N-07-149

Upgrade of the CMS Muon Spectrometer in the forward region with the GEM technology (#2482)

M. Bianco1

1 CERN, Meyrin, Switzerland

On behalf of CMS GEM group

The Large Hadron Collider (LHC) will be upgraded in several phases that will allow to significantly expanding its physics program. After the expected long shutdown in 2018 (LS2) the accelerator luminosity will be increased to 2 − 3 × 10^34 cm^−2 s^−1 exceeding the design value of 1 × 10^ 34 cm^−2 s^−1 allowing the CMS experiment to collect approximately 100fb^−1/year. A subsequent upgrade in 2022-23 will increase the luminosity up to 5 × 10^34 cm^−2 s^−1.

The CMS muon system must be able to sustain a physics program after the LS2 shutdown that maintains sensitivity for electroweak scale physics and for TeV scale searches similar to what was achieved up to now.

To cope with the corresponding increase in background rates and trigger requirements the installation of additional sets of muon detectors, referred to as GE1/1, GE2/1 and ME0 that use Gas Electron Multiplier (GEM) technology has been planned.

The installation and commissioning of the GE1/1 chambers is scheduled by 2019/20, while the GE2/1 and ME0 detectors are expected to be installed between 2022 and.

We present an overview of the Muon Spectrometer upgrade using the GEM technology, the ongoing GE1/1 chambers production with the first results of the Quality Assurance tests performed on a such a chambers as well as the design and the technical solution adopted for the foreseen GE2/1 and ME0 chambers, with a summary of the R&D activities ongoing.

Keywords: CMS Experiment, Upgrade, GEM Detector, Mass Production, New TDR
Poster panel: 151

Poster Number:
N-07-151

Design and Construction of sMDT Precision Muon Detectors for the Phase-1 ATLAS Muon Spectrometer Upgrade  (#2575)

H. K. Kroha1, O. Kortner1, P. Rieck1, V. Walbrecht1

1 Max-Planck-Institute for Physics, Munich, Germany

Content

The Monitored Drift Tube (MDT) chambers of the ATLAS muon spectrometer demonstrated that they provide very precise and robust tracking over large areas. Goals of ATLAS muon detector upgrades are to increase the acceptance for precision muon momentum measurement and triggering and to improve the rate capability of the muon chambers in the high-background regions when the LHC luminosity increases. Small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages with the MDTs, but have an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, reducing cost and construction time considerably and improving the the sense wire positioning accuracy to better than ten microns. In 2018, 16 sMDT chambers have been constructed for installation in the inner barrel layer of the ATLAS muon spectrometer at the ends of the toroid coils in the 2019/20 shutdown of the LHC.The chambers have complex shapes which are only feasible with the sMDT construction method. Each sMDT chamber is integrated with a triple thin-gap RPC chamber of only 60 mm thickness. The design and mechanical accuracy of the chambers are discussed as well as the commissioning test results.

 

Keywords: sMDT chambers, ATLAS muon spectrometer, precision muon tracking, RPC chambers, muon trigger
Poster panel: 153

Poster Number:
N-07-153

A High-Voltage Silicon JFET for the HV-MUX in ATLAS ITk  (#2644)

G. Giacomini1, D. Lynn1, W. Chen1

1 Brookhaven National Lab, UPTON, New York, United States of America

Content

We present a new kind of silicon device: a High-Voltage vertical JFET, conceived as a candidate for the High-Voltage Multiplexing switch in the ATLAS upgrade of the silicon microstrip Inner Tracker (ITk). It is based on a vertical structure, with the drain being the epitaxial layer. Both n-type and p-type HV-JFETs have been successfully fabricated in the silicon processing facility of Brookhaven National Lab. Probe station measurements of un-irradiated devices  show low leakage currents and high breakdown voltages (up to 600V) in the OFF state, and high currents in the ON state, which satisfy the requirements for the switch, at least before irradiation. Proton and neutron irradiation are planned to test the suitability of this device at the radiation levels foreseen in the ITk. We’ll present the design, the technology process flow, and the electrical characterization of these devices.

Keywords: high-voltage, ITk, JFET, power device
Poster panel: 155

Poster Number:
N-07-155

The Advanced Instrumentation Testbed: Remote monitoring of Nuclear Reactors with Antineutrinos (#2733)

S. A. Dazeley1

1 Lawrence Livermore National Laboratory (LLNL), Nuclear and Chemical Sciences Division, Livermore, California, United States of America

On behalf of the AIT-Collaboration

Content

Gadolinium-doped water Cherenkov antineutrino detectors at the kiloton and megaton scale are being considered for long-range remote monitoring of nuclear reactors. As a proof-of-concept, an Advanced Instrumentation Testbed (AIT) will be constructed at the Boulby mine in the United Kingdom, 25 km from the Hartlepool nuclear reactor complex, to assess various technology options for remote reactor monitoring. The first option will be the kiloton-scale water-based antineutrino detector WATCHMAN (WATer CHerenkov Monitor of AntiNeutrinos). Antineutrinos interact with protons in water via the inverse beta decay (IBD) interaction, resulting in two distinct cones of Cherenkov light correlated in position and time. Using this interaction WATCHMAN hopes to be the first detector to determine the active/inactive status of a single reactor at a standoff greater than 10 km. The water used in the detector will be doped with gadolinium sulfate, providing a demonstration of the potential of gadolinium doped water detectors for reactor monitoring and will confirm the potential of the technology for use in larger multi-kiloton neutrino experiments. Following the initial WATCHMAN phase of the experiment, the detector will serve as a testbed for new technologies that will have the potential to further increase detector sensitivity. These technologies will include Water-based Liquid Scintillator (WbLS) and Large Area Picosecond Photo-Detectors (LAPPDs), that together have the potential to facilitate the separation of Cherenkov and scintillation photons and better particle identification. We will present the status of the experiment and the experimental conditions that will be required for a successful detection.

 

This work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344, release number LLNL-ABS-751128

Keywords: reactor antineutrinos
Poster panel: 157

Poster Number:
N-07-157

Challenges and Solutions for Future Border Screening Systems (#1008)

R. T. Kouzes1, E. R. Siciliano1

1 Pacific Northwest National Laboraotry (PNNL), Richland, Washington, United States of America

Content

There is now almost two decades of experience with instrumentation at international borders that screen for the illicit transportation of special nuclear material or other radiological material. The technologies currently deployed at borders for radiation detection and imaging are largely even older than this. As we plan for the future, consideration should be given to possible improvements that could overcome the limitations of the currently deployed technology, and the operation of such instrumentation. This presentation will look at the challenges that exist, the technologies that are used, and the options that might be created for enhancing our capabilities to interrupt the possibilities for nuclear smuggling.

Poster panel: 159

Poster Number:
N-07-159

Performance evaluation of differential die-away system in an integrated active neutron NDA system for nuclear non-proliferation and nuclear security (#1164)

A. Ohzu1, M. Maeda1, M. Komeda1, Y. Toh1

1 Japan Atomic Energy Agency, Ibaraki-ken, Japan

Content

A Differential Die-away Analysis (DDA) system using a compact pulsed neutron (DT:14 MeV) generator has been successfully developed for nuclear non-proliferation and nuclear security in the Japan Atomic Energy Agency. The DDA system employing the fast neutron direct interrogation method is designed to quantify fissile materials in samples which have different volume from a vial bottle (4 cc) to pail container (20 liter). It has been demonstrated experimentally that the DDA system is capable of quantifying a nuclear fissile material (Pu-239) less than 10 mg in a vial bottle. The performance of the DDA system with a large measurement sample such as a MOX can container (2 liter) was evaluated through the Monte Carlo simulation studies. The simulation results show that the Pu-239 mass of around 10 mg even in the MOX can container can be detected. The results of the simulation study are discussed and compared to those of the experimental test.

Keywords: nuclear security, safeguards
Poster panel: 161

Poster Number:
N-07-161

Development of a Novel National Ignition Facility Platform for Simulating Nuclear Relevant Neutron Environments (#1271)

N. J. Quartemont1

1 Air Force Institute of Technology, Department of Engineering Physics, Wright Patterson AFB, Ohio, United States of America

Content

This paper describes an experimental design to provide a capability of generating spectrally accurate synthetic nuclear weapon fission product debris. Fission debris has broad application to the nuclear forensics, national security, and the nuclear scientific communities. An accurate production of fission debris requires a representative neutron energy spectrum, which requires alternative methods in the absence of nuclear weapons testing. Targeted modification of a source neutron flux is a solution to generating spectrally accurate fission product debris. An energy tuning assembly is created with the Coues metaheuristic design optimization software package. The objective is to modify the National Ignition Facility laser driven deuterium-tritium neutron fusion source to a notional thermonuclear and prompt fission neutron spectrum. An activation foil set for determining the neutron flux and highly enriched uranium foil for generating fission products are incorporated into the experimental energy tuning assembly. The resultant design is analyzed using Monte Carlo N-Particle Transport Code version 6.1. The design produces approximately one billion fissions in the highly enriched uranium foil with a neutron energy spectrum in very close agreement to the objective neutron energy spectrum. The large number of fissions will build up the wing, valley, and peaks of the fission product mass distribution. Analysis of selected fission products using energy dependent phenomenological models confirmed the energy tuning assembly is capable of producing the expected objective fission product distributions. The foil pack developed for the experimental design to measure the neutron energy spectrum produced was analyzed at two hours post shot. All radiation activities are above 400 becquerel, with the exception of three minor reactions thereby enabling gamma spectroscopy of the monitor reactions and spectrum unfolding to validate the energy tuning assembly spectral shaping performance.

Keywords: neutron energy spectrum tuning, fission debris
Poster panel: 163

Poster Number:
N-07-163

A novel radiation source location detector based on attenuation (#1340)

Q. Wei1, Z. Yang1, T. Dai2

1 University of Science and Technology of Beijing (USTB) , Automatic and Electrical Engineering, Beijing, China
2 China-Japan Friendship Hospital, Department of Radiation Oncology, Beijing, China

Content

A novel direction-sensitive gamma-ray detector is developed based on the attenuation characteristic. The detector consists of 29 GAGG scintillator (2x2x20 mm3) closely arranged around a tungsten cylinder (diameter=22mm). The scintillator crystals are covered by Teflon reflectors except the readout faces. The GAGG array is read out by a SiPM array. When a source irradiates the detector, each crystal could generate a vector. For crystal i, the vetctor is Vi, the modulus of Vi is the event count of the crystal while the direction is the detector center to the crystal. Then, the source direction can be simplely determined using the sum vector. The detector is 360-degree sensitivity. 

Primary experiments have verified the concept of the proposed detector. More experiments for the detector performance evaluation are being carried out.

Keywords: gamma-ray detector, attenuation
Poster panel: 165

Poster Number:
N-07-165

Antineutrino detectors: an evaluation of their use for monitoring of nuclear explosions (#1636)

M. Foxe1, T. Bowyer1

1 Pacific Northwest National Laboraotry (PNNL), Richland, Washington, United States of America

Content

Historically, nuclear explosion monitoring has been performed via atmospheric transport of radionuclides. In this paper, we aim to answer the question “Is there a role for antineutrino detectors for monitoring of nuclear explosions?” The International Monitoring System (IMS) is a network of detectors established under the Comprehensive Nuclear-Test-Ban Treaty that continuously monitors the world for nuclear explosions. While the IMS utilizes conventional detection techniques (seismic, infrasound, hydroacoustic, and airborne radionuclides), there is often discussion of the potential for antineutrino detectors to detect a nuclear explosion.  We suggest that the current generation detector capabilities and cost associated with antineutrino detectors make their use within the IMS-like monitoring infrastructure prohibitive at this time, especially when compared to an expanded capability of current IMS technologies. Throughout this paper, we discuss the capabilities and requirements of antineutrino detectors and provide the information utilized in arriving at the above conclusion.

Keywords: nuclear explosion monitoring, radioxenon, antineutrino, nuclear explosion
Poster panel: 167

Poster Number:
N-07-167

Portable megavolt x-ray generator (#1894)

N. M. Winch1, S. A. Watson1, E. B. Sorensen1, D. Platts1

1 Los Alamos National Laboratory, LOS ALAMOS, United States of America

Content

Radiography is an important tool for determining the internal structure of objects of interest to the homeland and nuclear security communities. The inherent density of these objects requires high-energy radiation (in the form of x-rays or gamma-rays) to be used which limits the range of available radiation sources and/or generators. Field personnel require compact megavolt radiography, the needs of which are not adequately addressed with the currently available x-ray generators. High-energy (>500 keV) x-ray generators are large and expensive capital items which severely limits both their availability and their applicability. Alternatively, high-energy radioisotope sources, for example Cobalt-60 have regulatory headaches making them undesirable. The need for man-portable, low-power alternatives currently remains unfulfilled.

We have developed a megavolt x-ray system which uses mechanical charge separation to create high-energy electrons which can then be used to create x-ray radiation. This type of source is also extremely versatile because it can be used in either a pulsed or steady-state manner making it suitable for multiple-pulse radiography, portable radiography, or simply as a compact, low-impedance, high-energy electron injector. The main advantages of MEXRAY over other megavolt x-ray systems are it is compact, light-weight, man-portable, rugged, easily repairable, and low-power. Results on the design and operation of the MEXRAY system will be presented.

Keywords: Megavolt, Radiography, X-ray, Electron, Generator
Poster panel: 169

Poster Number:
N-07-169
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A beta-gamma coincidence radioxenon detection system using SrI2(Eu) + SiPMs and a PIPSBox (#1920)

S. A. Czyz1, A. T. Farsoni1, H. R. Gadey1, K. D. McGee1, M. A. Mannino1, L. Ranjbar1, N. M. Shaheen1

1 Oregon State University, School of Nuclear Science and Engineering, Corvallis, Oregon, United States of America

Content

During a nuclear weapon test, several radioxenon isotopes (131mXe, 133Xe, 133mXe, 135Xe) are released in significant quantities. Because xenon is chemically inert, these gases will reach the atmosphere even if the test is conducted underground. As such, the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) has established a global array of detection systems known as the International Monitoring System (IMS) to perpetually monitor the atmosphere for these key isotopes. The detectors currently employed in the IMS, though effective, have various drawbacks associated with them including cost, memory effect, and cumbersome readout electronics. To address some of these concerns, Oregon State University has developed a new detection system comprised of a silicon gas cell and a pair of SrI2(Eu) scintillators coupled to silicon photomultipliers (SiPMs) that takes advantage of the beta-gamma coincidence decay of the radioxenon isotopes to achieve ultra-high sensitivity. The PIPSBox is comprised of two parallel passively implanted planar silicon plates and serves as the gas cell and electron detector. It provides high-resolution electron detection at room temperature without suffering memory effect inherent to plastic scintillator-based radioxenon detectors. A pair of D-shaped SrI2(Eu) crystals, chosen to detect photons for their brightness, high-resolution, rapid response time, and stopping power, are placed upon the outside faces of the PIPSBox. Each SrI2(Eu) is coupled to a 2 x 4 array of SiPMs, which serve as compact, low-cost, and rugged light collection devices. Four independent signals, one from each detecting body, are digitized using a custom multi-channel digital pulse processor. An onboard high-performance FPGA identifies coincidence events between detectors in real-time. The design of the system and preliminary results, including characterization and beta-gamma coincidence identification capabilities evaluated using radioxenon samples, will be discussed.

Keywords: Radioxenon, PIPSBox, Strontium Iodide, SiPM, CTBTO
Poster panel: 171

Poster Number:
N-07-171

The analysis sensitivity research of a photoneutron based drugs detection system (#2036)

T. Cui1, 2, Y. Yang1, 2

1 Tsinghua University, Engineering physics, Beijing, China
2 Key Laboratory of Particle & Radiation Imaging, Ministry of Education, Beijing, China

Content

Photoneutron based thermal neutron analysis (TNA) drugs detection system is a promising technology for drug control because of its capability on elemental concentration analysis. In this work, by simulating the signal emitted by drugs with this system and predicting the time required to control the false rates, the minimum detection time to detect smuggled drugs is evaluated. The result reveals that <0.2s inspection time is adequate to realize a <5% false positive rate and a <5% false negative rate for the detection of smuggled drugs.

Keywords: TNA, photoneutron, sensitivity, drug
Poster panel: 173

Poster Number:
N-07-173

Design of a muon imaging detector with machine-learning positioning method for muon tomography (#2103)

I. S. Kang1, M. K. Baek1, G. Lee1, S. J. Park2, K. B. Kim1, J. J. Ahn3, Y. H. Chung1

1 Yonsei university, Department of Radiation convergence Engineering, Wonju-si, Republic of Korea
2 Yonsei university, Department of Applied Statistics, Seodaemun-gu, Republic of Korea
3 Yonsei university, Department of Information and Statistics, Wonju-si, Republic of Korea

Content

Abstract

Muon tomography using multiple-coulomb scattering is a technique to detecting special nuclear materials(SNMs) such as uranium-235 and plutonium-239. Muon tomography is useful to monitor the spent fuel in dry storage casks due to a strong penetrating of the muon itself and not using an extra radiation source. Muon tomography system consists of four 2-dimensional position-sensitive detectors. Top two detectors measure the incoming trajectories of the incident muons, and bottom two detectors measure the trajectories of the scattered muons by the object volume. In this study, we proposed the new 2-dimension position-sensitive detector for the muon tomography. The detector module consists of a rectangular plastic scintillator and Silicon photomultiplier(SiPM) sensors coupled to four sides of the plastic scintillator. Interaction position of muon was identified by the machine learning positioning method. The effect of the design parameters, such as scintillator size and the number of SiPM sensors, on the imaging performance was evaluated by DETECT 2000 simulation.

Keywords: Muon tomography, Position-sensitive detectors, Silicon photomultiplier(SiPM), Machine-learning
Poster panel: 175

Poster Number:
N-07-175

Design of muon tomography system for monitoring spent fuel: a Monte Carlo study (#2249)

M. K. Baek1, H. Song1, C. Park1, I. S. Kang1, G. Lee1, K. B. Kim1, Y. H. Chung1

1 Yonsei University, Department of Radiation Convergence Engineering, College of Health Science, Wonju-si, Republic of Korea

Content

Muon tomography is a technique for generating 3-dimensional images of object using multiple Coulomb scattering of muons. The muon scattering angle is a function of size, density and atomic number of the object. The purpose of this study is to verify the applicability of muon tomography system on monitoring spent fuel rods in Dry Storage Container (DSC). A muon tomography system is composed of four detector modules consisting of 150 x 150 x 0.5 cm3 plastic scintillator and silicon photomultipliers (SiPM). To measure the scattering angle of muon the top two detectors measure the incoming trajectories of the incident muons and the bottom two detectors measure trajectories of the scattered muons escaping from the object volume. The effect of the design parameters such as size of Field Of View(FOV), distance between detectors and spatial resolution of detector, on system performance was evaluated by GEANT4 simulation. An array of spent fuel rods with a length of 82cm and a diameter of 0.95 cm was model and imaged. The design parameters were characterized and optimized by muon image analysis.

Keywords: Muon tomography, spent fuel, Monte Carlo study, Dry Storage Container (DSC), silicon photomultipliers (SiPM)
Poster panel: 177

Poster Number:
N-07-177

Real-time Gamma-ray Source Localization on the Mobile Urban Radiation Search (MURS) System (#2674)

J. Curtis1, T. H. Y. Joshi1, R. J. Cooper1, B. Cosofret2, T. Schmit2, J. Wright2, J. Rameau2, D. Konno2, D. Brown2, F. Otsuka2, E. Rappeport2

1 Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, California, United States of America
2 Physical Sciences Inc., Andover, Massachusetts, United States of America

Content

The Mobile Urban Radiation Search (MURS) system was designed for real-time detection and localization of radiological and nuclear sources during search missions in urban environments. The MURS system comprises of an array of commercial sensor technologies integrated into the cargo space of a sport-utility-vehicle, including six 2x4x16 inch NaI(Tl) detectors for gamma-ray detection, a 6LiF panel for neutron detection, visible and near-infrared cameras for contextual awareness, cellular/radio antennae for data-telemetry and a global positioning system stabilized by an inertial navigation system. The MURS protoype, built by Physical Sciences Inc., was completed in March of 2018 and features a state-of-the-art gamma-ray detection algorithm and two localization algorithms in order to provide the operators with real-time radioactive source identification and geo-spatial position. This work will focus on one of the algorithms which provides two-dimensional gamma-ray source localization and mapping using a Maximum-Likelihood by Expectation-Maximization (ML-EM) technique. The simulated and measured ML-EM localization performance for the MURS prototype will be discussed as well as methods to improve the computational efficiency. We will conclude with a comparison of the ML-EM performance improvements gained by the inclusion of physical scene context achieved through the integration of Lidar sensors which improves localization accuracy in two-dimensions and enables localization in three-dimensions.

Keywords: mobile gamma ray imaging, urban search, homeland security, imaging algorithm, maximum likelihood expectation maximization
Poster panel: 179

Poster Number:
N-07-179

Evaluation of Minimum Detectable Activity for Underwater Radiation Monitoring System (#2711)

J. Park1, S. Jung1, J. Moon1, D. Oh2, S. Kang2, Y. Kim2

1 Korea Atomic Energy Research Institute (KAERI), Daejeon, Republic of Korea
2 Korea Institute of Civil Engineering and Building Technology (KICT), Gyeonggi, Republic of Korea

Content

An underwater radiation monitoring system has been developed to monitor 137Cs (662 keV) and 131I (364 keV) radioisotopes in water using 3” × 3” NaI(Tl) detector. Since it is very important for the system to estimate the minimum detectable activity and the conversion factor to convert counts into Bq/L, some experiments and simulations were carried out. For the experiments, the water-proof detector system was placed at the center of a water tank into which 68Ga (511 keV) was homogeneously dispersed, and counts were recorded for 5 minutes. Monte Carlo simulations were performed for 68Ga with the same geometry as the experiments to compare each other, then, simulations were also carried out for 137Cs and 131I to evaluate the conversion factor. From the simulations, the conversion factors were found out as 1.86E-02 (Bq/L)/count and 1.38E-02 (Bq/L)/count for 137Cs and 131I, respectively. Based on the conversion factors and underwater background data, the minimum detectable activities of 137Cs and 131I for the system were evaluated as 0.83 Bq/L and 0.95 Bq/L, respectively.

Keywords: Radiation monitoring, Minimum detectable activity, Radioactivity conversion
Poster panel: 181

Poster Number:
N-07-181

Absolute Gamma Source Positioning with Position-sensitive Scintillation Detector Arrays (#2840)

R. Wang1, 2, Q. Ye1, 2, P. Fan1, 2, T. Xu1, 2, Z. Lyu1, 2, S. Wang1, 2, Y. Xia3, 4, Y. Liu1, 2, T. Ma1, 2

1 Ministry of Education (Tsinghua University), Key Laboratory of Particle & Radiation Imaging, Beijing, China
2 Tsinghua University, Department of Engineering Physics , Beijing, China
3 China Academy of Space Technology, Beijing Institute of Spacecraft Environment Engineering, Beijing, China
4 Beijing Institue of Spacecraft Environment Engineering, Science and Technology on Reliability and Environmental Engineering Laboratory, Beijing, China

Content

Radioactive sources are widely used in industrial and medical applications. In home-land security, it is important to monitor radioactive source in public areas to prevent public hazard. Traditional radiation detection devices such as Geiger counter cannot provide position information. Existing imaging devices including Gamma cameras with collimators, or Compton cameras can only determine directional information of sources over the 4π angular space, which is not enough for accurate source positioning in areas with high population density.

In this work, we propose a novel method to achieve 3-D imaging capability of the absolute radioactive sources position with position-sensitive scintillator detector arrays. Targeting at application in a typical public places such as airports, we propose a 6-detector array setup. The detector design is based on a pixilated dual-ended GAGG scintillation detector that has been developed in our lab. The measured photon count distribution of all the six detectors are combined together to form the projection data. A ML-EM algorithm is used to reconstruct the source intensity image in Cartesian coordinates. In MC simulation, both one single point source and multiple sources are placed to measure the projection data. The positioning accuracy and the FWHM image resolution were calculated from the reconstructed image to evaluate the performance of the proposed imaging method.

The reconstructed images converge to desired point-type distribution with certain spread for both one and multiple point sources situations. Perfect positioning accuracy is achievable in all cases for single point source. The average FWHM resolution measured from the reconstructed image is 7.71 +/- 2.69 cm in the x and y axis, and 3.13 +/- 2.14 cm in the z axis. 

In conclusion, the proposed method demonstrates feasibility for absolute positioning of radioactive sources in 3-D Cartesian space. We believe it will be useful in public safey applications.

 

Keywords: absolute source positioning, position-sensitive detector, ML-EM algorithm, public safety applications
Poster panel: 183

Poster Number:
N-07-183
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The Preliminary Results from the Charge Particle Detector at the “Back-n” White Neutron Source (#1028)

R. R. Fan1, 2, G. H. Zhang3, W. Jiang1, H. Yi1, C. J. Ning1, Y. T. Zhao1, Y. F. He1, H. Y. Bai3, H. Y. Jiang3, Z. Q. Cui3, L. Zhou1, Z. J. Sun1, 2, J. Y. Tang1

1 Institute of High Energy Physics Chinese Academy of Sciences, CSNS, Beijing, China
2 State Key Laboratory of Particle Detection and Electronics, Beijing, China
3 Peking University, Beijing, China

Content

At the end of 2017, the CSNS (China Spallation Neutron Source) started the running with the neutron beam. The white neutron source “Back-n” as the extended program of the CSNS had its first results from several experiments. The Light Charged Particle detectors array (LPDA) in this report is one of the experimental systems, including an elaborate vacuum chamber and some vary purpose detectors. During the developing and testing, this system gives excellent performance. Preliminary results from the Light Charged Particle detectors array (LPDA) show a good particle resolution with 6Li target. The more interested target will be implemented in future.

Poster panel: 185

Poster Number:
N-07-185

Measurement of microdosimetric quantaties of a neutron source using a tissue equivalent proportional counter (#1234)

N. Hu1, T. Takata3, S. Endo2, Y. Sakurai3, H. Tanaka3

1 Kyoto University, Graduate School of Engineering, Department of Nuclear Engineering, Radiation Medical Physics Division, Yoshidahonmachi, Japan
2 Hiroshima University, Quantam Energy Applications, Hiroshima, Japan
3 Kyoto University, Institute for Integrated Radiation and Nuclear Science, Osaka, Japan

Content

Boron neutron capture therapy (BNCT) is an emerging radiation treatment modality. It has the potential to selectively destroy cancer cells. Currently, BNCT is performed using a nuclear reactor. However, the future trend is to move toward accelerator-based system for use in hospital environments. A typical BNCT radiation field has many different types of radiation present. It is important to quantity the beam quality to maximise the treatment outcome. Tissue equivalent proportional counters are regarded as the gold standard dosimetry tool for mixed radiation fields.  This study utilised the TEPC to measure microdosimetric quantities of a reactor based and accelerator-based neutron source used for BNCT. The reactor used was the Kyoto University Reactor, which was operated at mixed irradiation mode, and the accelerator used was located at the Aomori prefecture Quantum Science Center. Both neutron sources are utilised for small animal and cell studies. Based on the microdosimetric measurements, the relative contributions from each radiation component present in the field were obtained. The accelerator-based source had a high component of fast neutrons, resulting in higher fraction of high LET particles being produced. The relative contributions from protons, carbon ions and alpha particles were approximately 0.8, 0.15 and 0.02 respectively for accelerator-based and 0.88, 0.08 and 0.03 for reactor based. Monte Carlo simulation using Particle and Heavy Ion Transport code System was also performed and close agreement with measured value was obtained.

Keywords: Boron neutron capture therapy, Tissue equivalent proportional counter, Microdosimetry, Monte Carlo simulation
Poster panel: 187

Poster Number:
N-07-187

A Design Study of an Application of the CsI Self-Activation Method to the Neutron Rem-Counter Technique (#1397)

T. Ueki1, A. Nohtomi1, G. Wakabayashi2

1 Kyushu University, Graduate school of Medical Sciences, Fukuoka, Japan
2 Kindai University, Atomic Energy Research Institute, Osaka, Japan

Content

In our previous works, the CsI self-activation method was successfully utilized for detecting photo-neutrons around medical linacs. In the present work, for a direct determination of neutron ambient dose, a design study of an application of the CsI self-activation method to so-called “the neutron rem-counter technique” was investigated. A CsI crystal served as both main target material and 4π counter of neutron activation method in our proposed CsI self-activation method. A commercially available CsI detector was selected as such neutron detector and arranged inside several neutron filters made of polyethylene and silicon rubber containing B4C. A geometrical structure of these neutron filters was optimized by a Monte-Carlo calculation so as to fit the neutron response to the ICRP-74 rem response. For the optimization, Residual Sum of Square (RSS) of the calculated neutron response and the ICRP-74 rem response was minimized by changing the thickness of each filter step by step. Finally, a comparison between the results of neutron ambient dose of a simulation calculation and an experimental evaluation has been carried out. Each evaluation was conducted in the same condition around a medical linac (Varian TrueBeam 10 MV-X); the value of experimental evaluation was obtained from our previous work for comparison. As a result, a simulation calculation was about 15 % smaller than an experimental evaluation. This relative error was practically acceptable, because generally about 30 % difference was reported previous research paper as an example of good agreement between rem-counter measurements and Monte-Carlo calculations. In our future work, we are planning to manufacture a rem-counter with the CsI self-activation method to realize the design concept of the present study.

Keywords: the CsI self-activation method, the neutron rem-counter technique
Poster panel: 189

Poster Number:
N-07-189

Development of position sensitive neutron detector element using circular cathode bumps (#1529)

K. Toh1, T. Nakamura1, K. Sakasai1, H. Yamagishi2

1 Japan Atomic Energy Agency, Tokai, Japan
2 Nippon Advanced Technology, Tokai, Japan

Content

A bump cathode element that consists of a polyimide insulator and small-sized circular cathode bumps was developed, and an irradiation experiment was performed using a Cf-252 neutron source. The developed element has triangularly arranged, small-sized circular cathode bumps (pads) made from Cu on the insulator, and the bumps are linked together in the x- and y-directions for the individual signal line readout. The sensitive area is 128 mm × 128 mm with a pitch of 1 mm in both directions. For use in the detector system, the bump element was placed on the base plate made from an alumina ceramic with thickness of 1.5 mm. The element was arranged with anode wires in the pressure vessel with a 20 mm conversion gap. The base plate had multichannel connectors (X: 128 ch, Y: 128 ch) for signal transmission from a detector element to signal processing electronics mounted outside of the pressure vessel. Irradiation experiments for the element were performed using a neutron detection system consisting of a pressure vessel, amplifier-shaper-discriminator boards, optical signal transmission devices, position encoders with field-programmable gate arrays, and a data acquisition device. The experiments were performed using a gaseous mixture of 3He and carbon tetrafluoride (CF4) at a total pressure of 0.7 MPa (He/CF4 = 0.6/0.1). The neutron-induced signals of all pixels were observed using 128 × 128 ch test element, and the signal pulse peak of neutron can be observed in the pulse height distribution of anode wires. The signal pulse peak become high and the uniformity become well as the applied voltage increases.

Poster panel: 191

Poster Number:
N-07-191

Effect of long gate and digitizer dynamic range on Pulse shape discrimination(PSD) using EJ299-33 (#1810)

K. W. S. Chung1, R. Moss1, J. C. Khong1, R. Speller1

1 University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom

Content

 

The organic plastic scintillator, EJ299-33, draws growing interest because of its improved pulse shape discrimination (PSD) capability and physically safe properties, potentially developing to a portable MeV neutron dosimeter. Its PSD performance depends on the detector geometry. The choice of parameters, such as long gate, on the PSD performance was rarely discussed. Peak distortion was observed in other groups but the underlying reasons were not fully understood. This work is to study the possible cause of peak distortion and the effect of long gate on the PSD performance. The scintillator was coupled to the ET Enterprises 9102B photomultiplier tube (PMT) in a sealed box. The 11 GBq AmBe source was 12 cm from the detector and 1.5 cm lead was used to reduce the gamma flux. We measured the source with different long gates after the FPGA analysis. Waveform data was also acquired at different digitizer settings. Waveforms were used for offline PSD analysis by MATLAB. A 2D scatter plot (i.e. PSD values against Qlong) was plotted for each measurement. Peak distortion, where gamma and neutron peaks bent upwards after exceeding a certain Qlong value, was identified. We studied the waveforms at various long gates and carried out PSD analysis. Some waveforms were clipped because their amplitudes exceeded the dynamic range of the digitizer. The data was subdivided into two groups: clipped waveform and unclipped waveform. Interestingly, the clipped waveforms mainly accumulated at the tails of gamma and neutron peaks. Therefore, the limited dynamic range of the digitizer, which was a systematic error, could relate to the peak distortion. The percentage increase in FoM value was 1.4 % when we increased long gate by 500 ns. Whereas, the memory to record an event increased by 70%. Considering the 3rd neutron mean decay component of EJ299-33, long gate was chosen as 700 ns for our system.

Keywords: EJ299-33, organic plastic scintillator, pulse shape discrimination, PSD, neutron detection
Poster panel: 193

Poster Number:
N-07-193
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Proof of concept of hot-spot superconductor neutron detectors and perspectives (#1901)

A. Pietropaolo1, G. Celentano1

1 ENEA, Frascati, Italy

Content

A neutron detection concept is presented that is based on superconductive niobium (Nb) strips coated by a boron (B) layer. The working principle of the detector relies on the nuclear reaction 10B(n,a)7Li, with a and Li ions generating a hot spot on the current-biased Nb strip which in turn induces a superconducting-normal state transition. The latter is recognized as a voltage signal which is the evidence of the incident neutron. The above described detection principle has been experimentally assessed and verified by irradiating the samples with a pulsed neutron beam at the ISIS spallation neutron source (UK). It is found that the boron coated superconducting strips, kept at a temperature T=8 K and current-biased below the critical current IC, are driven into the normal state upon thermal neutron irradiation. As a result of the transition, voltage pulses in excess of 40 mV are measured while the bias current can be properly modulated to bring the strip back to the superconducting state, thus resetting the detector. Measurements on the counting rate of the device are presented and the basic physical features of the detector are discussed.

Keywords: superconductor neutron detector, neutron imaging detectors, neutron instrumentation
Poster panel: 195

Poster Number:
N-07-195

Development of positional deviation detecting device using real-time neutron detector for BNCT (#1992)

H. Tanaka1, T. Takata1, K. Akabori2, S. Kawabata3, Y. Sakurai1, M. Suzuki1, S. - I. Masunaga1, K. Ono3

1 Kyoto University, Institute for Integrated Radiation and Nuclear Science, Osaka, Japan
2 Sumitomo Heavy Industries, Ltd,, Tokyo, Japan
3 Osaka Medical College, Osaka, Japan

Content

Recently, BNCT using an accelerator neutron source has been performed, and it is necessary to monitor the movement of the patient during irradiation. Since the irradiation field of BNCT has a high background of gamma rays and neutron rays, a monitoring device such as a CCD camera can not be used as a positional deviation detecting device. Therefore, we propose the method to detect misalignment of the patient using a real-time neutron detector. The real-time neutron detector is a combination of a small LiCAF scintillator and quartz fiber. In order to perform the principal demonstration, the irradiation test using an accelerator neutron source was performed. The real-time neutron detector was set at the surface of the head water phantom. We confirmed that this method was possible to detect the positional shift.
 

Keywords: Boron Neutron Capture Therapy, Neutron Detector, Position setting, LiCAF, Fiber
Poster panel: 197

Poster Number:
N-07-197

A Submillimeter Spatial Resolution Scintillation Detector for Neutron Diffraction Imaging (#2027)

T. Nakamura1, T. Kawasaki1, K. Toh1, N. Tsutsui1, M. Ebine2, A. Birumachi2, K. Sakasai1

1 Japan Atomic Energy Agency, J-PARC, Tokai, Naka, Japan
2 Japan Atomic Energy Agency, Nuclear Science Directrate, Tokai, Naka, Japan

Content

A two-dimensional scintillation neutron detector with a submillimeter spatial resolution was developed for pulsed neutron diffraction imaging. The detector comprised the thin, single ZnS/6LiF scintillator screen coupled with the crossed wavelength-shifting fiber array for light collection. For a high spatial resolution, the wavelength shifting fibers with diameter of 0.1 mm were used them for assembling the detector. The prototype detector that has a neutron-sensitive area of 24 x 24 mm2 exhibited a spatial resolution of 0.20±0.06 mm and 0.16 ±0.06 mm for x and y directions, respectively. The detector had a detection efficiency of 7% for thermal neutrons with a 60Co gamma-ray sensitivity in the order of 10-6. In this paper detailed detector design is presented together with experimental results using the pulsed neutron beam at the J-PARC MLF.

Keywords: position-sensitive neutron detector, scintillation detector, neutron diffraction imaging, pulsed neutron source
Poster panel: 199

Poster Number:
N-07-199

Novel Gd2O3 Scintillation Glass Fiber Faceplates for High Spatial Resolution, High Detection Efficiency Cold Neutron Imaging (#2150)

D. Li1, H. Li1, M. Niu1, C. Wan2, S. Sun3, X. Zhang1, 3

1 China Institute for Radiation Protection, Taiyuan, China
2 Lanzhou University, Lanzhou, China
3 North China Electric Power University, Beijing, China

Content

Novel Gd2O3 Scintillation glass fiber faceplates as a key component of cold neutron detector made of a 10-μm diameter and 6-μm diameter Gd2O3 glass fibers with a center-to-center distance of 12μm and 8μm respectively have been invented and fabricated. A high spatial resolution optical readout system composed of a customized lens, an optical mirror, a Canon 180mm micro-lens and a cooled Andor iKon-LDZ936 charge-coupled device(CCD) was used to read out the scintillation light from the faceplates. At present, the spatial resolution of optical readout system is approximately 62.5lp/mm (8μm). It was found that the detection system with 10-μm-fiber-diameter, 0.3-mm thick Gd2O3 scintillation glass fiber faceplate has a spatial resolution of 30.9lp/mm (16.5μm) and a detection efficiency of 93.4%. And the detection system with 6-μm-fiber-diameter, 0.4-mm thick Gd2O3 scintillation glass fiber faceplate has a spatial resolution of 35.1lp/mm (14.5μm) and a detection efficiency of 92.3%.

Keywords: cold neutron imaging, scintillation glass fiber faceplate, high spatial resolution, high detection efficiency
Poster panel: 201

Poster Number:
N-07-201

Non-linearity Analysis of digital SiPM arrays response in a Position Sensitive Neutron Detector Prototype (#2267)

S. Kumar1, M. Herzkamp1, S. van Waasen1

1 Forschungszentrum Jülich GmbH, Central Institute of Engineering, Electronics and Analytics ZEA-2 – Electronic Systems, Jülich, North Rhine-Westphalia, Germany

Content

Silicon photomultipliers (SiPM) are solid-state photodetectors based on Geiger mode avalanche diode technology. The features of SiPMs such as low operating voltages, insusceptibility to a magnetic field and low production costs make it a very appealing candidate for single photon detection applications. In the recent past, its applicability in neutron detection had been assessed and proved feasible. Motivated by this investigation, a new kind of scintillation neutron detector based on digital SiPMs is under development. This detector prototype with an active area of 13cm×13cm is assembled with SiPM modules from Philips Digital Photon Counting and a 6Li glass scintillator. It is aimed to be used in the future for neutron reflectometry (NR) at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, Germany for the TREFF instrument. In order to achieve the goal of two-dimensional spatial resolution of 1mm×1mm, and a neutron-counting rate of 20Mcps/m², non-linearity characterization of the SiPM has been performed. This work presents the simulation results performed using Geant4 tool-kit for the SiPM proportionality response at the pixel and cell levels under the design considerations of this detector prototype.

 

Keywords: Neutron detector, Non-linearity, SiPM, GAPD, DPC
Poster panel: 203

Poster Number:
N-07-203

In-Core Neutron Measurement using SiC Detector for Fast Response (#2366)

J. Park1, S. H. Park2, J. Son1, Y. K. Kim1

1 Hanyang University, Nuclear Engineering, Seoul, Republic of Korea
2 Korea Atomic Energy Research Institute, Daejeon, Republic of Korea

Content

A SiC PIN diode detector (4H-SiC with 30 μm thick epitaxial I-layer) was developed and evaluated its performance under the harsh environment of the High Flux Advanced Neutron Application Reactor (HANARO) reactor core at Korea Atomic Energy Research Institute (KAERI). The detector was designed to be tolerable against thermal and radiation damages, by adopting Ti/Au electrode structure and crimped connection between the sensor and signal wire. Fabricated SiC detector was inserted into the HANARO irradiation hole (IP-4) to test core neutron detection performance at in-core environment. The radiation induced signal was obtained as reactor power increased up to 10 MW. Maximum thermal and fast neutron fluxes were 9.4×1012 and 2.5×109 n/cm2/s, respectively, and total neutron fluence irradiated on the detector was 4.7×1016 n/cm2. Reverse bias of 60 V was applied to ensure maximum detector performance. The detector showed good linearity of response up to the tested fluence, with R2 = 0.9997. The SiC detector’s response speed was evaluated by comparison to that of a Rh self-powered neutron detector (SPND). The delay times of SiC detector signal and Rh SPND signal were determined by evaluating when the current increased to 90% of saturation current at each power step. Averaged SiC detector delay time = 12.8 s, approximately 11 times shorter that of the Rh SPND (140 s).

Poster panel: 205

Poster Number:
N-07-205

High Resolution Fast-Neutron Time-Encoded Imaging using an Asymmetric Mask (#2402)

N. P. Shah1, R. Krentz-Wee2, P. Schuster1, P. Marleau3, D. K. Wehe1

1 University of Michigan, Nuclear Engineering and Radiological Sciences, Ann Arbor, Michigan, United States of America
2 University of California, Berkeley, Department of Nuclear Engineering, Berkeley, California, United States of America
3 Sandia National Labs, Livermore, California, United States of America

Content

Time encoded imaging (TEI) refers to an imaging modality where a moving mask occludes particles from interacting with the detector(s) in order to temporally encode the source distribution in the measured data. The TEI system used in this study consists of an organic scintillator placed inside a randomly-coded, rotating mask. The angular resolution of a TEI system is strongly dependent on the angular width of the mask pixel with respect to the detector. To improve angular resolution without resorting to a larger mask or sacrificing detection efficiency, we shifted the detector off the rotational center of the mask to the inside edge of the mask. By moving the detector off-center, the mask-to-detector distance increases along an axis, named the imaging axis, leading to better angular resolution along that axis. In this work,  we characterize the performance of the detector-centered TEI and the detector-offset TEI as a function of measurement time. To generate the system response for this shift variant imaging system, the multigroup adjoint option in MCNP was utilized. Angular resolution was quantified by the system's ability to separate two activity matched 16 µCi Cf-252 point sources placed 100 cm from the mask center. From each set of measured data, 1000 bootstraps of synthetic data were generated and reconstructed to provide ranges for point estimates of resolution and signal to noise ratio. The asymmetric TEI system can accurately resolve two point sources placed 2.91° apart in less than an hour, and can separate two point sources placed $1.45° apart in 8 hours. Additionally, the behavior of the PSF is characterized as both a function of azimuthal angle off-axis and as a function of measurement time using a rigorous bootstrapped methodology.

 

Poster panel: 207

Poster Number:
N-07-207

Proof of concept on gamma monitoring of Neutron Chopper Phases (#2504)

F. Issa1, N. Tsapatsaris1, A. Quintanilla1, M. Olsson1, D. Zielinski1, R. J. Hall-Wilton1, 2

1 European Spallation Source ERIC, Lund, Sweden
2 Mid-Sweden University, Sundsvall, Sweden

Content

Neutron beam monitors are essential component of neutron scattering facilities. They are used to diagonize choppers and to measure neutron flux, allowing scientists to calibrate detectors and track beam stability. Low material beam monitors are needed to ensure less perturbation of the beam. Previous work shows commercial beam monitors attenuate the beam by few per- centage due to the entrance and exist window and the material inside. Parasitic method could be used as a solution for attenuation the beam. The principle is to put no direct beam monitor into the beam. This paper focuses on a parasitic method of monitoring the beam which can be used for chopper phasing. This is performed by placing a gamma detector close to a rotating chopper. Neutrons interact with boron from the chopper disc lead to gamma emission at 480 keV. Gamma detection from this interaction is used for chopper phasing.

Keywords: neutron detector, neutron scattering, beam monitoring
Poster panel: 209

Poster Number:
N-07-209
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Stilbene-based Fast Neutron Multiplicity Counter for Safeguards Applications (#2567)

T. H. Shin1, A. Di Fulvio1, S. D. Clarke1, S. A. Pozzi1

1 University of Michigan, Department of Nuclear Engineering & Radiological Sciences, Ann Arbor, Michigan, United States of America

Content

Traditionally, capture-based neutron multiplicity counters (i.e. He-3 based systems) are used for non-destructive assay of special nuclear material. Using capture-based detectors for non-destructive assay requires intervening moderating material that inhibits the ability to observe characteristic energy and angular signatures. Therefore, these systems rely on observing only the emitted neutron multiplicity to infer physical properties such as fissile mass, leakage multiplication, and contribution from non-fission neutrons (α-ratio). We have developed a fast neutron multiplicity counter using 24 – 5.08 cm x 5.08 cm stilbene detectors coupled to ETL 9214B photomultiplier tubes, and demonstrate that the system is sensitive to the emitted neutron energy and angular distributions, in addition to the multiplicity distribution. The system was used for passive assay of Pu-metal and Pu-oxide samples, and the detected neutron multiplicity, energy, and angular distributions are used to demonstrate that new correlated signatures exist related to the physical properties of the item. We also demonstrate the neutron cross-talk effects can be considered in order to yield more accurate estimates of the aforementioned physical properties. The final paper will present correlated signatures in energy, angle, and multiplicity that can potentially provide new quantities for characterizing special nuclear material when traditional techniques become unreliable.

Keywords: stilbene, neutron multiplicity counting, safeguards
Poster panel: 211

Poster Number:
N-07-211

Coded-Aperture Imaging with Very Low Counting Statistics (#2593)

M. Folsom1, K. - P. Ziock2, P. A. Hausladen2, J. Hayward1, 2

1 University of Tennessee, Knoxville, Department of Nuclear Engineering, Knoxville, Tennessee, United States of America
2 Oak Ridge National Lab, Oak Ridge, Tennessee, United States of America

Content

Coded-aperture imaging can be used to localize the interaction of an incident particle in a monolithic scintillator by imaging the optical scintillation light. The depth of interaction is obtained by varying the assumed interaction distance within the volume, performing a reconstruction at each distance, and then choosing the sharpest image. In most cases when imaging a point source, counting statistics in the detector are sufficient (number of counts > number of holes in the mask) to obtain a unique source location in the decoded image. This work explores the feasibility of using coded-apertures in the count-starved regime where the number of counts is much less than the number of holes in the mask. This regime is encountered  when localizing scintillation event locations from neutron scatters in a monolithic scintillator volume. Other applications that may face this challenge are the imaging of gamma-ray bursts and particle source tracking, where integration times must be just long enough that sufficient imaged particles are detected to uniquely obtain the source location. In short, any phenomenon with a low background but limited counting statistics. For neutron scatters in a scintillator, at the low energy limit, as few as ~15 detected scintillation photons may be detected. Results obtained using Monte Carlo simulations indicate that, depending on the number of coded-mask pixels, coded-aperture imaging is still expected to be functional for this application to as few as ~10 detected counts. 

Keywords: coded aperture, monolithic scintillator, fast neutron imaging
Poster panel: 213

Poster Number:
N-07-213

Commissioning of thermal neutron detector boxes for the time-of-flight spectrometer TOPAS (#2702)

G. Kemmerling1, M. Boucher3, K. Bussmann1, R. Engels1, H. Kämmerling2, W. Lesmeister2, K. Mckinny3, S. Pistel1, G. Vehres1, J. Voigt1, J. Voss3

1 Forschungszentrum Jülich, Jülich Centre for Neutron Science JCNS, Jülich, Germany
2 Forschungszentrum Jülich, Central Institute of Engineering, Electronics and Analytics – Engineering and Technology, Jülich, Germany
3 GE Reuter-Stokes, Twinsburg , Ohio, United States of America

Content

The thermal neutron time-of-flight spectrometer TOPAS will be equipped with a large detector system based on 2 meter long position sensitive 3He-tubes, each having an internal pressure of 10 bar 3He. In total there are 288 tubes with an overall active area of 14.7 m2. They will be positioned in vacuum at 2.5 meter distance from the sample on a circular arrangement to cover approximately 180° of the radial scattering angle. In order to decouple the detector from the vacuum chamber as well as to facilitate assembly and maintenance, the 3He-tubes are grouped on modular detector boxes. 16 tubes are mounted per detector box, which houses the digitizing readout electronics in a vacuum tight compartment at the back. A vacuum flange at the top of the box provides support for power supply, interface connection and air cooling. During commisioning of the detector boxes, special emphasis has been put on the straightness of the tubes, as the planarity and parallelism of the their mounting points must ensure a straightness of below 1.2 mm. Additionally, the homogeneity of the signal amplitudes for neutron events has also been inspected, as the tube manufacturer pointed us to deficiencies of the wire quality at the time of the tube production. Measurements for the 3He-tube and detector box acceptance have been carried out with a moderated 252Cf-source. The signal amplitudes and event positions have been simultaneously taken and studied for the selection and adjustment of the tubes, which is reported in this paper.

Keywords: neutron detector, 3He-PSD
Poster panel: 215

Poster Number:
N-07-215

Transparent mixed power neutron scintillator (#2849)

K. Watanabe1, M. Kataoka1, N. Mitsuboshi1, A. Yamazaki1, S. Yoshihashi1, A. Uritani1, N. Kawaguchi2, T. Yanagida2, Y. Ikeda3, K. Fukuda3

1 Nagoya University, Graduate School of Engineering, Nagoya, Japan
2 Nara Institute of Science and Technology, Ikoma, Japan
3 Tokuyama Corp., Shunan-shi, Japan

Content

    We are developing a new type of neutron scintillator.  This type of scintillator consists of mixed powder of a neutron converter and a scintillator, like a famous LiF-Ag:ZnS neutron scintillator.  The LiF-Ag:ZnS mixed powder is a very bright scintillator.  However, the detection efficiency and effective thickness of this type of a neutron scintillator is limited because it is opaque due to quite high refractive index of the Ag:ZnS.  Large gaps in the refractive index at interfaces of particles induce refractions with large angles.  Therefore, scintillation photons must run for quite long path before escaping from a scintillator region.  If mixed powder scintillator can be roughly transparent, we can freely change the scintillator composition, especially for lithium content and easily increase the scintillator thickness.  Transparency of a mixed powder scintillator can be improved by choosing a converter and a scintillator with similar refractive indices and filling a refractive index buffer, such as liquid glass resin.  We can choose a scintillator material with various properties, such as fast decay, high light yield etc.  In this paper, we attempt to use LiF and Eu:CaF2 mixed powder to demonstrate a roughly transparent mixed powder neutron scintillator.  The fabricated mixed powder scintillator was roughly transparent. We evaluated the scintillator responses for neutrons and gamma-rays.  The scintillator showed a peak shape in a pulse height spectrum when irradiated with thermal neutrons.

Keywords: Neutron scintillator, mixed powder, LiF, Eu:CaF_2
Poster panel: 217

Poster Number:
N-07-217

Measurements with nanoPSD, a New High Performance Real Time Fast Neutron Measurement System (#2909)

M. L. Iliev1, K. Ianakiev1, V. T. Jordanov2

1 LANL, Los Alamos, New Mexico, United States of America
2 LABZY, LLC, Santa Fe , New Mexico, United States of America

Content

 nanoPSD is a new hardware platform manufactured by the LABZY LLC [1] for fast neutron scintillation detectors with pulse shape discrimination (PSD) scintillators. It offers several very distinguishing features i.e. compactness, real time signal processing, ability to filter pulses by energies and PSD values, robust pileup rejection, control over charge collection times, and ability for independent calibration of neutron energies from the rest of the pulse height distributions. We present a study of the performance of the nanoPSD device with a set of important PSD scintillators (Stilbene, newly developed by LLNL plastic PSD materials, and CLYC).  nanoPSD is evaluated at high count rates, several energy regions of interest, several shaper duration times and their effect on count rate performance and PSD figure of merit. Also, we examine the rate of misclassification of gammas as neutrons (mainly due to undetected pileups) and how the pileup rejecter parameters affect this.

Keywords: PSD, Pulse Shape Discrimination, Real Time Signal Processing, Fast Neutron Measurements
Poster panel: 219

Poster Number:
N-07-219

Monte Carlo simulation study for a real-time gamma ray/neutron dual-particle coded-aperture imager (#1112)

M. Jeong1, B. T. Wells2, L. J. D’Aries3, M. D. Hammig1

1 University of Michigan, Nuclear Engineering and Rad. Sci., Ann Arbor, Michigan, United States of America
2 Galt Research LLC., Ypsilanti, Michigan, United States of America
3 US ARMY , Armament, Research, Development & Engineering Center , Picatinny Arsenal, New Jersey, United States of America

Content

The aim of this work is to develop a real-time gamma-ray/neutron dual-particle imager based on a coded aperture for application to general radiation characterization but focused on nuclear security and safeguards. A Monte Carlo simulation study is performed to design a coded aperture imaging system for dual-particle imaging, and modified uniformly redundant array (MURA) patterns were obtained for gamma-ray and neutron sources in various configurations. We applied image reconstruction algorithms utilizing the maximum likelihood expectation maximization (MLEM) method and a compressed sensing (CS) method that implemented the analytical modeling of various source-to-detector configurations to the Monte Carlo simulation results. Both gamma ray and neutron source distributions were reconstructed and evaluated in terms of signal-to-noise ratio, showing the viability of developing a coded aperture based gamma-ray/neutron dual particle imager using large area silicon-photomultiplier (SiPM) arrays.

Keywords: gamma-ray/neutron dual-particle imager, coded-aperture imaging system
Poster panel: 221

Poster Number:
N-07-221

Development of the symmetric neutron grating interfometer for highly sensitive phase contrast imaging and SANS related dark-field contrast imaging (#1211)

Y. Kim1, J. Kim2, D. Kim1, S. Lee1, O. Oh1, D. S. Hussey3, S. W. Lee1

1 Pusan National University, Nuclear system department/Mechanical engineering school, Busan, Republic of Korea
2 Korea Atomic Energy Research Institute, Research Reactor Utilization & Development Department/Neutron Science Center, Daejeon, Republic of Korea
3 National Institute of Standards and Technology, Neutron Physics Group, Gaithersburg, Maryland, United States of America

Content

This paper describes a symmetric neutron grating interferometer for highly sensitive phase contrast imaging and SANS related dark-field contrast imaging. The system was a symmetric Talbot-Lau interferometer consisting of a source grating, a phase grating, and an analyzer grating. The interferometer was installed at the cold neutron imaging instrument on NG6 of the National Institute of Standards and Technology Center for Neutron Research. For phase contrast imaging, using gratings with periods of 36 μm, the interferometer showed maximum phase sensitivity of 102.27 mm/μm. The phase contrast of metal and silicon samples was acquired, and alkaline/lithium ion batteries were imaged for application research. The grating interferometer with periods of 80 μm for the dark-field imaging provided an autocorrelation length of 27.5 nm when a sample to detector distance is 5 mm at a wavelength of 4.4 Å. The dark-field image of polystyrene particles was acquired, and it gave a minimum detection level of particle size below 1 μm, which is unseen previously. For its application, a 3D printed metal, an animal bone, and an industrial ceramic were also imaged.

Keywords: neutron, grating interferometer
Poster panel: 223

Poster Number:
N-07-223

A post pulse processing technique using dual time-over-threshold to estimate energy and decay time for scintillation detectors (#1515)

R. Ota1, 2

1 Hamamatsu Photonics K. K., Central Research Laboratory, Hamamatsu, Japan
2 University of Fukui, Faculty of Engineering, Fukui, Japan

Content

I developed a new method, which can extract both energy and decay time of a signal from a scintillation detector using two time-over-threshold (ToT) information, and referred it as dual-ToT. In a previous work, the dual-ToT method successfully extracted both the energy and the decay time although one issue, the method will degrade the energy resolution in a high energy region, was remained. In this work, I modified the dual-ToT method and propose a dual-ToT based post pulse processing technique to avoid the issue. The modified dual-ToT method was validated by measurements of the decay time and the energy of a phoswich detector, which consists of two fast scintillators, i.e. a 3×3×10 mm3 LYSO and a 3×3×10 mm3 plastic scintillator (Saint-Gobain, BC-408), with a 22Na point source. A 3×3 mm2 multi pixel photon counter (Hamamatsu Photonics, S13360-3050) was optically attached on the end surface of the plastic scintillator. As a result, the energy resolution obtained from the modified dual-ToT method at 511 keV was approximately better than that of the normal dual-ToT method by a factor of two. Moreover, separation of the two fast scintillators was clearly observed and a capability of the modified dual-ToT method as a phoswich detector was demonstrated. Thus, the modified dual-ToT method was validated. Moreover, these results revealed a potential capability of discrimination of neutrons and gamma-rays because the decay time constants of the neutron and the gamma-ray events are different from each other.

Keywords: time-over-threshold, phoswich detector
Poster panel: 225

Poster Number:
N-07-225
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Imaging of Actinide Nuclides using Neutron Resonance Absorption (#1715)

T. Sano1, D. Ito1, J. - I. Hori1, Y. Takahashi1, J. Lee1, N. Abe1, K. Nakajima1

1 Kyoto University, Institute for Integral Radiation and Nuclear Science, Sennan-gun, Japan

Content

In order to reduce the high-level radioactive waste from nuclear power plants, a fast reactor system with trans-uranium (TRU) fuel is one of the option for nuclide transmutation technique. To establish the fast reactor system with TRU fuel, identification and quantification of the nuclides in the TRU fuel are required to regard safety and nuclear security. A non-destructive assessment method for a TRU fuel with high decay heat and high radioactivity is required. The neutron resonance absorption (NRA) imaging would be applicable to non-destructive assay of the TRU fuel with high radioactivity. In the present study, the NRA imaging with a 2-D position sensitive detector was applied to identify 238U, 237Np and 243Am as samples. As the results, nuclide identified imaging was carried out successfully.

Keywords: 2-D position sensitive detector, identification, minor actinide, neutron resonance absorption imaging, pulsed neutron beam
Poster panel: 227

Poster Number:
N-07-227

Characterisation of a pixelated plastic scintillator for a coded aperture neutron/gamma imaging system (#1812)

M. Cieslak1, K. A. Akurugoda Gamage2

1 Lancaster University, Engineering Department, Lancaster, United Kingdom
2 University of Glasgow, School of Engineering, Glasgow, United Kingdom

Content

This paper investigates, experimentally, the suitability of an organic pixelated plastic scintillator for a coded aperture neutron/gamma imaging system. The scintillator used in this study has been designed as a small scale detector with an individual pixel size of 2.8 mm x 2.8 mm x 15 mm. Individual blocks of the scintillator have been separated from one another with ESRTM reflector foil to provide over 70% of optical isolation between pixels. Individual scintillator cells are arranged into 13x13 array with overall dimension of 39.52 mm x 39.52 mm. In this study the scintillator was attached to a single channel photomultiplier tube to assess its pulse shape discrimination capabilities. Initially the scintillator was irradiated with 137Cs gamma-ray source and gamma-ray pulses were benchmarked to mathematically model its pulse generation capabilities. The detector was then irradiated with a spontaneous fission source, 252Cf and preliminary results suggested poorer pulse shape discrimination performance of the scintillator when compared to a cylindrical plastic scintillator block (25.4 mm x 25.4 mm). It is believed, that it is the first time a small scale pixelated organic plastic scintillator has been tested in context of PSD capabilities for a coded aperture neutron/gamma imaging system.

Keywords: Organic plastic scintillator, Photo-multiplier tube, Pulse shape discrimination, Neutron detectors, Gamma detectors
Poster panel: 229

Poster Number:
N-07-229

Development and Characterization of a Triple PSD Heterogeneous Lithium Glass Shards/Polyvinyl Toluene Composite for Neutron Detection (#2234)

A. Foster1, A. Meddeb2, M. Wonders2, M. Flaska2, I. Jovanovic3, Z. Ounaies1, 3

1 The Pennsylvania State University, Intercollege Graduate Degree Program (IGDP) in Materials Science and Engineering (MATSE), University Park, Pennsylvania, United States of America
2 The Pennsylvania State University, Department of Mechanical and Nuclear Engineering, University Park, Pennsylvania, United States of America
3 University of Michigan, Department of Nuclear Engineering & Radiological Sciences, Ann Arbor, Michigan, United States of America

Keywords: triple PSD, composite, neutron detector, polyvinyl toluene, lithium glass
Poster panel: 231

Poster Number:
N-07-231

Poster panel: 233

Poster Number:
N-07-233

Quality control of nuclear fuel plates using the radioactivity emission and transmission methodology (#2658)

C. H. Mesquita1, A. F. Velo1, D. V. S. Carvalho1, M. M. Hamada1

1 IPEN/CNEN-SP, CTR, Sao Paulo, Brazil

Content

This work reports the development of a technology for the quality control of nuclear fuel plates used in research reactors and for production of radioisotopes generated by neutron reactions. In the IEA1 reactor of the Nuclear and Energy Research Institute (IPEN), Uranium nuclear fuel plates enriched at 20% of 235U have been used. These aluminum plates have 484 x 80 x 1 mm3 (length, width, thickness) dimensions and are designed to contain 235U nuclear fuel. Ideally, nuclear fuel plates should have 235U uniformity across the entire plate to avoid gradients of overheating in anomalous regions on the fuel plates. The data analysis were obtained simultaneously by emission and transmission scanning method, measuring the gamma radiation of 185 keV (yield of 54%) emitted by the 235U and the radiation transmitted by an external source of 192Ir in the photopic of 317 keV. Two 40 mm diameter NaI(Tl) detectors were aligned and coupled with 50 mm thick collimators and 2 x 2 mm2 septa were positioned on a fuel element plate. The radioactivity measurements were performed using a multi-channel type system and scanning the plate every 2 mm in the lateral direction. At each position of the detectors, measurements of the radioactivities of the 192Ir and 235U sources were carried out for 6s. After the 80 mm lateral advance, performed in 40 steps, the system advances 2 mm in the direction of the length (484 mm) of the fuel plate and restarts the lateral scan in the 80 mm width direction until it reaches the full length of the fuel plate. This quality control technology allows knowing the uniformity of the thickness of the fuel plate and the uniformity of the 235U distribution in it.

Keywords: control quality, multichannel, nuclear fuel plate
Poster panel: 235

Poster Number:
N-07-235

Additive Point Source Localization (#2769)

T. H. Y. Joshi1, D. Hellfeld2, M. S. Bandstra1, R. J. Cooper1, K. Vetter2

1 Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, California, United States of America
2 University of California, Department of Nuclear Engineering, Berkeley, California, United States of America

Content

Gamma-ray imaging attempts to reconstruct the spatial and intensity distribution of gamma-emitting radionuclides from a set of measurements. This technique is employed for activities ranging from medical imaging to nuclear security. In many cases this problem solved by discretizing the spatial dimensions and employing some variant of the Maximum Likelihood-Expectation Maximization (ML-EM) algorithm. While the generality of this formulation enables use in a wide variety of scenarios, it is also susceptible to overfitting and limited by the discretization of spatial coordinates. We present a novel approach to gamma-ray image reconstruction for scenarios where sparsity may be assumed, for example radiological source search. In this work we formulate point-source localization as an optimization problem where both position and intensity are continuous variables. We then extend this formulation and describe an iterative algorithm, additive point-source localization (APSL), for sparse image reconstruction. Finally, we consider a set of simulated source search scenarios and compare APSL with ML-EM in terms of image quality and computational efficiency, finding improved accuracy and reduced computational burden with APSL.

Keywords: Radiological source search, gamma-ray imaging
Poster panel: 237

Poster Number:
N-07-237

Neutron Multiplicity Measurement of the U/TRU/RE Ingot produced from Pyroprocessing (#1143)

J. Jeon1, C. J. Park1, G. Kim1

1 Sejong University, Nuclear Engineering Department, Seoul, Republic of Korea

Content

The Republic of Korea places high priority on the pyroprocessing and sodium-cooled fast reactor research in its nuclear R&D project. In this light, ‘next generation’ equipment to verify the related demonstration facilities and material therein should be designed in the near future. The mass of fissile isotopes in the material is of great interest for the purpose of nuclear safeguards and neutron multiplicity measurement is one of non-destructive methods to account for the mass.

The neutron multiplicity was calculated for the U/TRU/RE (uranium, transuranium and rare earth elements) ingot produced from pyroprocessing with MCNP6.1. code. The neutron multiplicity was measured by passive and active method with four stilbene scintillators, instead of He-3 tube which is used for conventional neutron coincidence counters.

From the T card of MCNP, appropriate predelay length and gate width for passive and active multiplicity measurement were suggested. The window length of stilbene detector (~ns) showed shorter length compared with those with He-3 tube (~μs), which stems from the capability of stilbene detector to count fast neutron without any moderation. The passive and active neutron multiplicity distribution from the PTRAC output showed slightly higher probability of neutron coincidence (v≥2) in active counting than passive counting. This result is attributed from the self-multiplication effect within the volumetric target which contains a significant amount of fissile material. This preliminary study demonstrated neutron multiplicity distribution of the material with complex composition and provided useful information for the real measurement in the future.

Poster panel: 239

Poster Number:
N-07-239

Localization of fuel debris in damaged nuclear power plants such as Fukushima Daiichi using fission chambers (#1385)

A. Sari1, K. Boudergui1, F. Carrel1, R. Coulon1, J. Dumazert1, C. Frangville1, H. Hamrita1, M. Trocmé1, C. Thiam2, B. Krausz3, R. Pissarello3, R. Delalez3

1 CEA List, Sensors and Electronic Architectures Laboratory, Gif-sur-Yvette, France
2 CEA List, Henri Becquerel National Laboratory, Gif-sur-Yvette, France
3 ONET TECHNOLOGIES, Nuclear Decommissioning, Pierrelatte, France

Content

In the event of a severe accident occurring at a nuclear power plant, loss of reactor cooling systems could potentially lead to core meltdown. In those circumstances, water would be injected in emergency to limit damage. Three units of the Fukushima Daiichi nuclear power plant encountered such situations in March 2011. Years later, dismantling operations must be preceded by localization of fuel debris. Visual inspections can be carried out with video cameras. However, it is not sufficient to distinguish accurately fuel debris from other materials with high level of confidence. Radiation measurements are then of major interest in addition to visual inspection as fuel debris emit both neutrons and gamma-rays. However, volatile fission products such as 137Cs are strong gamma-ray emitters. Therefore, neutrons represent a reliable signature of presence of fuel debris. At Fukushima Daiichi, neutron detectors should be able to operate in water. Moreover, measurements might be constrained by a thick sediment layer on top of fuel debris. Fission chambers are the most adapted neutron detectors to perform such measurements thanks to their high sensitivity to neutrons, insensitivity to gamma-rays, and waterproof properties.

In this paper, we evaluate performances of fission chambers to locate fuel debris in a damaged nuclear reactor by Monte-Carlo simulation using the MCNP6 code. First, we develop a fuel debris model based on the state of the art. Secondly, we characterize the neutron flux emitted by fuel debris in a water environment. Impact of water temperature has been evaluated. Thirdly, we show that fission chambers enable to locate fuel debris using a simplified model of the primary containment vessel of Fukushima Daiichi Unit 1. The CFUF34 fission chamber made by PHOTONIS was chosen to carry out this study. Impact of fission chamber rotation during measurements has been evaluated. Measurement sensitivity loss due to sediments covering fuel debris has also been estimated.

Keywords: Fuel debris, Fission chamber
Poster panel: 241

Poster Number:
N-07-241

New liquid scintillation counter development using silicon photomultipliers (#1426)

D. Maire1, C. Laconici1, R. Vidal1

1 Institute for Radiation protection and Nuclear Safety (IRSN), PSE-EN / SAME / LMN, Le Vesinet, France

Content

The French Institute for Radiation protection and Nuclear Safety (IRSN) is developing fast on-site measurement methods to estimate environmental samples radioactivity in case of a nuclear accident. In that case, a radioactivity level estimation is expected in a few hours for environmental samples. Usually long chemical preparations are required prior to measurements but they are too intricate to be considered for on-site measurements. Liquid scintillation counting is a rapid technique to directly measure alpha and beta activity in aqueous samples. But available commercial LSC are too heavy and fragile to be used outside a laboratory.

The IRSN chose to develop their own LSC to be used in its mobile laboratories. The main objective was to develop a robust, light, small and easy-to-handle LSC taking into account quenching effects, able to measure energy spectrum, and discriminating alpha and beta particles. Liquid scintillation counters (LSC) are usually composed of two photomultiplier tubes (PMT) surrounded by lead shielding. In order to get a smaller and more robust LSC, PMT were replaced by HAMAMATSU Multi-Pixels Photon Counters (MPPC®), also called silicon photomultipliers (SiPM). The inconvenient of MPPC is their high dark noise compared to PMT which lead to a lower sensitivity for low energy beta emitters. But for our purpose, beta emitters of interest have high enough energies to be detected (e.g. 90Sr with a beta mean energy of 195.7 keV).

The current detector geometry will be described. First tests were performed with MPPC S13360-3050CS and S13360-3025CS to prove the measurement capabilities of such detectors: with or without lead shielding, with a gamma source, with alpha and beta emitters. A 14C standard, alpha and beta sources measurements were performed and gave a counting efficiency of a few percent. Thus such a technology is suitable for our purpose.

Keywords: liquid scintillation, alpha
Poster panel: 243

Poster Number:
N-07-243

Development of a Measurement Condition Check System Using a Semiconductor Laser for a Fiber Optic Radiation Monitor (#1527)

T. Tadokoro1, S. Hatakeyama1, K. Ueno1, Y. Ueno1, K. Sasaki2, Y. Sakakibara2, T. Shibutani2, T. Ito2, K. Nebashi3, M. Koyama3

1 Hitachi, Ltd., Research & Development Group, Hitachi, Japan
2 Hitachi, Ltd., Control System Platform Division, Hitachi, Japan
3 Hitachi-GE Nuclear Energy, Ltd., Control & Instrumentation Design Sec, Hitachi, Japan

Content

Fiber optic radiation monitors are promising dosimetry devices for remote and real time radiation monitoring in nuclear power plants. However, since workers cannot approach the detection area while the reactors are in operation or during a severe accident, it is not possible to check whether or not the monitors are working normally. The focus of this presentation is on the design and experimental results of a prototype measurement condition check system which can carry out operation checks from a remote position. The transmission performance for the optical fiber of light with a wavelength less than 800nm suddenly decreases when the optical fiber is irradiated at a high dose (over 1MGy), thus we chose a neodymium-doped yttrium aluminum garnet crystal (Nd:YAG) as a light emission element for the radiation monitor which emits light with the wavelength of 1064nm, and we also chose a semiconductor laser with the wavelength of 808nm for the measurement condition check system. We fabricated a prototype system and evaluated its performance. Counting rate of 1064nm photons is proportional to the irradiation laser power in the range of about seven columns, and when we irradiate a laser with the same strength, the increase of the photon counting rate is independent of the dose rate. Thus, this system is able to not only check the measurement condition of the monitor, but also calibrate the monitor while it is operating.

Keywords: Radiation monitor, Optical fiber
Poster panel: 245

Poster Number:
N-07-245

Atomic Number Reconstruction Using Multi-MeV X-ray DECT in Concrete Drums (#1541)

L. Tamagno1, C. Eleon1, N. Estre1, S. Plumeri2, D. Tisseur1

1 CEA Cadarache, DTN/SMTA/LMN, Saint-Paul-Lez-Durance, France
2 ANDRA, Chatenay-Malabry, France

Content

The DECT technique consists in two distinct X-ray tomography measurements using sources with different energy spectra, and allows an estimation of both the density and the effective atomic number (Zeff) of the tested material. The present paper develops a methodology to extract Zeff of objects inside large concrete drums using DECT technique with multi-MeV X‑ray, for the needs of nuclear waste drums inspection. The X‑ray source is a LINAC which can deliver output electron energy from 6 MeV to 20 MeV. An appropriate definition of the energy-dependent effective atomic number of a compound material is established for this particular measurement, it is determined via tabulated X‑ray cross-sections. The choice of the two energy sources as well as the effect of the source filtering on the Zeff reconstruction accuracy is discussed. The proposed algorithm of Zeff extraction is based on the ratio of the two tomography images. It consists in an interpolation of the theoretical relationship between Zeff and this ratio, calculated using tabulated X-ray cross-sections, knowing the energy of both sources. An effective energy for each of the two sources is estimated as a function of the radial position of the object inside the drum, based on the experimental profile of concrete. This algorithm was tested by simulation, using the CEA code MODHERATO. The code generates tomography images of an object inspected, from the description of the object material, source (especially its energy spectrum) and detector response as a function of energy. The simulation accounted for materials of different categories (solvents, plastics, metals) blocked into a concrete matrix. Very good Zeff reconstruction is achieved (discrepancy below one) for materials with Zeff<40. However, the method becomes relatively imprecise for heavy materials (metals). Based on the present results, this method could help classify inspected objects into pre-defined categories (solvents, metals, etc.).

Keywords: DECT, Effective atomic number
Poster panel: 247

Poster Number:
N-07-247

A new model to predict Fission Product diffusion & release in (Pu,U)O2  matrix for SFR clad failure detection  (#1982)

S. Garti1, J. Dumazert1, R. Coulon1, P. Filliatre2, C. Jammes2, A. Sari1

1 CEA , Essonne, Gif-sur-Yvette, France
2 CEA, Cadarache, S-Paul-lez-Durance, France

Content

The matter of clad failure detection through the monitoring of fission products that may be released in the heat transfer fluid appears to be a major concern for generation IV SFR (“Sodium Fast Reactor”). It is all the more so with the next French industrial demonstrator ASTRID..

In fact, the early detection of any clad failure and the prediction of the fraction of released isotopes will contribute to reinforcing the safety of SFR. This work,  initiated by the CEA, describes a model of rapid spectrum gas fission behavior, from their production and diffusion in the fuel, to their release through different clad failure scenarios. The quantification and prediction of gas behavior is an important subject. It helps developping an appropriate instrumentation for monitoring them in real time. Consequently, it could prevent an accidental situation. This modeling follows several steps:

  • Creation and diffusion of fission products in the fuel
  • Accumulation in the free space (space between pellet and clad and the expansion vases)
  • Release into the heat exchanger fluid

First, an evolution code under a neutron fast flux (2.06 1014 n/cm2/s) has been performed in order to characterize the source term. Then, our research, based mostly on the empirical model derived by Turnbull, consider the effects of gas migration induced by temperature and by irradiation for SFR. Also, several parameters such as the quadratic variation of the radial temperature of the combustible pellet are taken into account in this model.

Finally, our model evaluates the number of gas fission atoms in the expansion vases and empty space (coming from isotope’s creation, radioactive decay and diffusion) when the clad is safely sealed. In cases of failures, our research is to establish what proportion of atoms will be released into the heat transfer fluid and according to which kinetics. We consider several clad failure scenarios and especially the dimension of the leak.

Keywords: SFR, ASTRID, Nuclear instrumentation & simulation, clad failure, safety
Poster panel: 249

Poster Number:
N-07-249

First images from a CeBr3 /LYSO:Ce Temporal Imaging portable Compton camera at 1.3 MeV (#2176)

A. Iltis1, M. Z. Hmissi2, C. Tata Zafiarifety1, G. Zeufack Tadonkeng1, L. Rodrigues1, B. Mehadji3, C. Morel3, H. Snoussi2

1 Damavan Imaging, Rosières près Troyes, France
2 University of Technology of Troyes, Troyes, France
3 Aix-Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France

On behalf of TEMPORAL-Collaboration

Content

During nuclear decommissioning or waste management operations, there is a need for imaging the contamination field while identifying and quantifying the contaminants. Our objective is to test a Compton camera within the energy range 300 keV-2 MeV that uses both light and timing distribution of fast scintillating monolithic crystals. In this experiment we use a 5 mm thick CeBr3 scatterer plate and a 20 mm thick LYSO absorber plate. Our algorithms record for each scintillation event the full position and energy of the event including DOI, even in the thin plate and the relative timing between the detection in the two plate. Our CRT was measured at 293 ps FWHM in coincidence mode without DOI correction. This good time resolution allows for a stringent veto on real Compton event that must be recorded simultaneously in both the scatterer and the absorber plates, thus reducing background very efficiently. Acquisitions were performed with a Phillips Digital Photon Counter SiPM 3200 matrix with a delay-time correction map applied pixel by pixel. After accurate detection of gamma interaction coordinates (x,y,z) and energy in each plate, a list-mode maximum likelihood iterative reconstruction algorithm is applied to better estimate the gamma source activity distribution. Our Compton camera is a promising device for imaging high energy gamma rays, moreover, it can be also suitable for on-line monitoring due to its timing performance.

The project TEMPORAL is funded by the ANDRA/PAI under the grant No. RTSCNADAA160019.

Keywords: Temporal Imaging, Compton camera, monolithic crystal, VETO
Poster panel: 251

Poster Number:
N-07-251

Nondestructive Assessment of Transportation Fuel Cask using Time-Tagged Neutron Interrogations (#2771)

Z. Liu1, J. George1, L. - J. Meng1, 3

1 UNIVERSITY OF ILLINOIS at Urbana-Champaign, Department of Nuclear, Plasma and Radiological Engineering, Urbana, Illinois, United States of America
2 UNIVERSITY OF ILLINOIS at Urbana-Champaign, Beckman Institute for Advanced Science and Technology, Urbana, Illinois, United States of America

Content

For most nuclear reactors under operation in the U.S., the spent nuclear fuels which will be discharged at the end of their fuel cycle can still produce non-negligible heat as well as radiation. These spent fuels will be stored in casks and shipped from reactor sites to away-from-reactor storage or reprocessing plants. To meet the radioactivity shielding and heat dissipation requirements, metal casks are chosen as a major solution and have been playing an increasing important role in these transportation services over the past decades. During the transportation, partial defects may exist inside the casks such as missing or dislocation of the fuel rods, or other large mechanical defects. Thus, the verification of the interior of the sealed cask is very important. However, the cask materials’ shielding property makes this monitoring application a challenging task. Non-destructive evaluation (NDE) can offer a potential way of reconstructing the cask from the radiation intensity profiles measured. In this study, a Monte Carlo simulation by Geant4 for NDE of spent fuel casks transportation based on an associate-particle neutron generator (APNG) and time-tagged neutron interrogation techniques was carried out. The penetrated and back scattered neutrons’ and the characteristic prompt gamma rays’ analyses were employed to assess the potential defects in transportation of the casks. In detail, this simulation modeled the D-T neutron generator’s beam profiles, a realistic transportation fuel cask, and various detector layouts for the detection of particles emerging from the surface of the metal cask. The timing and energy information of these signals will be studied to indicate the interior of the spent fuel cask. We will simulate various abnormalities scenarios that could potentially happen during the transportation of the spent fuel casks, and the feasibility of using the time-tagged neutron interrogations for nondestructive assessment of spent fuel casks.

Keywords: NDE, Time-Tagged Neutron Interrogation Techniques, APNG, spent fuel cask transportation
Poster panel: 253

Poster Number:
N-07-253

Advanced Detectors for Gross Gamma and Neutron Measurements of Spent Fuel (#2908)

K. Ianakiev1, M. L. Iliev1, M. C. Browne1, A. M. LaFleur1

1 Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, United States of America

Content

Spent Fuel measurements using 235U thermal neutron fission chamber and gamma DC Ionization Chamber is very robust and widely used technology for decades.  While most of the recent ionization chamber work was focused on the calibration and coping with the shortcoming of the existing detectors not too much effort was invested on improvement of the radiation sensors itself and overcoming non-linearity and recombination effects. Similarly, difficulties in transporting radioactive 235U fission chambers motivated efforts to replace them with 10B lined proportional counters, but not much work was done on improving the 10B detectors’ gamma tolerance.

In this paper we will discuss the historical prospective current status of the detection technology and will report a new 10B lined proportional counter with redesigned electrodes capable to operate without shielding at gamma field in order of tens to thousand R/h . The detector is incorporated in standalone sensor with dual neutron and gamma readout. Design aspects, efficiency calibration and characterization at mixed neutron and gamma field will be presented.

We have found the root cause of non-linearity in LND DC ionization chambers to be the construction of the detectors (they use thin anode wire typical for proportional counters). I-V plots for the typical LND gamma chambers will be presented along with recommendation for operation voltages.

Keywords: U-235 Fision Chamber replacement, gamma tollerant B-10 lined counter, gamma DC ionization cnambers nonlinearity, grosss gamma and neutron measuremenst with one B-10 lined detetcor, B-10 neutron Thruster
Poster panel: 255

Poster Number:
N-07-255
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Single Electron Generation and Its Imaging and Counting Using Microchannel Plate (#1748)

K. Ueno1, T. Iida2

1 High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki , Japan
2 University of Tsukuba, Tsukuba, Ibaraki, Japan

Content

Generation of the low energy single electron with the energy of the order of 0.1 – 1 eV and its detection with high precision are useful for the applications in the nuclear and high energy physics. Based on this situation, we have developed the compact electron generator consisting of the ultra-violet source and the target with low work function and its detection system using MCP, step by step. In order to confirm the scheme, we have developed the simple system which is composed of copper wire and Xe flash lamp as the generator and delay-line readout MCP assembly as the detector. Using this setup, we have confirmed to obtain the electron image and spectrum. To improve the system, we have developed the new electron generator consisting of UV LED and the target with lower work function and some MCP assemblies and those readout systems. In this presentation, we will report the details of the development of the single electron generator and MCP system and test results. Then the current status of the new system is described. The prospect is also presented.

Keywords: MCP, UV, single electron
Poster panel: 257

Poster Number:
N-07-257

The High-performance DIRC Detector for the Future Electron Ion Collider Experiment (#1781)

G. Kalicy1

1 The CUA University, Nuclear Physics, Washington, DC, Washington, United States of America

Content

Excellent particle identification (PID) is an essential requirement for a future Electron-Ion Collider (EIC) detector. Identification of the hadrons in the final state is critical to study how different quark flavors contribute to nucleon properties. A detector based on the Detection of Internally Reflected Cherenkov light (DIRC) principle, with a radial size of only a few cm, is a great solution for those requirements. The R&D process performed by the EIC PID consortium (eRD14) is focused on designing a high-performance DIRC that would extend the momentum coverage well beyond the state-of-the-art. A key component to reach such a performance is a special 3-layer compound lens. The status of the High-Performance DIRC R&D for the EIC detector will be presented, with a focus on the detailed Monte Carlo simulation results and performance tests of two 3-layer lens prototypes.

 

Keywords: DIRC, Cherenkov detectors, RICH, EIC, detectors
Poster panel: 259

Poster Number:
N-07-259

A study on the influence of electric field on dark noise in SiPMs for radiation detection applications (#1296)

K. T. Lim1, H. Kim2, M. Kim1, G. Kim1, K. Park1, E. Lee1, J. Kim1, J. Kim1, J. Hwang1, W. Kim1, G. Cho1

1 Korea Advanced Institute of Science & Technology (KAIST), Nuclear and Quantum Engineering, Daejeon, Republic of Korea
2 Korea Atomic Energy Research Institute, Daejeon, Republic of Korea

Content

In this paper, we investigate the degree to which the electric field developed within the depletion region can influence the primary dark count rates (DCRs) via thermal generation of carriers enhanced by the trap-assisted tunneling (TAT) mechanism. The purpose of this study is to highlight the significance of internal structure engineering in reducing the DCR for a target radiation detection application under the given, but limited, fabrication conditions. To study the influence of electric field in the DCR, we fabricated silicon photomultipliers featuring different electric field profiles in the identical device layouts and under the identical fabrication environments. By measuring the DCR as a function of temperature, we found the activation energy of the DCR (EA) based on the Arrhenius plot. This parameter proved to be useful in demonstrating the effect of the field-enhanced mechanism contributing to the DCR quantitatively. With a reduction of approximately 10% in the peak electric field, we were able to show that the DCR was decreased by a factor of four at room temperature and that EA was increased from 0.43 eV to 0.51 eV, approaching the expected value of Eg/2. Through electric field engineering, we demonstrate its effectiveness in weakening the influence of the TAT contributing to the DCR. Furthermore, we address some drawbacks due to the trade-off relationship between the reduction in the electric field and various SiPM parameters to discuss its feasibility in terms of radiation detection applications.

Keywords: Silicon photomultiplier; SPAD; dark count rate; activation energy
Poster panel: 261

Poster Number:
N-07-261

The Study on the Temperature Effect of Small Photoelectronic Devices (#1468)

L. Ma1, 2, S. Qian1, G. Huo3

1 Institute of High Energy Physics, Chinese Academy of Science, Beijing, China
2 North China University of Technology, Beijing, China
3 Harbin Institute of Technology, Harbin, China

Content

The purpose of this paper is to study the temperature effects of several small optoelectronic devices, and to provide basis for the use of small optoelectronic devices in different environments. The semiconductor thermostat is used to control the temperature of the small photoelectric devices, and the accuracy reaches 0.1 ℃, so as to realize the accurate measurement of the various properties of the devices. The performance of LED, LD, MPPC, PD and small PMT is studied in the range of -40℃ to 40℃.

Keywords: Temperature Effect, Photoelectronic Devices
Poster panel: 263

Poster Number:
N-07-263

Evaluation of the  Newest SiPM from SensL and Hamamatsu for Energy and Time Resolution When Coupled to LYSO, CeGAG, PrLUAG and Other Scintillators (#2292)

M. García-Díez1, V. Sanchez-Tembleque1, L. M. Fraile1, 2, J. M. Udias1, 2

1 Universidad Complutense de Madrid, Grupo de Fisica Nuclear and UPARCOS, CEI MONCLOA, Madrid, Spain
2 Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain

Content

SiPM are commonplace in radiation detection for nuclear physics experiments and nuclear imaging. New models appears every few months and  their evaluation becomes mandatory. SensL and Hamamatsu have recently introduced new series of their well-known SiPM with enhanced photon detection efficiency due to higher packing fraction. On the other hand recent scintillators are being available in addition to LYSO or LSO which have been used in countless PET scanners during last years. PrLUAG and CeGAG are of interest, the first one due to its faster decay time and possible better timing properties than LYSO, the second for its increased photon yield and better energy resolution. As PrLuAG has a peak emission at 310 nm, it would test the lower end of the spectral sensitivity of the SiPMs. Several combinations and sizes of these three scintillators are evaluated alongside with three SiPMs from Hamamatsu: S13360-3050CS, S13360-6050CS, S13360-6075CS, and two from SensL: the former  MicroES-SMA-30035TSV and the recent MicroFJ-SMA-60035. The results of these five SiPM coupled to PrLuAG, CeGAG and LYSO show the improvement in PDE and thus energy resolution and timing capabilities of the most recent SiPMs with regards to just one year ago (around 10%) . With the larger crystals employed here (10x10 mm2 cross-section and 10 to 30 mm height), resolutions of 8% (CeGAG), 10% (LYSO) and 16% (PrLuAG) can be obtained with the best SiPM combination (usually the  S13360-6075CS) . In this case eneegy resolution is limited by the loss of light due to the difference in cross-sections of the SiPM (6x6 mm2 or 3x3 mm2) and crystals. On the other hand,  LYSO crystals of 5x5x15 mm3 provided improved energy and time resolutions. Several combinations of SiPM and scintillator produced timing resolutions  below 250 ps  (FWHM, CRT) in this case with the newest SensL SiPM yielding the best results, thanks to its dedicated fast timing output.

 

Keywords: SiPM, Scintillator, CeGAG, LYSO, CsI
Poster panel: 265

Poster Number:
N-07-265

In-pixel Low-Threshold Comparator for Improved Timing-Resolution Digital SiPM (#2382)

A. Sachdeva1, E. Venialgo1, E. Charbon2

1 TU Delft, EEMCS, Applied Quantum Architectures, Delft, Netherlands
2 EPFL, STI IMT AQUA , Neuchâtel, Neuchâtel, Switzerland

Content

Coincidence resolving time (CRT) accuracy in time-of-flight (TOF) Positron Emission Tomography (PET) determines the signal-to-noise ratio (SNR) in interactive image reconstruction algorithms. In PET detectors, the photosensor’s single-photon timing resolution (SPTR) influences the coincidence resolving time (CRT by adding an uncertainty to the single photoelectron time-of-arrivals. This effect can be modelled as the convolution of the scintillation pulse shape function and the total photosensor jitter at single-photon level, before following an order statistics process. Particularly in Cherenkov-based PET detectors, SPTR has a direct impact on the CRT due to the low number of detected photons. This paper describes the implementation of in-pixel/SPAD-cell low-threshold comparator that improves SPTR at the pixel level, since it allows to detect the photoelectron-triggered avalanche as soon as possible, thus minimizing statistical fluctuations. We analyzed the tradeoffs between comparator performance and in-pixel area occupation. The comparator design is based on an ultra-low power architecture; consequently, large arrays of SPAD cells with dedicated comparator can be envisioned in digital silicon photomultiplier (D-SiPM) with improved SPTR. We present full post-layout simulation results for the different pixel/SPAD-cell implementations and comparator architectures. The implemented pixels contains the SPADs, the comparators, and the required operating electronics such as masking circuits. Additionally, the pixels are implemented on a 180 nm CMOS technology optimized for photon detection efficiency (PDE) and dark count rate (DCR).

Keywords: TOF-PET, SPAD Pixel, SPTR, Comparator, timing resolution
Poster panel: 267

Poster Number:
N-07-267

Laser-based scintillator crystal emulator for optical testing of SiPM readout technologies (#2418)

R. Bellini1, G. L. Montagnani1, 2, C. E. Fiorini1, 2, M. Carminati1, 2

1 Politecnico di Milano, Politecnico di Milano, milano, Italy
2 INFN, milano, Italy

Content

In most SiPM-based gamma detection technologies, it is important to precisely characterize both the optical sensor’s light response and the interfaced electronics readout performances. Traditional setups, involved in this procedure, are based on radioactive gamma sources, with a-priori known energy spectra, used to perform both an accurate characterization of SiPM non-linearity and a calibration of the acquisition system. However, several disadvantages affect these techniques, such as the low versatility and the need of using also highly energetic radioactive sources, in order to perform a correct calibration procedure. Moreover, high energy range (e.g. up to 20MeV) is very unpractical to explore with radioactive sources or beam tests. A possible alternative consists in a pulsed light source setup, emulating the behaviour of different source-crystal couplings and directly interfaced with the optical sensors. Purpose of this work is the development of an electro-optical device, generating light flashes with tuneable intensity and duration: the former ranges from few units to hundreds of thousands of photons, the latter can be set in order to be comparable to that of common scintillation events. A further specification consists in the optical power stability over time and temperature: a closed loop control system has been designed, based on a microcontroller performing a real time modulation of the light source driving current.

Keywords: laser, sipm, emulator, characterization, scintillators
Poster panel: 269

Poster Number:
N-07-269
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Development of Radiation-Hard Scintillators and Wavelength-Shifting Fibers (#1027)

B. Bilki1, 2, Y. Onel1, E. Tiras3, J. Wetzel1, D. Winn4

1 University of Iowa, Department of Physics, Iowa City, Iowa, United States of America
2 Beykent University, Istanbul, Turkey
3 Iowa State University, Ames, Iowa, United States of America
4 Fairfield University, Fairfield, Connecticut, United States of America

Content

Future circular and linear colliders as well as the Large Hadron Collider in the High-Luminosity era have been imposing unprecedented challenges on the radiation hardness of particle detectors that will be used for specific purposes e.g. forward calorimeters, beam and luminosity monitors. We perform research on the radiation-hard active media for such detectors, particularly calorimeters, in two distinct categories: Quartz plates coated with thin, radiation-hard organic or inorganic compounds, and intrinsically radiation-hard scintillators. In parallel to the effort on identifying radiation-hard scintillator materials, we also perform R&D on radiation-hard wavelength shifting fibers in order to facilitate a complete active medium for detectors under harsh radiation conditions.

 

Here we describe the recent advances in the developments of radiation-hard scintillators and wavelength shifting fibers. We will discuss recent and projected measurements and future directions in development of radiation-hard active media.

Keywords: radiation-hard scintillators, wavelength-shifting fibers
Poster panel: 273

Poster Number:
N-07-273

Measurement of electronic equipment failure rate in the proton radiation therapy center (#1771)

E. Shin1, D. Kim1, S. Park1, W. Lee1, Y. Oh1, B. Lee1, H. Lee1, S. Kim1, J. Shin1, M. Park1, S. Ahn1, Y. Han1, H. Pyo1, D. Lim1

1 Samsung Medical Center, Radiation oncology, Seoul, Republic of Korea

Content

At present, the use of various electronic equipment in the proton therapy center is essential an integral part of treatment equipment and facilities. However, such an electronic equipment use is caused a failure of the electronic equipment in accordance with SEE (single event effect), TDE (Total Dose effect) caused by the neutron. Therefore, it is necessary actions to ensure the integrity and safety of electronic equipment in a high neutron field. In this study, neutron radiation field measure around the cyclotron and gantry room during the Proton operation. And as one of the SEE and TDE evaluation of peripheral electronics, the false positive signals of the semiconductor of fire detector are analyzed in this neutron field. For the five representative energies and dose rate (230, 190, 150, 120, 70MeV; 0.06MU/sec.), neutron around the cyclotron (64 points) and treatment room gantry (17 points) were measured using the WENDI-ǁ and FH40G during proton use. The measured neutron field strength at the point 50cm away from the ESS in the cyclotron operation was 260 μSv / hr (230 MeV), 553 μSv / hr (190 MeV), 1,123 μSv / hr (150 MeV), 2,790 μSv / hr (110 MeV) and 14,189 μSv / hr (70 MeV), respectively. The Gantry measurements at 50 cm from the beam center were from 14.48 μSv / hr (230 MeV) to 7.97 μSv / hr (70 MeV). In the false positive signal analysis of the fire detector, 9 times false signal were caught in the common proton use situation per day. And this phenomenon became more frequent with time. In particular, FIG spurious signals passing to the threshold value was detected twice per day. The goal of this study is SEE and TDE evaluation of proton equipment components to prevent SEU and SEB. Using the neutron cross-section of various semiconductors and the spectrum obtained from MC, SEE and TDE evaluation can predict the system safety by taking measures to prevent DD of semiconductor devices. I think that the results will ensure the soundness of the proton center.

Keywords: SEE, neutron, proton therapy, safety
Poster panel: 275

Poster Number:
N-07-275

Study of the radiation damage of SiPMs by neutrons (#1962)

E. Garutti1, R. Klanner1, S. Cerioli1, D. Lomidze1, J. Schwandt1

1 University of Hamburg, Hamburg, Germany

Content

Silicon Photo-Multipliers (SiPM) are great tools for photo detection; they are being used in several applications in the fundamental and applied physics. One major consideration for their use at high-luminosity colliders is the radiation damage induced by hadrons, which leads to dramatic increase of the dark count rate. Last year our group presented a dedicated study of the effect of radiation on SiPM performance based on a sample of KETEK SiPMs exposed to reactor neutrons up to a fluence of ϕneq = 5x1014 cm-2 based on the analysis of I-V curves.  We have extended our studies to include detailed C-V analysis as well as transient spectra analysis.

This year result will focus on three main aspects: the fluence dependence of SiPM electrical parameters (pixel capacitance, Cpix, quenching resistance Rq and capacitance, Cq); the comparison of methods to determine DCR of irradiated SiPM; measurements of the signal degradation after irradiation and explanation of this effect in terms of increase of pixel occupation probability and changes in the electric field distribution in the multiplication region.

Keywords: SiPM, radiation hardness
Poster panel: 277

Poster Number:
N-07-277

A comparative study of single event effects induced by heavy charged particles in 180 nm technologies (#2094)

M. Marcisovska1, T. Benka2, M. Havranek2, M. Hejtmanek2, Z. Janoska2, V. Kafka2, M. Marcisovsky2, G. Neue2, J. Popule1, P. Suchanek3, P. Svihra2, L. Tomasek2, P. Vancura2, V. Vrba2

1 Czech Academy of Sciences, Institute of Physics, Prague, Czech Republic
2 Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Prague, Czech Republic
3 esc Aerospace, Prague, Czech Republic

Content

The primary motivation for the presented measurements is the assessment of space qualification of a novel Silicon-on-Insulator monolithic pixelated detector X-CHIP-03. In order to understand and compare effects of heavy charged particles upon microelectronic structures, a comparison of a standard 180 nm CMOS and a 180 nm SoI CMOS technology is made with respect to the effects of passing of heavy charged particles and also to the delivered ionization damage. The measurement employs shift registers in the X-CHIP-03 and PH32 ASICs, manufactured in the above-mentioned technologies. Bit flip cross sections and ASIC power consumption measurements were performed in both ASICs during and after accelerator beam irradiation with fluences up to 1012 particles /cm2. Particle beams of protons, 4He, 12C and 16O ions at several ion energies were provided by particle accelerators, ensuring different ionization densities for proper physical characterization. The TID damage was extrapolated from the measurement using a 60Co source. The data analysis is currently ongoing and preliminary results show the expected higher radiation tolerance of the SoI technology.

Keywords: pixel detector, SEE, Silicon-on-Insulator, monolithic detector
Poster panel: 279

Poster Number:
N-07-279

Proton induced radiation damage effects on the performance of the SDD based X-ray spectrometers onboard Chandrayaan-2 mission (#2331)

M. Shanmugam1

1 PRL, PRL, Ahmedbad, India

Content

Earth is surrounded by extremely intense radiation regions known as Van Allen radiation belts which consists of  highly energetic electrons and protons trapped within the Earth’s magnetosphere. Such harsh radiation environment is known to adversely affect the performance of X-ray detectors. Forth coming Chandrayaan-2 mission, the second Indian mission to the Moon will have two X-ray spectrometer experiments using Silicon Drift Detectors (SDD) namely Solar X-ray Monitor (XSM) and Alpha Particle X-ray Spectrometer (APXS). The displacement damage due to the Non Ionizing Energy Loss (NEIL) of charged particles leads to increase in the detector leakage current and thus degrades the energy resolution. Hence, it is essential to estimate the performance degradation of the X-ray spectrometers for its operational period. The total radiation dose encountered by the SDD is estimated for Earth to the Moon transfer and also for the mission duration on the lunar orbit using the SPENVIS software suit. It is estimated that the SDD will encounter the total dose of ~ 10 krad during its operational period. The proton irradiation experiment was carried out at the TIFR-BARC Pelletron facility using 10 MeV proton beam. The irradiation experiment was carried out in steps of proton doses and at each step, the proton beam was stopped and the detector leakage current and the energy resolution was measured. It is shown that the energy resolution degrades from ~142 eV at 5.9 keV to ~242 eV for the proton dose of ~10 krad for the detector operating temperature of ~ -35oC. This satisfies the performance requirement of the SDD based X-ray spectrometers onboard Chandrayaan-2 for the life time of one year. The experimental details and the results will be presented in the conference.

Keywords: SDD, radiation damage, proton, energy resolution
Poster panel: 281

Poster Number:
N-07-281
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Development of Real-Time 1-MeV Equivalent Neutron Fluence Monitor Based on SiPD for COMET Experiment (#2444)

K. Ueno1, J. Tojo2, K. Oishi2, Y. Nakai2, Y. Miyazaki2

1 High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki , Japan
2 Kyushu University, Fukuoka, Fukuoka, Japan

Content

The COMET experiment at J-PARC aims to search for the charged lepton flavor violating process of neutrinoless mu-e conversion. The goal sensitivities of its Phase-I and Phase-II experiments are respectively to be improved by a factor of 100 and 10000 to the current limit. To achieve those sensitivities, very high intensity beam from J-PARC is used in both Phase-I and Phase-II experiments. According to the simulation studies, 1 MeV equivalent neutron fluence of ~1012 n/cm2 in the COMET Phase-I was expected. Thus, the radiation tolerant parts have been selected and countermeasure against single event upset in FPGA has been considered. In addition to those investigations, we have developed the real-time neutron fluence monitor in order to promote those studies with high precision, and this monitor is expected to install near detector region in Phase-I experiment for the purpose of one of the environment monitors. The result of the monitor in Phase-I experiment is also assumed to be used for the studies for Phase-II experiment. We adopted the simple silicon photodiode (SiPD) produced by Hamamatsu for the monitor because the Si was well-known that the leakage current increased with the damage from neutron and it was available for the monitor. We have developed the prototype of the monitor based on the SiPD with the thickness of 320 micrometer and the size of 5 x 5 mm2 and 7 x 7 mm2, and neutron irradiation campaign was performed. In this test, it was confirmed that the increase rate of the leakage current depended on the neutron flux. The performance of the monitor has been evaluated. In this presentation, we describe the development of the real-time 1-MeV equivalent neutron fluence monitor. The results of the neutron irradiation campaign is also reported. The prospect of the monitor is also presented.

Keywords: neutron, real-time monitor, SiPD
Poster panel: 283

Poster Number:
N-07-283

Irradiation Test Result of a Communication Module for the Wireless Radiation Detection Sensor Network (#2764)

I. Kwon1, D. Shin1, C. H. Kim1

1 Korea Atomic Energy Research Institute (KAERI), Nuclear ICT Research Division, Daejeon, Republic of Korea

Content

This paper describes initial radiation test result of a commercial wireless sensor module to verify how it works with the increase of irradiation doses. The measured data will be used to design a radiation hardened wireless communication system that can provide the most important information of monitoring radiation dose in accident nuclear sites where they are leaked in unseen area to mitigate such a severe accident situation in the very early stage. According to the initial measured result, the power consumption of some wireless modules were increased around 5.5 kGy and the others were increased around 7.2 kGy depending on various control factors while a module of PER was started to decrease around 1 kGy. The tests were performed with various configurations such as distance, frequency, transmitting power, and shielding material at the gamma irradiation facility containing cobalt-60 γ-ray with high level activity of 490 kCi in KAERI. The measured data would be useful for researchers not only to find weak parts of the wireless module but also come up with radiation hardening methodologies for a common digital communication system. At the conference, more analyzed and collected data will be shared to discuss which part of the wireless communication system is weak and should be radiation hardened for exploiting specific applications, for example, severe accident monitoring system and unmanned system for nuclear decommissioning.

Poster panel: 285

Poster Number:
N-07-285

Fully 3D Sensitive Volume Microdosimeter: Charge Collection and Radiation Damage Studies (#2920)

B. James1, L. Tran1, D. Bolst1, V. Pan1, D. Prokopovich2, M. Petasecca1, M. Lerch1, S. Guatelli1, M. Reinhard2, Z. Pastuovic2, M. Povoli3, A. Kok3, A. B. Rozenfeld1

1 University of Wollongong, Centre for Medical Radiation Physics, Wollongong, Australia
2 Australian Nuclear Sciences and Technology Organisation, NSTLI Nuclear Stewardship, Lucas Heights, Australia
3 Sintef, Oslo, Norway

Content

In the course of this research, a radiation damage study of 3D microdosimeter structures were carried out using 5.5 MeV He2+ and 24 MeV 12C ions microbeam. Radiation damage study post irradiation of the microdosimeters with low energy Li, C, O and Ti ions was also investigated. Additionally, electrical and charge collection properties were studied for a new 3D SV microdosimeter covered with a tissue equivalent material.

Keywords: Silicon on insulator, Microdosimetry, 3D detector, Radiation hardness, Ion beam
Poster panel: 287

Poster Number:
N-07-287

Temporally separating Cherenkov light in pulsed beam dosimetry (#1098)

J. I. Archer1, E. Li1, M. Carolan2, A. B. Rozenfeld1, 3

1 University of Wollongong, Centre for Medical Radiation Physics, Wollongong, Australia
2 Wollongong Hospital, Illawarra Cancer Care Centre, Wollongong, Australia
3 University of Wollongong, Illawarra Health and Medical Research Institute , Wollongong, Australia

Content

Cherenkov radiation is the primary source of light contamination in an optical system exposed to high-energy radiation. Therefore the removal of the contribution of Cherenkov radiation to a light signal is vital, especially in the field of dosimetry where accurate measurements of radiation dose is critical for the quality assurance of radiation sources and treatment plan validation. We present and demonstrate a novel method for Cherenkov subtraction in a plastic scintillator fibre optic dosimeter applicable to regular, pulsed radiation sources. BC-444 plastic scintillator is used because of its long rise time of 19.5 ns, which helps the prompt Cherenkov signal be discriminated from the slower scintillator signal. By measuring a Cherenkov only waveform across a beam pulse, this can be used as a template to algorithmically fit to the data using simulated annealing. This allows a specific Cherenkov template for each linear accelerator to be used to remove the Cherenkov contribution from the waveform, yielding only the scintillation light. We compare this method to other temporal Cherenkov separation methods.

Keywords: dosimtetry, cherenkov, scintillator
Poster panel: 289

Poster Number:
N-07-289

Gamma Background Reduction by Plastic Phoswich Detector for the Very Low Background β Spectrometer (#1476)

M. Saito1, M. Mizui1, T. Saito1, S. Komatsu1, H. Itadzu1, S. Okazaki1

1 SEIKO EG&G Co., Ltd., Engineering Department, Tokyo, Japan

Content

A special plastic phoswich detector system has been developed for the very low background beta spectrometer. The target analysis energy range is from 100 keV to 2500 keV and its background count rate is less than 1 cpm against the total counts of the environmental gamma and the high energy cosmic-ray. The detector system is designed to have a sensitivity limited to the beta particle only it comes from frontend by detection of coincidence between front and rear scintillators. The front scintillator is 1 mm thick and 1.8 ns decay time. The rear scintillator is 10 mm thick and 285 ns decay time. The scintillation efficiency of those is 10400 and 6300 photons/MeV respectively. A 12 bit, 250 MS/s digitizer has been used at this work. The digitizer has online digital pulse processing capability intended to pulse shape discrimination by digital dual gated charge integration function. The digitizer calculate and build an event of the list mode data stream that made of a combination of trigger time stamp, prompt charge (QSHORT) and total charge (QLONG). A typical phoswich scintillation detector output waveform and digital pulse processing scheme of parameters are presented. A Sr-90 reference source has been measured for examination of the system. A 2D mapping of the event histogram is presented. Horizontal axis represent total light output and vertical axis represent fraction of slow component to the total light that calculated by followings: (QLONG-QSHORT)/QLONG. As the current consequence, obtained background rate is 10.38 cpm including cosmic-ray originated events. Over 88% of gamma background is reduced by phoswich detector and 2D filtering of events. Since the cosmic-ray dependence to this size of detector in our laboratory is known as about 10 cpm the targeted background rete of 1 cpm seems achieved. We are working on installing cosmic guard detector to the system.

Keywords: Beta Spectrometer, Phoswich Detector
Poster panel: 291

Poster Number:
N-07-291

Development of a 3D Position Sensitive Scintillation Detector (#1731)

J. R. Brown1, S. Paschallis1, F. Alsomali1, D. Jenkins1, P. Joshi1, E. Marsden2, I. Radley2

1 University of York, York, United Kingdom
2 Kromek Group plc, Sedgefield, United Kingdom

Content

Position sensitive gamma-ray scintillation detectors are of interest for a variety of applications such as nuclear security and safety, medical imaging, as well as for fundamental physics experiments. This is often achieved using segmented scintillator crystals coupled to an array of photosensors. The position resolution of such systems is limited by the granularity of the scintillator elements and its position sensitivity is typically limited to two dimensions. An alternative approach uses monolithic scintillators and measures the light distribution from a scintillation event allowing the reconstruction of the interaction position. Some success has been reported using this technique but is typically limited to thin scintillators and/or 2D position reconstruction.

We report on the development of a 3D position sensitive scintillator detector. Position sensitivity is achieved through measuring the light distribution on one or more faces of the scintillator, using arrays of silicon photomultipliers (SiPMs) coupled directly to monolithic scintillator crystals. Utilising the controlled-atmosphere station operated in our laboratory, we can handle bare hygroscopic scintillating crystals and couple SiPMs at different geometries around the crystal. A number of scintillator materials are currently being evaluated, including CsI:Tl and CeBr3.

A dedicated, high precision, x-y scanning station housing a high-intensity collimated 137Cs source has been designed and built that allows characterization of the response of different scintillator/SiPM configurations.  In this contribution we will present characterization results from different configurations along with the corresponding Geant4 simulations of optical photon transportation, which were used to investigate the optimum scintillator/SiPM configuration for this technique.

Keywords: silicon photomultiplier, position sensitivity, gamma ray, monolithic scintillator, depth of interaction
Poster panel: 293

Poster Number:
N-07-293
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Study of the 176Lu Background Spectrum from LYSO Scintillation Crystals (#2003)

H. Alva-Sánchez1, A. Zepeda-Barrios2, V. D. Díaz-Martínez2, T. Murrieta-Rodríguez1, A. Martínez-Dávalos1, M. Rodríguez-Villafuerte1

1 Instituto de Fisica, UNAM, Física Experimental, Mexico City, Mexico
2 Facultad de Ciencias, UNAM, Mexico City, Mexico

Content

Lutetium oxyorthosilicate (LSO) or lutetium yttrium oxyorthosilicate (LYSO) are the scintillator materials most widely used today in PET detectors due to their convenient physical properties for the detection of 511 keV annihilation photons. Natural lutetium contains 2.6% of 176Lu which decays by beta emission to excited states of 176Hf producing a constant background signal. Although previous works have studied the background activity from LSO/LYSO, the shape of the spectrum, resulting from β-particle and γ radiation self-detection, has not been fully explained. The present work examines the contribution of the different β-particle and γ-ray interactions to provide a fuller comprehension of this background spectrum and to explain the differences observed when using crystals of different sizes. To this purpose we have shifted the continuous β-particle energy spectrum of 176Lu from zero to the corresponding energy value for all possible combinations of the isomeric transitions of 176Hf (γ-rays/internal conversion). The area of each shifted β-spectrum was normalized to reflect the probability of occurrence. To account for the probability of the γ-rays escaping from the crystal, Monte Carlo simulations using PENELOPE were performed in which point-like sources of monoenergetic photons were generated inside LYSO crystals of two different dimensions: 1.0 cm side cube and a square prism of 5.74×5.74×1.0 cm3. The analytic distributions were convolved using a Gaussian function to account for the measured energy resolution. The calculated spectra were compared to those obtained experimentally using monolithic crystals of the same dimensions coupled to SiPM arrays. Our results are in good agreement with the experimental data, and even explain the differences observed due to crystal size. This work may prove useful to calibrate and assess detector performance, and to measure energy resolution at different energy values.

Poster panel: 295

Poster Number:
N-07-295
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A Feasibility Study of LYSO-GAPD Detector for Development of DEXA (#2072)

J. Yang1, T. Kim2, J. Kang1

1 Chonnam National University, Department of Biomedical Engineering, Yeosu, Republic of Korea
2 Hallym University, Department of Electronic Engineering, Chuncheon, Republic of Korea

Content

A LYSO-GAPD detector was developed for DEXA application and was characterized under a variety of conditions. The 1×8 LYSO array consisted of 3×3×2 mm2 pixels providing detection efficiency of > 99.9% for 80 keV, coupled to a GAPD array having a 3.07×3.07 mm2 active area and 5676 microcells for each pixel. Eight analog signals were fed into preamplifiers, and were further-processed in the energy discrimination unit and the data acquisition unit. A simulations study using the TASMIP algorithm was performed to generate the reference X-ray energy spectra. The exposure measurements were performed at the same settings. The effect of kVp and mA on energy spectra was assessed for different tube voltages and currents in air condition, and the count rate was measured. The effect of the K-edge Cerium filter on dual energy X-ray spectra was examined for different thicknesses ranging from 0.1 mm to 0.6 mm, with 0.1 mm steps. Long-term stability was performed for 14 days and the imaging capability was evaluated using a BMD phantom and conventional dual energy subtraction algorithm. The measured X-ray energy spectra as a function of tube voltage and current were similar in shape to the simulated one, the pulse pile-up effect was observed in the extremely high incident photon condition, at > 0.5 mA tube current. Maximum count rate was 2 Mcps due to mainly dead time of DAQ used in this study. The dual energy peaks were located around 32 keV and 65 keV and were clearly isolated. The peak-to-valley ratio as a function of K-edge filter thickness increased from 2.7 to 14.2 and from 1.7 to 3.8 for low- and high-energy, respectively. Long-term stability results show that there was no significant change in the beam peak positions and the photons count rate for 14 days. The DEXA phantom image for each steps was clearly resolved. These results demonstrate the feasibility of LYSO-GAPD detector allowing more potential merits than conventional CZT or CdTe detector for DEXA application.

Keywords: DEXA, LYSO-GAPD, X-ray energy spectra, Long-term stability
Poster panel: 297

Poster Number:
N-07-297
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Method for characterization of filters used for efficiency variation in TDCR (#2149)

C. C. Dutsov1, K. K. Mitev1, P. Cassette2

1 Sofia University, Department of Atomic Physics, Soifa, Bulgaria
2 CEA, List, Laboratoire National Henry Becquerel, LNE-LNHB, Gif-Sur-Yvette, France

Content

This work presents developments related to the efficiency variation technique used for the standardization of radionuclides in liquid scintillation counting by the Triple-to-Double Coincidence Ratio (TDCR) method.

We propose and developed a new type of 3D printed mesh filters for detection efficiency variation, as well as a method for the quantitative characterization of the filters. The method allows to estimate a priori the TDCR value which will be obtained in the measurement of a given sample with a given filter. The developed filters are characterized using the proposed method and are applied to absolute activity measurements of 3H by TDCR counting. Experiments on efficiency variation in 3H measurements were performed on two different detectors, the TDCR detector at Sofia University and the French primary TDCR detector at Laboratoire National Henri Becquerel. The experiments indicate that the proposed characteristic of the filters is independent of both the TDCR counter and the liquid scintillation cocktail. The results of this study will be very useful for the application of the efficiency variation technique for radionuclide standardization by TDCR counting.

Keywords: TDCR, efficiency variation, liquid scintillation counting, LSC, metrology
Poster panel: 299

Poster Number:
N-07-299

Mechanism of Pulse Shape Discrimination in LaBr3:Ce: Modeling with Dynamic Equations (#2215)

J. Cang1, M. Zeng1

1 Tsinghua University, Engineering Physics, BEIJING, China

Content

Pulse shape discrimination is widely used in many inorganic scintillators, which have different components, such as BaF2 and CsI. Conversely, LaBr3:Ce is considered not having different components but has been proved to have the capability of discriminating gamma and alpha events using fast digitizers. This paper describes the origin of very small pulse shape difference for incident particles with different ionization density or stopping power (dE/dx). We attribute the pulse shape difference to the second-order dipole-dipole Forster transfer of self-trapped excitons (STE), which is also one of the causes of non-proportionality of inorganic scintillators. Decay profiles of LaBr3:Ce are measured under the excitation of alpha particles and 6-100keV electrons or gamma rays, using time-correlated single photon counting (TCPSC) method. Dynamic equations, including the processes of diffusion, energy transfer, radiative decay and nonlinear quenching, are established to fit the measured decay profiles. The correlations between pulse shape and ionization density, diffusion rate or transfer rate are also established and to be verified with the dynamic equations.

Keywords: LaBr3:Ce, scintillation mechanism, Pulse Shape Discrimination
Poster panel: 301

Poster Number:
N-07-301

Evaluation of  a Large Monolithic LaBr(Ce,Sr) Codoped Scintillator (#2222)

V. Sanchez-Tembleque1, M. García-Díez1, V. Vedia1, J. M. Udias1, 2, L. M. Fraile1, 2

1 Universidad Complutense de Madrid, Grupo de Fisica Nuclear and UPARCOS, CEI Moncloa, Madrid, Spain
2 Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain

Content

Gamma spectroscopy entered a new era with the introduction of new inorganic scintillators, mostly halide compounds, with large effective atomic number, excellent timing properties and good energy resolution. The most prominent example is LaBr3(Ce), commercially available for more than a decade, a very fast crystal with a relatively high effective Z and high photon yield of 63 000 photons/MeV. Energy resolution at the 137 Cs 662-keV gamma energy  of 3% along with time resolution  below 100 ps (FWHM) for 60-Co peak to peak coincidences has been reported for an individual LaBr3 (Ce) cylindrical crystal 1 inch in height and 1 inch in diameter. This makes inorganic material very interesting for γ-ray spectroscopy and sub-nanosecond half-live measurements. Recently it has been shown that ionic co-doping with 0.5% Sr-2+ mauy enhance the light yield by  up to 15% while keeping a similar light emission spectra peaking at around 385 nm. This would translate in enhanced energy resolution compared to LaBr3(Ce). In this work we evaluate the performance of a codoped LaBr3(Ce,Sr) crystal, commercially available from Saint Gobain, under the trade mark B390S. The crystal is a cylinder of 38.1 mm high and 38.1 mm in diameter, encapsulated in a 45 mm x45 mm aluminium housing with a thin entrance window of 0.5 mm and glass light guide to couple it to the photosensor. We evaluate the energy resolution, expected to be below 3% at 662 keV, and the photon yield by comparing it to an identical shape and size LaBr3(Ce) crystal. We also measure the time resolution for the crystal coupled to a fast R9779 Hamamatsu photomultiplier tube and compare it to the standard crystal.  The results shows that LaBr3(Ce,Sr)  can surpass the performance of LaBr3(Ce) both for timing and energy spectroscopy.

Keywords: inorganic scintillators, gamma spectroscoyp, timing measurements, codoping
Poster panel: 303

Poster Number:
N-07-303

Basic analysis of OSL mechanism in an optical fiber type OSL dosimeter (#2316)

Y. Hirata1, K. Watanabe1, A. Yamazaki1, S. Yoshihashi1, A. Uritani1, T. Yanagida2, K. Fukuda3

1 Nagoya University, Engineering, Nagoya, Japan
2 Nara Institute of Science and Technology, Ikoma, Japan
3 TOKUYAMA corp., Shunan, Japan

Content

Radiotherapies are one of the main treatment modalities in cancer management.  In order to accurately estimate the irradiation dose, it is better to insert a dosimeter into an affected region in a patient body.  We, therefore, are developing a small size dosimeter consisting of an optical fiber and optically stimulated luminescence (OSL) elements.  The OSL elements shows the quenching effect when high linear energy transfer (LET) particles are irradiated.  In order to correct the quenching effect, using signal ratio from different OSL materials is considered to be effective.  Since the effective correction could be achieved by using proper combination of OSL materials, various dosimeter materials are required to realize the suitable combination of OSL materials for the quenching effect correction.  Investigation of the mechanism of the OSL process will help to look for new OSL elements.  In this paper, we investigate the dependency on some parameters of exponential decay coefficients of the OSL signals in order to understand the OSL mechanism.  We prepared the CaF2 OSL elements with different Ce dopant concentrations of 0.1, 0.5 and 1.0%.  The OSL signals often have two decay components.  The both decay coefficients linearly depend on the stimulation laser intensity.  We compared the slopes of the decay coefficients in the OSL signals to the laser intensity for various Ce dopant concentrations.  We confirmed that the slopes of the decay coefficients depend on the Ce concentration and decrease with the Ce concentration.  These knowledge are expected to help to understand the OSL mechanism.

Keywords: Optically Stimulated Luminescence, Optical Fiber, Dosimeter, Radiotherapy
Poster panel: 305

Poster Number:
N-07-305

Large Volume Solid State Neutron-Gamma Detectors (#2481)

L. Soundara-Pandian1, M. Spens1, J. Tower1, A. Gueorguiev1, J. Glodo1, K. S. Shah1

1 Radiation Monitoring Devices, Inc., Radiation Detection and Imaging Group, Watertown, Massachusetts, United States of America

Content

Large volumes of Cs2LiYCl6 (CLYC) and Cs2LiLa(Br,Cl)6 (CLLBC) scintillators are commercially available from RMD and have become potential replacement detectors for a combination of gamma-ray detectors and 3He tubes. The excellent energy resolution (CLLBC 3% and CLYC 4% at 662 keV) makes them effective for radio isotope identification. The high gamma-ray equivalent energy (> 3 MeV) of the thermal neutrons allows for pulse height discrimination with very good gamma rejection, which simplifies the electronics of the instrument but pulse shape discrimination is also available (FOM>3). These detectors, when made compact, can become an ideal choice for dual-mode detection in pagers, handheld, backpack, and many other instruments for nuclear security applications.

In this paper, we report on the large volume detectors constructed at RMD using 1.5”, and 2” diameter (OD) cylinders of CLYC and CLLBC crystals coupled to arrays of silicon photomultipliers (SiPM). Detectors constructed with 1.5” and 2” OD cylinders of CLLBC crystals coupled to a 24 mm x 24 mm total area SiPM array show an excellent energy resolution of ~3.5% and 3.8% at 662 keV, respectively. A 2” OD large volume CLYC crystal shows an energy resolution of ~6.6% at 662 keV, in the same configuration. Both detectors show pulse shape discrimination capabilities. Comparison of neutron efficiency with 3He tubes and temperature dependent properties will also be presented. New results with Tl2LiYCl6:Ce (TLYC) crystals including those coupled to SiPMs will also be presented.

This work has been partially supported by the US Defense Threat Reduction Agency, under competitively awarded contract HDTRA1-17-C-0053 and also partially supported by the US Department of Homeland Security, Domestic Nuclear Detection Office, under competitively awarded contract HSHQDC-09-C-00158. This support does not constitute an express or implied endorsement on the part of the Government. DISTRIBUTION A: Approved for public release.

 

 

Keywords: gamma rays, neutrons, scintillation detectors, pulse shape discrimination
Poster panel: 307

Poster Number:
N-07-307

Development of Compton PET Hybrid Camera with CeBr3 Array (#2517)

Y. Ohshima1, K. Shimazoe1, M. Yoshino5, 6, T. Orita3, K. Ohgane2, M. Takahashi4, K. Kamada5, 6, A. Yoshikawa5, 6, H. Takahashi1

1 The university of Tokyo, Graduate school of engineering, Bunkyou, Tokyo, Japan
2 The university of Tokyo, Graduate school of Medicine, Bunkyou, Tokyo, Japan
3 Kavli IPMU, The university of Tokyo, Kashiwa, Chiba, Japan
4 National Institute for Quantum and Radiological Science and Technology, Inage-ku,Chiba, Japan
5 IMR, The university of Tohoku, Aoba-ku, Sendai, Japan
6 NICHe, The university of Tohoku, Aoba-ku, Sendai, Japan

Content

We developed Compton PET hybrid camera with CeBr3 array which could obtain Compton images and PET image without any collimator at the same time. This hybrid camera will decrease burden on patients and increase the accuracy of diagnosis. The PET image and Compton image of 18F and 111In were obtained at once measurement. In order to apply ToF technich for PET, we consider to use CeBr3 array in the hybrid camera. The energy resolutions of CeBr3 scintillator were evaluated in order to confirm whether it could be applied for the hybrid camera.

Keywords: CeBr3, PET, Compton camer
Poster panel: 309

Poster Number:
N-07-309
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Design and Field Tests of Scintillation Spectrometer for Continuous 222Rn in Soil-gas Monitoring (#2626)

K. K. Mitev1, C. C. Dutsov1, L. T. Tsankov1, S. B. Georgiev1, M. G. Mitev2, N. M. Markov3, T. H. Todorov4

1 Sofia University , Department of Atomic Physics, Sofia, Bulgaria
2 Technical University of Sofia, Faculty of Electronic Engineering and Technologies, Sofia , Bulgaria
3 Festo Production EOOD, Sofia, Bulgaria
4 Formerly with DZU , Stara Zagora, Bulgaria

Content

This work presents the realization and the results of pilot field tests of a detector designed for continuous, unperturbed monitoring of 222Rn in soil-gas. The detector is based on scintillation spectrometry with plastic scintillators and pulse-shape discrimination (PSD) of the alpha- and beta- particle pulses of 222Rn and its progeny. The detector is portable and can be placed and buried in boreholes up to 2 m in depth. The salient feature of the detector is that it does not use any kind of air sampling which allows unperturbed and continuous 222Rn in soil-gas measurements.  The results from a 12 days pilot field test show that, due to its advantageous design and PSD discrimination capabilities, the detector has low background and good sensitivity to detect the diurnal radon in soil-gas fluctuations at 1m depth.  The detector can find applications in geology and seismology, for example in the experimental research of the potential relationship between the 222Rn in soil-gas anomalies and seismic activity  and the corresponding studies on the usage of soil-gas 222Rn as an earthquake precursor.

Keywords: radon in soil-gas, PSD, scintillation spectromery, seismology, earthquake precursors
Poster panel: 311

Poster Number:
N-07-311

Some Features of the Radiation Resistance of Composite Scintillators (#1076)

B. V. Grinyov1, N. Z. Galunov1, 2, A. Y. Boyarintsev1, A. V. Krech1

1 Institute for Scintillation Materials (ISMA), Kharkov, Ukraine
2 V.N. Karasin Kharkov National University, Physical dep., Kharkov, Ukraine

Content

This paper describes studying the radiation resistance of composite scintillators. The composite scintillators containing grains of organic single crystals are not radiation-resistant even to a dose of 1 Mrad. Studying the composite scintillators containing grains of some inorganic crystals (GSO:Ce, GPS:Ce, YSO:Ce, YAG:Ce or Al2O3:Ti) shows that these scintillators are radiation-resistant up to doses more than 125 Mrad. Some of them are radiation-resistant to doses not lower than 550 Mrad. The introduction of organic luminophores (like POPOP or p- terphenyl) in ultra low concentrations (10-3%) into gel-composition Sylgard-184 showed that it is possible to obtain radiation-resistant spectrum shifting materials, which are radiation-resistant to doses not lower than 110–170 Mrad. Such the materials can be used for the creation of light guides.

The paper studies possible processes of radiation-induced changes arising in scintillators under the irradiation as well as analyzes the effect of these processes on the radiation resistance. All crystalline scintillation materials contain defects, which can play the role of either luminescence or quenching centers. The irradiation destroys and changes not only the main material, but such the centers as well. As a result, the luminescence intensity can grow for a while. In this case, the luminescence spectrum of a scintillator does not change its shape under various doses because no new luminescence centers are generated. Another process is associated with the change of luminescence centers. It should result in a modification of the luminescence spectral characteristics.

In the composite scintillators containing grains of inorganic crystals, the variation of luminescence spectral characteristics either can or cannot take place. Therefore, to identify the possible processes giving rise to radiation-induced changes in scintillators, it makes sense to carry out such spectral researches before and after the irradiation.

Keywords: ...
Poster panel: 313

Poster Number:
N-07-313

n/g PSD properties of Li-based undoped oxide crystals (#1108)

T. Yanagida1, K. Watanabe2, G. Okada1, N. Kawaguchi1

1 Nara Institute of Science and Technology (NAIST), Graduate School of Materials Science, Ikoma, Japan
2 Nagoya University, Nagoya, Japan

Content

A scintillator is one of the luminescent materials that convert a high energy ionizing radiation photon/particle to hundreds of visible photons via energy migration from the host matrix to emission centers immediately. Recently, the shortage of 3He gas becomes a big issue in the radiation detector field, and some alternatives for neutron detectors are highly required. One of the solution for the alternative is a scintillators. Up to now, some inorganic scintillators such as elpasolite and LiCaAlF6 have been developed, and some organic scintillators have been also introduced. In neutron detectors based on scintillators, pulse shape discrimination (PSD) technique is sometimes used to distinguish the neutron signal from background g-rays.

In this study, we focus LiAlO2 and LiGaO2 scintillating crystals for neutron detectors since they contain Li in the chemical composition. In these crystals, thermal neutron can be measured in pulse height spectrum with clear neutron peak. Up to now, in inorganic scintillators, PSD can be possible in emission center doped materials, such as Ce-doped elpasolite and LiCaAlF6 by using the intrinsic and extrinsic luminescence. In LiAlO2 and LiGaO2, we observed PSD properties in these crystals. To our knowledge, PSD in undoped materials is not common, and this work opens a new possibility to develop scintillators with PSD function.

As a result, we can confirm the PSD function in LiAlO2 and LiGaO2 scintillating crystals. When we calculate the figure of merit (FOM) of these scintillators, FOM of LiAlO2 and LiGaO2 were 0.46 and 0.68, respectively. To the best of our knowledge, this is the first report of PSD function in undoped inorganic scintillators. Up to now, inorganic scintillators which can show PSD have been rare-earth doped halide crystals, such as LiCaAlF6 and elpasolite crystals. Therefore, the present work opens a new possibility to search for new PSD scintillators for neutron detectors.

Keywords: scintillator, neutron
Poster panel: 315

Poster Number:
N-07-315

High-Performance Composite Scintillators for Gamma and Neutron Detection (#1137)

S. Lam1, J. Fiala1, M. Hackett1, F. L. Ruta1, I. Khodyuk1, S. Motakef1

1 CapeSym, Inc., Natick, Massachusetts, United States of America

Content

Composite scintillators enable the production of high-performance low-cost gamma and neutron detectors in large sizes that would be otherwise expensive or impossible to produce. For example, SrI2(Eu) and CLYC(Ce) are ideal candidates for nuclear radiation detection, but these detectors become expensive at large diameters (e.g. 3-in. and greater) due to decreased crystal growth yield. However, the cost of embedding small diameter crystals into a large plastic matrix such as polyvinyltoluene (PVT) is low, and the plastic matrix can even be shaped to improve light collection. This presentation will discuss the design, fabrication, and performance of CLYC(Ce)-PVT and SrI2(Eu)-PVT composite scintillators. Fabrication of these composites were guided by Geant4 simulations to characterize the generation, transport, and collection of photons. Our recent 3-inch diameter CLYC(Ce)-PVT achieved an energy resolution of 4.5% at 662 keV and a PSD FoM of 2.8. We will also present on SrI2(Eu)-PVT composites, which have achieved 3.6% energy resolution at 662 keV. Finally, we will also discuss some of our recent progress on composites for large volume backpack and handheld detectors.

This work has been supported by the U.S. Department of Homeland Security, Domestic Nuclear Detection Office, under competitively awarded contract HSHQDN-17-C-00008. This support does not constitute an express or implied endorsement on the part of the Government.

Keywords: dual mode detector, composite
Poster panel: 317

Poster Number:
N-07-317

NEW SCINTILLATION MATERIAL BASED on ZnWO4 (#1159)

V. Zvereva1, I. Tupitsyna1, B. V. Grinyov1, A. Yakubovskaya1, S. Tretiak1

1 Institute for Scintillation Materials (ISMA), Kharkov, Ukraine

Content

Recently, much attention is paid to the development of composite organic and inorganic scintillators preparation methods.  Mentioned materials have several advantages as compared with single crystals, such as: high uniformity of scintillation parameters, no restrictions of the linear sizes, high technology of production. However, the preparation of composite scintillators are often involves grinding of bulk single crystals, which determines their greater costs. According to the aim of this work it was obtained composite scintillators based on microcrystalline ZnWO4, prepared by solid-phase synthesis.

Optimal conditions of the synthesis of microcrystalline zinc tungstate were determined by the results of DTA, SEM and X-ray analysis of obtained microcrystalline powders prepared from initial oxides mixture (ZnO and WO3). It was shown the complete conversion of the starting components in a certain phase (ZnWO4) occurs for 50 hours at a temperature of 950°C.

The influence of mineralizers - lithium salts as a function of their concentration in a solid-phase reaction was investigated. The positive effect of LiNO3 was observed: accelerating the chemical reaction and the grain growth, reducing of the synthesis time up to 30 hours.

The number of samples of size Ø30´2 mm was produced from prepared under different synthesis conditions powders. Silicone rubber was used as the polymer binder. Scintillation characteristics of the samples were measured. The light output of the best samples of the composites was at bulk crystals and above: sample based on solid-phase synthesized powder (950 °C, 50 h) -155% as compared to the bulk crystal ZnWO4, sample based on solid-phase synthesized powder (adding LiNO3 (0,1%), 950 °C, 30 h) – 273 %.

 

Keywords: composite scintillators, ZnWO4
Poster panel: 319

Poster Number:
N-07-319

Effect of Ionising Radiation of Low Cost Commercial Borosilicate Microscope Glass Slide as Thermoluminescence Radiation Dosimeters (#1279)

S. F. Abdul Sani1, M. H. U. Osman1, S. R. Zahariman1, N. Wahib1, S. A. Hashim3, M. U. Khandaker2, D. A. Bradley2, 4

1 University of Malaya, Department of Physics, Kuala Lumpur, Malaysia
2 Sunway University, Institute for Health Care Development , Petaling Jaya, Malaysia
3 Agensi Nuklear Malaysia (Nuklear Malaysia), Bangi, Malaysia
4 University of Surrey, Department of Physics, Guildford , United Kingdom

Content

Amorphous silica has been a potential candidate material for many promising thermoluminescence (TL) properties with respect to ionizing radiation for a wide range of application. However, ionizing radiation effects in the TL material glass, which comprise SiO2-B2O3 are still much less investigated in thermoluminescense dosimetry (TLD). Present work describes the efforts of finding a new TL media using commercial borosilicate microscope glass slides. The glasses of thickness 1.0 - 1.2 mm were cut into transparent chips to lengths of approximately 5.0 ± 0.1 mm and exposed to electron and photon irradiations, respectively with various dose ranges from 2 Gy to 150 kGy and 2 to 10 Gy to study their thermoluminescence (TL) properties. The key performance parameters include dose response linearity and sensitivity, energy dependency, glow curve analysis, repeatability and fading effects. The above mentioned TL properties of the borosilicate microscope glass slides are compared with TLD-100. The proposed dosimeter shows good linearity doses up to 150 kGy with evidence of no saturation. This work may contribute towards the development of a new dosimeter that would extend applications from measurement of the doses that are familiarly used in radiation processing and radiotherapy to diagnostic and environmental radiation doses (milligray down to fractions of a microgray, respectively). As such, one is looking to offer radiation sensitivity approaching or exceeding that of more well established TL dosimeters such as the LiF phosphor-based commercial product TLD-100.

Keywords: Ionising Radiation, Thermoluminescence
Poster panel: 321

Poster Number:
N-07-321

Crucible-free growth of Ce-doped (Gd,La)2Si2O7 bulk crystal for scintillator application (#1366)

V. V. Kochurikhin1, K. Kamada1, 2, Y. Shoji1, 2, M. Yoshino1, 2, H. Sato1, 4, A. Yoshikawa2, 3

1 C&A (Crystals and Applications) Corp., Sendai, Japan
2 Tohoku University, Institute for Materials Research, Sendai, Japan
3 Tohoku University, New Industry Creation Hatchery Center, Sendai, Japan
4 EXA Corporation, Sendai, Japan

Content

Ce-doped La,Gd)2Si2O7 crystal is a prospective scintillator material for the application at high temperature. The production of Ce-(La,Gd)2Si2O7 is limited due to serious growth difficulties of such crystals by the Czochralski technique. At the first time this crystal was grown without crucible using Scull melting technique combined with pulling up. It was found that the electric conductivity of Ce-(La,Gd)2Si2O7 melt was enough for the direct heating by electric field produced by the high frequency power generator (0.5-1 MHz). Several different electrically conductive materials were tested for the formation of starting amount of the melt at the process beginning. Application of such combined technique allowed us to use air as the growth atmosphere instead traditional inert one and to realize melt overheating before beginning of the growth process for the gas bubbles removing without visible evaporation of SiO2. Also, the application of air as growth atmosphere has resulted to the decrease of the Oxygen vacancies concentration in the grown crystal and improve of the scintillation properties. Scintillation and optical properties of the crystal grown by the crucible-free technique were compared with the properties of bulk Ce-(La,Gd)2Si2O7 crystal grown by the conventional Czochralski technique.

Keywords: oxide scintillator, growth from melt
Poster panel: 323

Poster Number:
N-07-323

Temperature variation of the scintillation properties of Cs2HfCl6 described with a three state model (#1466)

M. Koshimizu1, K. Saeki1, Y. Fujimoto1, G. Okada2, T. Yanagida2, S. Yamashita3, K. Asai1

1 Tohoku University, Department of Applied Chemistry, Graduate School of Engineering, Sendai, Japan
2 Nara Institute of Science and Technology, Division of Materials Science, Ikoma, Japan
3 The University of Tokyo, Nuclear Professional School, School of Engineering, Tokai, Japan

Content

The temperature dependence of the scintillation intensity of Cs2HfCl6 was measured and found to increase monotonically from 10 K to 300 K, whereas no significant dependence on temperature was observed in scintillation decay. A simple three-state model in which two excited levels are slightly different in their energies and have similar radiative rates was able to describe the experimental trends. The model is consistent with the experimental observation of two kinds of Vk centers and with theoretical predictions of two types of self-trapped excitons reported in the literature.

Keywords: Cs2HfCl6, self-trapped exciton, scintillation, temperature dependence
Poster panel: 325

Poster Number:
N-07-325

X-ray induced luminescence properties of Sr2CeO4 ceramics (#1522)

T. Kato1, G. Okada1, N. Kawaguchi1, T. Yanagida1

1 Nara Institute of Science and Technology, Graduate School of Materials Science, Ikoma, Japan

Content

Inorganic scintillators, which convert high energy ionizing radiation to thousands of photons, have been playing a major role in many fields of radiation detection, including medicine, security, oil-logging, environmental monitoring, astrophysics and particle physics. There are primarily three types of inorganic materials used in radiation detections: single crystal, ceramic and glass. Scintillators are properly selected depending on the applications. Single crystal scintillators such as NaI:Tl, CsI:Tl, CdWO4 and Bi4Ge3O12 are used in gamma cameras, detectors for security and baggage inspection, X-ray detectors in computed tomography (CT) and block detectors in positron emission tomography and high-energy physics. Ceramic scintillators such as (Y,Gd)2O3:Eu and Gd2O2S have been used in both medical and industrial X-ray detectors for CT-scanning applications. Terbium-activated gadolinium silicate glass as a glass scintillator is useful in large-area and fiber-optic plate detectors for industrial X-ray inspection systems.

In this study, we have synthesized a series of Sr2CeO4 ceramics sintered at different temperatures by solid-state reaction. Then, we investigated the scintillation and PL properties such as X-ray induced scintillation spectra, scintillation decay curves, pulse height spectra under 137Cs γ-ray irradiation, PL excitation/emission spectra and PL decay curves.

In X-ray induced scintillation spectra of Sr2CeO4 ceramic samples, an emission peak at 510 nm was observed in all the samples. Similar emission peak was also reported by the earlier work, in which the origin of this mission was ascribed to ligand-to-metal CT. Then, we measured pulse height spectra of all the Sr2CeO4 samples measured under 137Cs γ-ray irradiation. The absolute light yields were derived as relative values to that of conventional Y3Al5O12:Ce crystal scintillator. The derived absolute light yield was 3,200 ph/MeV.

Keywords: scintillator, Ceramic
Poster panel: 327

Poster Number:
N-07-327

Effects of Mo co-doping on luminescence and scintillation properties of Ce doped LYSO single crystal scintillators (#1729)

K. J. Kim1, 3, K. Kamada2, 3, M. Yoshino1, G. Luidmila4, 3, Y. Shoji3, 1, V. V. Kochurikhin3, 4, A. Yamaji1, S. Kurosawa2, Y. Yokota2, Y. Ohashi2, A. Yoshikawa1, 3

1 Tohoku University, Institute for Materials Research, Sendai, Japan
2 Tohoku University, New Industry Creation Hatchery Center, Sendai, Japan
3 C&A Corporation, Sendai, Japan
4 General Physics Institute, Russian Academy of Sciences, Moscow, Russian Federation

Content

Scintillator materials combined with photodetectors are used to detect high energy photons and particles e.g., in X-ray computed tomography (CT), positron emission tomography (PET) and other medical imaging techniques, high energy and nuclear physics detectors, etc. In the last two decades, great R&D effort brought several new material systems, namely the Ce-doped orthosilicates as Gd2SiO5 (GSO), Lu2SiO5 (LSO), (Lu1−xYx)2SiO5 (LYSO), pyrosilicates based on RE2Si2O7 (RE=Lu, Y, Gd) and most recently LaX3 (X=Cl,Br) single crystal hosts.

Mo co-doping with Pr3+ and Ce3+ in the several host materials were investigated such as YAlO3 (YAP), LuAlO3 (LuAP), LuxY1-xAlO3 (LuYAP), and Lu3Al5O12 (LuAG). Those studies showed that the co-doping of Mo is capable of improving the scintillation properties. However, there were no reported results about the Mo co-doping with Ce for LYSO host.

The aim of this work is to investigate the Mo co-doping effects on luminescence and scintillation properties of Ce:LYSO single crystal scintillators for the first time. The Mo co-doped Ce:LYSO single crystals were prepared by micro-pulling down(m-PD) method with a wide concentration range of the co-dopants. Absorption, radioluminescence, PLE and PL spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of Mo co-doping. Comparing to Ce3+ only doped LYSO, Mo 1000 ppm co-doped crystal has almost 1.5 times higher light yield and shows accelerated scintillation decays. Details of changes in scintillation properties with Mo co-doping will be reported in my presentation.

Poster panel: 329

Poster Number:
N-07-329

Improved Growth of Intrinsic and Highly Proportional Scintillator Cs2HfCl6 (#1879)

R. Hawrami1, E. Ariesanti1, L. Matei1, V. Buliga1, A. Burger1, S. Lam2, S. Motakef2

1 Fisk University, Life and Physical Sciences/Physics, Nashville, Tennessee, United States of America
2 CapeSym, Inc., Natick, Massachusetts, United States of America

Content

This research focuses on the growth of single phase Cs2HfCl6 (CHC) as well as improvement its radiometric and scintillation performance. A single crystal CHC boule of 15mm in diameter is grown using the vertical Bridgman method. Samples retrieved from the boule are characterized for their optical and scintillation properties. Energy resolution of 3.1% (FWHM) at 662 keV has been obtained. Gamma-ray non-proportionality of CHC will be compared to that of NaI:Tl, BGO, and LaBr3. Light yield, decay time as well as physical properties of CHC will be reported.

Poster panel: 331

Poster Number:
N-07-331

Optical and Scintillation Properties of Pb2ZnF6 Crystals (#2004)

R. Mao1

1 SICCAS, Shanghai, China

Content

We present in this work the optical and scintillation properties of Pb2ZnF6 (PZF) crystals. Undoped and Eu doped PZF samples were grown by Non-vacuum Bridgman method. The cutoff wavelength for the undoped PZF was determined to be 230 nm. Strong emission was found peaking at 380, 580, 610 and 695nm under X-ray excitation in Eu doped sample. While undoped PZF Crystal may serve as a Cherenkov material, the Eu doped PZF Crystal may find its usage in filed where fast scintillation is not necessary.

Keywords: Scintillator, cherenkov radiator, cutoff wavelength
Poster panel: 333

Poster Number:
N-07-333

Characterization of Ce-doped Tb3Al5O12 scintillators with various Ce-concentrations (#2075)

D. Nakauchi1, G. Okada1, N. Kawaguchi1, T. Yanagida1

1 Nara Institute of Science and Technology (NAIST), Graduate School of Science and Technology, Ikoma, Japan

Content

Scintillators have been utilized to detect high-energy photons and particles in various fields including medical imaging, security, astrophysics, high-energy physics, and well-logging. In general, the desired characteristics of scintillators include high light yield (LY), short decay time, high energy resolution, low afterglow, and high effective atomic number especially for X- and gamma-ray detections. To date, Ce-doped rare-earth aluminum garnet (RE3Al5O12, RE=Y, Gd, Lu) scintillators have been intensively studied owing to their distinct scintillation properties such as high LY and fast response. We previously investigated scintillation properties of Ce-doped Tb3Al5O12 (TAG) bulk crystals and confirmed a notably high LY (57,000 photons/MeV). To extend our previous studies on Tb-based garnet materials for scintillator applications, we studied TAG single crystals with different Ce-concentrations.

Under X-ray irradiation, the samples exhibit scintillation with a broad emission band peaking at around 550 nm as well as a few sharp peaks at 580 nm. The former emission is attributed to the 5d-4f transitions of Ce3+ while the latter seems to be the 4f-4f transitions of Tb3+ (5D47F4). From the pulse height spectrum of 137Cs gamma-ray measured using Ce:TAG crystals, all the samples show clear photoabsorption peaks. From the peak position, the 3% Ce-doped sample seems to exhibit the highest LY.

Keywords: scintillator, photoluminescence, radioluminescence, singel crystal
Poster panel: 335

Poster Number:
N-07-335

Evaluation of Eu:SrAl2O4 crystal and translucent ceramic scintillators (#2083)

D. Nakauchi1, F. Nakamura1, G. Okada1, N. Kawaguchi1, T. Yanagida1

1 Nara Institute of Science and Technology (NAIST), Graduate School of Science and Technology, Ikoma, Japan

Content

Luminescent materials have been utilized in radiation detection, and they are classified into two types such as scintillators and storage-type phosphors. Scintillators convert a single quantum of ionizing radiation into thousands of low energy photons immediately, so they have been playing an important role in various fields of radiation detections including medical imaging, security and so on. On the other hand, storage-type phosphors have a function to store and accumulate the incident radiation energy and emit a light with external stimulations of light or heat. In our previous study, we have shown that singly Eu-doped SrAl2O4 crystals show notably high scintillation light yield (46,000 photons/MeV). In this study, we prepared Eu:SrAl2O4 translucent ceramic for the first time, and the scintillation properties of translucent ceramic and single crystal are evaluated for comparison.

Under X-ray irradiation, the samples exhibit scintillation with a dominant broad emission around peaking at 520 nm. Suggested from the spectral shape, the emission origin would be due to Eu2+. From the pulse height spectra of 137Cs gamma-rays measured using Eu:SrAl2O4, the light yield of the crystal and ceramic samples are 26,000 and 5,500 ph/MeV, respectively.

Keywords: scintillator, single crystal, photoluminescence, radioluminescence
Poster panel: 337

Poster Number:
N-07-337

Photoluminescence and scintillation properties of TlMgCl3 crystal (#2088)

Y. Fujimoto1, K. Saeki1, M. Koshimizu1, G. Okada2, T. Yanagida2, K. Asai1

1 Tohoku University, Department of Applied Chemistry,, SENDAI, Japan
2 Nara Institute of Science and Technology, Graduate School of Materials Science,, NARA, Japan

Content

We report the luminescence and the scintillation properties of a newly developed thallium magnesium chloride (TlMgCl3) crystal. The crystal sample can be easily fabricated from the melt using the Bridgman method. The photoluminescence band appeared near the wavelength of 405 nm under excitation at 230 nm. An X-ray-induced scintillation spectrum showed an intense emission band near the wavelength of 405 nm. The decay time constant was estimated to be approximately 60 ns (~25%) and 350 ns (~75%) using a bi-exponential fitting. The scintillation light yield reached 46,000 photons/MeV with an energy resolution of 6% at 662 keV.

Poster panel: 339

Poster Number:
N-07-339

Quantum dot nanocomposite polymers for radiation detection and nuclear security (#2153)

T. Crane1, N. Bazin1, C. Macqueen1, J. Burns1

1 AWE, Reading, United Kingdom

Content

Plastic scintillators offer a low cost radiation detection platform readily scalable to large area detectors of interest for nuclear security applications. However, organic materials typically have limited spectroscopic capability due to their low effective atomic number and small photoelectric cross section. The traditional approach to developing improved plastic scintillators has been doping with high atomic number elements, however, more recent efforts have investigated polymers containing fluorescent nanocrystals. In this study we describe the fabrication of polyvinyl toluene scintillators incorporating semiconductor quantum dots. We characterise the optical emission profiles of the samples using photoluminescence spectroscopy and measure their radiation detection performance using a selection of radiological sources

Keywords: Plastic scintillators, Composites, Nanomaterials, Quantum dots, Nuclear security
Poster panel: 341

Poster Number:
N-07-341

Comparative Analysis of Common Scintillator Crystals in Emission Tomography Using Fuzzy PROMETHEE (#2206)

B. Uzun1, I. Ozsahin2, N. A. Isa2, D. Uzun Ozsahin2, 3

1 Near East University, Department of Mathematics, Nicosia, Turkey
2 Near East University, Department of Biomedical Engineering , Nicosia, Turkey
3 Massachusetts General Hospital & Harvard Medical School, Gordon Center for Medical Imaging, Boston, Massachusetts, United States of America

Content

With the recent improvement and development of nuclear medicine imaging devices, the need for new or improved crystals is also triggered. Undoubtedly, the main component affects the performance of a nuclear medicine imaging device is the crystal. There are several factors that contribute to the overall performance of the crystals used in these devices, including density, decay time, energy resolution, and relative light output. Some of these factors are highly desirable for the optimal performance of the crystal material while other factors should be minimal for their performance. The performance values of these crystals are closely related to each other in such a way that it becomes challenging for engineers or manufacturers to effectively utilize. It is important to understand that ideal crystal does not exist, but the choice of existing crystal is done based on the crystal's quality parameters. The aim of this research is to use fuzzy Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE) multi-criteria decision-making theory to analyze and compare commonly used scintillator crystals using the factors affecting their performance. The evaluation result showed that lutetium oxyorthosilicate (LSO) and lutetium-yttrium oxyorthosilicate (LYSO) are the best scintillator crystals mainly due to their high density and relatively high energy resolution. Results also showed that CsI(Tl) came last on the ranking because of its relatively very low performance value form the important parameters. With fuzzy PROMETHEE, one can determine the most suitable crystal based on the selected criteria and pre-defined weight according to desired application.

Keywords: PROMETHEE, Scintillator Crystals, Emission Tomography
Poster panel: 343

Poster Number:
N-07-343

Scintillation and Thermoluminescence Properties of Sn-doped Zinc Sodium Phosphate Glasses (#2479)

N. Kawaguchi1, G. Okada1, T. Yanagida1

1 Nara Institute of Science and Technology (NAIST), Ikoma, Japan

Content

Scintillation and thermoluminescence properties of Sn-doped zinc sodium phosphate glasses were studied. We synthesized the glass samples by the conventional melt-quenching method under ambient atmosphere. The obtained glasses were highly transparent in 400-2700 nm. Depending on the Sn concentration, PL quantum yield (QY) ranged from 7.7 to 25.7%, and the PLQY increased with increasing the Sn concentration. The Sn-doped samples showed radioluminescence (scintillation) with a broad feature due to the 5sp→5s2 transition of Sn2+ ions under X-ray excitation. The PL decay constants were 4.72-4.83 microseconds, and any dependence on the concentration of Sn was not observed. These decay constants are acceptable for typical applications of the scintillator. The glasses showed intense thermoluminescence, and the glow curves had a broad feature peaking at 110°C. Among the present samples, the 0.5% Sn-doped sample exhibited the highest sensitivity with a good linearity over 5 orders of magnitude (0.1-10000 mGy).  Sn-doped zinc sodium phosphate glasses should be promising for personnel dosimeter applications.

Keywords: glass, scintiilator, dosimeter
Poster panel: 345

Poster Number:
N-07-345

Hierarchical clustering of CsI(Tl) scintillation detector pulses (#2573)

O. Sobolev1, A. Y. Boyarintsev1, A. Gektin1, T. Gladkikh2, V. Suzdal1

1 Institute for Scintillation Materials NAS of Ukraine, Kharkiv, Ukraine
2 National Technical University , Kharkiv, Ukraine

Content

Traditionally, all the photons generated during the scintillation process are considered to be "identical" and their contribution to the formation of the amplitude spectrum is not differ­entiated. Last results show that "fast" and "slow" pulse components, arising apparently from various processes possess with different statistics. Let us hypothesize that the photons gener­ated by different processes are not statistically identical. In such case, the decomposition of the multitude of pulses measured at the output of the photomultiplier based on the domina­tion of a certain type photons in them will make it possible to differentiate the contribution of various scintillation mechanisms.

A series of scintillation and numerical experiments were carried out. Their essence is as follows: a set of approximately 500 thousand pulses (18 microseconds long) were vectorized. Under vectorization procedure we understand the counting of a certain number of partial sums (integrals) of each pulse and the formation of these sums to vectors for each pulse in the set. The amplitude spectrum for this set was plotted.The clusterization of the obtained vectors that have fallen into one channel of the amplitude spectrum was carried out. In all experiments, the multitude of pulses in each channel was divided into 3-5 groups of which 1 or 2 in terms of the number of elements exceeded significantly the others.

An extra series of experiments is aimed to the study of the pulses shape without differ­entiating them by amplitude spectrum channel. The result is a set of clusters and a dendrogram of clusters (easy visualization of decom­position of pulses to groups). Amplitude spectra plotted basing on the obtained clusters, in most cases, have different width at half height of the maximum absorption pulse.

Proposed decom­position methods could be helpful both for the study of a scintillation process and for a number of engineering solutions for spectrometric tasks. 

Keywords: energy resolution, hierarchical clustering
Poster panel: 347

Poster Number:
N-07-347

Temperature dependence and bandgap evaluation for Ce:(La, Gd)2Si2O7 scintillator (#2859)

S. Kurosawa1, 2, T. Horiai3, Y. Shoji3, R. Murakami3, S. Yamato3, A. Yamaji3, M. Yoshino3, Y. Yokota1, Y. Ohashi1, K. Kamada1, A. Yoshikawa1, 3, A. Ohnishi2, M. Kitaura2

1 Tohoku University, New Industry Creation Hatchery Cente, Sendai, Japan
2 Yamagata University, Faculty of Science, Yamagata, Japan
3 Tohoku University, Institute for Materials Research, Sendai, Japan

Content

Ce:(La, Gd)2Si2O7 (Ce:La-GPS) scintillator crystals with a good energy resolution (FWHM) of 5% at 662 keV were obtained, and good scintillation properties were found to be stable up to 450 K. The temperature dependence was found to be related to the band gap energy and defect level; generally, a sample with large energy-deference between the bottom of conduction band and 5d level of Ce3+ can maintain the light output at even high temperature. In this paper, we measure the energy-deference for Ce:La-GPS, using several methods such as photon-stimulated luminescence. However, the difference of Ce:La-GPS was approximately 1 eV, and it is not higher remarkably than that of other samples such as Ce:(Lu,Y)2SiO5. Thus, we assume that Ce:La-GPS has the number of some trap sites between the bottom of conduction band and 5d level of Ce3+ than other scintillators, and we measured the thermo-luminescence for several samples. The results showed Ce:La-GPS has smaller number of the traps than others. We show the detail of the results and discuss the band gap structure in this paper.

Keywords: scintillator, La-GPS, tmepearture dependence
Poster panel: 349

Poster Number:
N-07-349
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Optimisation of Monolithic Nanocomposite and Ceramic Garnet Scintillator Thickness for PET (#2899)

K. Wilson1, R. Alabd1, D. R. Franklin1

1 University of Technology Sydney, School of Electrical and Data Engineering, Faculty of Engineering and IT, Ultimo, Australia

Content

Two new classes of materials have recently emerged as lower-cost alternatives to single-crystal scintillators, particularly where complex shaping of the scintillator is required: nanocomposites and ceramic garnets. These materials offer interesting opportunities for medical imaging applications due to their lower cost and their ability to be easily formed into complex or unconventional shapes. A common shortcoming of both nanocomposites and transparent ceramic scintillators is their lower optical transparency compared to single-crystal scintillators; for nanocomposites or ceramics, increasing the thickness beyond a certain point reduces the effective sensitivity due to increased optical attenuation. Therefore, determining the thickness for the scintillator which will result in the maximum detection probability is an important design question for those wishing to utilise these materials in PET systems and other radiation detection applications. This work proposes a general method for determining the optimal thickness for maximum detection accuracy and efficiency, given the physical properties of the scintillator material, based on Monte Carlo simulations of monolithic scintillator slabs. The method is demonstrated by applying it to provide a quantitative comparison between a range of proposed nanocomposite and transparent ceramic scintillators.

Keywords: nanocomposites, PET, scintillators, ceramic garnets, monolithic
Poster panel: 351

Poster Number:
N-07-351

On monolithic silicon array detectors for small-field photon beam dosimetry (#1459)

G. Biasi1, J. A. Davis1, M. Petasecca1, S. Guatelli1, V. Perevertaylo3, T. Kron1, 2, A. B. Rozenfeld1

1 University of Wollongong, School of Physics, Wollongong, Australia
2 Peter MacCallum Cancer Centre, Melbourne, Australia
3 SPA-BIT, Kiev, Ukraine

Content

Small radiation fields are used in x-rays radiotherapy to deliver highly conformal dose distributions. In this context, sub-millimetre spatial resolution is a crucial detector requirement for quality assurance applications.
2D monolithic silicon array detectors can be fabricated of large area while optimizing the spatial resolution with small sensitive volumes. They have the potential to offer a stable and near photon energy-independent response, good linearity with absorbed dose and real-time read-out. Sensitive volumes are ion-implanted on a silicon wafer whose geometry and physical characteristics (resistivity, defects concentration) affect the detector performance.
The Octa is a novel 2D monolithic silicon array detector dedicated to small-field dosimetry. Its 512 diode-sensitive volumes are arranged with a sub-millimetre pitch along 4 intersecting linear arrays.
We report on the numerical characterization (performed with Sentaurus™ Workbench within the Synopsys® framework) of two Octa detectors, manufactured respectively on a bulk and on an epitaxial silicon substrate. We show that the Sentaurus™ Heavy Ion Model and the Sentaurus™ Gamma Radiation Model could be invaluable tools to characterize the expected performance of a semiconductor dosimeter in terms of its spatial resolution and the charge collection efficiency of its sensitive volumes as a function of pitch and substrate parameters.

Keywords: small-field dosimetry, x-ray radiotherapy
Poster panel: 353

Poster Number:
N-07-353

CACTUS : A High-Voltage CMOS Monolithic Active Pixel Timing Sensor (#1534)

Y. Degerli1, F. Balli2, F. Guilloux1, C. Guyot2, M. Lachkar1, J. - P. Meyer2, A. Ourarou2, P. Schwemling2, M. Vandenbroucke1

1 IRFU, CEA, Université Paris-Saclay, DEDIP, Gif-sur-Yvette Cedex, France
2 IRFU, CEA, Université Paris-Saclay, DPhP, Gif-sur-Yvette Cedex, France

Content

The increase of luminosity foreseen for the Phase-II HL-LHC upgrades calls for new solutions to fight against the expected pile-up effects. One approach is to measure very accurately the time of arrival of the particles with a resolution of few tens of picoseconds. In addition, a spatial granularity better than a few millimeter will be needed to obtain a fake jet rejection rate acceptable for physics analyses. These goals could be achieved by using the intrinsic benefits of a standard High-Voltage (HV) CMOS technology -in conjunction with a high-resistivity detector material- leading to a fast, integrated, rad-hard pixel sensor ASIC. Proofs of the detection capability and radiation hardness have already been shown for HV technology. We will present here the architecture and simulation results of a 1 cm² monolithic pixel sensor, called CACTUS, dedicated to timing measurements. This sensor has been designed in LFoundry 150 nm HV CMOS process and submitted in December 2017. Each pixel of the sensor comprises a large charge collection diode and the front-end (charge preamplifier and discriminator) integrated inside the diode. Two pixel pitches have been implemented: 1 x 1 mm² and 0.5 x 1 mm². Most parameters of the sensor are programmable via slow-control. Device (TCAD) simulations and electrical simulations studies based on the technology design kit have shown that a resolution of the order of 50 to 80 ps per MIP impact point can in principle be reached for a HV-CMOS MAPS pixels sensor with 1 mm pixel pitch. The wafers are expected back from Foundry in May 2018. They will be thinned at 50, 100 and 200 microns and post-processed for backside polarization, to study timing performance as a function of sensor thickness and polarization. A test-bench has been developed around a Raspberry-Pi and a precision waveform digitizer (Wavecatcher), and will be used to measure the performance of the sensors, using cosmic rays, and electron beams of a few MeV available at Saclay.

Keywords: Timing sensor, CMOS Monolithic Pixel Sensor, Precision Timing
Poster panel: 355

Poster Number:
N-07-355

First Measurement of X-rays Generated by Runaway Electrons in Tokamaks Using a TimePix3 Device with 1 mm thick Silicon Sensor (#1591)

V. Linhart1, D. Bren1, A. Casolari2, J. Cerovsky2, M. Farnik2, O. Ficker2, M. Hetflejs1, J. Jakubek3, P. Kulhanek2, E. Macusova2, M. Marcisovsky1, J. Mlynar2, P. Svihra1, V. Svoboda1, J. Urban2, J. Varju2, V. Vrba1, V. Weinzettl2

1 Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering , Prague 1, Czech Republic
2 Czech Academy of Sciences, Institute of plasma Physics, Prague, Czech Republic
3 Advacam, s.r.o., Prague 7, Czech Republic

Content

An application study of modern pixel semiconductor detectors for characterization of runaway electron events in tokamaks is presented. Characterization techniques utilizing both spectroscopy and monitoring of the intensity of secondary X-rays produced by the runaway electrons were used. Energy spectra of X-rays and time evolutions of their intensity on two tokamaks (Golem and Compass) were measured under different conditions, compared with results of standard plasma diagnostics techniques and analyzed using physical models. The energy spectra measured on both tokamaks have similar exponential shapes, but with a significant variation in numbers of events per shot. Estimation of mean velocity of runaway electrons on the tokamak Golem was performed using comparison of numbers of events generated by runaway electrons flying frontward and backward with respect to a limiter of this tokamak. The time evolutions of the X-ray intensity during several discharges on the tokamak Golem were measured using both the TimePixe3 device and scintillation detectors (NaI(Tl) and YAP(Ce)). On a microsecond time scales, the signal time evolution measured by the TimePix3 device shows patterns in a form of unexpected increases of the intensity. The positions of these intensity maxima correlate with signals recorded from the scintillation detectors. Measurements in the immediate vicinity of tokamak Compass were impossible to perform because of a rapid change of the tokamak magnetic field. Measurements performed in the distance of at least 0.5 m from the tokamak Compass gave millions of correctly measured events per shot and an unknown number of events affected by pileups. The correctly measured events were used for construction of energy spectra and the time evolutions of the X-ray intensity. The recorded patterns in this evolution have been in a form of either unexpected or periodic-like increases of the X-ray intensity on a microsecond scale.

Keywords: pixel detector, time evolution
Poster panel: 357

Poster Number:
N-07-357

Design, Fabrications, and Performance Tests of the Pixelated Silicon Sensors with a JFET Readout Structure. (#1765)

S. Song1, H. Jeon1, K. Kang1, H. Kim1, H. Lee2, S. Lee1, H. Park1

1 Kyungpook National University, Physics, Daegu, Republic of Korea
2 Institute for Basic Science, Center for Underground Physics, Daejeon, Republic of Korea

Content

We design and fabricate a position sensitive pixelated detector on the high resistivity n-type silicon of > 5 kΩ•cm with a thickness of 650 µm, considering the detection efficiency for the direct illumination of low energy X-ray. A concept of JFET (Junction Field Effect Transistor) is employed as the switch to readout so that the number of readout channels is reduced and fast signal processing is possible. A combination of the silicon PIN diode and JFET has the double metal structure, which is inevitably complicated and difficult fabrication process. The TCAD simulations show the detector performance is sensitive to the design of the P-well on the junction side and we design the pixels with a size of 30 µm, 100 µm, and 200 µm lengths with different design parameters. The prototype of the detector is fabricated with a photomask which has a multi-chip configuration consisted of six layers into a single reticle. We present TCAD simulations, design, fabrication and electrical characteristics of prototype pixelated detector with JFET switch.

Keywords: Pixel sensor, JFET switch, Simultation, Fabrication, Transistor
Poster panel: 359

Poster Number:
N-07-359

A Compton polarimeter based on planar Si(Li)-detector technology (#1871)

T. Stoehlker1, 3, T. Krings4, U. Spillmann1, M. Vockert2, 3, G. Weber2

1 GSI, AP, Darmstadt, Hesse, Germany
2 Helmholtz Institute Jena, Jena, Thuringia, Germany
3 Friedrich Schiller Universitaet, IOQ, Jena, Thuringia, Germany
4 Forschungszentrum Juelich, IKP, Jülich, North Rhine-Westphalia, Germany

on behalf of the SPARC Collaboration

Content

We present a Compton polarimeter which is based on a single thick planar silicon crystal that has its front and backside segmented into horizontal and vertical strips, respectively. Each segment is read out as an individual detector, resulting in an energy, time and position sensitive detector technology. It was specially designed with the focus on quantitative measurements of the degree of linear polarization of x-rays in the energy range from 40 keV to 200 keV. By applying preamplifiers with cryogenically cooled input stages we were able to improve the energy resolution of the present polarimeter system by a factor of two compared to our former systems which is resulting in a significant increase in data quality. Directly connected to the higher resolving power of the system is the increased event reconstruction selectivity. By this we are widening the applicability of this technology in our studies that aim for the study of fundamental atomic processes at ions storage rings or synchrotron facilities in the aforementioned energy range.

Keywords: Si(Li), Compton Polarimetry
Poster panel: 361

Poster Number:
N-07-361

Design and simulations of CLIPS monolithic pixel detector (#1899)

S. Bugiel1

1 AGH-University of Science and Technology, Faculty of Physics and Applied Computer Science, Cracow, Poland

on behalf of CLICdp collaboration

Content

This contribution presents the test-beam results of a monolithic pixel-detector prototype fabricated in \SI{200}{\nano\meter} Silicon-On-Insulator (SOI) CMOS Fully-Depleted Low-Leakage technology provided by the Japanese Lapis Semiconductor Company. The presented detector is a first prototype for studying the spatial resolution possibilities and it is targeting a CLIC vertex detector requirements of \SI{3}{\micro\meter} resolution.
The detector is fabricated on a \SI{500}{\micro\meter} thick high-resistivity float-zone n-type (FZ-n) wafer. The pixel size is \SI{30x30}{\micro\meter} and two readout electronic architectures were implemented: a source-follower and a charge preamplifier configuration. The SOI detector was tested at the CERN SPS H6 beam line in 2016. The test-beam data were analysed in order to compute the spatial resolution and detector efficiency. The analysis chain includes pedestal and noise calculation, cluster reconstruction, as well as alignment and $\upeta$-correction for non-linear charge sharing. The SOI prototype is characterized by high signal to noise ratio in range from \numrange{250}{350} above full depletion, that is achieved at around \SI{70}{\volt}. The results show a spatial resolution of around \SI{2}{\micro\meter} at full depletion for each pixel type. For low back-bias voltages corresponding to depletion thickness of about \SI{100}{\micro\meter} the resolution for charge-preamplifer matrix is still around \SI{3}{\micro\meter}, which fulfil the CLIC vertex detector requirements. The combined detector and readout efficiency is estimated to \SI{99.4}{\percent}.

Keywords: pixel detector, spatial resolution simulations, SOI, vertex detector, monolithic
Poster panel: 363

Poster Number:
N-07-363

A novel and simple method for fabrication of edgeless silicon radiation detectors (#1954)

O. Koybasi1, A. Kok1, A. Summanwar1, M. Povoli1, L. Breivik1

1 SINTEF, Department of Microsystems and Nanotechnology (MiNaLab), SINTEF Digital, Oslo, Norway

Content

There is a need in many applications of silicon radiation detectors including high energy physics, synchrotron experiments and nuclear medicine to reduce the insensitive volume of the sensor at the periphery, where guard rings are located, to a negligible level. Sensors without an inactive edge can be grouped together in a tile-up configuration to build large area imaging systems that can capture seamless images or can be operated in "edge-on" configuration with minimal signal loss. A few institutes including SINTEF have been employing micromachining and MEMS technology in radiation sensors over the last decade to develop so-called "edgeless sensors" by replacing the insensitive guard ring area with an active edge. The traditional approach taken so far to make an active edge involves direct bonding of the device wafer to a support wafer, opening a continuous trench all around the active area of the sensor by deep reactive ion etching (DRIE) and then doping of the trench. Once the sensor processing has been completed, the support wafer, which is needed to keep the integrity of the device wafer after DRIE, has to be removed for most applications, and this has been the main drawback of this traditional approach due to the difficulty of the removal process. We have recently developed a simplified method for fabrication of edgeless sensors with edge insensitivity of < 10 micron, which does not require a support wafer for processing. The need for a support wafer is eliminated by replacing the continuous trench by a segmented trench. We will present the design, fabrication, and characterization results of our newly developed mass-manufacturable edgeless detectors.

Keywords: active edge detector, edgeless detector, silicon radiation detector, pixel detector, strip detector
Poster panel: 365

Poster Number:
N-07-365

Characterisation of an ‘Edgeless’ Dosimeter for Angular Independent Measurements in Advanced Radiotherapy Treatments (#2181)

S. Alhujaili1, 2, J. A. Davis1, J. Davies3, M. Lerch1, A. B. Rozenfeld1, M. Petasecca1

1 University of wollongong, physics, Wollongong, Australia
2 Aljouf University, Radiology and medical imaging, sakaka, Saudi Arabia
3 Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia

Content

In this paper, the performance of an ‘edgeless’ device is evaluated for use as an angular independent detector for dosimetric quality assurance in intensity modulated radiotherapy. The ‘edgeless’ diodes were tested in terms of their electrical properties (IV and CV), charge collection efficiency and radiation hardness. A model of the ‘edgeless’ device was developed in order to simulate its behaviour using Synopsys TCAD and has been validated against experimental measurements. The charge collection efficiency is tested by IBIC for n-type and p-type edgeless detectors. The simulation provides a reason for the different behaviour of the two configurations. The angular dependence measurements of edgeless devices before and after 2 Mrad irradiation shows negligible effect of the variation of the effective lifetime of the carriers. The findings of this work illustrates the ability of edgeless diodes to provide high quality performance in radiotherapy dosimetric QA with minimal angular dependence.

Keywords: Silicon detector, Angular dependance, Radiotherapy dosimetry
Poster panel: 367

Poster Number:
N-07-367

SINTEF 3D Pixel Run-4 fabrication and characterisation (#2219)

O. Røhne1, M. Povoli2, B. Stugu3, A. Heggelund1, O. Dorholt1, H. Sandaker1, A. Read1, A. Kok2, O. Koybasi2, A. Summanwar2

1 University of Oslo, Fysisk institutt, Oslo, Norway
2 SINTEF, Digital, Oslo, Norway
3 University of Bergen, Department of Physics and Technology, Bergen, Norway

Content

  This contribution details the fabrication procedure together with
  electrical characterisation results. The pre-irradiation evaluation
  of the sensor assemblies will be shown and the irradiation campaign
  will be described.  Post-irradiation results will be discussed and
  analysed and future planned development and activities will be
  outlined, aiming at the qualification of the Norwegian collaboration
  for the production of 3D pixel sensors for the innermost layer of the
  ATLAS ITk.
 

Keywords: silicon, sensor, tracking, pixel
Poster panel: 369

Poster Number:
N-07-369
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A novel detector for low-energy photon detection with fast response. (#2381)

N. Moffat1, R. Bates1, M. Bullough2, N. Tartoni3

1 University of Glasgow, Particle Physics Experimental, Glasgow, United Kingdom
2 Micron Semiconductor Ltd, Lancing, United Kingdom
3 Diamond Light Source, Didcot, United Kingdom

Content

A new avalanche silicon detector concept is introduced with a low gain in the region of 5 to 10,

known as a Low Gain Avalanche Detector, LGAD. The lower gain reduces noise compared with

a standard avalanche photodiode. The LGAD can be segmented to produce hybrid pixel detectors

for low energy X-ray detection. Thin LGAD's produce the same, or larger, signals as standard

PIN diode detectors produced by minimum ionising particles (mips), however the collection time is

reduced. The thickness reduction factor of an LGAD sensor is equal to the gain of the LGAD. For

example; a 30μm thick sensor with a gain of 10 will give the same signal from a mip as a 300μm

thick PIN diode. The LGAD has a fast rise time, useful for fast silicon timing detectors with sub-

ns rise times from X-ray or mip interactions. Simulation of LGADs, using Sentaurus TCAD, of a

pixelated device has been performed to determine the implant structures for the required gain and

high voltage characteristics and to understand the in-pixel gain uniformity for a range of pixel sizes.

Devices have been fabricated at Micron Semiconductor which produce the desired gain, 10, and electrical performance with a breakdown voltage > 400V. LGAD sensors

compatible with the Timepix readout system with varying pixel sizes have been fabricated. The

X-ray fluorescence photon counting technique is used with the Timepix arrays looking at the spectra

produced for devices with and without gain and demonstrating the detection of the lowest incident

X-ray energy, below that of the Timepix noise floor. Demonstrating the applicability of these devices

for low energy synchrotron applications. Along with the detection of low energy photons these devices

have produced a very fast response. Devices with this technology will be used in both

the ATLAS and CMS timing detectors using pixels of the order 1mm x 1mm. Pixels have been

fabricated in 2x2 and 5x5 arrays. The measurements of gain and timing are presented, with timing

resolution of the order 30ps.

Poster panel: 371

Poster Number:
N-07-371

Characterization of SINTEF 3D diodes with different inter-electrode spacings after neutron irradiation up to 2x1016 n eq/cm2 (#2443)

R. Mendicino1, 2, G. - F. Dalla Betta2, 1, G. T. Forcolin1, 2, A. Kok3, O. Koybasi3, N. Neha2, 1, M. Povoli3, A. Summanwar3

1 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Trento, Trento, Italy
2 University of Trento, Department of Industrial Engineering, Trento, Italy
3 SINTEF , MiNaLab, Oslo, Norway

Content

Due to radiation hardness requirements, 3D detectors are the best candidate technology for the innermost tracking layers at the High Luminosity LHC (HL-LHC) as well as for radiation monitoring in long space missions. In the framework of the project “Three-dimensional Low-Voltage Silicon Detectors” funded by ESA, SINTEF MiNaLab has developed novel full-3D detectors with slim- and active-edges. Functional tests to measure the charge collection efficiency after irradiation at the fluences expected at the HL-LHC cannot be accurately measured using the current readout chips due to their limited radiation tolerance. As an alternative, small-size 3D diodes connected to discrete read-out channels can be used. This study is aimed at investigating the performance of 3D sensors of different inter-electrode spacing which were designed and fabricated by SINTEF MiNaLab (Oslo, Norway).
At the conference, we will recall the main design and technological aspects for these sensors, and report selected results from their characterization with IR laser after neutron irradiation up to 2x1016 neq /cm2

Keywords: 3D Detector, Semiconductor characterization, radiation damage, charge collection efficiency
Poster panel: 373

Poster Number:
N-07-373

 Efficiency and resolution performance of the largest-diameter, commercial semi-planar HPGe detectors (#2553)

E. G. Roth1, G. G. Geurkov1, A. Bosco2

1 ORTEC/AMETEK, Oak Ridge, Tennessee, United States of America
2 Consultant, Vienna, Austria

Content

AMT-ORTEC has pioneered development of a large-diameter series of semi-planar profile detectors eclipsing other commercial offerings in the market by competitors. Two new 105 mm and two new 94 mm diameter detector models have been developed to expand ORTEC’s popular Stable Thin Front Contact (STFC) detector product lines. The GEM-S10530 and GEM-S10535 detectors will be offered with two different crystal lengths 30 and 35 mm. The GEM-S9430 and the GEM-SP9430 detectors will be offered with a single crystal length of 30 mm, but with two different back contacts.

Several experimental measurements have been performed to study the actual performance of these new detector models. These measurements were done with two different sets of electronics both analog modules and a digital Multi-Channel Analyzer (MCA) and two different cooling methods, liquid nitrogen and mechanical cooling. The results of this study include relative efficiency and energy resolution performance for gamma energies ranging from 3 keV up to 3 MeV. In addition, a series of Monte-Carlo simulations benchmarked to experimental results have been performed to evaluate the absolute efficiencies of these new large-diameter detectors for the most common counting geometries. These absolute efficiencies have been compared to those obtained using conventional coaxial high purity germanium (HPGe) detectors with comparable relative efficiencies to illustrate the superior performance of these new detector models at low-to-medium energies, and continued quality performance at high-energies.

Keywords: Large diameter, HPGe, ORTEC, Stable Thin Front Contact (STFC)
Poster panel: 375

Poster Number:
N-07-375

Development of a monolithic array of linear silicon drift detectors for energy-dispersive materials characterization (#2719)

G. Pepponi1, G. Borghi1, E. Demenev1, F. Ficorella1, D. Matsunaga2, A. Picciotto1, N. Zorzi1, P. Bellutti1

1 FBK, Trento, Italy
2 HORIBA, Ltd., Kyoto, Japan

Content

Silicon drift detectors (SDDs) are the most widely used sensors for energy dispersive x-ray detection. SDDs can detect x-rays with energies from a few hundred eV to some tens of keV. In particular, sensitivity to low energy x-rays depends on the quality of the process in terms of thickness of the non-active layer on the x-ray exposure side whereas sensitivity to high-energy x-rays depends on the thickness of the detector (and hence of the active layer). When connected to a state of the art CMOS preamplifier SDDs provide high energy resolution at short shaping times and therefore can be used at high count rates. Typical commercial sensors are single drift chambers with an active area ranging from a few mm2 to 150mm2. Nuclear science experiments as well as x-ray astronomy has pushed the development of large area and multi element silicon drift detectors. In this work a monolithic array composed of 10 linear silicon drift detectors has been developed for different applications in the field of materials characterization, targeting in particular the combination of X-ray fluorescence with non-monochromatic scattering techniques (X-ray diffraction, X-ray reflectivity). The design is based on linear drift chambers of 1 mm width and 8 mm length with a small anode placed in the middle of the strip for a total sensitive area of 80mm2. The sensors were produced on <100> high resistivity floating-zone Si wafers having a diameter of 150 mm and a thickness of 0.45 mm. The electric characterization indicated a leakage current below 0.3 nA/cm2 at room temperature that should allow the sensor to reach an energy resolution below 160 eV FWHM for the Mn Kα line (5.89 keV) even at room temperature. Spectroscopic performances of the detector will be presented and discussed.

Keywords: silicon drift detector (SDD), array, materials characterization
Poster panel: 377

Poster Number:
N-07-377

Application of silicon planar structures for the determination of the spectrum of the proton beams produced by laser-driven proton medical accelerators. Part II. Dose rate effect. (#2817)

I. E. Anokhin1, A. B. Rozenfeld2

1 Institute for Nuclear Research, Department of Theoretical Physics, Kyiv, Ukraine
2 University of Wollongong, Centre for Medical Radiation Physics , Wollongong, Australia

Content

The using of super-powerful lasers (petawatt and higher) for the producing of the controlled proton beams and their application in various fields is an intensive research area in the last 20 years. It is supposed that such lasers can be used as an alternative to radio-frequency accelerators to obtain beams with appropriate characteristics that are necessary for the cancer treatment.

The present work continues investigation the possibility of the application of thin silicon planar p-i-n diodes for the proton spectrum determination of the laser-driven proton beams. The most notable differences between particle irradiation from laser-driven and conventional sources are the wide angular divergence and dose rate. For example, dose rates provided by a conventional accelerator are usually below 1 Gy/sec (but can be as high as ~103 Gy/sec for the spot scanning mode). By contrast, with laser-driven radiation, the dose rate can exceed 109 Gy/sec and the irradiation time can be much shorter (typically nanoseconds).

In the present work, the effect of the very high dose rate on the charge generation and collection is theoretically investigated. The model of the detector response on the proton beam irradiation with the super high dose rate has been proposed.

Keywords: Silicon radiation detectors, Laser-driven particle accelerators, Nuclear medicine, Dose rate
Poster panel: 379

Poster Number:
N-07-379

Evolution of silicon Single Strip detectors for use in microbeam radiation therapy. (#2944)

A. Dipuglia1, 3, J. A. Davis1, M. J. Cameron1, M. Petasecca1, 2, V. Perevertaylo4, A. B. Rozenfeld1, 2, M. Lerch1, 2

1 University of Wollongong, Centre for Medical Radiation Physics, Wollongong, Australia
2 University , Illawarra Health and Medical Research Institute, Wollongong, Australia
3 Royal North Shore Hospital, Department of Radiation Oncology, St Leonards, Australia
4 SPA-BIT, Kiev, Ukraine

Content

In this study, we demonstrate the improved performance of the second generation epitaxial silicon based Single Strip detector developed by the Centre for Medical and Radiation Physics. The improved design for the device implemented a thinner epitaxial silicon layer (50->38 µm) and reduced strip width (10->5 µm) intended to reduce the sensitive volume size and improve further radiation hardness. The result is an improved spatial resolution of the device and subsequent suitability for dosimetry in microbeam radiation therapy. Measurements were also undertaken in this study to demonstrate the improved spatial resolution as compared to the first generation device. The effect of improved spatial resolution with respect to dosimetric QA in microbeam radiation therapy is quantified.

Keywords: MRT, SSD, Dosimetry
Poster panel: 381

Poster Number:
N-07-381
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TRISTAN: a novel 10M pixels Time Resolved detector based on Timepix3. Firmware development at Diamond Light Source. (#1245)

G. Crevatin1, D. Omar1, I. Horswell1, H. Yousef1, E. Gimenez-Navarro1, N. Tartoni1

1 Diamond Light Source Ltd, Didcot, United Kingdom

Content

The time stamping capabilities of the Timepix3 readout chip, developed by the Medipix3 collaboration led by CERN, can be applied very effectively to time resolved X-ray experiments at synchrotron facilities. Diamond Light Source is developing a large area detector (TRISTAN) based on Timepix3. TRISTAN will tile 160 Timepix3 chips to achieve a sensitive area of 16 by 23 cm (10M pixels), large enough to be used in beam lines such as the small molecule crystallography beam line I19 at Diamond.

This development presents some major challenges in several areas that include mechanics, interconnections, data acquisition software and firmware. In this contribution the challenges related to the firmware and how they have been resolved are described.

TRISTAN is arranged in 10 independent modules. The firmware running in the Virtex7 FPGA of each module needs to handle in parallel 128 LVDS data lines coming from the 16 chips of the module (8 lines per chip). Each module can output up to 80 Gb/s. To sustain this sheer data rate the firmware implements an architecture of 8 parallel buffers that contains the data of the events ordered by their Time of Arrival. The time boundary between buffers is programmable and is set to maximize the data throughput.

The Time of Arrival delivered by Timepix3 chips is 18 bits, meaning that the maximum time interval that can be measured from the start of the acquisition is 409.6 us with the nominal clock cycle of 640 MHz. The firmware in the FPGA extends the Time of Arrival of each event to 52 bits leading to a time interval that is suitable for any practical experiment. As the events are sent by the Timepix3 chip with unpredictable delays, the bit extension feature in the firmware needs to account for it to prevent errors. A state machine has been developed to implement this function.

The data acquisition firmware has been thoroughly tested with the first prototype module both on the bench and with the synchrotron X-ray beam. The results will be shown.

Keywords: X-Ray detector, Time-resolved experiment
Poster panel: 383

Poster Number:
N-07-383

Beam Position Monitors of High Flux Synchrotron Radiation Based on Pixel Diamond Detector for HEPS in CHINA (#1361)

Z. Li1, G. Chang1, Q. Li1, Y. F. Zhou1, P. Liu1

1 Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, BEIJING, China

Content

High Energy Photon Source (HEPS) with a beam energy of 6GeV and emittance less than 1.0nm·rad will be constructed in China, which can provide high-brightness hard X-ray in the order of 1022(phs/s/mm2/mr2/0.1%B.W.). The broadband and high-brightness monochromatic beam flux and white beam flux need new detector other than the ion chambers for measurement in case of saturation under high-flux conditions. The Diamond X-ray detector for the beam position monitoring and high brightness X-ray detection is developing for High Energy Photon Source in China. The diamond detector has advantages over other detector materials: a low atomic number resulting in a low absorption cross-section when used as beam position monitor and a high radiation and wide linear range when used as beam intensity measuring. In this paper, the polycrystalline chemical-vapor-deposition diamond detectors with an aluminium contact have been tested at 1W2B beamline at Beijing Synchrotron Radiation Facility (BSRF). A transmission-mode diamond X-ray detector is designed to simultaneously measure the X-ray flux, beam position in real time.

Keywords: diamond detector, HEPS
Poster panel: 385

Poster Number:
N-07-385

X-Tream dosimetry of synchrotron radiation with the PTW microdiamond (#1525)

J. A. Davis1, 2, M. Petasecca1, 2, A. Dipuglia1, J. Paino1, A. B. Rozenfeld1, 2, M. Lerch1, 2

1 University of Wollongong, Centre for Medical Radiation Physics, Wollongong, Australia
2 University of Wollongong, Illawarra Health and Medical Research Institute, Wollongong, Australia

Content

In this study, we demonstrate that the X-Tream dosimetry system developed by the Centre for Medical Radiation Physics can be used with both commercial and non-commercial dosimeters. A custom adaptor was constructed to connect the PTW microdiamond to the X-Tream DAQ. This allowed for the measurements of continuous depth dose curves, broad beam and microbeam profiles. The X-Tream system enables real time measurement of the instantaneous dose rate of synchrotron generated radiation with the PTW microdiamond. Finally, measurements undertaken in this study demonstrate that the X-Tream system is able to mitigate the alignment issue that has previously hampered the uptake of the PTW microdiamond in clinical QA for small field dosimetry.

Keywords: synchrotron, microbeam radiation therapy, dosimetry
Poster panel: 387

Poster Number:
N-07-387

Performance Test of Focal-Plane Modules of the DSSC X-ray Imager (#2371)

P. Kalavakuru1, K. Hansen1, H. Klaer1, C. Reckleben1, M. Kirchgessner2, F. Erdinger2, P. Fischer2, M. Porro3, J. Soldat2

1 Deutsches Elektronen-Synchrotron, Hamburg, Hamburg, Germany
2 Universitaet Heidelberg, Heidelberg, Baden-Württemberg, Germany
3 European XFEL GmbH, Schenefeld, Schleswig-Holstein, Germany

Content

The DSSC mega-pixel X-ray imager is being developed for experiments at the European XFEL for low energies between 0.5 keV and 6 keV. The smallest unit comprises the electronics for the operation and readout of 512-by-128 pixels. The current version is based on miniaturized silicon-drift detector (mini-SDD) cells and is under series production. A future active sensor type based on DEPFETs is currently available in a smaller format of 64-by-64 pixels and uses the same ladder electronics. For both detector types, the readout ASIC comprises a filter for analog signal processing, an 8-bit ADC for digitization, and a memory to store 800 images on pixel level. Due to versatility of the control system, both detector types can be flexibly operated at different types of X-ray sources (radioactive, synchrotron, FEL). We present the operation and results of the small-format DEPFET module at a synchrotron beam line of Petra-III and the functionality tests of the first full-format mini-SDD ladder utilizing a pulsed LED source at XFEL timing condition.

Keywords: DSSC, DEPFET, XFEL, single photon resolution, X-ray imager
Poster panel: 389

Poster Number:
N-07-389

Design of LCLS-II ATCA BPM System (#2951)

A. Young1, J. frisch1, S. Hoobler1, L. Sapozhnikov1, T. Straumann1

1 Stanford Linear accelerator Center National Laboratory, Menlo Park, California, United States of America

Content

Abstract-- SLAC’s new Linac Coherent Light source (LCLS-II) is a next generation X-ray Free Electron Laser (FEL) that will use a CW 4 GeV superconducting linac with nominal bunch spacing of 1µs to deliver both soft and hard X-Rays FEL to experimenters. A continuous stream of CW pulses with timing precision in the femtosecond region promises unprecedented beam luminosity of about 104 times the existing LCLS-I, but also poses many new challenges for precision measurement and controls electronics.  In order to achieve the required performance, the SLAC Technical Innovation Directorate (TID) has developed a common hardware and firmware platform with carrier boards for beam instrumentation based on the ATCA crate format. The team has designed a family of applications including Stripline and Cavity Beam Position Monitors, Timing, Bunch Length, Bunch Charge and Machine Protection Subsystem, all based on this common platform.  The BPM system has a dynamic range between 1 pC to 300 pC at a resolution of 12.4 Effective Bits; and Timing has precision of 7.2 picoseconds. The paper will discuss the design of the beam diagnostic electronics, overall architecture and performance on LCLS-I and other projects where we are using the ATCA platform including a novel cryogenic sensor project for understanding Dark Energy and probing the physics of Inflation through the Cosmic Microwave Background (CMB).

Keywords: Cosmic Microwave Background, Linac Coherent Light source, Beam Position Monitors