IEEE 2017 NSS/MIC/RTSD ControlCenter

Online Program Overview Session: N-23

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NSS Poster Session II

Session chair: Stylianos Chatzidakis Oak Ridge National Laboratory; Azaree Lintereur Penn State University
Shortcut: N-23
Date: Wednesday, October 25, 2017, 10:20
Room: Grand Hall West
Session type: NSS Session


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Poster panel
(face) ID: 2

Poster Number:

A 128-Channel High Performance Time-to-Digital Converter Implemented in an UltraScale FPGA (#1390)

J. Kuang1, Y. Wang1, C. Liu1

1 University of Science and Technology of China, Modern Physics Department, Hefei, Anhui, China


A 128-channel time-to-digital converter (TDC) with decimation TDC architecture was implemented in a Xilinx UltraScale field programmable gate array (FPGA) and the performance of 16 TDC channels was evaluated. The TDC RMS time precisions were measured in the range of 4.7 – 5.6 ps, and TDC measurement throughput reaches 350 M events/second. The test results show that the decimation method, which we proposed in our previous work, can balance well TDC time precision and FPGA resource consumption, so that integrating a very high channel count TDC system into an FPGA with high performance is very practicable. FPGA based TDC has bright future in applications of particle physics experiments and nuclear medicine imaging.

Keywords: TDC, FPGA
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(face) ID: 4

Poster Number:

The development of a pixel ion detector for stigmatic time-of-flight imaging mass spectrometry (#1472)

Y. Fujita1, Y. Arai1, T. Hondo2, H. Matsuoka2, H. Hazama2, Y. Kawai3, J. Aoki3, M. Toyoda3, K. Awazu2

1 High Energy Accelator Research Organization, Institute of Particle and Nuclear Studies, Tsukuba, Ibaraki, Japan
2 Osaka University, Graduate School of Engineering, Suita, Osaka, Japan
3 Osaka University, Graduate School of Science, Toyonaka, Osaka, Japan


The studies of a stigmatic imaging mass spectrometry that magnify spatial distribution of samples by an electrostatic lens and measure the entire measurement field at one time have been conducted to realize higher spatial resolution and shorter measurement time relative to the mainstream scanning imaging mass spectrometry. The detector for the stigmatic imaging mass spectrometer requires detecting the position and the flight time of flying ions simultaneously. Currently the available detector for this application is a delay line detector, but this is unsuitable for multi-hit detection since it has been developed for the low rate ion collision event measuring. The multi-hit detector which can accept multiple ions is required to realize a useful stigmatic imaging mass spectrometer. To solve this problem we have started to develop a position and time detector by using a Silicon-On-Insulator (SOI) CMOS technology.

Since high speed response is required to measure the time of flight, we have developed prototypes of a two dimensional time detectable pixel array detector by 0.2 um SOI CMOS process. Each pixel has an electrode pad which accepts ions, an independent discriminator and memory. When ions arrive at the electrode pad, the discriminator detects it and the time stamp is stored in the memory. The time information is distributed from a time generator.

The main elements of the prototype consist of 64 x 64 pixel array and a time generator that provides the flight time of ions. The time generator consists of an 8-bit gray code counter and Time Memory Cell (TMC). TMC is prepared for 1ns time resolution. Thanks to TMC higher frequency clock is not necessary to realize high time resolution. The pixel size is 64 x 64 um2 and the detectable area is 4,096 x 4,096 um2. To get better signals from MCP we prepared the custom package integrated with MCP for the detector. In the result we successfully obtained single ion images in the ion irradiation test.

Keywords: ASIC, MALDI-TOF, imaging mass spectrometer, pixel detector, time measurement
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(face) ID: 6

Poster Number:

A Modular Architecture for the Semi-Automatic Design and Layout of Pipelined ADC Arrays (#1725)

C. Grace1, E. Fong1, D. Gnani1, T. Stezelberger1, H. von der Lippe1, P. Denes1

1 Lawrence Berkeley National Laboratory, Berkeley, California, United States of America


The Pipelined ADC is popular for imaging ASIC applications due to its tolerance of errors and good balance between speed, accuracy, die area, and power consumption, particularly when each stage is custom designed. Unfortunately, optimizing a Pipelined ADC can be challenging given tight schedule and budget constraints. In order reduce to the implementation overhead of high-performance Pipelined ADCs, a modular architecture and a set of software scripts to design and implement optimized Pipelined ADC arrays in a semi-automatic way have been developed based on a simple unit cell. This architecture allows a high-performance ADC to be designed without custom-designing each stage, significantly reducing design time.

The key to the architecture is the unit cell, multiple instances of which can be placed in parallel to implement a larger stage. Because parallel capacitors add and the equivalent on-resistance of CMOS switches decreases when put in parallel the overall RC time constants of the stages can be kept constant. Placing amplifier stages in parallel increases their driving capability. After the required capacitance is calculated based on noise considerations, the biasing details of the stages can be calculated automatically. The scripts also size and place appropriate clock buffers and reference voltage buffers.

The modular ADC architecture has been used to implement a 24-channel, 12-bit, 25 MS/s ADC array for scientific imager readout in 180 nm CMOS technology. The ADC array achieves input-referred noise of 190 µV-rms, DNL of 0.54 LSB and dissipates 70 mW per channel.

Keywords: Analog-to-Digital Conversion, Mixed-Signal IC Design, Automated Layout, Solid-State Imaging
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(face) ID: 8

Poster Number:

PACIFIC: LHCb Scintillator Fibre Tracker Readout ASIC (#2001)

A. Comerma1

1 Heidelberg Universitat, Physikalisches Institut, Heidelberg, Germany


A short introduction about the Scintillator Fibre Tracker (SciFi) detector including it's basic characteristics and signals generated will be followed by a comprehensive description of the PACIFIC readout ASIC architecture and characterization results focusing on latest prototype measurements. Special emphasis will be done in commenting the electrical and test-beam results. Different data coming from simulation, electrical characterization, radioactive source signal injection and test-beam will be used to ilustrate the main features and performance of PACIFIC. The design modifications in the elctronics driven by the detector performance will also be presented. Finally single event upset mitgation techniques and test results will be commented.

Keywords: PACIFIC, LHCb, ASIC, SciFi
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(face) ID: 10

Poster Number:

The Associative Memory Serial Link Processor of the ATLAS Fast TracKer Processing System (#2152)

C. - L. Sotiropoulou1

1 University of Pisa and INFN Sezione di Pisa, Department of Physics, Pisa, Italy


The trigger system of the ATLAS experiment at LHC will improve the capability of the detectors to select the events with the greatest scientific potential. During operations in 2017-2018 the Fast TracKer system (FTK) will be introduced. FTK is a hardware based system capable of finding charged particle tracks by analyzing hits in silicon detectors at the rate of 105 events per second. The track reconstruction is executed by first finding the candidate tracks by matching a combination of low resolution hits to predefined patterns; hits selected from these matched to these patterns are used in a second processing step for a more precise track fitting algorithm. The main processing element of FTK is the Associative Memory (AM) system that is used to perform pattern matching with high degree of parallelism. Its implementation is called the AM Serial Link Processor (SLP) and it is a very efficient pattern matching machine that handles massively parallel data.
The AM SLP consists of two types of boards: the Little Associative Memory Board (LAMB), a mezzanine where the AM chips are mounted, and the Associative Memory Board (AMB), a 9U VME motherboard which hosts four LAMB daughter-boards. We report on the complex FPGA design that has been implemented to operate the high degree of parallelism of the board. We also report on the commissioning status of the AM SLP and on the performance of the Processor during the first data taking.

Keywords: Trigger, tracking, FPGA, electronics, associative memory
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(face) ID: 12

Poster Number:

Two-level DLL with Femtosecond Added Jitter for a Low Power 20 GS/s Sampling ASIC (#2257)

P. Orel1, G. S. Varner1

1 University of Hawaii at Manoa, Physics and Astronomy, Honolulu, Hawaii, United States of America


Vertex detectors in high luminosity colliders are subject to high hit rates leading to high occupancies. The proposed Timing Vertex Detector (TVD) is a potential solution that requires a readout application specific integrated circuit (ASIC) that measures pulse arrival times with a timing resolution in the range of 100 fs or less. Present efforts are centered on the development of such ASIC. One critical requirement is low added jitter. At the same time, high channel density (126 per chip) also imposes strict requirements in terms of power consumption. In this paper, we present results of the study on added jitter and jitter propagation in inverter chains for the 130 nm technology node. Furthermore, we propose a novel two-level delay-locked loop (DLL) topology for the RFpix prototype with an estimated worst case added jitter of 40.5 fs and power consumption of 0.98 mW per DLL.

Keywords: DLL, PLL, Femtosecond timing, ASIC, jitter, TVD, vertex detector
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(face) ID: 14

Poster Number:

Development of CdTe Hybrid Pixel Detector ASIC for Spectroscopic Fine Imaging (#2688)

T. Orita1, S. Takeda1, H. Ikeda2, T. Takahashi2, 3, H. Sugawara1

1 Okinawa Institute of Science and Technology Graduate University, Advanced Medical Instrumentation Unit, Onna-son, Okinawa, Japan
2 Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Sagamihara, Kanagawa, Japan
3 The University of Tokyo, Department of Physics, Bunkyo-ku, Tokyo, Japan


Cadmium telluride (CdTe)  semiconductor has been regarded as a promising material for hard X-ray and gamma-ray detector. Its high atomic number gives high detection efficiency in the energy range between several tens and several hundreds in keV. Since it also has a good energy resolution, it has been applied to many fields such as medical application, non-destructive inspection, astronomy observation.  It can have a fine pitch structure with its matured semiconductor fabrication process to realizes a higher position resolution needed for high quality imaging.  To read out the large number of a fine pitch structure detector, we utilize a pixel type ASIC where circuit cells are two-dimensionally arranged to be directly connected to each pixel sensor. It has advantages of connectivity with low input stray capacitance. In high count rate case such as medical applications, pixel type ASICs and detector can avoid ghost hits. Based on the past design, we designed and fabricated 28 by 28 pixel type ASIC whose pixel size is 250 um by 250 um with TSMC 0.35-um process. It can work either in both of peak-hold mode or sample-hold mode and performs parallel AD conversion. We tested circuit performance and confirmed that its ENC was 40 electrons and its INL was about 1%.

Keywords: CMOS, Front-end ASIC, CdTe Pixel sensor, Hard X-ray Imaging, Gamma-ray Imaging
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(face) ID: 16

Poster Number:

A Rad-Hard 12-bit Auto-Calibrated ADC in CMOS 65nm (#2858)

F. Ciciriello1, C. Marzocca1

1 Polytechnic of Bari, Department of Electrical and Information Engineering, Bari, Bari, Italy


In the framework of the CHIPIX65 project, that aims at prototyping a new generation readout ASIC in 65nm CMOS for pixel detectors at HL-LHC, a 12-bit ADC has been designed for monitoring slowly varying signals and dc voltage reference levels. The maximum conversion rate is expected to be 5 kHz, limiting the power consumption to less of 400uW. The architecture of the ADC is based on a dual-slope integrating structure and the circuit developed has a 460umx275um area. All the analog blocks have been placed in a deep n-well for better rejecting noise coming from the digital part. In addition, an innovative self-calibration procedure has been implemented in hardware to set the internal configuration registers of the ADC, which control its configurable parameters, as soon as the circuit is powered up. Two versions of the ADC have been prototyped and the second one has been also integrated in the CHIPIX65 demonstrator ASIC. First measurement tests have been carried out to validate the performance of the circuit in terms of linearity and resolution.

Keywords: Rad-Hard, CMOS 65nm, 12-bit ADC
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(face) ID: 18

Poster Number:

High Speed Electronics for Sensitive Neutron Detection in High Count Rate Scenarios (#3169)

J. L. Lacy1, N. S. King1, H. Phung1, T. Lyons1, A. Athanasiades1, C. S. Martin1

1 Proportional Technologies, Inc., Houston, Texas, United States of America


Proportional Technologies, Inc. continues to develop detectors using boron-coated straw technology for 3He replacement in Homeland Security applications. Increasingly, such applications are targeting neutron detection in high gamma flux scenarios, which may include neutron rates near background or on the order of thousands of counts per second. In support of our neutron detectors, we have continued to develop faster, lower power electronics to qualify them for these operational scenarios. Unlike 3He detectors, boron-coated straw technology provides the freedom to operate at low counting gas pressures, thus increasing the speed of electron migration, without reducing sensitivity of the detectors. Therefore, we present a series of improvements on our current amplifier circuit to read out these detectors. In this work, we demonstrate that optimized amplifier designs can decrease the circuit’s time to return to baseline from 20 microseconds down to 0.2 microseconds, providing a ~100-fold increase in detection rate capabilities without significant power or cost trade-off. Further improvements to the circuit design indicate that this baseline restoration can be further reduced to a mere 80 ns.

Keywords: amplifier, count rate, baseline restoration, neutron detector
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(face) ID: 20

Poster Number:

A Verification Platform to provide the Functional, Characterization and Production testing for the VFAT3 ASIC. (#3413)

P. Aspell2, M. Dabrowski2, 5, G. De Lentdecker3, G. De Robertis4, A. Irshad2, T. Lenzi3, F. Licciulli4, F. Loddo4, H. Petrow1, F. Robert3, J. Rosa3, T. Tuuva1

1 Lappeenranta University of Technology, Lappeenranta, Finland
2 CERN, Meyrin, Switzerland
3 Université libre de Bruxelles, Bruxelles, Belgium
4 Istituto Nazionale di Fisica Nucleare – Sezione di Bari, Bari, Italy
5 Katholieke Universiteit Leuven, Leuven, Belgium


VFAT3 is a front-end ASIC designed for the readout of GEM detectors in the CMS Muon system. The strategy for the chip design was to design the full chip at once but provide extensive test and de-bug facilities for individual characterization of each internal chip module.  The verification platform consists of three parts; namely the software (running on a PC), the firmware (designed for a Kintex-7 FPGA development board) and a selection of VFAT3 dedicated hardware boards for the different stages of verification. The system was designed to accommodate all of the steps needed to fully test the chip. The first step is the functional testing for which only rather simple functions are needed. For the functional testing the software has an interactive interface to communicate with the chip through the FPGA. The requirements for the hardware are mostly the possibility for the use of the main communication channels. For the characterization of the chip the software offers a possibility to easily generate lists of routine instructions that can be uploaded to the FPGA and run as synchronous commands. This allows for example the scanning of the chips internal calibration DACs and creation of S-curves for all of the front-end channels. The hardware boards of the system allows access to the vast amount of test pads needed for the characterization and de-bug of the chip. The production tests require concatenated test routines where speed and execution efficiency are crucial. The software and the firmware of the system were designed to allow flexible evolution to increase the efficiency of complicated test routines.

Keywords: high energy physics, verification platform
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(face) ID: 22

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MATISSE: A Versatile Readout Electronics for Monolithic Active Pixel Sensors Characterization (#3599)

J. Olave1, 2, A. Rivetti1, L. Pancheri3, 6, S. Panati1, 2, F. Cossio1, 2, P. Giubilato4, 5, D. Pantano4, 5, S. Mattiazzo4, M. D. Da Rocha Rolo1

1 INFN di Torino, Torino, Italy
2 Politecnico di Torino, DET, Torino, Italy
3 Università di Trento, Trento, Italy
4 Università di Padova, Padova, Italy
5 INFN di Padova, Padova, Italy
6 TIFPA, Trento, Italy


Monolithic Active Pixel Sensors are becoming increasingly attractive as charge particle tracking devices for the next generation of High Energy Physics experiments. For this reason several R&D activities are ongoing in different laboratories to improve the performance of conventional monolithics in terms of signal to noise ratio and radiation tolerance. Those improvements come both from the use of different technologies and materials and from the optimization of the front-end electronics. In this context, technologies which allow simultaneous integration of analog and digital electronics in the same pixel are also increasingly exploited.

Here, a versatile readout electronics has been specifically developed for a detailed characterization of MAPS with an expected depletion depth of more than 30 µm. Different silicon substrates have been explored to achieve the best performance. The ASIC prototype has been fabricated in 0.11 µm CMOS technology with a die area of 2x2 mm2 and a low voltage operation of 1.2 V. The test chip consists of a matrix of 24x24 pixel units organized in four independent sectors and an End of Column logic. The in-pixel electronics fits an area of 30x30 µm2 and it is therefore suitable to develop compact monolithic pixels of 40x40 µm2 or more.

The strong point of such readout system is the flexibility which allows to get a low power consumption, a very easy scalability and a good adaptability for both sensor polarities.

Hereafter, the front-end electronics will be described and detailed tests obtained on a first submission will be presented.

Keywords: MAPS, ASIC, Front-end Electronics, Monolithic Sensors, Silicon Sensors
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(face) ID: 24

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Pico-TDC: a novel FPGA-based TDC with 2.2ps RMS timing resolution (#4061)

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


The purpose of this work is to develop low-cost high-performance TDCs to meet the requirement from the next generation sub-10ps TOF-PET camera. A TOF-PET system may need hundreds of high resolution TDCs to read timing from many detectors. FPGA-based TDC designs, such as conventional delay-line (DL) TDCs and Wave-Unions (WU) TDCs, are a more viable solutions compared with expensive ASIC-based TDCs. However, the performances of those FPGA-based TDCs are more or less depended on the specific structures and performances of the delay lines, which are usually the carry chains in the adders of a FPGA.    

In this paper, we present a new method called Pico-TDC method to construct the TDCs in FPGA. The uniqueness of the Pico-TDC method is to use single registers in the FPGA as low-precision TDCs, and to combine many of those low-precision TDCs to construct a high-precision TDC. The advantages of Pico-TDC method are: (1) the timing performance of a Pico-TDC is not limited by the performance of delay lines in the FPGA. As a result, it is possible to achieve unprecedented resolution with a low-cost FPGA. (2) Hundreds of high-performance Pico-TDCs can be constructed in a low-cost FPGA which normally has millions of registers. (3) Theoretically, the Pico-TDCs can be conveniently migrated from one FPGA to another, regardless of the differences in the internal structures of the FPGAs.

We have successfully constructed four channels of Pico-TDCs in a low-cost FPGA (Altera Cyclone V 5CEBA4F23C7N, price: $66.63). Each TDC uses 640 registers (low-precision TDCs). The four Pico-TDCs were tested with both the internal and the external pulses. The RMS of the timing measurements is 2.2 ps. The temperature stability is excellent. We conclude that Pico-TDCs have excellent timing performance which meets the requirement of the next generation sub-10ps TOF-PET.

Keywords: TDC, Time of Flight, FPGA, CRT
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(face) ID: 26

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Development of data-acquisition system for reducing dead time in our Gamma Ray Compton Telescope (#1165)

K. Yoshikawa1, T. Tanimori1, A. Takada1, T. Mizumoto1, Y. Mizumura1, S. Komura1, T. Kishimoto1, T. Takemura1, Y. Nakamasu1, T. Taniguchi1, Y. Nakamura1, H. Kubo1, T. Sawano2, K. Nakamura1, S. Sonoda1, K. Miuchi3, S. Kurosawa4, 5, J. D. Parker1

1 Kyoto University, Depertment of Physics, Kyoto, Japan
2 Kanazawa University, Division of Mathematical and Physical Sciences, Kanazawa, Japan
3 Kobe University, Depertment of Physics, Kobe, Japan
4 Tohoku University, Institute of Material Research, Sendai, Japan
5 Yamagata University, Department of Physics, Yamagata, Japan


For MeV gamma-ray astronomy, we have developed an electron-tracking Compton camera (ETCC) as a next generation satellite telescope. Our detector consists of a Compton scattering target and a scattered gamma-ray absorber. The target is gas with a Time Projection Chamber (TPC), which uses micro pixel chamber (micro-PIC) as the 2-dimensional readout detector, and the absorber is a position sensitive scintillation arrays (PSAs). The ETCC provides all the parameters of Compton-scattering, and determines the direction of incident gamma-ray, event by event. With a well-defined Point Spread Function (PSF), the ETCC realize imaging spectroscopy. We have an observation plan of the ETCC on a satellite. At first, we launched a small size ETCC with a 10 cm cube TPC on balloon in 2006 and observed successfully the fluxes of the diffuse cosmic and atmospheric gamma rays (SMILE-I). As the next step, we constructed a middle size (30 cm cube) ETCC and performed ground-based experiments (SMILE-II). The SMILE-II ETCC had about 100 times higher sensitivity than the SMILE-I detector. We plan to update the SMILE-II ETCC and observe the electron-positron annihilation line in the galactic center, using a balloon in Australia in early 2018 (SMILE-II+). The SMILE-II+ and the future ETCC have a lager effective area than the SMILE-II, and trigger rates increase. In the SMILE-II data acquisition (DAQ) system, the dead time is about 40 % at the trigger rate of 200 Hz due to sending data via VME bus and common start system in PSA. Reducing the dead time, test model ETCC is made which uses ethernet and common stop system in PSA. Although the dead time is about 20 % at 30 Hz in the ETCC with SMILE-II DAQ system, the dead time is about 20 % at 2 kHz in the new system.

Keywords: Nuclear Imaging, gamma ray detectors, solid scintillation detectors, time projection chamber, readout electronics
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(face) ID: 28

Poster Number:

Performance and Environmental Compatibility of a High Resolution Single Photon UV imaging Detector Readout (#2188)

A. Seljak1, G. Varner1, V. Virta1, K. Le1, J. Vallerga2, R. Raffanti3

1 University of Hawaii, Department of Physics and Astronomy, Honolulu, Hawaii, United States of America
2 University of California, Berkeley, Space Sciences Laboratory, Berkeley, California, United States of America
3 Techne Instruments, Oakland, California, United States of America


For future NASA space missions that use high-rate, single UV photon imaging we produced a prototype,
50 mm x 50 mm aperture, UV single photon imaging detector. The new readout system for this detector is composed of programmable Charge Sensitive Amplifiers (CSA), and a 12bit, Giga Sample Per Second (GS/s) digitizing ASIC (HalfGRAPH). Both ASICs were designed by the group and were recently irradiated with 200 kRad dose using Gamma rays in order to qualify for Jupiter mission. The detector readout system consists of 160 readout channels and consumes a total power of 12 Watts. This figure includes as well the two ARTIX 7 FPGAs for data processing. We present the construction of the readout system and initial results obtained from the detector. Additionally, We discuss a novel ASIC topology (named GRAPH) presently in design, which encapsulates the front end on a single chip.

Keywords: ASICs, Readout systems, Single photon detection
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(face) ID: 30

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Neon solid crystals as hybrid detector for low energy deposition events (#2347)

M. Guarise1, 2, C. Braggio3, 4, R. Calabrese1, 5, G. Carugno3, 4, A. Dainelli2, A. Khanbekyan1, 5, E. Luppi1, 5, E. Mariotti6, 7, M. Poggi2, L. Tomassetti8, 5

1 Università di Ferrara, Dipartimento di Fisica e Scienze della Terra, Ferrara, Italy
2 INFN, Laboratori Nazionali Legnaro, Legnaro (Pd), Italy
3 Università di Padova, Dipartimento di Fisica e Astronimia, Padova, Italy
4 INFN, Sezione di Padova, Padova, Italy
5 INFN, Sezione di Ferrara, Ferrara, Italy
6 Università di Siena, Dipartimento di Scienze Fisiche, della Terra, e dell'Ambiente, Siena, Italy
7 INFN, Gruppo collegato di Siena, Siena, Italy
8 Università di Ferrara, Dipartimento di Matematica e Informatica, Ferrara, Italy


In this work we present a novel approach for detection of low energy release that exploits solid crystals made of inert gases al cryogenic temperature that can be furthermore doped with alkali atoms. The electrons free within the crystal following the interaction of the detectable particle, drift toward the surface and are then emitted through the crystal--vacuum surface. With high efficiency silicon detector or micro--channel--plate (MCP) a single electron sensing can be possible, allowing in principle to develop a detector with low energy threshold. With un--doped crystals a few hundreds of electrons, that carry an information of few eV per each, can be detected; otherwise the alkali doping could permit an energy threshold in the milli--eV range.

We present the very preliminary measurements carried out in a Neon crystal with a cm3--volume. These starting tests are aimed at the verification of electrons emission through the crystal--vacuum interface. With this test we also verify the purity of the crystal. In these tests, electrons aren't generated by an interacting particle but are injected into the Neon matrix using photoelectric effect in a gold foil where the crystal is attached.

Keywords: particle detector, dark matter detector, inert gases crystals
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(face) ID: 32

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A very large-area linear Silicon Drift Detector for high-throughput spectral-timing X-ray astrophysical missions (#2799)

R. Campana1, Y. Evangelista2, M. Feroci2, A. G. Vacchi4, P. Bellutti5, G. Bertuccio3, F. Fuschino1, M. Grassi7, C. Labanti1, P. Malcovati7, A. Rachevski4, I. Rashevskaya6, G. Zampa4, N. Zampa4, M. Ahangarianabhari3, M. Gandola3

1 INAF, IASF-Bologna, Bologna, Italy
2 INAF, IAPS, Rome, Italy
3 Politecnico di Milano - INFN, Milano, Italy
4 INFN - Trieste, Trieste, Italy
5 FBK, Povo (Trento), Italy
6 INFN, TIFPA, Trento, Italy
7 Università di Pavia, Department of Electrical, Computer, and Biomedical Engineering, Pavia, Italy


In the framework of the ReDSoX collaboration and of the proposed ESA high energy astrophysics mission LOFT (Large Observatory For x-ray Timing), a large area multi-anode Silicon Drift Detector (SDD) has been developed, sensitive in the 2-30 keV energy range. Having overall dimensions of about 11 cm x 7 cm, a sensitive area of 76 cm^2 read out on both sides by 224 anodes at a pitch of 970 um, this is likely the SDD with the largest monolithic sensitive area ever built. Results from laboratory characterization of a full-scale prototypes are shown, together with a discussion on future perspectives and applications as a payload for future space astrophysics missions, such as LOFT, eXTP and STROBE-X.

Keywords: X-ray instrumentation; Silicon Drift Detectors; Large area detectors; High energy astrophysics
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(face) ID: 34

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Characterisation of an ASIC for Small Satellite Space Radiation Monitors (#3167)

T. A. Stein1, 2, D. Meier2, K. Røed1

1 University of Oslo, Department of Physics, Oslo, Norway
2 Integrated Detector Electronics AS (IDEAS), Oslo, Norway


We are characterising an application-specific integrated circuit (ASIC) for a space radiation monitor aboard small satellites. This ASIC, the IDE3466, has been recently designed for the Radiation-hard Electron Monitor (RADEM) of the JUpiter ICy moons Explorer (JUICE). The ASIC is able to count coincidence triggers from an assembly of silicon diodes. The work is done to assess the use of the ASIC in radiation monitors for instance for CubeSats. The ASIC has 36 charge-sensitive pre-amplifiers, 36 counters and one analogue output for multiplexing the pulse heights from all channels. The counters count pulses from charged particles impinging the silicon sensors depending on the charge magnitude and the coincidence trigger pattern from the 36 channels. We have characterised the ASIC design and measured performance parameters at three different temperatures from -40 °C to +60 °C. We also have tested the on-chip latch-up detection unit and the internal gain calibration circuit. We find that the ASIC works over the entire temperature range with only small changes in peaking time and trigger thresholds. The changes are acceptable for the use in space radiation monitors. The latch-up detection unit reliably flags currents higher than 0.14 A to 2.10 A for a 0.2 ohm external shunt resistor and depending on the programmed current threshold. We also find that the internal gain calibration circuit performs as designed and expected. Based on this ASIC characterisation and the specific needs in CubeSats we propose a simplified design implementation of a space radiation monitor.

Keywords: ASIC, CubeSat, IDE3466, readout, charged particle detection, coincidence counting, radiation monitor
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(face) ID: 36

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Particle Charge and Energy Identification with Single Layer Hybrid Pixel Detectors in Space (#3720)

S. P. George1, M. Kroupa2, N. Stoffle2, T. J. E. Campbell-Ricketts2, R. Mastrangelo1, D. Fry3, E. Semones3, L. Pinsky1

1 University of Houston, Physics, Houston, Texas, United States of America
2 Leidos, Houston, Texas, United States of America
3 NASA Johnson Space Center, Space Radiation Analysis Group, Houston, Texas, United States of America


We describe a method for identifying the charge and velocity of cosmic rays in space with a single layer Timepix hybrid pixel detector measuring 1.4 cm × 1.4 cm × 500 μm. Timepix is currently used on the International Space Station and the Orion spacecraft to measure the radiation exposure of NASA astronauts. Currently Timepix is used as an LET (dE/dx) measurement device. It is however desirable to instead estimate particle charge and energy, especially given recent concerns about adverse radiobiological effects from heavy ions such as central nervous system and cardiovascular effects. The pixels in Timepix act as a solid state nuclear emulsion, and traversing particles leave a characteristic track in the detector. The morphology and energy deposition of these tracks can be analysed to give properties such as the LET and track polar angles. For any measured track there are several probable candidate galactic cosmic rays with different charges and energies with the same measured LET. We describe a method for separating these candidates by using morphological features of the track. We extract the stopping curve along the track and compare it to a database of theoretically generated stopping curves based on experimentally validated Geant4 Monte Carlo simulations. For simplicity this database is restricted to species which are abundant in Galactic Cosmic rays, normally fully ionized Protons, Helium, Carbon, Silicon and Iron. Comparison to the stopping curve alone can sometimes be enough for high confidence identification, especially for stopping particles. Many heavier ions in the Timepix also produce district delta electrons. We search for the largest delta electron, which places a restriction on the minimum energy of the particle. Between them these two tests are normally sufficient for a charge estimate. This procedure has been tested on a wide variety of beamline data of various species and energies

Keywords: Hybrid pixel detectors, Timepix, Dosimetry, Mixed Field Dosimetry, Space Radiation
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(face) ID: 38

Poster Number:

Comparison of XRMC and Geant4 on dosimetry applied to mammography (#1030)

G. Hoff1, 2, A. Brunetti3, V. Fanti4, B. Golosio4

1 University of the State of Rio de Janeiro, Polytechnic Institute, Nova Friburgo, Rio de Janeiro, Brazil
2 Università di Cagliari, Dipartimento di Fisica, Cagliari, Sardinia, Italy
3 Università degli Studi di Sassari, Dipartimento di Scienze Politiche, Scienze della Comunicazione e Ingegneria dell'Informazione, Sassari, Sardinia, Italy
4 Università di Cagliari and INFN Sez. di Cagliari, Dipartimento di Fisica, Cagliari, Sardinia, Italy


This is an under development work. The objective of this project is to compare xrmc version 6.5.0-2 to Geant4 version 10.02.p02 and the results of both Monte Carlo tools to experimental data collected by using three different mammographs for dosimetric applications in mammography (external dosimetry), validating xrmc and Geant4 for dosimetric applications in mammography. To validate the quantities simulated was structured a experimental database from three different mammographic equipment (Mammomat Inspiration, Mammomat 3000 and LORAD MIII) of the quantities exposure and kerma, and the calculation of the derived quantities half-value-layer (HVL), backscattering (BSF). At the moment the data analyses are being realized. To evaluate the difference in results due the differences on description of the incident spectra it was modeled spectra from two different sources: catalogue IPEM Report 78 and the spectra generate to Lorad MIII equipment based on model published by Tucker et al 1991. The preliminary results show good agreement between xrmc and experimental data and between Geant4 and experimental data.The xrmc is presenting similar agreement to experimental data as the results presented by Penelope model, but with a significant reduction in running time (in transmission mode it can reduces the running time, at least, 5 time compared to Geant4 Penelope model) when HVL values are compared. We are planning to present the complete set of absolute and derived quantities comparing each transport model (from XRCM and Geant4).

Keywords: Monte Carlo, validation, Mammography
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(face) ID: 40

Poster Number:

Pulse Shape Analysis Techniques in γ-Ray Coincidence Measurements (#2993)

G. Styliaris1, E. Stiliaris2

1 University of Southern California (USC), Department of Physics and Astronomy, Los Angeles, California, United States of America
2 National & Kapodistrian University of Athens, Department of Physics, Athens, Greece


Pulse Shape Analysis (PSA) techniques operating with innovative algorithms can be implemented in various detection systems replacing the traditional electronic shaping and timing modules. In the current work, the implementation of PSA techniques in nuclear gamma-ray spectroscopy with conventional detector systems consisting of inorganic (NaI/Tl) scintillators and Photomultiplier tubes is introduced. A two-head rotating system has been used for coincidence measurements of the 60Co and 22Na sources. Apart from the Data Acquisition System, developed with low-cost PCI cards using the LabVIEW programming environment, a collection of PSA routines developed for differentiation, integration and special signal handling will be presented. This includes timing routines for various discrimination levels, energy calculation with different methods and pileup signal identification and correction.

Keywords: Pulse Shape Analysis (PSA), Gamma Ray Spectroscopy, PileUp
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(face) ID: 42

Poster Number:

A study of the cosmic-ray muon signature at sea level in NaI(Tl) scintillation detectors (#3275)

Q. Lecomte1, J. Dumazert1, R. Coulon1, V. Kondrasovs1, M. Becht1, S. Garti1, F. Carrel1

1 CEA, LIST/DM2I/LCAE, Gif sur yvette, France


Cosmic-rays are energetic are energetic particles that constantly rain through the Earth’s atmosphere, their origins in supernovae, quasars, and other exotic astronomical events, and how they acquire and how they acquire their sometimes colossal energy (over 1020 eV) is a topic of current research. Significant progresses have been achieved thanks to the development of the transport codes for particle physics applications. These codes have become faster, flexible, more robust and accurate. However, their flexibility requires a good knowledge of physics and programming skills from a user. The idea implemented in specially developed muon transport is to neglect secondary particles produced by muon assuming it is enough to consider accurately only muon interactions and muon energy losses. In addition, some tasks, for example, muon transport through a homogeneous material, may be accomplished without using multipurpose codes. The principle of the proposed method is based on a simple and efficient way to estimate the muon energy deposition in a cylindrical sensor. Muon initial energy is randomly sampled from experimental distributions and the traveled distance through the scintillator volume is assessed from a Monte-Carlo model in cylindrical coordinates. Energy deposition is estimated by solving Bethe-Block formula thanks to digital Euler approximation. This model has been experimentally tested in our laboratory using NaI(Tl) scintillator apparatus. Results from this comparison show good agreement and confirm the potential of the model. Sources of discrepancy are emphasized, while explaining peak shift between experimental results and theoretical calculations. Further research will be carried out to optimize the model and notably take into account angle dependence on the energy distribution muons.

Keywords: cosmic-ray muon, NaI(Tl), model, energy deposition
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(face) ID: 44

Poster Number:

Linear Regression for Radioactive Source Detection (#1900)

G. A. Cordone3, R. R. Brooks3, N. S. V. Rao1, S. Sen1, C. Q. Wu2, M. L. Berry2, K. M. Grieme2

1 Oak Ridge National Laboratory (ORNL), Computational Sciences and Engineering Division, Oak Ridge, Tennessee, United States of America
2 New Jersey Institute of Technology, Department of Computer Science, Newark, New Jersey, United States of America
3 Clemson University, Department of Electrical and Computer Engineering, Clemson, South Carolina, United States of America


Detection of radioactive sources is an important capability that led to the deployment of networks for detecting and localizing low-level, hazardous radiation sources. It is generally expected that such networks outperform the individual detectors by intelligently fusing information from several dispersed sensors. In this paper, we develop a network detection method that uses the slope of a linear regression fit as a test statistic for detecting a point radioactive source within a field of detectors.  In our regression model, we compute a least-squared linear fit between the average radiation counts at the detectors and the inverse-squared distances of known detector locations to an estimated source location. We show that the slope of this regression fit is an estimate of the source intensity and can be used as a threshold for source detection purposes. We compare performance of our proposed detection method with that of a fusion-based Sequential Probability Ratio Test (SPRT) method. For performance analyses, two datasets from the Domestic Nuclear Detection Office’s Intelligence Radiation Sensors Systems (IRSS) outdoor tests are used. Each of these tests consists of several runs of a single radioactive source moving in and out of a detector network. We present receiver operating characteristic (ROC) curves and optimal threshold values for the performance each detection method, and determine that our detection method using linear regression fit has slightly better overall performance than SPRT method.

This work has been supported by the US Department of Homeland Security, Domestic Nuclear Detection Office, under competitively awarded IAA HSHQDC-13-X-B0002. This support does not constitute an expressed or implied endorsement on the part of the Government.

Keywords: Detection, Fusion, Regression
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(face) ID: 46

Poster Number:

Deontic agents enforcing logical conditions in nuclide identification algorithms (#2896)

M. J. Neuer1, 2

1 innoRIID GmbH, Research & Development, Grevenbroich, North Rhine-Westphalia, Germany
2 VDEh Betriebsforschungsinstitut, Quality and Information Technology, Düsseldorf, North Rhine-Westphalia, Germany


Deontic logic allows the formal description of obligation and permissions. A reasoning algorithm is presented, that applies these formal concepts for enhancing the performance of an existing nuclide identification algorithm. Radio-isotope identification devices rely on a robust deduction of those nuclides, contributing to the radiation field. Traditional nuclide identification results are calculated by solely relying on the energy spectrum of the radiation. But in many cases, more information about a certain measurement situation is a priori known and this information is of semantic nature, mostly providing a set of constraints or conditions depending on the involved nuclides.

Introducing the example of simultaneously measuring iodine and plutonium, the deontic formalization is demonstrated by considering a binary classifier for the presence of neutrons. The algorithm itself uses a multi-agent system, in which each agent represents a nuclide. It is shown, how the deontic rules are implemented by the agents and how an exemplary communication is designed. Based on a test measurements collected with a 3’’x1’’ sodium iodide detector during multiple test campaigns, the algorithm performance increase gained by applying the deontic reasoning is evaluated and verified. 

Keywords: nuclide identification algorithm
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(face) ID: 48

Poster Number:

A General Approach to Combining Pulse Shape Discrimination Algorithms Based on Best Performance Window for Each Individual Method (#3493)

S. Woldegiorgis1, T. Zhu1, H. Yemam2, J. Baciak1, A. Enqvist1

1 University of Florida, Deparment of Material Science and Engineering, Nuclear Engineering Program, Gainesville, Florida, United States of America
2 Colorado School of Mines, Department of Chemistry, Golden, Colorado, United States of America


The performance of spectroscopic techniques that are based on analyzing neutron signatures, such as many methods used for identifying special nuclear materials, is heavily affected by the background gamma signals. If the active medium in the detectors used are made of materials such as He-4, this inherently makes them much less sensitive to gammas. However, they are not completely insensitive to the gamma radiation, so the signals collected still consist of significant amount of gamma signature. Numerous techniques have been developed separating neutrons from gammas based on the fundamental difference between their signals, which is mainly the time characteristics of the pulses while they decay. In this work, extensive study was performed on applying two previously tested and two new pulse shape discrimination methods (that have not been tested with He-4 detector) on separating He-4 signals collected using 252Cf source in to neutrons and gammas, respectively. After finding the detector response region where each method performs the best, all the methods are going to be combined in a piece-wise format so that an effective separation between the two radiations will be carried out throughout a wide range of energy. The same approach will also be taken on separating signals collected using newly synthesized plastic scintillator detectors to demonstrate the approach and attempt to ensure a universal PSD optimization algorithm working for more than just noble gas scintillators.

Keywords: Scintillation Detectors, Pulse Shape Discrimination (PSD), Special Nuclear Materials
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(face) ID: 50

Poster Number:

An Improved Gamma Interaction Position Estimation using Artificial Neural Networks for Resistor Based Multiplexing Circuit (#4034)

D. Kim1, Y. Choi1, J. Jung1, K. Kim1, D. Jang1

1 Sogang university, Electronic engineering, Seoul, Republic of Korea


A resistor based multiplexing circuits such as discretized positioning circuit (DPC) and symmetric charge division have been commonly used to reduce the number of output channels and the associated cost in gamma detectors. However, they can lead to a degradation of image quality as the number of pixels increases because of their nonlinear property. The purpose of this study was to develop artificial neural networks (ANNs) fitting algorithm to improve the gamma positioning accuracy of a pixelated detector with a resistor based multiplexing circuit. The detector module was composed of a 12 x 12 crystal array of LYSO (3 x 3 x 20 mm3) with one to one coupling to a 12 x 12 SiPM array (3 x 3 mm2) and 144:4 resistor based DPC. Training dataset was acquired by a point source collimated on individual pixel. Four output signals from the detector module were measured by picking up the peaks of four pulses. Each ratio of the peaks was applied for position estimation during ANNs training procedure. The ANNs consist of first input layer of five nodes and six hidden layers of 144, 48, 36, 24 and 12 nodes at each layer. Last output layer has two nodes that give each x and y coordinate. To evaluate the performance of ANNs fitting algorithm using training dataset, the accuracy of pixel identification and peak-to-valley ratio were calculated at the center and the edges of detector. The results show that the pixel identification accuracy was enhanced by 26% at the edges of detector. The peak-to-valley ratio was also improved from 4.4 to 6.0 at the center and from 2.1 to 4.4 at the edges. Further study will be performed with additional pulse shape features measured from output signals to improve the gamma positioning accuracy.

Keywords: Neural network, ANN, position estimation, multiplexing, DPC, SiPM
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(face) ID: 52

Poster Number:

The KLM front end electronics and data acquisition upgrade for the Belle2 experiment. (#1159)

P. Branchini1, B. Kunkler2

1 INFN Roma Tre, Fisica, Roma, Italy
2 Indiana University, Bloomingtoon, United States of America


The Belle2 experiment will operate at the SuperKEKB e+e- collider, designed to reach an instantaneous luminosity of 8*10^35 cm-1 s-1 at the Y(4S) resonance. Semi-leptonic b decays and b-decays with a K long meson in the final state are of paramount importance in addressing the physics goal of Belle2. The most relevant detector to identify and reconstrut Klong and muons is KLM. To keep the pace with the high throughput the experiment front-end data acquisition system has been upgraded. In this paper we describe the KLM front-end architecture, its upgrade and performance.

Keywords: data acquisition system, trigger system, front-end electronics
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(face) ID: 54

Poster Number:

Development of Fully FPGA-based 3D (X, Y, t) Detection Systems using Multi-channel Tapped Delay-Line Time-to-Digital Converter with Cross Delay-Line Detectors (#1398)

N. Lusardi1, G. Cautero2, C. Dri2, F. Garzetti2, P. Pittana2, R. Sergo2, L. Stebel2, A. Geraci1

1 Politecnico di Milano, DEIB - Department of Electronics, Milano, Italy
2 Elettra - Sincrotrone Trieste, Detectors & Instrumentation Laboratory, Basovizza, Trieste, Italy


Time-resolved experiments often need detection devices able to provide information about position and arrival time of each detected event. Time resolution is a fundamental requirement for these devices, along with the high versatility and fast real-time computing of the acquisition system. Typical architectures, based on Time-to-Digital Converters (TDC) followed by a FPGA, combine very fast parallel computing with a time precision better than hundreds of picoseconds, allowing to perform state-of-the-art time-resolved experiments. Nevertheless, time resolution is still a limiting factor, in particular for imaging applications, since it affects the spatial resolution of the detector. Furthermore, the separation between the TDC devices and a readout FPGA has some drawbacks in terms of versatility of the system. In this article, we present a new approach, combining FPGA-based multi-channel Tapped Delay-Line TDC and an efficient multipurpose readout logic, to greatly improve the overall performance and versatility of Cross Delay-Line (CDL) detector systems.

Keywords: CDL Detectors, TDC, FPGA
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(face) ID: 56

Poster Number:

Hardware and Software Co-Design of a System-On-Chip for Real-Time Bidirectional Transfer and Processing of Data from a Time-to-Digital Converter (#1490)

N. Lusardi1, F. Garzetti1, M. A. Cibin1, R. Sury1, A. Geraci1

1 Politecnico di Milano, DEIB - Department of Electronics, Milano, Italy


We present the implementation of a hardware and software co-design system for real-time bidirectional data transfer and processing on a System-of-Chip (SoC) platform, the ZedBoard™ development kit, for timing measurements performed by a multi-channel, high-performance Time-to-Digital Converter implemented in the Programmable Logic (PL) section of the Zynq®-7 XC7Z020 hosted on board.

The Time-to-Digital Converter is an IP-core characterized by area saving architecture, average resolution and full-scale-range completely and independently tunable from 20 ps to 2 ps and from 40ns to 10.7s respectively. Moreover, the number of channels implemented is programmable from 2 up to 8 at user level.

Keywords: Co-Design, SoC, FPGA, TDC
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(face) ID: 58

Poster Number:

Fully Programmable System for Multi-Channel Experiments Targeting to Time Measurement at High Performance (#1717)

N. Lusardi1, F. Garzetti1, A. Geraci1

1 Politecnico di Milano, Department of Electronics, Information and Bioengineering, Milano, Italy


In this contribution, we introduce a new hardware/firmware/software bundle for experiments in which high-performance time resolving is a primary request.

Main features of the global system are multi-channel operation up to 16 parallel measures with resolution of 250 fs and precision below 12 ps r.m.s. with hardware full-scale-range of 9.54 s, and the possibility of enabling different time tagging techniques that can indefinitely extend the full-scale-range via software.  Moreover, each channel can support multi-hit measurements with a maximum rate of 45 MHz.

Time measurements are performed by a Time-to-Digital Converter instantiated as HDL Module in a Serie-7 28-nm Xilinx FPGA module hosted on a custom hardware.

The firmware and the software are modularly structured, meaning that each module has firmware and software images that split the processing in parallel and temporal computing segments.

Keywords: Time-resolving, Co-design, SoC, FPGA, TDC
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(face) ID: 60

Poster Number:

The Phase-I Trigger Readout Electronics Upgrade for the ATLAS Liquid-Argon Calorimeters (#2110)

Y. Enari1

1 University of Tokyo, ICEPP, Tokyo, Japan


Electronics developments are pursued for the trigger readout of the ATLAS Liquid-Argon Calorimeter towards the Phase-I upgrade scheduled in the LHC shut-down period of 2019-2020. The LAr Trigger Digitizer system will digitize 34k channels at a 40 MHz sampling with 12 bit precision at the frontend system, and transmit to the LAr Digital Processing system in the backend to extract the transverse energies.

Low power, radiation tolerent ASICs for ADC, serializer and transmitter have been developed for the frontend electronics. In the backend system, the received digital data will be processed with a FIR filter on the FPGA (Intel-FPGA Arria-X) to identify the bunch crossing and extract the transverse energy with a fixed latency. The backend system consists 31 ATCA blades carrying 4 Advanced Mezzanine Cards for each. The talk will give a status on hardware developments towards the final design of the new system.  Results of the high-speed link test with the prototypes of the final electronic boards, the performance of the demonstrator with collision data will be also reported.

Abstract submitted on behalf of the ATLAS Liquid Argon Speaker's Committee Speaker to be nominated later

Keywords: LHC, Calorimeter, Readout electronics, ASIC, ATCA
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(face) ID: 62

Poster Number:

A multi-channel device for scintillation crystal testing (#2414)

A. Zhao1, W. Xiong1, Z. Deng1, Z. Duan1, Q. Xie1

1 Huazhong University of Science and Technology, College of Life Science and Technology, Wuhan, Hubei, China


We present a scintillation crystal testing device that has 1) list-mode data output for the random radiation events, and 2) richer spatial information than the single channel recording devices to achieve multiple crystal measurement, and 3) good practicability, stability and expansibility. The device consists of position-sensitive PMT, events trigger electronics and 50MSps ADC. The goal of this study is to describe the device and evaluate the utility it provides. It suggests that the device can be used effectively to examine the scintillation crystal and measure the environmental radiation dose rapidly with standard scintillation crystal. The testing result demonstrates the high efficiency of the device, and shows the potential advantage of digital electronics design in scintillation crystal testing.

Keywords: multi-channel, scintillation crystal, CTD system
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(face) ID: 64

Poster Number:

An updated front-end data link design for the Phase-2 upgrade of the ATLAS Tile calorimeter (#2482)

A. White1

1 University of Texas at Arlington, Physics, Arlington, Texas, United States of America


Following extensive developing and testing of new on-detector electronics for the Phase-2 ATLAS hadronic Tile calorimeter upgrade, we present a new revision of the Link Daughter Board (DB) that performs local control and communication with the off-detector electronics. The upgraded system will include 1024 DBs, each serving up to 12 photomultiplier channels. The DB provides continuous high-speed readout of all PMT data samples, as well as configuration, control and timing over multi-Gbit/s optical links, and has a fully redundant design to eliminate virtually all single failure points. Major design changes in the new revision include upgrading from Xilinx Kintex-7 FPGAs to Kintex Ultrascale+ devices, for better high-speed link timing and improved radiation tolerance. The role of the two radiation-hard, CERN-developed gigabit link ASICs (GBTx) has been expanded to perform configuration and slow control of the FPGAs and other front-end boards, in addition to LHC timing distribution and remote JTAG access to the FPGAs and configuration memories via the optical links. To save cost and complexity, DB optical connectivity has been reduced from two fully-populated QSFP+ modules to six fibres (four uplinks and two downlinks) serviced by four SFP+ modules. Only two uplinks and one downlink are required for nominal running, so failing links can be switched out at the inputs to the off-detector electronics. The FPGA firmware will be implemented with Triple Mode Redundancy to greatly reduce radiation-induced errors, and Forward Error Correction in the read-out links will further enhance data reliability.

Keywords: Calorimeter, Data-link, Readout
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(face) ID: 66

Poster Number:

Development and Optimization of the GammaNet Event Classifier for the AdEPT Pair Production Satellite (#2526)

R. Garnett1, A. R. Hanu2, E. Johnston1, W. V. Prestwich1, S. H. Byun1

1 McMaster University, Medical Physics and Applied Radiation Sciences, Hamilton, Ontario, Canada
2 Bruce Power, Dosimetry Section, Tiverton, Ontario, Canada


The ability to remove background signals in radiation detection is important, particularly in applications limited by processing power or signal communications. This study aims at addressing the problem of background reduction by applying machine vision to event classification. To this end, we propose to employ convolution neural networks on a graphics processing unit, which enables the classification of events from the Advanced Energetic Pair Telescope satellite mission that is under preparation by NASA. The detector for this mission is an Argon filled time projection chamber, which generates images of radiation detection events in two perpendicular planes. The goal of the mission is to measure the polarization, energy, direction, and time of arrival of gamma-rays through pair production events. The requirement for background rejection is set by the data transfer rate the satellite is capable of, and the relative abundance of the pair production events. It is estimated that the raw data rate of the satellite will be 4 orders of magnitude higher than the currently available downlink speed. This sets the goal of the convolution neural network, GammaNet, at a background classification accuracy of 99.99%. Additional to the concerns of data rate reduction is the need for any processing of an event to be completed within a time window dictated by the sampling frequency of the detector. The sampling period is 50 ms, requiring GammaNet to provide a classification within 50 ms. We report a preliminary work on development and optimization of the GammaNet convolution neural network for the Advanced Energetic Pair Telescope detector.

Keywords: Machine Vision, Gamma Telescope, Satellite, Astroparticle Physics, Event Classification, Detector
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(face) ID: 68

Poster Number:

Development, Implementation and Performance of a NaI Scintillator System and Model for the Detection of 137Cs in Wildlife (#2950)

A. D. Brand1, T. J. Aucott1, T. S. Whiteside1, D. P. DiPrete1

1 Savannah River National Laboratory, Aiken, South Carolina, United States of America


The Environmental Dosimetry group at Savannah River National Laboratory makes field measurements of the Cs-137 concentration in wildlife that is killed onsite. This is done in order to determine the dose that the hunter receives from the ingestion of the animal meat. The group had been performing the analysis using two, 2” by 2” NaI detectors. Those detectors were connected to scalers which reported the number of counts in the Cs-137 energy range over the course of a minute long count. However, based on the lack of agreement between that data and the data collected by measuring the deer meat with a calibrated Ge detector system, the group desired an upgraded system that measured this concentration more accurately.

A new system was developed which utilized a 2” x 4” x 16” NaI detector coupled with a model created using a Monte Carlo n-Particle Code (MCNP) to determine the activity in the animal. Models were created for deer, turkeys, boars, and coyotes. The models were validated using standards made from 25-L bottles filled with a resin mixed with Cs-137. A computer program was created to help automate the process as well as log the results from each animal and correlate the result with the hunter to keep track of total dose. The values measured by the new system were in better agreement with the laboratory than the original system. A correction factor was determined between the new system and the lab results so that the field measurements were accurate and could be reported with certainty over a range of animal Cs-137 concentrations.

Keywords: Non-Destructive Assay, Computer Modeling, detector system development, model verification, programming
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(face) ID: 70

Poster Number:

Design, Implementation and Verification of a Data Acquisition System for the Prototypes of the Front-End Electronics of the PANDA Micro Vertex Detector (#3042)

A. Lai1, T. Stockmanns1, J. Ritman1, A. Zambanini2, A. Riccardi3, V. Di Pietro3, T. Quagli3, K. T. Brinkmann3, H. - G. Zaunick3, R. Schnell3, D. Calvo4, R. Wheadon4, M. D. Da Rocha Rolo4, A. Rivetti4

1 Forschungszentrum Jülich GmbH, IKP-1, Jülich, North Rhine-Westphalia, Germany
2 Forschungszentrum Jülich GmbH, ZEA-2, Jülich, North Rhine-Westphalia, Germany
3 Justus-Liebig-Universität, Gießen, Gießen, Hesse, Germany
4 INFN, Sezione di Torino, Torino, Italy


This paper describes the current status of the design, implementation, and test of a data acquisition (DAQ) system for the prototypes of the front-end electronics of the Antiproton Annihilation at Darmstadt (PANDA) Micro Vertex Detector (MVD). The features of this DAQ, called Juelich Digital Readout System (JDRS), are driven by the requirements imposed by the physics program of the experiment, such as continuous data collection without external triggering. Flexibility and modularity are thus key points for this system, which is meant to operate during a test beam, as well as in a laboratory environment.
The implementation of the system is based on an off-the-shelf field-programmable gate array (FPGA) board. So far, two different application-specific integrated circuits (ASICs) have been successfully connected to the JDRS. Tests to establish the performances of the JDRS in terms of processing speed, detection efficiency, and reliability have been carried out and are still ongoing.

Keywords: read-out, PANDA, Micro Vertex Detector, FPGA, JDRS, data acquisition
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(face) ID: 72

Poster Number:

Network time synchronization for detector data acquisition electronics (#3698)

W. Hennig1

1 XIA, LLC, Hayward, United States of America


Large scale nuclear physics experiments often use arrays of radiation detectors, which can be physically separated, for example in separate rooms or along a beamline. Time synchronization of the detector readout electronics is essential to detect related events, which is often accomplished by sharing clock, trigger and reset signals within and between racks of digitizing electronics. This works well over short distances, but requires dedicated cabling and/or modules and becomes cumbersome for widely separated arrays. As the detector readout electronics is in many cases operated by computers linked over standard data networks, an alternative to dedicated clock distribution trees is the synchronization of clocks over the network. Network time synchronization protocols like IEEE 1588 or White Rabbit are reported to achieve low/sub nanosecond timing resolution, but these results generally refer to clock offsets computed in software or to once-per-second reference pulses, not to the capture of detector pulses with amplitudes and waveforms.

The work reported here thus focuses on integration of network time synchronization techniques with digital data acquisition for radiation detectors. Detector waveforms are captured with analog to digital converters that are synchronized to the network master clock and/or are tagged with time stamps related to the network time. Key to this integration is the handling of network clock and time in the same FPGA firmware that processes the analog to digital converter’s data stream. We will describe implementations based on FPGA firmware and on network hardware, and report timing resolutions obtained for two synchronized detectors capturing coincident radiation.

Keywords: detector readout electronics, precision time protocol
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(face) ID: 74

Poster Number:

A new DAQ solution: otsdaq (#3715)

B. Schneider1

1 Fermi National Accelerator Laboratory, Batavia, Illinois, United States of America

On behalf of the CMS Collaboration


The Data Acquisition System (DAQ) software of an experiment is usually integrated in a finite state machine that controls the state of the detector. While the configuration of the detector is hardware specific, the data acquisition, the data monitoring and the states of the finite state machine are typically similar for a wide range of different experiments. OTSDAQ (Off-the-shelf Data Acquisition System) is a highly scalable, flexible data acquisition system that provides common and reusable components of a DAQ system. It can be used by a wide range of experiments, for a wide range of purposes: from bench-top prototype system tests through beam tests to detector control systems during full scale data taking. The OTSDAQ graphical user interface allows users to run the system from any platform and device through a web browser. The OTSDAQ has already been successfully deployed at the Fermilab Test Beam Facility. The entire silicon tracking detector of the CMS experiment at CERN will be upgraded to cope with the high instantaneous luminosity expected at the HL-LHC (from 2026). In this presentation I will show the status and plans of the OTSDAQ implementation for the new silicon tracker.

Keywords: particle physics, software, daq, data
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(face) ID: 76

Poster Number:

Optimizing Time-pickup Algorithms in Radiation Detectors with a Genetic Algorithm (#3900)

V. Sánchez-Tembleque1, L. M. Fraile1, J. M. Udías1

1 University Complutense of Madrid, Nuclear Physics Group (GFN), Madrid, Spain


Pulse digitation at high rates has opened the way to complex, non-standard algorithms to be employed to obtain the time-stamps of gamma photons arriving to nuclear detectors, beyond the conventional constant fraction discriminator (CFD) option. Detector pulses can be shaped with digital filters in DSP hardware, and timestamps can be derived interpolating and/or, extrapolating the samples acquired. Digitized pulses can be stored in a computer for off-line analysis, and this allows for trying many different algorithm variations on the same data. Very soon, the number of filters and parameters to tune in order to optimize the best timing performance becomes too large. In this work we use a genetic algorithm to tune the in-silico digital filter, figital time pickup algorithm and associated parameters. The data set consisted in 500,000 pulses obtained from the last dynode of an ultrafast PMT (model R9779 form Hamamatsu) coupled to large monolothic fast inorganic BrLa(Ce) scintillators, in a truncated cone geometry and 1.5x1x1.5 geometry. With finely tunedconventional (CFD+TAC) timing electronics, CRT of 155 ps (FWHM) have been in our group, the state of the art with detectors this size. Our alternate digital, in-silico implementation of  CFD+TAC, fine tuned with the same parameters obtained during manual adjustement of the conventional DAQ, applied to pulses digitized at 5 GS/s and 12 bits, reproduces the performance of the conventional DAQ. On the other hand, a genetic algorithm (GA) is employed to optimize digital recursive filters with up to 8 parameters, and different time-pickup strategies (upper level tresholding, CFD, time extrapolation). The same 500,000 pulses are employed to test fitness of the population in the GA. The GA finds several families of filters outperforming the timing performance of the manually tuned algorithm by more than 5%. 

Keywords: Digital analysis, genetic algorithm, CFD, scintillator
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(face) ID: 78

Poster Number:

Auto-calibrating TDC for a SoC-FPGA data acquisition system (#4179)

P. Carra1, 2, N. Belcari1, 2, M. Bertazzoni1, 2, M. G. Bisogni1, 2, M. Morrocchi1, 2, G. Pazzi1, 2, G. Sportelli1, 2, A. Del Guerra1, 2

1 University of Pisa, Department of Physics, Pisa, Italy
2 National Institute of Nuclear Physics, Pisa, Italy


A two-channel data acquisition system for time-of-flight positron emission tomography (ToF-PET) based on a high-resolution time-to-digital converter (TDC) has been implemented in a high-end FPGA. In this field of research TDCs are used to estimate the position of a radioactive source along a so-called line of response (LOR) by detecting the ToF of the two photons created by a positron-electron annihilation. It has been shown that the use of time ToF information in imaging reconstruction can greatly improve spatial resolution and increase robustness angainst artifacts. The advantage of integrating the TDC in an FPGA comes from the higher level of integration with the processing pipeline and the unparalleled high data bandwidth at the detector front-end. This TDC implementation uses a chain of delay lines to measure the arrival time of an input trigger with respect to the clock rising edges. In particular, the dedicated carry chain connections available in the FPGA are used, since they have the smallest propagation time and thus offer the best timing resolution. One of the most important features of this project is that the design is device agnostic, which makes it portable to most modern FPGA architectures and highly scalable, thus being suitable for applications that emply a high number of channels as in state of the art ToF-PET systems. The temporal resolution of this instrument has been measured to be 44 ps.

Keywords: Medical Physics, Data acquisition, TDC, PET, Time of flight PET, Digital design
Poster panel
(face) ID: 80

Poster Number:

The Initial Results of Experiment on board the International Space Station using Position Sensitive Tissue-Equivalent Proportional Chamber "PS-TEPC" (#1601)

Y. Kishimoto1, S. Sasaki1, K. Saito1, K. Takahashi1, K. Terasawa2, K. Miuchi3, A. Nagamatsu4, M. Katsuta4, T. Fuse4, H. Matsumoto4, T. Tanimori5, H. Kubo5, Y. Uchihori6, T. Kitamura6

1 High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan
2 Keio University, Yokohama, Kanagawa, Japan
3 Kobe University, Kobe, Hyogo, Japan
4 Japan Aerospace Exploration Agency (JAXA), Tsukuba, Ibaraki, Japan
5 Kyoto University, Kyoto, Kyoto, Japan
6 National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Chiba, Japan


Radiation effects on human body are commonly evaluated using a dose equivalent H, defined as a product of an absorbed dose D and a quality factor Q given as a function of the Linear Energy Transfer (LET). In space, there exist many kinds of cosmic radiations, where primary charged particles and neutrons generated secondarily are the main components contributing to the radiation dose. Since the LET values of these radiations spreads over a wide range, it is essential to measure it directly in order to evaluate H. We have been developing a space dosimeter named as PS-TEPC (Position Sensitive Tissue Equivalent Proportional Chamber). PS-TEPC consists of a miniaturized μ-PIC with a detection volume of 2.6×2.6×5.0cm3 and tissue-equivalent materials. PS-TEPC works as a 3D time projection chamber. It allows to measure not only the energy deposit but also to record the trajectories of the incident charged particles. Thus, an event-by-event LET can be directly measured.

Now we are performing an experiment on board the International Space Station (ISS) using PS-TEPC for an operation check and an evaluation of the performance to measure dose equivalent in space crafts. In this presentation, we will introduce performance of the flight model PS-TEPC and report the initial results of the ISS experiment.

Keywords: Dosimeter, LET, International space station
Poster panel
(face) ID: 82

Poster Number:

Study of Baseline Restoration Circuits for Small Diameter Drift-Tube Chambers (#3543)

S. Abovyan1, V. Danielyan1, M. Fras1, O. Kortner1, H. Kroha1, S. Nowak1, R. Richter1, K. Schmidt-Sommerfeld1

1 Max-Planck-Institut fuer Physik, Munich, Bavaria, Germany


Drift-tube chambers are a cost-effective technology for equipping large areas of muon systems with precision tracking detectors at high-energy hadron colliders. Chambers with cylindrical aluminium drift tubes of 30~mm diameter are successfully used in the ATLAS muon spectrometer at the LHC. A new generation of these chambers with half the tube diameter was developed for the operation in the ATLAS experiment after the high-luminosity upgrade of the LHC. Beam tests of these new chambers in the gamma irradiation facility at CERN showed that the new chambers can be safely operated up to γ background counting rates of 30 kHz/cm2 which is twice the maximum expected rate in ATLAS at the upgraded LHC. At theses rates the drop of the gain due to presence of space charge in the tubes and, in particular, signal pile-up diminish the spatial single resolution of a tube from about 100 µm to about 200 µm. The large degradation caused by signal pile-up can be avoided by using a baseline restoration circuit at the output of the bipolar shaper. A variant of such a circuit with a classical passive baseline restoration using a diode was successfully tested with cosmic-ray muons and a strong radioactive γ source in the laboratory and finally also in a muon beam at CERN's gamma irradiation facility. In the presenation we shall present these results and discuss further optimization of the existing circuit as well as alternative active baseline restoration circuits.

Keywords: drift tube, muon, chamber, MDT, sMDT, high rates, baseline restoration
Poster panel
(face) ID: 84

Poster Number:

Aging and performance studies for the CMS RPC system (#4010)

J. A. Eysermans1

1 BUAP, Physics, Puebla, Puebla, Mexico

On behalf CMS-Collaboration


During the High Luminosity LHC (HL-LHC) running period the CMS RPC system will be subjected to high background conditions which can affect the overall performance and the possibility to induce aging effects. A dedicated consolidation program was set up using the CERN Gamma Irradiation Facility ++ (GIF++), where RPC detectors are exposed to intense gamma radiation for a long term period equivalent to the HL-LHC operational time. Based on the past operational experience during run 1 and 2, the high background conditions are estimated and the RPCs are tested under such circumstances. Several parameters are monitored as function of integrated charge and dedicated test beam periods allow to measure the detector efficiency as function of the background rate. In this work, an overview is given of the measurements performed at GIF++ and the preliminary results are discussed. After having collected a significant amount of the total irradiation, no aging effects nor degradation of the RPC detectors has been observed so far which suggest that the RPC system is capable to run during the HL-LHC running period.

Keywords: muons
Poster panel
(face) ID: 88

Poster Number:

Development of a Handred-Picoseconds Pulse Laser as a Calibration Source (#1302)

Y. Inome1, T. Yamamoto1, M. Teshima2, H. Ohoka2, D. Nakajima2, M. Razmik3

1 Konan University, Faculty of Science and Engineering, Hyogo, Japan
2 University of Tokyo, Institute of Cosmic Ray Research, Chiba, Japan
3 Max Planck Institute for Physics, Munich, Germany


We have developed a pulse laser for a calibration of photon sensors in a high energy experiments.
Short pulse of light, such as Cherenkov or scintillation light, is one of the important signals in the high energy experiments. Therefore time resolution of photon detectors and front-end electronics is important factor in such experiments. Consequently a short-pulse light source is necessary for the calibration of these devices. We have developed a pulse laser as a light source to calibrate photon detectors in a high energy experiment.
In this light source, electric pulses are generated by a simple circuit. Firstly a square wave is created by a high speed comparator, which makes 5 V pulse with less than 1 ns rising time. Then a differentiating circuit transform this wave to a short pulse, which is sent to a transistor as a switching current. The amplified electric pulse is sent to a laser diode, which is weakly oscillated continually by a low voltage DC current so that a pulsed beam is radiated immediately. Pulse width of the laser is 285 ps in FWHM and peak intensity is more than 100 mW. The details of this light source will be presented.

Keywords: pulse Laser, calibration of photon sensors, pulse generator
Poster panel
(face) ID: 90

Poster Number:

Operational Experience with Radioactive Source Calibration of the CMS Hadron Endcap Calorimeter Wedges with Phase I Upgrade Electronics (#1529)

V. Andreev3, P. De Barbaro4, B. Bilki1, 2, P. Bunin5, S. Cooper6, A. Gribushin7, A. Kaminskiy7, S. Obraztsov7, Y. Onel1, P. Rumerio6, I. Schmidt1, D. Tlisov8, M. Toms9

1 University of Iowa, Iowa City, Iowa, United States of America
2 Beykent University, Istanbul, Turkey
3 P.N. Lebedev Physical Institute, Moscow, Russian Federation
4 University of Rochester, Rochester, New York, United States of America
5 Joint Institute for Nuclear Research, Dubna, Russian Federation
6 University of Alabama, Tuscaloosa, Alabama, United States of America
7 Moscow State University, Moscow, Russian Federation
8 Institute for Nuclear Research, Moscow, Russian Federation
9 Institute for Theoretical and Experimental Physics, Moscow, Russian Federation


The Phase I Upgrade of the CMS Hadron Endcap Calorimeters consist of new photodetectors and front-end electronics. The upgrade will allow the elimination of the high amplitude noise and drifting response of the Hybrid Photo-Diodes, at the same time enabling the mitigation of the radiation damage of the scintillators and the wavelength shifting fibers with a larger spectral acceptance of the Silicon Photomultipliers. The upgrade will also allow to increase the longitudinal segmentation of the readout to be beneficial for pile-up mitigation and recalibration due to depth-dependent radiation damage.

As a realistic operational exercise, the responses of the Hadron Endcap Calorimeter wedges were calibrated with a 60Co radioactive source both with current and upgrade electronics. The exercise provided significant experience towards the full upgrade during the Year End Technical Stop 2017-2018. Here we describe the instrumentation details and the operational experiences related to the sourcing exercise.

Keywords: CMS, hadron endcap calorimeter, calibration
Poster panel
(face) ID: 92

Poster Number:

ILD for the International Linear Collider (#1810)

K. Kawagoe1, K. Buesser2, W. Ootani3

1 Kyushu University, Department of Physics, Fukuoka, Japan
2 Deutsches Elektronen-Synchrotron (DESY), FLC, Hamburg, Germany
3 University of Tokyo, International Center for Elementary Particle Physics, Tokyo, Japan


The International Large Detector (ILD) is a detector concept for the International Linear Collider (ILC), a 250-500 GeV (extendable to 1 TeV) center-of-mass high-luminosity linear electron-positron collider. The ILD is optimized with the concept of particle flow for overall event reconstruction so that it will deliver excellent performance for high-precision Higgs and top measurements, as well as high-sensitivities for possible new phenomena, utilizing the advantages of an electron-positron collider. Particle flow implies that all particles in an event, charged and neutral, are individually reconstructed. This requirement has a large impact on the design of the detector, and has played a central role in the optimisation of the system. Superb tracking capabilities and outstanding detection of secondary vertices are other important aspects. The overall layout, sub-detector technologies, expected performance, and recent progress of the ILD will be presented.

Keywords: ILC, electron-positron collider, particle flow
Poster panel
(face) ID: 94

Poster Number:

Determination of Luminosity with Thermal Neutron Counting using TPX Detectors in the ATLAS Cavern in LHC Proton-Proton Collisions at 13 TeV (#2143)

A. Sopczak1, B. Ali1, J. Begera1, B. Bergmann1, B. Biskup1, T. Billoud2, P. Burian1, D. Caforio1, E. Heijne1, J. Janecek1, C. Leroy2, P. Manek1, Y. Mora1, S. Pospisil1, M. Suk1, Z. Svoboda1

1 Czech Technical University in Prague, Institute of Experimental and Applied Physics, Prague, Czech Republic
2 University of Montreal, Group of Particle Physics, Montreal, Canada


The network of the TPX detectors installed in the ATLAS cavern has the unique capability of measuring the luminosity with thermal neutron counting in LHC proton-proton collisions at 13 TeV. Compared to the hit counting method, the method of thermal neutron counting has the advantage that it is not affected by induced radioactivity. The results of the luminosity determination are presented for several independently-operated TPX detectors. The short-term precision and long-term time-stability of the measurements are presented. The high-statistics data-set allows a detailed comparison between neutron counting and hit counting luminosity determination techniques.

Keywords: Neutron counting, luminosity, pixeldetectors
Poster panel
(face) ID: 96

Poster Number:

Proposal of Gamma Rays Detector with Position Resolution of 0.1 mm (#2227)

T. Yuzawa1, H. Matsunaga1, T. Tanaka1, H. Kawai2, H. Ito2, A. Kobayashi2, Y. Emoto2, K. Fujihara2, S. Kimura2, T. Mizuno2, T. Nakamura2

1 Chiba University, Faculty of Sciene, chiba, Chiba, Japan
2 Chiba University, Graduate School of Sciene, Chiba, Chiba, Japan


In particle physics experiment, position resolution of typical detectors for gamma rays is approximately 10 mm at most because the center of the electromagnetic shower in inorganic scintillators is measured. If the position where the incident gamma ray produce the electron-positron pair can be measured, the position resolution of the incident gamma ray becomes much better. We are developing 511-keV gamma rays detectors for PET (Positron Emission Tomography). When 511-keV gamma rays enter scintillators, scintillation light is emitted due to photoelectric effect and Compton scattering. Our detectors have high position resolution because wave-length shifting fibers with a diameter of 0.2 mm are spread over the upstream face and the downstream face of the scintillator plate without a gap in the scintillator part.  Therefore, detectors can measure all the emission position by using plate-like scintillators and wavelength-shifting fibers. When a gamma ray whose energy is approximately 1 GeV enters these detectors, the positions and the energy of scintillation light by charged particles in the electromagnetic shower will be measured. Considering the density of the two types of scintillators we use, it is estimated that the scintillation light will be emitted at interval of 1 mm or 3 mm which are the thickness of the two types of the scintillators. The scintillation light will continue to be emitted over four times the length of the initial radiation length of the incident gamma ray. By this detectors installed on the upstream of conventional calorimeter, the position where an incident gamma ray create the electron-positron pair could be measured with an efficiency of 99% or more with a standard deviation of approximately 0.1 mm.

Keywords: gamma ray detector, High position resolution
Poster panel
(face) ID: 98

Poster Number:

The reliability research about HV units applied in Jiangmen underground neutrino experiment (#2320)

Z. Ning1

1 Institute of High Energy Physics, Experiment physics division, Beijing, China


Readout electronics will be integrated with front-end photomultiplier tubes in Jiangmen underground neutrino experiment, which includes high voltage units, front-end chips, analog-to-digital units, FPGA and so on. If one of components is broken, this channel doesn't work and it is impossible to be replaced with a normal unit during operation. Considering the cost of photomultiplier tubes and requirement of physics analysis, a high reliability requirement for readout electronics is necessary. As an important component, the reliability of high voltage units produced by Russian as one of collaborators is a focus. But most of research about reliability of high voltage units is based on calculation whose data source is from US army reliability prediction handbook. But it is unlucky that this handbook is canceled in 1996 by US army due to large deviation of prediction and very old component reliability data. Because main failure of electronics component is contributed by thermal aging, an acceleration life test of high voltage units is done whose ambient temperature is 70 °C and the output will be monitored in real time during the test. The 6000 hours test result shows that there no any failure during the test, but a degradation phenomenon is seen. According to the degradation trend, a linear extrapolation is used to get a pseudo lifetime of high voltage units.

Keywords: high voltage units, reliability, acceleration life test
Poster panel
(face) ID: 100

Poster Number:

Development of a neutrino detector and electronics for precise measurement of neutrino cross section ratios (#2660)

R. Tamura1, N. Chikuma1, F. Hosomi1, T. Koga1, M. Yokoyama1, M. Antonova2, A. Lzmayloy2, M. Khabibullin2, A. Khotjantsev2, A. Kostin2, Y. Kudenko2, A. Mefodiev2, O. Mineev2, T. Ovsjannikova2, S. Suvorov2, N. Yershov2, T. Ishida3, T. Kobayashi3, S. Cao3, T. Hayashino4, A. Hiramoto4, A. Ichikawa4, N. Nakamura4, T. Nakaya4, B. Quilain4, R. Cornat5, O. Drapier5, O. Ferreira5, F. Gastaldi5, M. Gonin5, J. Imber5, M. Licciardi5, T. A. Mueller5, O. Volcy5, Y. Azuma6, T. Inoue6, K. Kin6, Y. Seiya6, K. Yamamoto6, A. Blondel7, F. Cadoux7, K. Karadzhov7, Y. Favre7, E. N. Messomo7, L. Nicola7, S. Parsa7, M. Rayner7, Y. Hayato8, 1, A. Minamino9

1 University of Tokyo, Physics, Meguro-ku, Tokyo, Japan
2 Institute for Nuclear Research of the Russian, Physics, Moscow, Russian Federation
3 KEK, Physics, Tukuba, Japan
4 Kyoto University, Physics, Kyoto, Kyoto, Japan
5 Laboratoire Leprince-Ringuet, Ecole Polytechnique, Physics, Paris, France
6 Osaka City University, Physics, Osaka, Japan
7 University of Geneva, Physics, Geneva, Switzerland
8 Institute of Cosmic-Ray Research, Physics, Meguro, Japan
9 Yokohana National University, Physics, Yokohama, Japan


The J-PARC T59 experiment, named WAGASCI, has been developing a neutrino detector to measure a cross section ratio of charged current interaction on nucleus between water and plastic targets with uncertainties of a few percent at the J-PARC neutrino beamline. The WAGASCI detector adopts three-dimensional grid structure of 3mm-thick plastic scintillator bars around water target, to perform three-dimensional reconstruction of a particle trajectory, to improve the acceptance for large angle tracks. The light from scintillator is read out by MPPCs. An array of 32-channel MPPCs has been newly developed for this experiment. The total number of channels for the WAGASCI detector is 1280. The SPIROC2D ASIC chip, developed by OMEGA, has been employed in the frontend electronics. SPIROC2D is an auto-triggered, bi-gain, 36-channel ASIC, allowing the measurement of the charge from one to 2000 photoelectrons and the time with 100ps resolution. It contains a 16-deep analog memory array, which allows 16 hits to be stored in an acquisition gate. The backend electronics utilize Spartan6 FPGAs. The system to synchronize the data acquisition to the beam timing from J-PARC has been also developed. The data acquisition system has been developed, and its operation has been tested with J-PARC neutrino beam and cosmic rays. The data taking with neutrino beam is planned to start from autumn 2017. In this presentation, the performance and status of the WAGASCI detector and electronics will be described. 

Keywords: electronics, detector system, scintillator, MPPC, neutrino
Poster panel
(face) ID: 102

Poster Number:

Performance and Future Upgrades of the CMS DT Muon Detector (#2832)

D. D. Redondo1

1 CIEMAT, Particle Physics Division, Madrid, Madrid, Spain


A key component of the CMS (Compact Muon Solenoid) experiment is its muon system. The tracking and triggering of muons in the central part relies on Drift Tube (DT) chambers.

The DT system keeps evolving in order to cope with long term operational challenges, as well as future constraints for rate reduction imposed by future increases of LHC luminosity, maintaining the highest possible efficiency. During the first long LHC shutdown (LS1) a significant number of improvements and upgrades started being implemented, in particular concerning the readout and trigger electronics. Ever since LS1, each LHC winter shutdown is used to install and test these new developments towards HL-LHC.

Regarding the long term operation of the DT system, in order to cope with up to a factor 2 nominal LHC luminosity, several modifications will be required. The in-chamber local electronics will be modified to cope with the new environment. Also the second level of the readout system needs to be redesigned to minimize event processing time and remove present bottlenecks.

This talk will present, along with the main system improvements implemented in the system, the current performance results from our detector, using data collected at 13 TeV center-of-mass energy, confirming the satisfactory operation of both DT. Also the talk will review the present design, status and plans for the future DT system upgrades towards HL-LHC.

Keywords: lhc cms gaseous detectors drift chambers muon
Poster panel
(face) ID: 104

Poster Number:

The Inner Tracker of the KLOE-2 experiment (#2981)

D. Domenici1

1 Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Frascati, Italy


The KLOE-2 experiment at the INFN Laboratori Nazionali di Frascati is currently taking data at the e+e- DAFNE phi-factory. It is the continuation of the KLOE experiment, upgraded with state-of-the-art detectors to improve its performances and extend its physics reach. KLOE-2 has already collected an integrated luminosity of 3.5 fb-1, aiming to reach a total amount of more than 5 fb-1 by the Spring of 2018.

KLOE-2 is the first high-energy physics experiment instrumented with a fully cylindrical GEM detector. This innovative Inner Tracker has been inserted between the outer Drift Chamber and the beam-pipe to improve the tracking performance and the vertex resolution. It is composed by 4 layers of cylindrical triple-GEM realized using a leading-edge technology developed in Frascati, exploiting the kapton properties to build a light and compact device. The azimuthal and longitudinal coordinates are given by a peculiar readout electrode segmented with X strips and V pads. The signals are processed by a custom 64-channel ASIC with digital output mounted on a front-end board. Performance and capabilities of the detector will be reported in detail, including calibration procedure, space and vertex resolution.

Keywords: Tracking detector, Gas Electron Multiplier, Cylindical GEM
Poster panel
(face) ID: 106

Poster Number:

Latest developments on the highly granular Silicon-Tungsten Electromagnetic Calorimeter technological prototype for the International Large Detector. (#3198)

A. Irles1

1 Laboratoire de l’Accélérateur Linéaire, ILC - ECAL, Orsay, France



High precision physics at future colliders require unprecedented high precision calorimeters. The needed precision is achieved thanks to the Particle Flow Algorithm (PFA) and highly granular calorimeters. The physical proof of concept was performed in the prvious campaign of beam tests of physic prototypes within the CALICE collaboration. We present here the latest beam and laboratory test results and R&D developments for the Silicon-Tungsten Electromagnetic Calorimeter technological prototype with fully embedded very front-end (VFE) electronics for the International Large Detector at the International Linear Collider future project.

Keywords: high-granularity calorimetry, instrumentation, high energy physics, calice, linear collider
Poster panel
(face) ID: 108

Poster Number:

Direct Calibration of the Field Response Functions for the Liquid Argon Time Projection Chamber (#3974)

Y. Li1, M. Diwan1, J. Joshi1, S. Kettell1, B. Kirby1, X. Qian1, T. Rao2, J. Stewart1, W. Tang1, C. Thorn1, T. Tsang2, B. Viren1, C. Zhang1

1 Brookhaven National Laboratory, Physics Deparment, Upton, New York, United States of America
2 Brookhaven National Laboratory, Instrumentation Division, Upton, New York, United States of America


In a Liquid Argon Time Projection Chamber (LArTPC), ionization electrons drift through the induction wire planes toward the collection wire plane, current is induced on nearby wires.  The induced current as a function of time is defined as the field response function. As the field response function is the first step of signal processing of a LArTPC, it is essential to establish a precise knowledge of the field response. Due to the numerical challenges of the 3D electric field generate, the existing field response functions of LArTPC is based on 2D GARFIELD simulation. In addition, the simulation is required to be validated by measurement. We propose to direct calibrate the field  response functions for the wire-readout-based single-phase Liquid Argon Time Projection Chamber (LArTPC) by constructing a dedicated system to simulate the wire configurations of the LArTPC.  A direct calibration of the field responses will improve the TPC signal processing, which is the foundation of thautomated event reconstruction. This work is expected to benefit the MicroBooNE data analysis and to provide critical inputs for protoDUNE and DUNE. We also propose an in-situ field response calibration device in the future DUNE experiment. 

Keywords: Liquid Argon, Time Projection Chamber, Neutrino, Field Response, Calibration, DUNE, MicroBooNE
Poster panel
(face) ID: 110

Poster Number:

Processing of the Liquid Xenon Calorimeters Signals for Timing Measurements. (#4233)

L. Epshteyn1, 2, Y. Yudin1, 3, I. Logashenko1, 3, K. Mikhaylov1, 3, A. Grebenuk1, 3, A. Kozyrev1, 2, A. Ruban1

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

On behalf of CMD-3 Collaboration


One of the goals of the Cryogenic Magnetic Detector at Budker Institute of Nuclear Physics SB RAS (Novosibirsk, Russia) is a study of nucleons production in electron-positron collisions near threshold. The neutron-antineutron pair production events can be detected only by the calorimeters. In the barrel calorimeter the antineutron annihilation typically occurs by 5 ns or later after beams crossing. For identification of such events it is necessary to measure the time of flight of particles to the LXe-calorimeter with accuracy of about 3 ns. The LXe-calorimeter consists of 14 layers of ionization chambers with anode and cathode readout. The duration of charge collection to the anodes is about 4.5 mks, while the required accuracy of measuring of the signal arrival time is less than 1/1000 of that. Besides, the signal shapes differ substantially from event to event, so the signal arrival time is measured in two stages. At the first stage, the signal arrival time is determined with an accuracy of 1-2 discretization periods, and initial values of parameters for subsequent fitting procedure are calculated. At the second stage, the signal arrival time is determined with the required accuracy by means of fitting of the signal waveform with a template waveform. To implement that, a special electronics has been developed which performs waveform digitization and On - Line measurement of signals' arrival times and amplitudes.

Keywords: Digital signal processing, Front-end electronics, Trigger system, High Energy Physics instrumentation
Poster panel
(face) ID: 112

Poster Number:

A Field Deployable Imaging Neutron Detector (FIND) for SNM (#1331)

J. S. Legere1, P. F. Bloser1, A. C. Madden2, J. M. Ryan1, M. L. McConnell1

1 University of New Hampshire, Space Science Center, Durham, New Hampshire, United States of America
2 Los Alamos National Lab, Los Alamos, New Mexico, United States of America


Neutron detection is of particular interest for nuclear or radiological material identification for security and proliferation deterrence, as well as for nuclear waste detection and monitoring.  We present a concept for a Field-Deployable Imaging Neutron Detector (FIND) based on modern, commercially available detector technology that is compact, low-power, low-mass, and rugged.  Individual detector cells are composed of plastic scintillator with pulse-shape discrimination (PSD) ability read out by arrays of silicon photomultipliers (SiPMs).  A double-scatter neutron camera is formed by two layers of such detector cells.  The compactness, ruggedness, and low weight of this technology allows these layers to be easily transported in standard portable containers for rapid deployment and assembly in the field.  Gamma-ray imaging and low-resolution spectroscopy can be achieved as well.  We describe the FIND instrument concept in detail and present imaging and spectroscopy results for a prototype system containing a 3 x 3 array of detectors in each layer.  

Keywords: Neutron Detection, Neutron Imaging, Field Deployable
Poster panel
(face) ID: 114

Poster Number:

Development of differential die-away technique in an integrated active neutron NDA system for nuclear non-proliferation and nuclear security (#1431)

A. Ohzu1, M. Maeda1, M. Komeda1, Y. Toh1, M. Koizumi1, M. Seya1

1 Japan Atomic Energy Agency, Nuclear Sensing Research Group, tokai-mura, Ibaraki, Japan


A Differential Die-away Analysis (DDA) system using a compact pulsed neutron (14 MeV) generator has been newly developed for non-nuclear proliferation and nuclear security in the Japan Atomic Energy Agency (JAEA). The DDA system was designed to be able to detect a nuclear fissile material (Pu-239) of as low as 10 mg and to handle samples of a different volume: a vial bottle (20 mL), a pail container (20 L), through a Monte Carlo simulation. In the DDA system, the Fast Neutron Direct Interrogation (FNDI) technique, which utilizes fast neutrons for interrogation, was applied to measure the amount of fissile mass contained in the sample. The fundamental performance of the DDA system was investigated in the demonstration experiment. The results of the experiment are discussed and compared with those of the simulation.

Keywords: nuclear material, nuclear security, nuclear non-proliferation, differential die-away, analysis system
Poster panel
(face) ID: 116

Poster Number:

Assessment of Quantum Dots for Nuclear Security and X-ray Dosimetry (#1677)

T. Crane1, A. Gavin1, P. Sellin2, J. Burns1, C. Shenton-Taylor2

1 AWE, Reading, Berkshire, United Kingdom of Great Britain and Northern Ireland
2 University of Surrey, Department of Physics, Guildford, Surrey, United Kingdom of Great Britain and Northern Ireland


Under X-ray or gamma irradiation, nanocrystal quantum dots (QDs) can be made to emit optical photons in the visible or near-visible spectrum. As the emission profile of the QDs can be tailored during their fabrication process, it is possible to create a tuned light output in response to incident radiation. Various configurations can be used; particles can be embedded within scintillating materials or suspended within transparent matrices. In this study we present measured light outputs from a series of oleic acid and alkyl functionalised QDs in toluene and water-based suspensions. Results indicate promising performance from QDs suspended in a toluene solution, with water-based scintillators presenting a potential low hazard alternative. Photoluminescence spectra were obtained from a series of cadmium based dots (CdSeS/ZnS), with light emissions ranging from 450 to 665 nm. Optical coupling configurations were explored using above-band UV photoexcitation. In addition, X-ray and gamma induced light measurements were analysed alongside an assessment of the applicability of QDs as an active material for dosimetry. This research sits within a larger effort to leverage use of QDs within nuclear security applications; commentary is included on these aspirations within this paper.

Keywords: Novel detection concepts, Scintillators, Quantum dots, Nanomaterials, Nuclear security
Poster panel
(face) ID: 118

Poster Number:

Development of Compact Coded Aperture Gamma Camera for Radiation Monitoring in Nuclear Facility (#1842)

D. M. Im1, J. H. Jung1, Y. Choi1, D. Jang1, D. Kim1, Y. H. Kim1, J. - H. Kim2

1 Sogang University, Department of Electronic Engineering, Seoul, Republic of Korea
2 Woojin Engineering & Technology, Technology Laboratory, Gyeonggi-do Hwaseong-si, Republic of Korea


Gamma camera is a useful device to monitor various radiation sources in a wide range of areas at nuclear facility. To localize and identify radiation sources in large area, angular resolution and detection efficiency of gamma camera should be high, which can be achieved by employing coded aperture in gamma camera. The purpose of this study was to develop a compact gamma camera consisting of coded aperture, SiPM based detector and dedicated electronics. Coded mask, which consisted of 2 × 2 mosaic of 19 × 19 asymmetric modified uniformly redundant array pattern with 1.5 mm hole size and 15 mm thickness, was designed. To assess the performance of the designed coded aperture, spatial resolution and sensitivity of gamma camera employing the coded aperture were estimated by Monte Carlo simulation using GATE and compared to that of gamma camera with pinhole collimator. SiPM based detector and dedicated electronics were also designed and fabricated. The gamma camera detector block was composed of 3 × 3 matrix of detector modules, each consisting of a 4 × 4 GAGG array coupled to a 4 × 4 SiPM array. The 144 output signals of the detector block were sent to 144:4 multiplexing circuit employing a symmetric charge division network developed in this study and then digitized by custom-made DAQ. To evaluate the intrinsic performance of the developed gamma camera, initial flood image and energy spectrum were acquired. Gamma camera image was successfully reconstructed and its SNR was further improved by subtracting background noise using mask/anti-mask method. Spatial resolution and sensitivity were 7.6 mm/4.9 cps/MBq for coded aperture and 7.3 mm/0.2 cps/MBq for single pinhole collimator. Each crystal pixel was clearly identified in the flood images and average energy resolution was 14.5±1.7%. Preliminary investigation results indicate that the coded aperture gamma camera developed in this study could accurately localize and identify radiation sources with improved sensitivity.

Keywords: coded aperture, gamma camera, SiPM, GAGG
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(face) ID: 120

Poster Number:

An X ray-cosmic ray combined dual-model reconstruction approach for vehicle/container inspection (#1855)

X. Yi1, Z. Zhao1, 2, B. Liu1, S. Liang1, G. Xu1, H. Zhang1, Z. Zeng2, M. Zeng2, J. Gu1, X. Wang2

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


Cosmic-ray tomography is an effective non-destructive technology which was developed to detect high-Z nuclear materials. By reconstructing the scattering density image of muon, it can easily discriminate high-Z materials from medium- or low-Z ones. Further, after taking part in soft cosmic ray (such as electrons), this technology can discriminate medium- and low-Z materials, which is much more significant for fighting against smuggling and seizing hazardous goods. However, because of incompleteness of the measured data, the reconstruction image presents an ambiguous side view and low material resolution (especially for the medium- and low-Z materials), which brings great difficulty in discriminating the contrabands from normal goods and limits the application of cosmic-ray tomography technology. In order to achieve higher material resolution, we propose an X-ray & cosmic-ray combined dual-model reconstruction approach in this paper. X-ray system obtains transparency, structure and height information of the inspected vehicle/container, then cosmic ray tomography system reconstructs image using both cosmic-ray and X-ray information, where the cargo transparency value helps to divide different Z regions, structure determines the location of stopping effect, and material thickness improves the calculations of stopping power and scattering density. Validated by Geant4 simulation program, we can improve the detection rate of nylon-heroin model from 39% to 90% by combining the two systems. As a result, in reasonable inspection time, the dual-model reconstruction approach can effectively enhance the classification ability of medium- and low-Z materials.

Keywords: Muon tomography, nuclear material detection, contraband inspection, X-ray imaging
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(face) ID: 122

Poster Number:

Optical Yield Optimization Studies for Muon Tomography Applications (#2286)

E. T. Rand1, A. Gaulin1, V. Anghel1, A. Erlandson1, C. Jewett1, O. Kamaev1, S. Livingstone1, M. Thompson1

1 Canadian Nuclear Laboratories, Applied Physics Branch, Chalk River, Ontario, Canada


The detection and identification of illicit special nuclear material (SNM) and shielded radiological material at border crossings is a serious national security threat. These materials are difficult to detect using existing passive border monitors when heavily shielded. Muon scattering tomography (MST) offers an elegant solution to this problem, as cosmic-ray muons are highly penetrating and can be used to detect the presence of materials such as uranium, plutonium, or lead. Facilities like the Cosmic Ray Inspection and Passive Tomography (CRIPT) detector located at the Canadian Nuclear Laboratories (CNL) have demonstrated the effectiveness of this technology. Reconstructed images using advanced algorithms clearly show the presence of SNM. However, the number of events, and thus length of time, required to reconstruct an image is significant. This ultimately limits the border security application of this technology. In this work we investigated a number of MST "upgrades" to increase the efficiency of the CRIPT detector; reducing the overall scanning time required. A sophisticated and novel Monte Carlo simulation using the Geant4 toolkit was developed to track optical photons and measure the light yield. A number of upgrades were considered, including new scintillator bar geometries and the application of optical couplers between the scintillator bars and the Y11 Kuraray wave-length shifting (WLS) fibers. Cylindrical bars outperformed the standard triangular prism bars in both light production and light collection when comparing bars of the same physical volume. We found approximately a 75% to 84% increase in optical photon production, and a 59% increase in light collection in the WLS fiber. Furthermore, a PMT optical gain of 1.37(2) was found using water as an optical coupler between the scintillator bar and WLS fiber. These results including various commercially available optical couplers and other light yield optimization results will be presented.

Keywords: Muon Scattering Tomography, Monte Carlo, Geant4, Wave-length Shifting Fibers
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(face) ID: 124

Poster Number:

Gamma Spectrum Enhancement in a Metal Loaded Plastic scintillator using Pulse Shape Discrimination (#2712)

H. R. Gadey1, A. T. Farsoni1, S. A. Czyz1, L. Ranjbar1

1 Oregon State University, Corvallis, United States of America


Photoelectric and Compton events are the common interaction mechanisms observed when gamma photons interact with matter. These interactions are depended on energy and the Z number of the detector. Conventional scintillators have high Z atoms and are useful in giving spectroscopic information. From a manufacturing stand point huge blocks of NaI can’t be manufactured and from an economic stand point, inorganic scintillators are expensive. These short comings can be overcome by using plastic scintillators, which are both easy to manufacture and costs effective. Historically plastic scintillators have not been good at detecting photopeaks. Efforts at Sandia national lab have resulted in producing a polystyrene based scintillator with a high Z atom loaded in the plastic base. Therefore, from a spectroscopic point of view, a photopeak and a huge Compton continuum is observed.

This study aims at understanding differences in pulse shapes from low Z and high Z materials. These differences can be employed to perform pulse shape discrimination (PSD) to preferentially reject pulses from low Z materials while preserving counts under the photopeak thereby providing us a Compton suppressed spectrum.

Three single photon sources were used; 198Au, 137Cs and 54Mn. Charge Integration, Pulse Gradient Analysis, and Frequency gradient analysis algorithms were used to perform the discrimination. The detector yielded a resolution of 9.23%. Preliminary results indicate that the algorithms were successful in suppressing the Compton continuum and preserving a large portion of the counts under the photopeak. Following the correction 198Au, 137Cs and 54Mn have shown an improvement in the figure of merit (FOM) by a factor of 1.7, 2.3 and 1.8 respectively. Initial results for studies performed at reduced sampling of 1.25 GHz and 833 MHz also indicates that the algorithms were successful in improving the FOM.

Keywords: Compton, Photoelectric, Plastic, Pulse Shape Discrimination, Scintillator
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(face) ID: 126

Poster Number:

Shielding Calculation for 9MeV X-Ray Cargo Container Inspection System for Multi-View Image Acquisition using Monte Carlo Method (#2770)

I. - H. Kim1, C. - H. Lim1, J. - H. Lee1, J. - W. Park1, Y. - K. Lim1

1 Korea Research Institute of Ships & Ocean Engineering, Ocean System Engineering Research Division, Daejeon, Republic of Korea


The container inspection system is an equipment that inspects the inside of the container without opening the container using the X-ray. It has been mainly used for the smuggling of container cargo but recently it has been widely used to monitor terrorist material in order to prevent terrorism in the world. The inspection system using X-rays may not be accurate depending on the loading direction of the container cargo and the shape of the object. For example, in the case of a pipe-type object, it is not easy to identify an object because it is seen as a round object when the object is viewed in the straight-ahead direction. In order to compensate for this, two x-ray imaging systems(straight and orthogonal) are usually used for image acquisition. This method increases the number of systems and increases shielding, which adds a lot of cost to system construction. As an alternative to this, we are developing a multi-view image acquisition system for container inspection to acquire two images using one X-ray generator. This inspection system uses x-rays generated in a specific angular range rather than the commonly x-rays(fan beam type). Therefore, it is required to design a shielding facility suitable for multi - view image acquisition facilities. In this research, the approximate shielding thicknesses of the primary and secondary barriers were set by referring to NCRP 49. and NCRP 151. The optimal thicknesses of the primary and secondary barriers for the maximum 9 MeV X-ray were calculated using MCNP6.

Keywords: Shielding Calculation, Monte Carlo Method, 9 MeV X-ray
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(face) ID: 128

Poster Number:

Identification of the Man-made Radiation Sources Using a PVT Plastic Scintillation Detector (#2909)

M. Moon1, J. Lee1, 2, K. Lim1, B. Jeon1

1 Korea Atomic Energy Research Institute, Neutron Science Research Center, Yuseong, Daejeon, Republic of Korea
2 Hanbat National University, Electronics and Control Engineering Depaerment, Yuseong, Daejeon, Republic of Korea


This paper introduces a new and simple method with which to identify for the presence of man-made radiation sources in materials or passing objects using a polyvinyltoluene (PVT) plastic scintillation detector. This method was derived by continuously comparing the low-channel and high-channel counting ratios of the PVT detector spectrum. Firstly it is needed to obtain a continuous ratio of the low-channel sum divided by the high-channel sum from the detector spectrum. The low- and high-channel sum represent the sum of the total counts in the range below and over the reference channels which vary lowest channel value to highest channel value in detector spectrum. Because the shape of background spectrum is mostly constant, the presence of man-made radiation sources can change the shape of spectrum. Therefore, the presence of man-made radiation sources can easily be confirmed by dividing the measured spectral low- and high-channel ratio by the background spectrum ratio, or vice versa. It is also possible to determine the type of radiation source with this method. Moreover, the proposed method can easily distinguish between Co-60 and K-40, which is abundant in certain materials.

Keywords: Artificial radiation sources, Man-made radiation sources, Naturally occurring radioactive materials, Organic scintillation detector, Polyvinyl toluene scintillation detector
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(face) ID: 130

Poster Number:

Development of a Centrifugal Tensioned Metastable Fluid Detector Array to Detect SNM using Active Neutron Interrogation (#3039)

B. C. Archambault2, A. R. Hagen1, T. F. Grimes3, R. P. Taleyarkhan1, 2

1 Purdue University, Nuclear Engineering, West Lafayette, Indiana, United States of America
2 Sagamore Adams Laboratories, LLC, Chicago, Illinois, United States of America
3 Intelligence Community Postdoctoral Research Fellowship Program, West Lafayette, Indiana, United States of America


A novel, portable, and lightweight active neutron interrogation system is under development by our collaboration incorporating a man-portable inertial electrostatic confinement (IEC) based D-D neutron source and centrifugal tensioned metastable fluid detector (CTMFD) panels to enable the detection of SNM in cargos less than 1 m3. Threshold energy neutron analysis (TENA) techniques are utilized to discriminate the ~2.5 MeV interrogation neutrons used to induce fission in a SNM target while remaining sensitive to the ~30% of the fission spectrum emitted at energies >2.5 MeV. CTMFDs are ideal for TENA applications due to their inherent ability to selectively discriminate lower energy neutrons by tailoring the tensioned metastable negative pressure (Pneg) state and their proven gamma insensitivity (gamma intrinsic detection efficiency <1×10-9). A prototype panel of 6 CTMFD units, each with a ~16cm3 SV, was developed, constructed and evaluated with D-D, D-T, and 252Cf neutron sources. Experimentation highlighted several areas capable of targeted field-relevant functionality improvement, and as a result the Lightweight(LW)-CTMFD architecture was developed to meet these challenges. The resultant LW-CTMFD was then configured into a portable modular configuration consisting of 5× ~16cm3 SV units. Each module was targeted for operation in a stacked configuration resulting in a total of 10~20× ~16cm3 SV units per panel. Preliminary assessments indicate that an intrinsic detection efficiency ratio (εCfDD) of >104:1 is achievable with the LW-CTMFD at a Pneg of ~2.8 bar and becomes effectively infinite at lower Pneg indicating complete insensitivity neutrons from the D-D interrogation source. The construction of the LW-CTMFD module and the results of experimentation indicates that the Modular LW-CTMFD system not only meets but also exceeds the design goals therefore enabling the detection of small (10s~100s of gram) quantities of HEU hidden in 1m3 containers within minutes.

Keywords: Neutron Detector, Active Interrogation, Special Nuclear Material, Neutrons, Tensioned Metastable Fluid Detector
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(face) ID: 132

Poster Number:

Design of a One Dimensional Dual Particle Time Encoded Imaging System (#3430)

N. P. Shah1, D. K. Wehe1

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


Localization of radiological sources is an important task for non-proliferation and homeland security. Imaging of neutrons and gammas is typically done through expensive coded aperture imaging systems or low efficiency scatter cameras. Time encoded imaging (TEI) is an alternative method that modulates the count rate observed by a non-position sensitive detector via a rotating mask. In this case, the detector has far few restrictions allowing for a more simple, cost effective, and robust detector that harbor other capabilities such as multiple particle detection. To develop a dual particle TEI system, a dual particle mask was designed to block both neutrons and gammas. Using a combination of Geant4 simulations and a discrete analytical model, different detectors, mask patterns, radii, and thicknesses were evaluated to predict the system response and acquire an estimate for the angular resolution. Presented here is a conceptual design for a compact, one dimensional, dual particle time encoded imaging system. The cylindrical mask consists of 5 cm thick HDPE and 1 cm thick tungsten bars placed in a 1-D URA pattern. The mask has a height of 10 cm, a radius of 20 cm, and weighs ~25 lbs. Placed at the center is a 2 inch stilbene detector that can detect and separate both fast neutrons and gammas through pulse shaped discrimination. For an idealized far field point source, the full width at half maximum is ~10°. The expected time to image a 1 mCi Cf-252 source at 1 m is less than 10 minutes.

Keywords: neutron, gamma, imaging, nonproliferation, homeland security, time encoded imaging, nuclear security
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(face) ID: 134

Poster Number:

Characterization of tin-loaded liquid scintillator for gamma spectroscopy and neutron detection (#3454)

X. Wen1, J. Walker2, Y. Noh2, R. Farley2, A. Enqvist1

1 University of Florida, Nuclear Engineering Program, Gainesville, Florida, United States of America
2 Nanoptics Inc., Gainesville, Florida, United States of America


Tin-loaded organic liquid scintillator has been developed and characterized including energy resolution, pulse shape discrimination, neutron light output function and timing resolution for gamma spectroscopy and neutron detection. The loading of tin into scintillators with low effective atomic number was demonstrated to provide photopeaks with acceptable energy resolution. The scintillator was also shown to have reasonable neutron-gamma discrimination capability based on the charge comparison method. The effect on the discrimination quality of the total charge integration time and the initial delay time for tail charge integration was studied. To obtain the neutron light output function, the time-of-flight technique was utilized with a 252Cf source. The light output function was validated with the MCNPX-PoliMi code. In addition, the timing resolution of the scintillator was evaluated using the coincidence counting method. The tin-loading was found to have negligible impact on the scintillation decay times. However, degradation of timing resolution was observed due to the reduced light yield.

Keywords: tin-loaded liquid scintillator; energy resolution; timing resolution; neutron light output; pulse shape discrimination;
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(face) ID: 136

Poster Number:

6 Wheel Terrestrial Robot for Radiation Detection (#3536)

R. M. Vázquez-Cervantes1, F. J. Ramirez-Jimenez1

1 Instituto Nacional de Investigaciones Nucleares, SISTEMAS ELECTRONICOS, OCOYOACAC, ESTADO DE MEXICO, Mexico


The development of a 6-wheel remote controlled prototype robot is shown. The robot has two radiation detectors, a 1.5 "X 1.5" NaI(Tl) scintillator detector and a Ge-Hp isotope identifier. The robot has a payload capacity of 50 kg. The control of this robot can be performed up to 2 km away in line of sight. The robot is designed to be used as a remotely operated unmanned vehicle for radiological monitoring and search for radioactive sources in case of emergencies. A map of the robot trajectory with the sample points and radiological measurements can be obtained. The map is generated from the data of the geographical coordinates, GPS. A remote visual monitoring station is used for visual inspection of the robot's operation. The image of the monitored scenario incorporates the radiation data through an On Screen Display, OSD, module.

Poster panel
(face) ID: 138

Poster Number:

Readout Electronics of a Handheld Dual Particle Imager (#3560)

N. P. Giha1, M. L. Ruch1, A. Di Fulvio1, W. M. Steinberger1, S. A. Pozzi1

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


We designed and realized the front-end readout circuit for a matrix of silicon photomultipliers (SiPM), to be used in handheld dual particle imagers. In this work, we optically coupled two 6-mm by 6-mm by 6-mm stilbene crystals to two separate pixels on the same SiPM matrix and studied the performance of the readout architecture in terms of energy resolution and timing. A Na-22 source was placed on the array between the two pixels and energy and time resolution were measured. We varied the resistance of the AC stage of the readout circuit for each pixel by placing resistors of various resistance values in parallel with the signal readout jack. The energy resolution of the system improved with increasing resistance values, as expected. The time resolution in the 200 to 400 keV energy band did not vary significantly as a function of resistance value.

Keywords: silicon photomultipliers, stilbene, SiPM, Custom Electronics
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(face) ID: 140

Poster Number:

Localization of Gamma Ray Sources Using Handheld RadioIsotope Identification Devices: Comparative Tests (#3616)

T. R. Garcia1, M. Foster2, M. Schear1, M. Dallimore2

1 Symetrica, Inc, Maynard, Massachusetts, United States of America
2 Symetrica Security Ltd., Roman House, North Baddesley, Southampton, United Kingdom of Great Britain and Northern Ireland


Gamma source categorization is an important capability for nuclear security personnel looking to interdict illicit special nuclear material. In a handheld scenario, categorization is often handled by Radioisotope Identification Devices (RIDs or RIIDs). In addition to source categorization, RIDs are often also tasked with source detection and localization. Deployment scenarios also exist where a fleet of Personal Radiation Dosimeters (PRDs) are used to localize gamma sources first, and a smaller number of RIDs are used for identification. Recently, RIDs have become available which localize sources via Compton scatter imaging using pixelated CZT gamma detectors. One downside to these devices is the total time to image a location to the point where localization is sufficient, as well as cost and low sensitivity. Multi-scintillator-based RIDs may allow for a quicker localization of gamma sources in comparison to single-crystal handhelds, or even GM-based handhelds. Such a RID effectively treats the small number of crystals as large pixels, which sacrifices angular resolution for reduced readout complexity. In certain cases, the total volume of scintillator is maintained without greatly increasing the cost of the system, and the amount of directionality which is gained may be sufficient to reduce the time to clean a room compared to single-crystal RIDs without any position-sensitive readout.

This work will show a comparison of the total time to sweep a room, including an estimate in the total time to detect, localize, and identify gamma-ray sources. The baseline scenario is surveying a room with a VeriFinder NaI RID. The second, comparison scenario is surveying a room with a detector that has a handful of small scintillator crystals, whose total volume is approximately the same as a VeriFinder RID. The scenarios are further extended by reducing the mobility of the operator to simulate backpack or robotic-type movement.

Keywords: RIID
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(face) ID: 142

Poster Number:

A Prototype Cosmic-ray Muon Tomography System for Dry Storage Cask Monitoring (#3700)

C. Liao1, H. Yang1, Z. Liu2, J. P. Hayward2

1 Oregon State University, Nuclear Science and Engineering, Corvallis, Oregon, United States of America
2 The University of Tennessee, Knoxville, Department of Nuclear Engineering, Knoxville, Tennessee, United States of America


Cosmic-ray muon tomography has been studied for various applications. It was proved to be a good non-destructive assay technique for high-Z materials. In this work, we present a prototype muon imaging system for monitoring spent nuclear fuel content inside dry storage casks. The prototype system contains four identical position-sensitive muon detectors, forming two muon trackers. Each position-sensitive detector is a single layer of EJ-200 plastic scintillator with orthogonal grooves etched at top and bottom. Wavelength shifting (WLS) optical fibers are embedded in each groove to transfer the scintillation light to a Hamamatsu H8500C multi-anode PMT. The anode signals are then passed on to resistor networks where position information is extracted through voltage interpolation. The calibration of the position-sensitive detectors has been completed using a blue LED powered by a function generator. The prototype system has been assembled and is currently under testing. Experimental results and comparison with Monte-Carlo simulation will be presented in full submission.

Keywords: Position-sensitive Plastic Scintillator, Dry Storage Cask, Cosmic-ray, Muon Tomography
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(face) ID: 144

Poster Number:

Development of Diode Coupled Symmetric Charge Division Circuit for a Radiation Monitoring Gamma Camera (#3953)

D. Jang1, Y. Choi1, J. H. Jung1

1 Sogang University, Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul, Republic of Korea


The multiplexing circuits have been widely utilized to reduce the number of readout channels of gamma camera employing conventional photosensor such as photomultiplier tube (PMT). However, careful attention is required to design the multiplexing circuit for SiPM array which is a promising alternative to PMT because it can lead to the degradation of the resolvability and energy resolution due to the accumulation of dark currents produced by each SiPM pixels. To overcome this problem, a new multiplexing method, which use diodes to decouple SiPM pixel and readout channel, was recently proposed by a few research groups. The purpose of this study was to develop a diode coupled multiplexing circuit and to compare its performance with that of conventional resistor coupled multiplexing circuit. The gamma camera detector was composed of 3 × 3 matrix of detector modules, each of which consisting of a 4 × 4 GAGG array coupled to a 4 × 4 SiPM array. Symmetric charge division (SCD) circuit using diodes was designed and fabricated to reduce the 144 outputs from SiPMs to 24 outputs. The SCD circuit connected with resistors instead of diodes was also fabricated. Resistive encoder circuit was developed to further reduce 24 SCD outputs to 4 outputs. To evaluate the performances of the gamma camera with diode or resistor coupled SCD circuits, flood histogram quality and energy resolution were measured from acquired flood histogram and energy spectrum at different SiPM overvoltages. Average 8.8 of flood histogram quality was obtained using diode SCD at different bias voltages while resistive SCD obtained 4.7 at the center and 2.5 at the corner of the field of view showing low resolvability and uniformity. Average energy resolution was 12.9% for resistive SCD while that of diode SCD was 16.1%. The preliminary experimental results showed that diode SCD provided better performance than resistive SCD for gamma camera although the energy resolution obtained by diode SCD needs to be improved

Keywords: gamma camera, diode SCD, multiplexing circuit
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(face) ID: 146

Poster Number:

Development of a XRF Detection System for MOX Samples (#4118)

M. Carminati1, 2, A. D. Butt1, 2, A. Arbat3, R. Alberti3, L. Bombelli3, C. Fiorini1, 2

1 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
2 INFN, Sezione di Milano, Milano, Italy
3 XGlab srl, Milano, Italy


The design of the detection system for non-destructive analysis of MOX pellets by the accurate measurement of the Pu/U ratio in trace concentrations (few %) by means of XRF spectrometry is presented. The parameters of multiple Peltier-cooled compact CdTe detectors are optimized through systematic experimental characterization, leading to a FWHM resolution better than 1 keV at 122 keV (3.2 µs shaping time) stable for days of operation. Given the small separation between the analyzed peaks (9 keV) and the low concentration of Pu, accurate spectrum analysis is mandatory. Acquired spectra are processed by an algorithm that subtracts the background and fits the peaks with a combination of Gaussian and exponential tail functions, required to model the slow collection of hole in these detectors. The lack of calibrated Pu/U samples has been addressed by realizing mixtures of Bi/Pb powders (with similar spectral separation) and by creating a virtual spectrum by measuring the background-subtracted U spectrum which is then scaled, shifted and added back to the total spectrum to emulate the Pu spectrum in 1-10% concentrations. Experimental results obtained with the former samples allowed the assessment of repeatability (relative error within ±1.7%) for 10 measurements lasting 5 minutes (with a count rate of 20 kcps giving a total of ~900 kcounts), while the latter “virtual” spectra enabled the validation of the relative accuracy of whole analytical instrument within ±0.6%. Both values are well within the design specifications (±2% with a measurement time of max. 10 minutes). Thanks to a reliable net area calculation algorithm, the geometry and materials (filters, collimators) of the final instrument design have been optimized as well.

Keywords: spectroscopy, trace analysis, fitting, CdTe
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(face) ID: 148

Poster Number:

Compton Suppression System for Nuclear Safeguards Applications (#4278)

R. Venkataraman1, S. Croft1, L. Fabris1, D. Glasgow1, J. Knowles1

1 Oak Ridge National Laboratory, Nuclear Security and Isotope Tecchnology Division, Oak Ridge, Tennessee, United States of America


Quantification of nuclear material such as uranium and plutonium isotopes as well as actinides suncs as 241Am is required for nuclear material accountancy for safeguards. Regulatory bodies such as the International Atomic Energy Agency (IAEA) also need to know the isotopic attributes of nuclear material, e.g. 235U enrichment, 239Pu fraction. Prominent gamma ray signatures from nuclear materials are predominantly at low energies. Besdies actinides, samples may contain high activities of fission product nuclides, many of which emit higher energy gamma rays (> 600 keV). High Purity Germanium (HPGe) detectors are commonly employed in safeguards applications that require the best possible energy resolution. The analysis of low energy gamma rays is rendered difficult becaitivitiesuse of the high Compton continuum (partial energy deposition in HPGe) due to high energy gamma rays originating in the sample. This results in the degradation of the sensitivities that can be achieved at low energies of interest. Use of Compton Suppression Spectrometer (CSS) is explored for enhancing the senitivity of isotopic analysis and for improving the detection limits of radionuclides of interest in safeguards. An extended version of the Monte Carlo N-Particle (MCNP) code called MCNP-CP  (Correlated Particles) is used to systematically study the performance of the CSS. Gamma ray spectra were simulated for various safeguards scenarios including spent nuclear fuel with low, medium, and high burn up categories, and 241Am, uranium, and plutonium isotopes in thhe presence if high fission product activity. The CSS consists of an annular NaI(Tl) guard detector, an NaI(Tl) plug detector, and a HPGe spectrometer. Spectra will be acquired using spent nuclear fuel available at ORNL and other samples representative of the safeguards scenarios. Compton suppression factors will be presented at gamma rays of interest from  233U, 235U, 239Pu, and 241Am. Improvement in sensitivitivities will be presented.

Keywords: Gamma Spectrometry Compton Suppression Nuclear Safeguards
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(face) ID: 150

Poster Number:

Development of an advanced gaseous neutron imaging detector based on THick Gas Electron Multiplier (#1897)

D. S. Burke1, S. H. Byun1, A. Hanu2, C. Höglund3

1 McMaster University, Physics and Astronomy, Hamilton, Ontario, Canada
2 Bruce Power, Tiverton, Ontario, Canada
3 European Spallation Source, Lund, Sweden


3He alternative devices are sought after due to shortages in the 3He supply. We are developing a neutron imaging system using an alternative to 3He as a neutron converter. We propose as an alternative, a thin layer of 10B4C which will convert neutrons to 7Li and 4He leading to energy deposition in the proportional gas. Reaction product induced signals will be amplifed by Townsend avalanches in a thick gas electron multiplier (THGEM) geometry. Charges exiting the THGEM geometry will be resolved. We expect combining a solid state neutron converter with THGEM signal amplifcation will result in a neutron detector with effciency comparable to that of a conventional 3He detector but at considerably reduced cost. Preliminary measurements using a 3.2  μm thick 10B4C converter are underway.

Keywords: neutron, imaging, 3He alternative, THGEM, proportional counter, GEANT4, boron converter
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(face) ID: 152

Poster Number:

Scaling Delayed Neutron Measurements to Large Detector Areas (#2155)

F. Sutanto1, I. Jovanovic1

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


The performance of a cargo screening system that consists of two large-area scintillation detectors and a monoenergetic neutron interrogation source in measuring β-delayed neutron emission from illicit special nuclear material is explored by modeling and simulation. Measuring delayed neutrons is a difficult task due to their small yield in comparison with the yield of the secondary fission products and their relatively low energy. A detector for delayed neutrons needs to exhibit a high intrinsic efficiency and cover a large solid angle, making it also sensitive to background radiation. We present a case study where we attempt to detect the presence of 5 kg-scale quantities of 235U in a standard air-filled cargo container. The detector is a rectangular shaped non- scintillating PVT wrapped with a thin 6LiF:ZnS(Ag) scintillator. The detector is partially shielded with a 0.05 cm thick cadmium foil to reduce the low energy cosmic neutron detection rate. The probing particles are 14 MeV neutrons. We find that using a total measurement time of ∼5 s and a dose equivalent of ∼1 mrem, the presence of the special nuclear material can be detected with false positive and false negative probabilities that are no larger than 5% and 0.15%, respectively.

Keywords: Active interrogation, Delayed neutron, Cargo screening
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(face) ID: 154

Poster Number:

Simplification of Neutron-Monitoring System by Using Cs-134m Conversion Electrons in a Self-Activated CsI Scintillator (#2204)

R. Kakino1, A. Nohtomi1, G. Wakabayashi2, J. Fukunaga3, Y. Umezu3, Y. Nakamura4, S. Ohga5

1 Kyushu University, Department of Health Sciences, Fukuoka-shi, Japan
2 Kindai University, Atomic Energy Research Institute, Higashiosaka-shi, Japan
3 Kyushu University Hospital, Department of Radiology, Fukuoka-shi, Japan
4 Kyushu University Hospital, Department of Medical Technology, Fukuoka-shi, Japan
5 Kyushu University Hospital, Department of Clinical Radiology, Graduate School of Medical Sciences, Fukuoka-shi, Japan


A CsI scintillator has been applied to the evaluation of neutron ambient dose equivalent around a clinical linac. The CsI scintillator served as both target material and 4π counter of activation method. The experiments were performed at a 10-MV linac with two types of polyethylene moderator and a cadmium sheet for extracting the neutron energy information. After the termination of irradiation, the activation of CsI was measured by CsI itself with a multi-pixel photon counter (MPPC) readout. In the energy spectrum observed by the CsI detector itself, β-rays of I-128 and internal conversion electrons of Cs-134m were dominant. The amounts of I-128 and Cs-134m were accurately derived by fitting the time variation of counting rates with a “biexponential function”. Neutron spectrum fluence rate was evaluated from activities of I-128 and Cs-134m in the scintillator with four filtering conditions. By convoluting the spectrum fluence rate with dose equivalent conversion factor given by ICRP, the neutron ambient dose equivalent H*(10) was evaluated to be 9.0 x 10-2 [mSv] per unit Gy to the isocenter. In addition, neutron spectrum fluence rates were also evaluated from activities with three filtering conditions, and found that it is possible to reduce filtering conditions by using Cs-134m as well as I-128. In conclusion, the additional use of conversion electrons of Cs-134m is beneficial to simplify the present neutron-monitoring system. 

Keywords: CsI self-activation method, Cs-134m, I-128, Neutron ambient dose equivalent, X-ray linac
Poster panel
(face) ID: 156

Poster Number:

An image analysis for neutron distribution measurement by CsI plates with CCD camera using a decaying self-activation imaging technique (#2389)

M. Tokunaga1, A. Nohtomi1, J. Fukunaga2, Y. Umezu2, Y. Nakamura3, S. Ohga4, G. Wakabayashi5, Y. Koba6, K. Shinsho7

1 Kyushu University, Department of Health Sciences, Fukuoka-shi, , Japan
2 Kyushu University Hospital, Department of Radiology, Fukuoka-shi, Japan
3 Kyushu University Hospital, Department of Medical Technology, Fukuoka-shi, Japan
4 Kyushu University Hospital, Department of Clinical Radiology, Fukuoka-shi, Japan
5 Kindai University, Atomic Energy Research Institute, Higashiosaka-shi, Japan
6 National Institutes for Quantum and Radiological Science and Technology, Chiba-shi, Japan
7 Tokyo Metropolitan University, Graduate school of Human Sciences, Arakawa-ku, Japan


In our previous study, we successfully demonstrated that a CCD read-out technique was applicable to neutron distribution measurement with the self-activation method using CsI plates. In the present study, neutron distributions on CsI plates have been analyzed by a newly-proposed “decaying self-activation imaging technique”. The inherent non-uniformity of each CsI plate was also corrected. Experiments were conducted by using a Pu-Be neutron source (3.7×1010 Bq) and a 10-MV linac (Varian True Beam). Neutrons were irradiated to a CsI plate (2 mm in thickness) for 75 min and 30 min, respectively. In the linac, photo-neutrons were filtered by polyethylene brocks around the CsI plate and the half of the region on it was covered with Cd filter (1 mm in thickness) to change neutron intensity incident on each region. After the termination of irradiation, the luminance distributions were recorded as a series of images by a cooling type CCD camera (SBIG STF-8300M) every 1 min as 16 bit FIT images in a PC. Then the luminance values of the images were fitted on a pixel-by-pixel basis with a multi exponential function. Their initial luminance values of 128I and 134mCs were extracted as the fitting parameters for respective pixels. When these initial luminance values, which correspond to the values at the termination of neutron irradiation, were plotted separately as an image, other components were reasonably eliminated [“decaying self-activation imaging technique”]. In addition, inherent non-uniformity of each CsI plate was examined by standard irradiation of 70kV X-rays and corrected. After the corrections mentioned above, finally-obtained image showed a significant improvement. When the luminance distribution was divided into 16 regions for simplicity, mean initial luminance value in the region without a Cd filter is 8% higher than that with Cd filter.

Keywords: CCD camera, Decaying self-activation imaging method, neutron distribution measurement, CsI scintillator
Poster panel
(face) ID: 158

Poster Number:

Controlled thermal diffusion of trivalent Ce in 6Li loaded glass for selective scintillation (#2461)

M. E. Moore1, H. Xue1, J. D. Auxier II1, P. Vilmercati1, J. P. Hayward1

1 University of Tennessee, Knoxville, Tennessee, United States of America


While X-ray imaging can resolve spatial features well below the micron level, the state-of-the-art for neutron scattering instrumentation is approximately 10-15 microns. Neutrons represent an imaging challenge because they have no charge. So, their detection often relies on nuclear capture reactions that produce ionizing heavy charged particles that can then be detected. Currently, the spatial resolutions of cold neutron imaging methods are fundamentally limited by the variance introduced by the tracks of these charged particles. Therefore, we are experimentally testing microstructured arrays of scintillating 6Li loaded glass fibers that are capable of particle tracking. To avoid light loss and to preventing damage to the photosensor, we propose to directly couple a bent microstructured fiber array to the photosensor. However, neutron captures along the arc of the bent fibers will create position confusion, as there would not be a one–to–one detection/capture relationship. Thus, we are evaluating selective doping techniques using controlled thermal diffusion of a Ce (AcAc)3 (cerium (III) acetylacetonate) solution into the surface of undoped 6Li loaded glass. Herein, we present our doping technique, micron scale diffusion assayed with Rutherford backscattering spectrometry, and verification of the presence of trivalent Ce with X-ray photoelectron spectroscopy.

Keywords: cerium, diffusion, lithium glass, microstructured detectors, neutron imaging, Rutherford Backscattering Spectrometry, scintillation, X-Ray Photoelectron Spectroscopy
Poster panel
(face) ID: 160

Poster Number:

Medipix3RX neutron camera for ambient radiation measurements (#2689)

S. Bheesette1, 3, A. Butler1, 3, P. Butler2, 3, A. Dabrowski3, A. Lokhovitskiy2, 3

1 University of Otago, Department of Radiology, Christchurch, New Zealand
2 University of Canterbury, Department of Physics and Astronomy, Christchurch, New Zealand
3 European Centre for Nuclear Research, Beam Radiation Instrumentation and Luminosity, Geneva, Switzerland


Precise evaluation of composition and spectral characteristics of radiation in and around the Compact Muon Solenoid (CMS) on the LHC are necessary to ascertain the performance of various detector systems as well as to predict their useful lifetimes. The CMS-NZ collaboration is planning to deploy Medipix detectors in the CMS cavern for these measurements. Medipix3RX is the latest version of the hybrid pixelated detectors developed at CERN for medical imaginary but widely used in high energy physics experiments. These detectors will be capable of delivering real-time images of fluxes and spectral composition of different particles including slow and fast neutrons. The detector consists of a semiconductor sensor layer made of silicon, which is bump-bonded to the front-end electronics ASIC. Electronics and readout of these detectors, which were originally developed for the MARS spectral x-ray scanner at the University of Canterbury, Christchurch, were suitably adapted for their deployment in the CMS cavern. Neutrons are detected by using conversion layers such as lithium fluoride or polyethene to produce charged particles, which are then detected by the sensor. We studied the mixed-field radiation at seven Medipix detector proposed locations in the cavern by scoring particle tracks using FOCUS, a CMS FLUKA tool and analysed their energy as well as angular distributions. Good agreement was observed between average fluxes predicted by standard FLUKA methods and those obtained by integrating over FOCUS output data. The response function of the Medipix detectors with different neutron conversion layers has been simulated using Monte Carlo methods. A post-processing algorithm was developed for track reconstruction and recognition using cluster analysis techniques, which labels and determines the density of clusters formed by groups of particles. We will present overall scope of this work, its status and the results obtained so far. 

Keywords: Radiation, Physics, CERN, Neutron, Silicon, Medipix3RX, CMS, New Zealand, Switzerland
Poster panel
(face) ID: 162

Poster Number:

Development and Characterization of a Position Sensitive Neutron Scintillation Detector using Digital Silicon Photomultipliers (#2877)

M. Herzkamp1, D. Durini1, C. Degenhardt1, A. Erven1, H. Nöldgen1, A. Feoktystov2, L. Jokhovets1, M. Streun1, S. van Waasen1, 3

1 Forschungszentrum Jülich GmbH, Central Insitute of Engineering, Electronics and Analysis ZEA-2 -- Electronic Systems, Juelich, Germany
2 Forschungszentrum Jülich GmbH, Jülich Center for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany
3 University of Duisburg-Essen, Faculty of Engineering, Communication Systems (NTS), Duisburg, Germany


Due to the world-wide shortage of 3He, alternative, cost effective detection methods for neutron radiation are needed. A popular possibility is the use of neutron scintillators like 6Li-glass in combination with a photodetector. Due to their vulnerability to neutron irradiation, silicon photomultipliers (SiPM) have not been widely used for this kind of neutron detectors. However, in small angle neutron scattering (SANS) applications, lifetimes of well over 10 years can be expected for this technology in case of typical neutron doses, and thus the advantages of SiPM over conventional photomultipliers outweigh the risk of system failure. We developed a position sensitive neutron scintillation detector demonstrator based on a 6Li-glass scintillator screen and a digital SiPM array as photodetector. In this work we present the detector design, as well as validation measurements carried out using a cold neutron source. We further show the algorithm used for position reconstruction of neutron events as well as results concerning the spatial resolution of the demonstrator.

Keywords: Scintillation detectors, Silicon photomultipliers (SiPM), Neutron detectors, Cold and thermal neutrons
Poster panel
(face) ID: 164

Poster Number:

The research on the effect of boron layer roughness for the detection efficiency of boron-lined gaseous neutron detector (#2925)

Z. Fang1, 2, Y. Yang1, 2, Y. Li1, 2

1 Tsinghua University, Department of Engineering Physics, Beijing, China
2 Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, China


The boron-lined gaseous neutron detector has been shown as a promising detector that may replace the 3He counter. The roughness of the boron layer, which is one of the key components in this detector, can affect the probabilities of both neutron absorption and charged particles escaping into the working gas, and in turn, have an impact on the detection efficiency of this detector. A research is conducted in this paper to investigate the relationship between the roughness of boron layer and the detector's performance. GEANT4 based simulations are carried to calculate the neutron absorption probabilities, charged particles escaping probabilities, detection efficiencies, and average energies of escaped charged particles versus different roughness of boron layer. Results show that a roughness smaller than 1 μm has no appreciable effect on the detection efficiency. Thus, a newly developed boron coating method, dip-coating method that can realize boron layer roughness with the standard deviation of 0.38 μm, is acceptable for the boron layer production to manufacture the boron-lined gaseous neutron detector.

Keywords: roughness, neutron detection efficiency, boron layer, boron-lined gaseous neutron detector
Poster panel
(face) ID: 166

Poster Number:

Measurements with a new pixelated scintillation detector prototype for thermal neutrons (#3060)

G. Kemmerling1, S. Desert2, R. Engels3, K. Fissum4, H. Frielinghaus1, C. Gheorghe5, R. Hall-Wilton6, 7, S. Jaksch1, K. Kanaki6, P. Oya5, H. Perrey4

1 Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science, Jülich, North Rhine-Westphalia, Germany
2 CEA CNRS, LLB University Paris Saclay, Saclay, France
3 Forschungszentrum Jülich GmbH, Central Institute of Engineering, Electronics and Analytics - Electronic Systems, Jülich, North Rhine-Westphalia, Germany
4 Lund University, Department of Nuclear Physics, Lund, Sweden
5 Integrated Detector Electronics AS, Oslo, Norway
6 European Spallation Source ERIC, Lund, Sweden
7 Mid-Sweden University, Sundsvall, Sweden


A new position sensitive detector for thermal neutrons is currently being developed within the EU funded project SoNDe. It aims at the small angle neutron scattering instrument SKADI at the future European Spallation Source, where high rate and high efficiency neutron detection for medium scale areas is required. At SKADI, a peak rate of scattered neutrons of up to 20 MHz on an area of a square meter is expected, which should be measured with a position resolution of about 6 mm and a neutron detection efficiency of 80% or more. In order to cope with all these requirements, a modular and scalable detector concept has been chosen. It is based on a fast neutron detection process and a high segmentation of the detection area with individual and independent channels. It comprises a pixelated structure of Li-glass scintillator in combination with a multianode photomultiplier. Individual and independent detection channels are provided by an accurate positioning of the scintillator pixels on the photomultiplier channels and by building a light barrier between the scintillator pixels. As the light produced by the neutron capture with Li-glass scintillators and detected by photomultipliers deliver a range of pulse heights that can be assigned to neutrons, a simple and fast pulse processing electronics can be used to identify neutrons and discriminate against gamma-background. A first prototype of such a detector module has been developed and measurements with thermal neutrons have been carried out to prove and optimize the detector concept. The pixel crosstalk, the neutron/gamma discrimination and the count rate capability have been studied and are reported in this paper.

Keywords: pixelated neutron detector, neutron scintillation detector, multianode photomultiplier
Poster panel
(face) ID: 168

Poster Number:

Neutron Measurements with 4He SiPM Gas Scintillation Detectors in High Gamma Environments (#3099)

S. Gokhale1, R. Kelley1, T. Zhu1, Y. Liang1, S. Kiff2, R. Chandra3, A. Enqvist1, K. Jordan1, J. E. Baciak1

1 University of Florida, Nuclear Engineering, Gainesville, Florida, United States of America
2 Sandia National Laboratories, Livermore, California, United States of America
3 Arktis Radiation Detectors Ltd, Zurich, Zürich, Switzerland


This work assesses the performance of 4He SiPM gas scintillation neutron detectors in high gamma-ray intensity mixed radiation environments. The neutron-gamma discrimination capability of the 4He detectors is vital for applications such as spent nuclear fuel monitoring. A 315 Ci 137Cs collimated gamma-ray source was used to provide a high gamma environment in which the gamma flux incident on the detector could be varied. A 1 Ci PuBe neutron source was used to evaluate capability of the detectors to differentiate neutron events in the presence of the high gamma flux. Neutrons from this source could be unambiguously detected in gamma-ray exposure rates up to 318 mR/hr. corresponding to a gamma-to-neutron ratio of 218 to 1. Neutron counts could be distinguished from gamma-rays up to a gamma-to-neutron ratio of 5603 to 1. These results show the suitability of these detectors for measurement in high radiation field applications.

Keywords: Radiation detector, gas scintillation detector, neutron detector, silicon photomultiplier, gamma-ray detector
Poster panel
(face) ID: 170

Poster Number:

A Novel Water-Based Approach to Plutonium Detection (#3383)

A. Asghari1, S. Dazeley2, A. Bernstein2

1 Exponent, Inc., Menlo Park, United States of America
2 Lawrence Livermore National Laboratory (LLNL), Nuclear and Chemical Sciences Division, Livermore, United States of America


Helium-3 has traditionally been the gold standard for neutron detection because the medium is relatively insensitive to gammas, has a high neutron capture cross-section, and is safe.  However, due to the recent shortage of helium-3, a need has arisen for alternate detector technologies.  One such alternative is the Water Neutron Detector (WaND) developed at the Lawrence Livermore National Laboratory.  The WaND is a well detector that comprises a homogeneous mixture of 1.0 m3 de-ionized water and gadolinium tri-chloride (GdCl3), which acts as the moderator and detection medium.  A 19-cm-diameter source deployment well extends approximately to the center of the detector and allows for source interrogation.  The absolute single neutron detection efficiency of the detector is (23.4 +/- 1.1)%.  Recent results have shown that the WaND system is extremely effective at detecting small quantities of plutonium, as well as distinguishing it from other fissioning isotopes.  Compared to traditional deterministic methods of neutron multiplicity analysis, WaND triggered events are analyzed post-process, affording flexibility in data analysis.  The combination of relatively high neutron detection efficiencies and an algorithmic approach to neutron multiplicity counting permits the detection of 240Pu masses as small as 4 mg with one-hour acquisitions.  Furthermore, there is a significant laboratory-measured difference between 240Pu and 252Cf neutron multiplicities.  The combination of isotope identification and 240Pu mass determination could potentially make the WaND a powerful tool for the nondestructive analysis of nuclear materials for nonproliferation.  This presentation will highlight recent technical results and offer potential applications for the WaND system.

Keywords: neutron detection, neutrons, nonproliferation, novel detectors
Poster panel
(face) ID: 172

Poster Number:

Image Uniformity and Position Accuracy in Neutron Imaging Detector with Bundled Straws (#3527)

J. L. Lacy1, A. Athanasiades1, M. Regmi1, N. S. King1, C. S. Martin1, G. J. Vazquez-Flores1

1 Proportional Technologies, Inc., Houston, Texas, United States of America


Previous projects funded by the DOE have allowed Proportional Technologies, Inc. to develop a neutron imaging detector based on boron-coated straw (BCS) technology, aiming to replace 3He tubes in large-scale neutron science instruments. A neutron imaging panel, with a sensitive area of 0.18×1.0 m2, has been fabricated and tested. The panel consists of bundles of straws, each 7.5 mm in diameter, 1 m in active length, and coated on the inside with a pure, micron-thick layer of 10B-enriched boron carbide (10B4C). Straws are bundled in groups of 7 inside aluminum tubes, each 1-inch in diameter. A custom-designed electronic readout scheme employs charge division along the 1-m length, to determine the longitudinal coordinate of neutron interactions, and decode individual straws within the panel. Given that straws are bundled together in groups of 7 per tube, we investigate the ability of the panel to accurately determine the location of neutron interactions along the full active length of the detector. A number of factors may adversely affect position accuracy, including improper accounting of analog-to-digital converter offsets (pedestals), amplifier impedance, and misalignment of individual straws within the tube.

Keywords: neutron detectors, 3He replacement, boron-coated straws, charge-division
Poster panel
(face) ID: 174

Poster Number:

Developing and characterizing glass microcapillary arrays filled with silica gel bound sub-micron ZnS:Ag phosphor and 6LiF powders and 10-μm scintillation Gd-glass fiber faceplates for a neutron microscope (#3875)

X. Zhang1, C. Wan1, H. Qiao1, J. Lei1

1 Lanzhou University, School of NUclear Science and Technology, Lanzhou, Gansu, China


A neutron microscope is a very promising tool for characterizing hydrogen, oxygen, and/or lithium-6 related materials for the basic and application researches such as hydrogen fuel cells, organic materials, and lithium battery electrodes. As one of the two key components in such a system, a high spatial resolution (~μm) neutron imaging detector needs to be made of a microstructural neutron sensitive scintillator or phosphor. The previous experimental results for the 10-μm glass capillary arrays filled with sub-micron Gd2O2S:Tb phosphor powder show a worse resolution of 230 μm @ CTF=3% other than the expected around the order of the diameter of capillary. It may be caused by the longer tracks of secondary electrons produced by the neutron absorption and the refractive index mismatch between the phosphor and the capillary glass. The other two 5- and 15-mm thick 10-μm scintillation Gd-glass fiber faceplates also show a degraded resolution than the expected one and a higher uniform background in cold neutron images. The degraded resolution may be caused by the long tracks of secondary electrons produced by the neutron absorption reaction and the high uniform background may be caused by the higher sensitivity for the background gammas and low energy X-rays due to the thick Gd-glass. To further explore the reasons that degrade the spatial resolution and elevate the background noise, two upgraded microstructures have been developed and characterized in this work: 1) the different thicknesses glass microcapillary (2.2 and 10 μm) arrays filled with sub-micron ZnS:Ag phosphor and 6LiF powders bound together with silica gel and 2) the four thinner (50, 100, 300, and 600 μm) 10-μm scintillation Gd-glass fiber faceplates. The experimental results about these samples will be presented in this conference in more details. In addition, the invented method and process about filling sub-micron powder into microcapillary arrays, patenting in process, will be disclosed as well.

Keywords: Neutron Microscope, High Spatial Resolution, Cold Neutron Imaging
Poster panel
(face) ID: 176

Poster Number:

GAMBE: Thermal Neutron Detector for Directional Measurement of Neutron Flux (#4094)

A. Ahmed1, S. Burdin1, G. Casse1, H. Van Zalinge2

1 University of Liverpool, Department of Physics, Liverpool, United Kingdom of Great Britain and Northern Ireland
2 University of Liverpool, Department of Electrical Engineering and Electronics, Liverpool, United Kingdom of Great Britain and Northern Ireland


This paper investigates an alternative approach for determining the direction of neutron flux based on the combination of a single solid-state neutron capture detector and neutron scattering material such as high-density polythene (HDPE). The neutron capture detector has a sandwich configuration of two silicon sensors of 1 cm2 active area and a layer of 6LiF 7 um thick. It has been fixed at the centre of Aluminium enclosure (inner dimension 60 mm x 50 mm x 30 mm) for eliminating photoelectric noise. HDPE sheets encircle the entire detector from all directions except one in front of 1 Ci Am-Be neutron source where lead blocks 5 cm thick have been used for suppression of gamma-ray background. Thermal neutron detection efficiency has been estimated according to different setups where the whole system is rotated by an angle of 90 degree insight of Am-Be neutron source. The variation of thermal neutron detection efficiency due to the rotation process provides an evaluation about the location of the utilised neutron source. This location is identified by the maximum thermal neutron detection efficiency is achieved and the lowest count rate of gamma-ray where the lead window faced the neutron source. Theoretical investigation using MCNP 4C code approved the variation of thermal neutron flux through 6LiF film according to the rotational angle.

Keywords: Thermal Neutron Detector, Solid-state Neutron Detector, Neutron Flux, Neutron Conversion
Poster panel
(face) ID: 178

Poster Number:

A Compton camera using a single 3D position-sensitive LYSO scintillator (#2667)

H. Lee1, T. Lee3, W. Lee2

1 Korea University, Bio-Convergence Engineering, Seoul, Republic of Korea
2 Korea University, School of Health and Environmental Science, Seoul, Republic of Korea
3 Korea University, Health Science Research Center, Seoul, Republic of Korea


We developed a Compton camera using a single 3D position-sensitive LYSO scintillator coupled multi-pixel photon counter array. The LYSO scintillators had a 4×4×4 voxelized structure and the size of each voxel was 3×3×3 mm3. On the top and the bottom of the scintillator was coupled to 4×4 channel multi-pixel photon counter arrays and the size of each counter element was 3×3 mm2. The density of LYSO scintillators was 7.1 g/cm3. The emitted light from the scintillator after radiation interaction was detected by multi-pixel photon counters at the ends of a crystal block, and the depth information could be calculated based on the ratio of signals induced from the top and bottom photo counters. With this information, we could measure multiple scatterings inside the cubic scintillator and Compton imaging will be reconstructed.

Keywords: Compton camera, LYSO, 3D position-sensitive detector
Poster panel
(face) ID: 180

Poster Number:

3D nuclide imaging method using neutron and X-ray synergy imaging (#2836)

H. Hasemi1, T. Kamiyama1, H. Sato1, K. Nakajima2

1 Hokkaido University, Faculty of Engineering, Sapporo, Japan, Japan
2 Kyoto University, Research Reactor Institute, Kumatori-cho, Japan, Japan


Computed tomography (CT) using X-ray and neutron is a useful technique for geometry measurements. Although the neutron provides the information of nuclides in contrast to the X-ray, it takes a long time to measure the neutron CT due to the intensity of neutron source and the limitation of the performance of the detector. Therefore, we developed the 3D imaging method that combines the X-ray CT with the neutron imaging. This method creates the 3D nuclide data by mapping the nuclide information from the neutron transmission imaging in a limited direction into the 3D voxel data from the X-ray CT using the synergy imaging. The synergy imaging is the imaging technique that obtains a high resolved nuclide image using the differences between cross sections of neutron and X-ray. In this study, we demonstrated the 3D nuclide imaging concept by a computer simulation. At first, we created the X-ray CT data of this sample on the computer. On the other hand, using the Monte-Carlo simulation code “PHITS”, we obtained the neutron radiograms of this sample in three directions (x-, y-, z-axis). In next, we performed the synergy imaging between the X-ray projection image and the neutron radiograms. Finally, we tried reconstruction by the back projection method using these three nuclide distributions and obtained the 3D nuclide image by analyzing the voxel data after the back projection. We developed the 3D nuclide imaging method that combines the X-ray CT and the neutron transmission imaging. As conclusion, we obtained the 3D nuclide voxel data using the neutron and X-ray synergy imaging by the computer simulation.

Keywords: Computed tomography, Neutron radiography, X-ray radiography, Synergy imaging
Poster panel
(face) ID: 182

Poster Number:

An Efficient Method for Ellipse Reconstruction Using Hough Transform for Cherenkov Cone Detection (#2926)

A. H. Walenta1, 2, R. Beyerlein1, A. B. Brill3, I. Fleck1, L. R. Furenlid4, W. Khalid1, T. E. Peterson3

1 University of Siegen, physics, Siegen, Germany
2 Vanderbilt University, physics, Nashville, Tennessee, United States of America
3 Vanderbilt University, radiology & radiological science, Nashville, Tennessee, United States of America
4 University of Arizona, College of Optical Science, Tucson, Arizona, United States of America


With the availability of silicon photo diode arrays new imaging concepts such as the detection of Cherenkov light pattern generated in thick radiators become feasible. The advantage of very fast timing is already exploited for TOF applications in PET systems. There the Cherenkov light is emitted from the energetic Compton electrons generated after gamma ray interaction. In simulations it had been shown that under conditions, where the multiple scattering of an electron track perpendicular to the read-out plane is sufficiently reduced, the position and the depth of interaction can be reconstructed using the Hough transform. However, the angular distribution of Compton electrons generated from gamma rays necessitates the reconstruction of ellipses which for the Hough transform requires the use of a 5-dimensional parameter space with the consequence of unpractical exponential increase in computing time and loss of sensitivity. Here it is shown that the use of a priori knowledge reduces the reconstruction to the circular problem with the direct result of the depth of interaction and a simple geometrical calculation for positional and angular determination. It is found that for electrons with an energy of 4 MeV stopped in PMMA a precision of 4% for the depth of interaction (DOI) compared to the complementary thickness CD of the radiator (CD = thickness of the radiator minus DOI) can be obtained. For the directional resolution (relative angular resolution) the same value is obtained yielding finally a position resolution similar to DOI since the Cherenkov angle to be used is close to 45 degrees. These results are obtained with a rather straight-forward modeling and further possible improvements are reported in particular to exploit the usefulness for lower energy events. Applications of the method will be found in imaging of high energy radio nuclides, industrial imaging and homeland security.

Keywords: Image Analysis, Elliptic curves, Pattern Recognition, Hough Transform, Radiation detectors, Cherenkov Ring Imaging, Gamma Ray Imaging
Poster panel
(face) ID: 184

Poster Number:

Design and Operation of a Large NaI(Tl) Detector Array for High Energy Photon Imaging (#3376)

T. Nolan1, I. Jovanovic1

1 University of Michigan, Nuclear Engineering and Radiological Science, Ann Arbor, Michigan, United States of America


The threat of nuclear proliferation and nuclear terrorism continues to drive critical detection requirements in challenging scenarios, such as shielded configurations and cargo traffic. Material interdiction at ports of entry has primarily relied on passive detection methods; however, active interrogation has been shown to increase the signal-to-background in such measurements. For example, monoenergetic high-energy gamma rays resulting from low-energy nuclear reactions can be used to penetrate thick shielding and perform radiography. Spectroscopic high-energy photon measurements offer advantages for scanning in the time and radiation dose limited environments common to SNM detection applications at ports of entry. In this work, we discuss the design and operation of an array of large NaI scintillation detectors for use in dual energy photon imaging systems. We discuss the practical implementation of this method using the 11B(d,n/gamma)12C gamma producing reaction and an array of eight NaI scintillators. We discuss the design process, system performance in material identification, and consider the improvement in imaging through the use of anti-coincidence to reduce detector crosstalk.

Keywords: gamma radiography, detector array, detector crosstalk
Poster panel
(face) ID: 186

Poster Number:

Performance Evaluation in Transmission Neutron Tomography using Geant4 (#3673)

A. Datta1, A. I. Hawari1

1 North Carolina State University, Nuclear Engineering, Raleigh, United States of America


Thermal neutron tomography is a non-destructive technique used for the investigation of the internal structure of objects. This technique provides complementary information to X-ray tomography for a wide range of applications in science and engineering. Alongside the well collimated beam which reduces geometrical blurriness, the use of a thin scintillator can improve the resolution significantly. A representative scintillator that has been applied widely for thermal neutron imaging is 6LiF:ZnS(Ag). In this work, Geant4 is used to model and study the performance of a thermal neutron tomography system which includes a thermal neutron source, a scintillation screen and a pixilated imaging detector. The thermal neutron source is assumed to be a beam extracted from the PULSTAR research reactor at North Carolina State University (NCSU). The 6LiF:ZnS(Ag) scintillator is modelled along with the pixelated detector to record the projection data. The projection data is obtained by simulating 50 µm and 250 µm thick scintillators with a phantom at two positions from the beam aperture. The filtered back projection (FBP) algorithm with Hanning filter is used for the reconstruction of the projection data. Further simulations are carried out for the measurement of the spatial resolution of the radiographs and the scintillator screen separately. The results show that as the scintillator screen thickness decreases and/or as the object and detector distance from the beam aperture increases, the spatial resolution improves. Estimation of the contribution of tomographic image reconstruction was performed and found to be of similar magnitude to other components.

Keywords: Neutron tomography, Geant4, Spatial resolution
Poster panel
(face) ID: 188

Poster Number:

Time-Course 3D Imaging of Multiple Radio-Tracers in Living Mice with a Single Imaging Head of Semiconductor Compton Camera GREI (#4042)

S. Motomura1, Y. Murakawa1, 2, M. Munekane1, 2, T. Fukuchi1, Y. Watanabe1, S. Enomoto1, 2

1 RIKEN, CLST, Kobe, Japan
2 Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan


We have succeeded in obtaining the three-dimensional time-course images of multiple radio-tracers simultaneously injected in live mice using a single imaging head of the Ge semiconductor Compton camera GREI. Unlike other radiation imaging modalities such as PET or SPECT, the Compton camera does not need to arrange multiple sensor heads or to perform rotation around the object to obtain the multiple views. This is because the Compton camera can obtain images by detecting single gamma rays emitted from the gamma-ray sources, and accepts various angles of the incident gamma rays. We performed time-course GREI imaging experiment using live mice to observe the efficacy of radiation protective agents. We prepared two live mice that 85Sr, 131I and 137Cs were simultaneously injected, where one of them was orally administered with KI (100 mg/kg) one hour prior to the injection and the other was the vehicle treated control, and performed time-course GREI imaging of each mouse for eight hours. As a result, we were able to obtain three-dimensional time-course images that visualize the movement of each radio-tracer and significant reduction of 131I accumulation into the thyroid gland and the stomach in the KI administered mouse.

Keywords: Compton camera, Gamma-ray imaging, bio-medical application, radiation protection
Poster panel
(face) ID: 190

Poster Number:

High-Sensitivity Fiber Optic Radiation Monitor Using High-Density GdTaO4 Single Crystals (#1117)

S. Hatakeyama1, K. Ueno1, Y. Ueno1, T. Tadokoro1, K. Kamada2, R. Murakami2, A. Yoshikawa2

1 Hitachi, Ltd., Research & Development Group, Hitachi, Japan
2 Tohoku University, New Industry Creation Hatchery Center, Sendai, Japan


Fiber optic radiation monitors are a promising dosimetry tool for remote and real time radiation monitoring in nuclear power plant facilities. Improvement of the detection sensitivity is required, in order to measure the extremely low dose rate of 10-4 mGy/h which is found under controlled and monitored conditions during plant operations. In this work, a high-sensitivity fiber optic radiation monitor is designed and experimentally demonstrated. The detection sensitivity is improved by using high-density single crystals (8.8 g/cm3) of Eu3+ and Tb3+ doped gadolinium tantalates (GdTaO4) as the detection part. The fabricated prototype detector using GdTaO4:Eu(2%) measured the dose rate of 7.0 x 10-5 mGy/h with the precision of 0.2% full scale. In addition, it was confirmed that the detector operates in a single photon counting mode for the dose rate range of 7.0 x 10-5 to 1 mGy/h.

Keywords: Gamma-ray detector, Optical fiber, Single photon counting, Single crystal tantalate, Dose rate linearity
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(face) ID: 192

Poster Number:

Gamma-ray direction detector with triple scintillators for searching radioactive matter (#1616)

Y. Shirakawa1

1 Waseda University, Center for Research Strategy, Tokyo, Japan


The gamma-ray direction detector is the world’s first detector that measure the incoming direction of gamma-rays as well as usual radiation dose rate. The detector composes of triple NaI(Tl) scintillators. Each scintillator has the top shape of a 120-degree sector. Combination of each scintillator makes a 75mm in diameter and 75mm in length cylinder. Each scintillator of the detector gives a different output as a function of incoming direction. Hence a relation concerned with triple outputs of triple scintillators can express the information of the direction. The index of (A/T, B/T, C/T) works well as the representative of the direction, where A, B and C mean outputs of gamma-ray counts and T equals the sum of A, B and C. Laboratory experiments and field tests have been carried out for more than ten years. At the next stage, two types of applications are proposed and prototypes have been manufactured. One is the new monitoring post. There is a great interest in finding out a nuclear accident of a nuclear power station. Prompt detection of radiation leakage from the site will allow mitigation of the effects of the accident and thereby minimize the potential health safety and financial consequences. When the accident occurs in these sites, it is very important to obtain the information on the place where radiations or radioactive materials are leaked. New monitoring posts have been equipped in some nuclear power plant in Japan. The other application is the radioactive hot-spot monitor. Fukushima and adjacent regions in Japan still have many high dose rate areas called radioactive hotspots. It is strongly required to rapidly know these hotspots for efficient decontamination of radioactive substances such as Cs-137 and for relief of residents coming home. Both types of monitors will be expected to be introduced to more nuclear facilities and Fukushima related areas.

Keywords: gamma-ray, scintillator, NaI(Tl), direction, dose rate, nuclear power station, radioactive hotspot
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(face) ID: 194

Poster Number:

Direct Alpha Spectrometry of Irradiated Nuclear Fuel (#2532)

D. L. Chichester1, J. T. Johnson1, B. D. Miller1

1 Idaho National Laboratory, Idaho Falls, Idaho, United States of America


Alpha-particle spectrometry was performed on irradiated nuclear fuel using a single-crystal (sc) diamond semiconductor particle detector. The detector was manufactured using chemical vapor deposition (CVD) methods, square in shape measuring 4.6-mm per side, and 0.5-mm thick. Square aluminum electrodes deposited on each side of the detector, 4.0-mm per side, defined the semiconductor's sensitive area while a smaller, 1-mm diameter round aperture defined the region of the detector exposed to the fuel. This aperture was approximately 3 mm from the substrate face. The fuel sample consisted of a rectangular piece of irradiated nuclear fuel measuring approximately 2.2 mm x 0.5 mm in area and 0.15-mm thick. The fuel was made as a compact of metallic fuel powder in an aluminum matrix. The powder was an alloy of 93% uranium and 7% molybdenum (U7Mo), with a 235U starting enrichment of 19.75%. Fuel powder particles ranged in size from 10 mm to 100 mm in diameter. The pre-irradiation uranium density in the fuel was 8 g U cm-3. The sample's burn-up was exceptionally high at 42% FIMA. The on-contact photon dose rate from the sample was measured to be ~1 R hr-1 (0.01 Gy hr-1), the on-contact beta dose rate from the sample was measured at ~ 30 R hr-1 (0.3 Gy hr-1). Data was collected in air for 8,572 s with the detector suspended over the fuel sample by approximately 10 mm. The spectrum collected during the measurement showed the presence of significant quantities of higher-order transmutation actinides including 238Pu, 241Pu, and 244Cm, in agreement with radiochemical assay data for the sample. The beta-particle event rate in the detector exceeded the alpha-particle rate by a factor of ~5 x 105; despite this, the extremely fast signals from the scCVD diamond semiconductor allowed operation with a dead-time of 10.62% during the measurement.

Keywords: Alpha spectrometry, Nuclear fuel, HIgh burn-up fuel, Post-irradiation examination
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(face) ID: 196

Poster Number:

Development of an Easy and Simple Method to Measure Environmental Radioactivity in a Forest using Efficient Personal Dosimeter (#2997)

K. Kurita1, M. Yamaguchi1, Y. Nagao1, N. Suzui1, Y. - G. Yin1, T. Yoshihara2, N. Kawachi1

1 National Institutes for Quantum and Radiological Science and Technology (QST), Takasaki Advanced Radiation Research Institute, Takasaki, Japan
2 Central Research Institute of Electric Power Industry (CRIEPI), Laboratory of Environmental Science, Abiko, Japan


Large areas, including agricultural fields and forests, were contaminated with radiocesium (Cs-137) in northern Japan following the Fukushima Daiichi Nuclear Power Plant accident. Subsequently, many decontamination plans have been implemented in agricultural areas, but not in forests; therefore, it is necessary to monitor the radionuclide deposition in forested areas. However, most monitoring methods are based on invasive techniques. Therefore, an easy and simple method is necessary to measure the degree of contamination and distribution of Cs-137 in the forests. An efficient personal dosimeter has recently been developed, which can display hourly cumulative doses and store data for a long time. In the present study, we developed a new method to measure the radioactivity of trees and spatial distribution of radiocesium in trees by using commercially-available integrating dosimeter (D-shuttle; Chiyoda Technol. Corp., Japan). To estimate the effects of the dosimeter design, installation, and Cs-137 maldistribution in trees, a Monte-Carlo simulation (PHITS code) was performed using a large-scale computer system. Also, experiments with raw woods (Sugi; Japanese cedar) were performed to confirm characteristics of the dosimeters. Based on the results of the simulations and the experiments, we evaluated the dosimeter measurement method quantitatively. For probability-risk assessments of plant research, the simple method that we have developed is useful to determine the Cs-137 kinetics in trees and forests, efficiently and effectively.

Keywords: radionuclide deposition, Dosimeter
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(face) ID: 198

Poster Number:

Directional Sensitivity to Reactor Antineutrinos with pulse shape discriminating plastic scintillator (#3546)

S. Dazeley1, T. Classen1, M. Duvall2, A. Mabe1, E. Reedy1

1 Lawrence Livermore National Laboratory (LLNL), Nuclear and Chemical Sciences Division, Livermore, California, United States of America
2 University of Hawaii, Dept. of Physics and Astronomy, Honolulu, Hawaii, United States of America


Recently, several organic-scintillator-based antineutrino detectors, such as SONGS, NUCIFER, JOYO and PANDA have been used to monitor the operational status of nuclear reactors from close range via the inverse beta decay reaction. Three of these employ liquid organic scintillator doped with gadolinium. One uses plastic scintillator bars surrounded by a layer of gadolinium. In each case the antineutrinos are identified as ~few MeV positron signals followed soon after by a neutron capture. The correlation in both position and time is used to positively identify the antineutrinos from the uncorrelated (mostly gamma-ray) backgrounds. The primary source of correlated background is from cosmogenically sourced fast neutrons, which produce signals from proton recoils followed by neutron capture. Typically, detectors are deployed below ground and surrounded by large volumes of hydrogenous shielding to reduce these backgrounds. An alternative might be to reconstruct the direction of the incoming antineutrinos by measuring the relative positions of the positron and the neutron capture. Fine-grained segmentation, made feasible in the form of a 6Li-doped plastic PSD organic scintillator, which can be machined into thin rods and coupled with position sensitive photomultipliers, may provide the position resolution needed. The PSD characteristics inherent to the plastic, and particle track length sensitivity (via rod multiplicity) will also add sensitivity. If successful, a detector that exploits this new material may be able to reduce the requirements for bulky shielding and specialized underground deployment locations. Our group is building a detector with the aim of testing these characteristics in a flux of reactor antineutrinos. We will report on progress and some of the challenges involved.

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-730877

Keywords: antineutrinos, correlated backgrounds, PSD, inverse beta decay
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(face) ID: 200

Poster Number:

Evaluation of In-water Wireless Transmission System under the Conditions Simulated the Severe Accident (#3864)

N. Otsuka1, T. Takeuchi1, K. Tsuchiya1, T. Shibagaki2, H. Komanome2

1 Japan Atomic Energy Agency, Oarai Research and Development Center, Oarai, Ibaraki, Japan
2 Ikegami Tsushinki Co.,Ltd., Ohta, Tokyo, Japan


Since the accident at the Fukushima Dai-ichi Nuclear Power Plant, the techniques, which can monitor the inside of nuclear reactor building under severe accident conditions (high-temperature, high-radiation and so on), have been required. Therefore, the in-water wireless transmission system has been developing. The system consists of the transmitter and receiver which communicate by the visible light.  The information of spent fuel storage pool (water-temperature, water-level, etc.) obtained by sensors set under the water of the pool can be sent by the transmitter to the receiver using visible light signal. The receiver, which is set on the ceiling of nuclear reactor building above the pool, analyzes the signal and decodes it to measurement values. During severe accidents, the transmitter and the receiver are thought to be exposed to the heat and radiation and the visible light signal is likely to be interrupted by bubbles, turbidity and obstacle occurred in the water between the transmitter and the receiver.

In this study, the heating test and irradiation test were performed to select the components of transmitter and receiver which have the resistances of radiation and temperature. The image analysis program using interleaving and tracking were also developed in order to correct the interrupt of bubbles, turbidity and obstacle.

As the results of the above mentioned components and methods, the in-water wireless transmission system was designed and a prototype system was completed with a high-speed camera. The performance test results showed that the prototype system had the temperature resistance at 100°C for 100 hours and the radiation resistance of 1 MGy, and showed that that the visible light signal could be transmitted with enough accuracy in the water including bubbles, turbidity and obstacle.

The project is supported by R&D program for Plant Safety Enhancement of the Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry (METI), Japan.

Keywords: In-water wireless transmission, Severe accident, Radiation resistance, Spent fuel storage pool
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(face) ID: 202

Poster Number:

256-channel differential to single ended antialiasing filter for pulse shape analysis in nuclear physics experiments (#1007)

A. Castoldi1, 2, P. Chang1, C. Guazzoni1, 2, T. Parsani1, 2, G. Cardella3, G. Sacca'3

1 Politecnico di Milano, DEIB, Milano, Italy
2 INFN, Sezione di Milano, Milano, Italy
3 INFN, Sezione di Catania, Catania, Italy


In view of the first application in the framework of the FARCOS project, we designed a compact 6U board that provides in a single module 256 channels featuring: i) differential to single-ended low-noise conversion with 120 Ω input impedance, ii) a second order anti-aliasing filter, iii) a selectable output offset voltage. The first stage is responsible of the conversion from the differential mode to single-ended and features an additional input for offset regulation. The second stage is the filtering stage, designed as a Sallen-Key cell with cutoff frequency of 40 MHz. The design relies on very small case dual operational amplifiers and clusters 4 channels in a common design sharing the offset regulation section. The 4-channel cluster occupies an area of 3.5 mm x 78 mm. The presentation will focus on the designed module topology and the characterization of its functionality. In addition the results of some real cases in which the differential to single ended antialiasing filter was applied will be described.

This work has been supported by INFN in the framework of the NEWCHIM experiment.

Keywords: digital pulse shape, digital pulse shape; differential to single-ended conversion, 256 channel board
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(face) ID: 204

Poster Number:

Monte Carlo Simulation and Collimator Optimization for Tomographic Gamma Scanning (#1184)

J. Zhang1, X. Tuo2, Y. Leng2, R. Shi2

1 National Ocean Technology Center, Tianjin, Tianjin, China
2 Sichuan university of science and technology, Zigong, Sichuan, China


We present the design and optimization of a Tomographic Gamma Scanning (TGS) collimator using Monte Carlo methods. In these simulations, an accurate TGS model was built and the radius, depth and shape of the TGS collimator were optimized. The simulation results reveal that the optimal collimator aperture radius and depth for this system are 3.1 cm and 18.6 cm, respectively, achieved when the full width at half-maximum (FWHM) is 26.7 cm. Also, a rotated 30° hexagon is found to be the optimal shape. Our TGS design shows significantly improved performance.

Keywords: Tomographic Gamma Scanning, Monte Carlo, Collimator, Dead layer, Point Spread Function
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(face) ID: 206

Poster Number:

Optimization a thickness of GAGG scintillator for detecting plutonium in a field of high beta and gamma background (#1587)

Y. Morishita1, S. Yamamoto2, K. Izaki1, J. H. Kaneko3

1 Japan Atomic Energy Agency, Radiation control department, Tokai-mura, Naka-gun, Ibaraki, Japan
2 Nagoya University, Graduate School of Medicine, Nagoya, Aichi, Japan
3 Hokkaido University, Graduate School of Engineering, Sapporo, Hokkaido, Japan


Spectroscopy of alpha particles is necessary to distinguish plutonium isotopes from radon progeny. We previously developed an alpha particle imaging detector by combining a 0.1-mm-thick GAGG scintillator with a silicon photomultiplier (SiPM). This detector had better energy resolution than the ZnS(Ag) scintillator–based alpha particle detector. However, it had beta or gamma sensitivity because the GAGG scintillator was too thick compared with the range of 5.5 MeV alpha particles. Therefore, it is difficult to measure alpha particles from plutonium in a field with high beta and gamma background. To solve this problem, we optimized the thickness of GAGG scintillator by comparing three GAGG scintillators with thicknesses of 0.05 mm, 0.07 mm, and 0.1 mm. Each of the GAGG scintillators was optically coupled to SiPM, which was used as the photodetector. The peak channels and energy resolutions for 5.5 MeV alpha particles of three GAGG scintillators were compared. Also, the count rates of beta particles of the GAGG scintillators were evaluated by using a 90Sr source. The peak channel of the 0.05-mm-thick GAGG scintillator was 1.6x higher than that of the 0.1-mm-thick GAGG scintillator and 3.7x higher than that of the plastic scintillator. The 0.05-mm-thick GAGG scintillator had the best energy resolution of 11.6 % FWHM and the lowest beta count rate of 0.2 cpm among the three GAGG scintillators. Thus, the alpha particle detector with the 0.05-mm-thick GAGG scintillator is promising for precise detection of plutonium, even in a field with high beta background.

Keywords: GAGG, Silicon photomultiplier, Alpha particle, Background Beta-Gamma radiation
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(face) ID: 208

Poster Number:

Results of High Precision Measurements of Optical and Geometrical Properties of the PANDA DIRC Radiators (#1683)

G. Schepers1

1 GSI Darmstadt, Hadron Physics, Darmstadt, Hesse, Germany

On behalf of the PANDA Cherenkov Group


This contribution describes the results on the measurements of the crucial optical and geometrical properties of the prototype radiators of the Barrel DIRC (Detection of Internally Reflected Cherenkov light) detector of the PANDA experiment at FAIR. In order to meet the PANDA Particle IDentification (PID) requirements, the Barrel DIRC has to provide precise measurements of the Cherenkov angle, which is the key quantity for identifying charged particles that traversed the radiators. Since the Cherenkov photons propagate through the radiators by total internal reflection until they reach the photon sensors a large bulk transmission value of the radiator and a surface roughness, that is connected to the coefficient of total internal reflection, of less than 10 Angstroem are required to keep the loss of photons small. A deviation from the squareness of all sides of less than 0.25 mrad is necessary to avoid a significant distortion of the Cherenkov angle. During the PANDA Barrel DIRC prototyping program a total of about 30 bars and plates were produced by eight manufacturers using different fabrication techniques and raw materials. The quality of these prototypes are or will be tested with two measurement methods, that work without making direct contact with the delicate surfaces. A laser-setup permits to determine the surface roughness of the bars with an accuracy of less than 1 Angstroem using a method that can be sensitive to production process-dependent subsurface damage. With a second setup, using a Nikon 6D autocollimator, that can measure small angular displacements with an accuracy of 0.002 mrad, the squareness and parallelism of the radiator bars is determined. Thus several optical companies successfully have been validated as potential vendors for PANDA Barrel DIRC mass production.

Keywords: Hadron Physics, Cherenkov, DIRC, Photon sensor, Autocollimator, Quality Assurance
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(face) ID: 210

Poster Number:

Establishment of a Novel Detection System for Measuring Primary Knock-on Atoms (#3150)

P. - E. Tsai1, Y. Iwamoto1, M. Hagiwara2, T. Sato1, T. Ogawa1, D. Satoh1, S. - I. Abe1, M. Ito3, H. Watabe3

1 Japan Atomic Energy Agency, Nuclear Science and Engineering Center, Tokai, Ibaraki, Japan
2 High Energy Accelerator Research Organization (KEK), Radiation Science Center, Tsukuba, Ibaraki, Japan
3 Tohoku University, Cyclotron and Radioisotope Center (CYRIC), Sendai, Miyagi, Japan


The energy spectra of primary knock-on atoms (PKAs) in spallation reactions, which range from sub-MeV to a few tens of MeV with a continuous mass distribution from target nuclides to hydrogen isotopes, are essential for radiation damage assessment in accelerator facilities. At present, the available experimental data are still limited, due to the insufficient mass resolution and the high measurement threshold energies in the conventional setup of nuclear physics experiments using solid state detectors, which is typically above a few MeV/nucleon. Physics models implemented in Monte Carlo radiation transport codes are commonly used to assess the radiation damage in accelerator facilities, yet they have not been fully validated due to the lack of experimental data. Therefore, in this study, a novel detection system based on the time-of-flight (TOF), TOF-E, and dE-E techniques is proposed, and is in the process of being constructed, to measure the PKA spectra. The design of the detection system, which is composed of two timing detectors and one dE-E energy detector, was based on Monte Carlo simulations by using the PHITS code. The PHITS simulations show that the system is able to distinguish the PKA isotopes above ~0.2-0.3 MeV/nucleon for whose atomic mass is between 20 and 30 amu, and below 0.2 MeV/nucleon for PKA isotopes lighter than 20 amu. The detection system will be tested at the JAEA Tandem Accelerator Facility and the Cyclotron and Radioisotope Center (CYRIC) at the Tohoku University in summer of 2017. The test results and the comparison with the PHITS simulations will be presented at the conference.

Keywords: Primary knock-on atom (PKA), PHITS, time-of-flight, dE-E, gas ionization chamber
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(face) ID: 212

Poster Number:

First on-beam tests of the FARCOS frontend electronics (#3246)

L. Acosta1, 2, L. Auditore3, 4, C. Boiano5, G. Cardella2, A. Castoldi6, 5, M. D'Andrea2, E. De Filippo2, D. Dell'Aquila7, 8, S. De Luca3, 4, F. Favela2, F. Fichera2, N. Giudice9, 2, B. Gnoffo9, 2, A. Grimaldi2, C. Guazzoni6, 5, G. Lanzalone10, 11, F. Librizzi2, I. Lombardo7, 8, C. Maiolino11, S. Maffessanti6, 5, N. S. Martorana9, 2, S. Norella3, 4, A. Pagano2, E. V. Pagano9, 11, M. Papa2, T. Parsani6, 5, G. Passaro11, S. Pirrone2, G. Politi9, 2, L. Quattrocchi9, 2, F. Rizzo9, 11, P. Russotto11, G. Sacca'2, G. M. Salemi2, D. Sciliberto2, A. Trifirò3, 4, M. Trimarchi3, 4, M. Vigilante7, 8

1 Universidad Nacional Autónoma de México, Instituto de Física, Mexico City, Mexico
2 INFN, Sezione di Catania, Catania, Italy
3 Universita’ degli Studi di Messina, Dip. di Scienze MIFT, Messina, Italy
4 INFN, Gruppo Collegato di Messina, Messina, Italy
5 INFN, Sezione di Milano, Milano, Italy
6 Politecnico di Milano, DEIB, Milano, Italy
7 Universita' degli Studi di Napoli Federico II, Dip. Fisica, Napoli, Italy
8 INFN, Sezione di Napoli, Napoli, Italy
9 Universita’ degli Studi di Catania, Dipartimento di Fisica e Astronomia, Catania, Italy
10 Universita' KORE, Facolta' di Ingegneria e Architettura, Enna, Italy
11 INFN, Laboratori Nazionali del Sud, Catania, Italy


FARCOS (Femtoscope ARray for Correlation and Spectroscopy) is a novel modular detection system featuring high angular and energy resolution able to reconstruct the particle’s momentum at high precision and capable of performing correlation measurements of LCPs and of LCPS and IMFs. Given the unique feature of FARCOS of aiming to identify in charge and mass even the fragments that are fully absorbed in the first Si layer, the frontend electronics must meet stringent requirements in terms of dynamic range and integral-non-linearity. To this aim we designed and qualified a VLSI frontend able to readout signals of both polarities and suitable both for the DSSSD and the photodiodes reading the scintillation light.

During February 2017 for the first time the performance of a workhorse of the FARCOS telescope equipped with the designed VLSI frontend electronics has been experimentally qualified in a test beam at the Laboratori Nazionali del Sud (LNS) of INFN in Catania. The 16O beam at 88 MeV accelerated by the Tandem accelerator has been used impinging on different targets (LiF, Au, C, Ni).

The presentation will focus on the results of the test beam, highlighting the performance of the designed frontend electronics when coupled with the different detection stages of the FARCOS telescopes.

This work has been supported by INFN in the framework of the NEWCHIM experiment.

Keywords: beam test, pulse shape analysis, particle identification
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(face) ID: 214

Poster Number:

Improvement on the Purity Performance of the Liquid Argon Detectors (#3866)

Y. Li1, C. Thorn1, X. Qian1, W. Tang1, J. Joshi1, J. Stewart1, M. Diwan1, S. Kettell1, W. Morse1, T. Tsang2, T. Rao2

1 Brookhaven National Laboratory, Physics Department, Upton, New York, United States of America
2 Brookhaven National Laboratory, Instrumentation Division, Upton, New York, United States of America


We present a mathematical model for describing the dynamics of impurity distribution in liquid argon detectors. This model considers the impurity sources, sinks, and transport between and within the gas and liquid argon phases of a large detector. Two applications of this model are presented. In the first application, the detector is equipped with a purification system only circulating and cleaning the gas argon. The Henry's coefficient for oxygen is extracted through fitting the time dependence of the concentration in the liquid argon with the model. The Henry’s coefficient for oxygen is extracted to be 0.92±0.04. The fact that this result is in good agreement with the previous measurements by other methods serves as an important validation of the model. In the second application, we consider a large LAr detector with a baffle installed in the gas phase with large coverage on the liquid surface to reduce the impurity concentrations in the liquid phase. Advantages of this proposal are discussed and predictions of improvements are presented.

Keywords: Liquid Argon, Time-projection-chamber, purity, electron lifetime, Henry's coefficient, Neutrino
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(face) ID: 216

Poster Number:

“Diamondpix”: a CVD diamond detector with Timepix3 chip interface (#4087)

G. Claps1, 2, F. Murtas1, 3, J. Alozy3, L. G. Foggetta1, C. Di Giulio1, G. Cavoto1

1 INFN, Laboratori Nazionali di Frascati, Frascati, Italy
2 ENEA, Frascati Research Center, Frascati, Italy
3 CERN, CERN, Geneva, Switzerland


The following work presents a new pixelated diamond detector. It has been realized with a ‘chemical vapor deposition’ (CVD) polycrystalline diamond plate combined with the new C-MOS Timepix3 chip. The CVD plate is 500 µm thick, has an area of 10x10 mm2 and has been covered on the opposite side respect to the chip by 1 µm of gold layer to polarize the diamond. In the present work, an electric field of 1 V/ µm has been applied. A bump bonding links the diamond plate to a chip pixel which is 55x55 um2 in area. The charge released in the diamond by a ionizing particle can be detect and processed by Timpix3 chip providing info about not only the collected charge on each pixel, but also the its time of arrival respect to an internal or an external trigger. Detector has been tested successfully as beam monitor on the BTF facility (INFN, Frascati) with 500 MeV electrons. It realizes both a 2D image of the beam spot and the time profile of the bunch. It has been tested also on a 14 MeV neutron beam on the FNG facility (ENEA, Frascati). Fast neutrons release a charge and create a characteristic pixel cluster from which useful info for particle discrimination can be obtained. Based on the characteristic parameters of clusters, a particle id algorithm has been realized. It can be integrated on the Timepix3 control software in order to provide a real time discrimination between  fast neutrons and gammas.

Keywords: CVD diamond, Timepix, beam monitor, neutron detector
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(face) ID: 218

Poster Number:

The development of SiGHT and its first prototype (#1744)

Y. Wang1

1 UCLA, Physics and Astronomy, Los Angeles, South Carolina, United States of America


Silicon geiger hybrid tube (SiGHT) is a novel photosensor which is currently under development for the future rare event searches, such as the search for dark matter and the observation of neutrinoless double beta decay. The total radioactivity of a 3 in diameter SiGHT can be controlled lower than 0.11 mBq with limited materials dosage. Its characterizations, such as high photon detection efficiency for desired wavelength and stable operation at cryogenic temperatures are determined by three key technologies: indium seal, photocathode to convert photons into photoelectrons and SiPM to directly detect photoelectrons, respectively. The first SiGHT prototype has already been fabricated and assembled at the UCLA SiGHT lab, and a clear SPE spectrum was obtained.

Keywords: Noble liquid detectors, Photocathode, SiPM, SiGHT
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(face) ID: 220

Poster Number:

Gain Stabilization of Silicon Photomultiplie (#2765)

G. Eigen1, J. Cvach2, J. Kvasnicka2, I. Polak2, A. Træet1, J. Zalieckas1

1 Bergen, Physics and Technology, Bergen, Norway
2 ASCR, Physics, Prag, Czech Republic


The gain of silicon photomultipliers (SiPMs) increases with bias voltage and decreases with temperature. To operate SiPMs at stable gain, the bias voltage can be adjusted to compensate temperature changes. We have tested this concept with 30 SiPMs from three manufacturers (Hamamatsu, KETEK, CPTA) in a climate chamber at CERN varying the temperature from 1°C to 50°C. We built an adaptive power supply that used a linear temperature dependence of the bias voltage readjustment. With one selected bias voltage readjustment, we stabilized four SiPMs simultaneously. We fulfilled our goal of limiting the deviation from gain stability in the 20°C-30°C temperature range to less than ±0.5% for most of the tested SiPMs.

Keywords: Photodetector, calorimeter, photoreadout
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(face) ID: 222

Poster Number:

Quality Assurance on a custom SiPMs array for the Mu2e experiment (#3176)

I. Sarra1, S. Miscetti1, G. Pezzullo1

1 LNF, INFN, Frascati, Italy, Italy

on behalf of the Mu2e Calorimeter group


he Mu2e  calorimeter is composed by two disks of 1348 un-doped parallelepiped CsI crystals of 34$\times$34$\times$200 mm$^3$ dimension,  each one readout by two large area SiPM arrays. We translated the calorimeter requirements in a series of technical specifications for the SiPMs that are summarized by the following list:

\item a high gain, above 10$^6$, for each monolithic (6$\times$ 6) mm$^2$ SiPM cell;
\item  a good photon detection efficiency, PDE, of above 20\% at 310 nm to well match the light emitted by the un-doped CsI crystals;
\item a large active area that, in combination with the PDE, could provide a light yield of above 20 p.e./MeV;
\item a fast rise time and a narrow signal width to improve time resolution and pileup rejection;
\item a Mean to Time Failure (MTTF) of O(10$^6$) hours;
\item and a good resilience to neutrons for a total fluency up to 10$^{12}$ n(1 MeV$_{\rm eq}$)/cm$^2$.

A {\em modular and custom SiPM layout} has been chosen to satisfy these requirements. To well match the wavelength of the emitted light produced by the CsI crystals, the SiPM detection efficiency have been extended in the UV region. The configuration readout of 2 series of three 6$\times$6 mm$^2$ monolithic SiPMs has been selected to overcome the issues related to the parallel connection that, due to the large capacitance, could have spoiled  the pileup rejection and the energy and time measurements.

A pre-production of 150 Mu2e SiPMs  has been procured by three international firms (Hamamatsu, Sensl and Advansid). A detailed quality assurance, QA, has been carried out on each SiPM for the determination of its own operation voltage, gain, quenching time, dark current and PDE.

he measurement of the MTTF for a small random sample of the pro-production group has been also completed as well as the determination of the dark current increase as a function of the neutron fluency.

Keywords: SiPMs, calorimeter, Quality Assurance, MU2E, Lepton Flavour
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(face) ID: 224

Poster Number:

Chemiluminescence Detection Method Using SiPM with Dedicated Readout Circuit (#3229)

M. Baszczyk1, P. Dorosz1, W. Kucewicz1, L. Mik1, 2, W. Reczynski1, M. Sapor1

1 AGH University of Science and Technology, Krakow, Poland
2 State Higher Vocational School, Tarnow, Poland


The paper presents a chemiluminescence detection method using SiPM. The intensity of measured light is on the level of single photons. Chemiluminescence is a phenomenon triggered by a chemical reaction and is used in a vast range of applications in medicine, chemistry, biology, biotechnology, environmental protection. Apart from measuring single photons the readout electronics should be sufficiently fast in order to distinguish overlapping signals generated by the chemiluminescent light. The front-end electronics consists of a preamplifier and fast shaper. It produces pulses which peaking time, for the single photon, is equal to 3.6 ns and the FWHM is 3.8 ns. The performance of the detection method has been verified with measurements of the chemiluminescence of luminol (used e.g. in the criminology to detect traces of blood). The system is optimal for chemiluminescence detection. It generates low number of overlapping pulses and is accurate. The relationship between the light intensity and concentration of luminol is linear and have high r-squared parameter equal to 0.9995 and low prediction intervals.

Keywords: Chemiluminescence, SiPM, front-end, MPPC, fast shaper
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(face) ID: 226

Poster Number:

On the characterisation of SiPMs from pulse-height spectra (#3452)

M. Zvolsky1, E. Garutti1, R. Klanner1, D. Lomidze1, T. Loesche1, J. Schwandt1

1 University of Hamburg, Hamburg, Germany


Our group has developed a model for the analysis of pulse-height spectra of SiPMs measured in the dark and illuminated by pulsed light. The model is used to determine the pulse shape, the dark-count rate, the gain, the average number of photons initiating a Geiger discharge, the probabilities for prompt cross-talk and after-pulses, as well as the electronics noise and the gain fluctuations between and in the pixels. The entire pulse-height spectra, including the regions in-between the peaks corresponding to the integration of partial Geiger discharges, are described by a single function. The model is described and demonstrated in [1], using on KETEK SiPM with 4384 pixels of 15μm×15μm area.

The current paper discusses the implementation and validation of the model for large number of fitting procedures.

The original MATHCAD code has been implemented in an object-oriented phyton-based frame and significantly speed-up (few min. compared to 30 min./fit). The determination of the data-driven starting parameters for the fit has been refined and is now fully automatic.   Most important, the model is now validated using several data sets from various SiPM with varying pixel sizes from Hamamatsu and KETEK. Additional studies will be finalized by the time of the conference using 50 ps sampled waveforms as input to the generation of pulse-height spectra. In this way the effect of after-pulse in the spectra can be varied by offline selection and integration gate optimization.

Keywords: Silicon photomultipliers, SiPM, gain, correlated noise, cross-talk, after-pulses, excess noise factor, calibration
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(face) ID: 228

Poster Number:

Picosecond Time Resolution with Avalanche Amorphous Selenium (#3590)

A. H. Goldan1, W. Zhao1

1 Stony Brook University, Radiology, Stony Brook, New York, United States of America


The localization accuracy of annihilation events in a time-of-flight (TOF) radiation detector is determined by its time-resolution (∆t). The ultimate TOF detector is one with ∆t < 10 picosecond (ps), but such a detector has still not been realized. Silicon photomultipliers (SiPMs) are rapidly developing and have achieved better ∆t than PMTs (i.e., SiPM ∆t ~ 100 ps). However, they suffer from poor system-level photon detection efficiency, optical crosstalk, small area, poor uniformity, and high cost. For the first time, we show measured picosecond ∆t using avalanche amorphous selenium (a-Se), a material which (1) can be readily produced uniformly over large area at lower cost compared to crystalline solids and (2) has 90% detection efficiency in the blue wavelength which makes it ideal to be coupled to TOF-specific scintillators for high-energy radiation detection. The major drawback of a-Se is its poor time-resolution and low mobility due to shallow-traps, problems that must be circumvented for TOF applications. Thus, we propose a nanopattern multi-well a-Se detector to enable the utilization of both avalanche multiplication gain and unipolar time-differential (UTD) charge sensing in one device. Advantages of avalanche-mode a-Se are having photoconductive gain and band transport in extended states with the highest possible mobility and negligible trapping. Most importantly, UTD charge sensing enables operating the detector at its theoretical limit of charge diffusion. Experimental results of timing jitter, from 100 laser pulse excitations, show a remarkable RMS value of σ∆t = 52 ps for our fabricated unipolar avalanche a-Se photodetector. The presented experimental results successfully prove the feasibility of a low-cost unipolar a-Se photodetector for TOF applications, and pave the way for future development of prototype detectors. For future work, we will investigate the scintillator-coupled ∆t and excess noise.

Keywords: picosecond time-resolution, avalanche gain, time-of-flight, amorphous selenium
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(face) ID: 230

Poster Number:

Performance of 2 inch and 3 inch Scintillation Detectors with SiPM Light Readout (#3664)

T. Szczęśniak1, M. Grodzicka-Kobylka1, M. Moszyński1, M. Szawlowski1, S. Mianowski1, D. Wolski1

1 National Centre for Nuclear Research, Otwock-Swierk, Poland


Large scintillating crystals are widely used in different applications, both in industry and physical experiments. Presently, the light readout in most of such detectors is done by means of classic photomultipliers. The aim of this study is to verify if light from large crystals with diameters of 2 or 3 inches can be effectively  read by silicon photomultipliers and if replacement of classic photomultipliers with silicon photomultipliers can bring additional benefits. Spectroscopic performance of 5 types of large detectors consisting of different scintillators (LaBr3, CeBr3, NaI(Tl) and BGO) coupled to MPPC array are presented. The measurements are made with S12642-1616PB-50(X) Hamamatsu TSV MPPC array having a 50x50 µm2 cell size and effective active area of 48x48 mm2 (16x16 channels). In all measurements the common readout of all channels is used. The results obtained with MPPC such as energy resolution and linearity are compared with measurements of the same crystals on classic photomultipliers. Also the possible optimization of data acquisition electronics is presented as well as comparison between readouts based on classic spectroscopy amplifier and digital MCA.

Keywords: SiPM, MPPC, LaBr, CeBr, NaI(Tl), BGO, energy resolution
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(face) ID: 232

Poster Number:

Study of light collection in a 1-in. diameter PMT coupled to LaBr3(Ce) scintillators of various aspect ratios (#3901)

O. Philip1, I. Shestakova1

1 Schlumberger, Houston Formation Evaluation, Sugar Land, Texas, United States of America


We have evaluated several LaBr3(Ce) scintillators with two distinct aspect ratios: 1-in diameter x 1-in length and 1 in. diameter x 4-in. length produced by Saint Gobain Crystals. Both types of crystals were packaged in an envelope with an identical sapphire window. However, when tested on PMTs of various active window sizes, these 2 types of crystal behave differently: 1-in. long crystals displayed poorer energy resolution (tested with Th 2615-keV line) than the 4-in. long crystals when tested on a 1-in. diameter ceramic PMT (designed and built by the Schlumberger Princeton Technology Center).

To explain this difference in the crystal performance behavior, we have modeled light collection efficiency in a 1-in. PMT for the two scintillator sizes mentioned above. The results of the study point to areas of poor light collection, which contribute to deteriorated resolution in the shorter crystals to a greater degree than in the longer crystals when coupled to 1-in. diameter photomultipliers.

In our paper we will present the details of crystal resolution testing and light transport modeling will be presented.

Keywords: Scintillator light collection optimization, photodetector optimization, scintillation detectors, ceramic photomultiplier, LaBr3(Ce) performance
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(face) ID: 234

Poster Number:

X-ray imaging with a gaseous flat-panel detector combining a glass gas electron multiplier and a micro-photodiode array (#4095)

Y. Mitsuya1, T. Fujiwara2, H. Miyoshi1, M. Uesaka1, H. Takahashi1

1 The University of Tokyo, Tokyo, Japan
2 National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan


We report on the recent development of our gaseous flat-panel detector (gaseous FPD) consisting of a glass gas electron multiplier (G-GEM) and a micro-photodiode array. 

A gaseous detector based imaging device has its advantage when visualizing a variety of radiations by using an appropriate operational gas mixture or radiation converter. In addition, a gaseous detector can achieve both of low material cost and large sensitive-area at the same time. G-GEM is one of the most promising MPGDs to be coupled with optical readouts, since it has high gas gain of more than 104 with a single stage and produces scintillation photons proportional to the number of multiplied electrons.

The scintillation photons from a hole of G-GEM can be more effectively detected with an optical sensor, if the gap between G-GEM and the readout is minimized, since the solid angle of the emitted scintillating photons to each pixel of the optical sensor is maximized. 
We recently developed a prototype of flat-panel type micro-photodiode array with a liquid crystal display technology. Thus We propose a gaseous FPD, by the combination of a G-GEM and a micro-photodiode array plate.

We demonstrated preliminary imaging with the flat-panel imaging system. The photodiode plate had 512 × 512 pixels. The size of a pixel was approximately 200 × 200 μm2. Both the G-GEM and the photodiode panel had a sensitive area of 100 × 100 mm2. We successfully obtained a preliminary result of X-ray imaging with this system. The position resolution was estimated to be 0.93 mm in FWHM by fitting an edge profile with an error function.

To improve the image resolution, it is important to reduce the thickness of the coupling glass plate.  Another possible solution is introducing a micro-lens array or a fiber-optic plate. It is also important to improve detection efficiency of the system. Using other gases such as Ar/CF4 or Kr/CF4 will help improving the detection efficiency. 

Keywords: MPGD, GEM, X-ray imaging, Flat-panel detector, Glass GEM
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(face) ID: 236

Poster Number:

Accelerated aging in 4H-SiC as a betavoltaic semiconductor using an electron beam system (#1908)

Q. Shao1, L. F. Voss1, J. W. Murphy1, C. D. Frye1, R. A. Henderson1, M. A. Stoyer1, D. Qu1, R. J. Nikolic1

1 Lawrence Livermore National Laboratory, Livermore, CA, United States of America


Radiation tolerance and output power of 4H-SiC p-i-n diodes as betavoltaic semiconductors are investigated. Beta emitters of Strontium-90/Yttrium-90 (combined activity of 0.5 mCi) and Promethium-147 (1 mCi) are used to test the device response. The electric current-voltage characteristics of devices with close proximity to beta emitters are measured and output powers are calculated. The test results show the power degrades 23% at a dose of 1013 cm-2 with Strontium-90/Yttrium-90 (mean beta energy: 196 keV/931 keV) and no power degradation with Promethium-147 with a dose up to 1014 cm-2. Accelerated aging experiments using a custom designed electron beam system were conducted to further extend beta dose to the range of 1017 cm-2 with energy of 62 keV, which is the mean beta energy of Promethium-147. The system is capable of emitting current from 10 nA to 1 mA with electron energy up to 100 keV.  No output power degradation is observed with a dose up to 3.15 x 1017 cm-2. The time required to reach that dose is 1.4 hours with 10 µA emitting current, compared with hundreds of years required for a mCi level Promethium-147 source. An in-situ output power density of 102 mW/cm3 was also measured by increasing the beam current up to 100 nA. The electron beam system offers a quick aging examination technique for high power betavoltaic batteries instead of utilizing a large amount of radioisotope material. The experiments demonstrate that SiC p-i-n diode is a high radiation tolerant device with beta particles of 62 keV and dose of 1017 cm-2 or higher.

Keywords: SiC, betavoltaic, electron beam system
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(face) ID: 238

Poster Number:

Evolution of MPPC properties as a function of neutron fluence (#2003)

S. Mianowski1, J. Baszak1, Y. N. Kopatch2, Y. M. Gledenov2, Z. Mianowska1, M. Moszyński1, P. Sibczynski1, T. Szczęśniak1

1 National Centre for Nuclear Research, Radiation Detector Physics Division, Otwock, Mazowieckie, Poland
2 Joined Institute for Nuclear Research, Frank Laboratory of Neutron Physics, Dubna, Moscow region, Russian Federation


The goal of this work was to study MPPC properties as a function of neutron fluence. We investigate parameters like gain, non-proportionality, dark rate spectra and play close attention to the energy resolution of irradiated photodetector coupled to nonirradiated scintillator. The last parameter is crucial for gamma spectroscopy with scintillators. In our measurements we used two types of MPPC photodetectors from Hamamatsu: S13360-3050CS and S13360-6050CS, which are characterized by different active area: 3x3mm2 and 6x6 mm2 respectively. To eliminate gain-temperature dependency of MPPC in our experiment we used Hamamatsu evaluation board (C12332-01) equipped in a precision power supply and a temperature compensation circuit, which allows us to set temperature compensation factor individually for each type of MPPC.

In the first part we present data obtained for neutron fluence in a range of 108-1010 n/cm2. In this case the 4.8 MeV neutron beam was produced in (d,d) reaction, where incoming deuterons were accelerated by Van der Graph accelerator. This experiment was performed at Frank Laboratory of Neutron Physics in JINR (Dubna, Russia).

In the second part we show results for a low neutron fluence up to 107 n/cm2. In these measurements the same type of MPPCs were irradiated by neutrons from PuBe source with 4.5 MeV average neutron energy and total source activity of 25 GBq, which corresponds to emission of 1.47x106 neutrons/4π/s.

Keywords: MPPC properties, irradiation, neutron fluence
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(face) ID: 240

Poster Number:

Determination of Radiation Hardness in the Operation of TPX Detectors in the ATLAS Cavern in LHC Proton-Proton Collisions at 13 TeV (#2207)

D. Caforio1, B. Ali1, J. Begera1, B. Bergmann1, T. Billoud2, B. Biskup1, P. Burian1, E. Heijne1, J. Janecek1, C. Leroy2, P. Manek1, Y. Mora1, S. Pospisil1, A. Sopczak1, M. Suk1, Z. Svoboda1

1 Czech Technical University in Prague, Institute of Experimental and Applied Physics, Prague, Czech Republic
2 University of Montreal, Group of Particle Physics, Montreal, Canada


Radiation hardness of pixel detectors is an important characteristic of pixel detectors in the operation of high-radiation environments. The LHC delivered proton-proton collisions at 13 TeV center-of-mass energy during 2015 and 2016. The resulting secondary particle fluxes were recorded by the TPX network installed in the ATLAS cavern. Fifteen TPX detectors were exposed to largely varying particle fluxes. The detectors receiving the largest fluxes clearly show effects of radiation damage during the LHC operation. Evidence of self-healing effects during technical stops is also observed. The radiation damage and the self-healing effects were quantified. The novel results on radiation damage could contribute to the future operation of the devices as luminosity monitor, as well as contributing to the design of more radiation hard devices. 

Keywords: Radiation hardness, pixel detectors
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(face) ID: 242

Poster Number:

Stability of IGZO based Thin Film Transistors under Heavy Ion Irradiation (#2573)

A. Koyama1, K. Shimazoe1, H. Miyoshi2, Y. Otaka3, M. Nitta4, F. Nishikido5, T. Yamaya5, H. Takahashi1

1 The University of Tokyo, Bioengineering, Bunkyo-ku, Tokyo, Japan
2 Sharp Corporation, Research division, Sakai, Osaka, Japan
3 Tokyo Metropolitan University, Faculty of Health Siences, Arakawa-ku, Tokyo, Japan
4 Chiba University, Graduate School of Science, Inage-ku, Chiba, Japan
5 National Institute for Quantum and Radiological Science and Technology, Molecular Imaging Center, Inage-ku, Chiba, Japan


In order to estimate dose distribution and make a treatment plan for heavy ion radiotherapy, there is a strong demand for accurate beam spot measurements using flat panel detector (FPD). Particularly, FPD based on  In-Ga-Zn-O (IGZO) TFTs showed great potentials in the point of low off state leak current and radiation stability. Therefore, we report the radiation effects of IGZO TFTs in a 12C6+ beam irradiation environment, and discuss prospects for use in heavy ion beam spot measurements. Electrical properties were measured before the irradiation procedure, as well as after the irradiation for 1 min (equivalent to 200~300 krad, total dose of 3 weeks in practical situation) . Moreover, recovery effects by temporal annealing were also investigated. From results, we have concluded IGZO TFTs was confirmed to maintain efficient levels even in the practical situation of beam spot measurements.

Keywords: Heavy ion radiotherapy, Radiation tolerance, Thin film transistors
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(face) ID: 246

Poster Number:

Effect of Ceramization Temperature on Growth of Scintillating Nanocrystals Within Glass-Ceramics (#1044)

M. B. Beckert1, C. Struebing1, J. H. Nadler1, Z. Kang1, B. Wagner1

1 Georgia Tech Research Institute, Atlanta, GA, United States of America


The effect of ceramization temperature on the growth of rare-earth scintillating crystallites within a silicate host glass was studied. Glass formulations super-saturated with GdBr3 and CeBr3 (38 and 4mol%, respectively) were synthesized and heat-treated at ceramization temperatures ranging from 650°C to 1000°C for 2-16 hours to form GdBr3(Ce) nanocrystallites. The optical behavior of the coupons was characterized both before and after ceramming at each temperature. Minimal effect was observed for glass coupons cerammed up to 850°C in either radiation spectroscopy, transmission, or emission measurements. A slight narrowing of the excitation peaks, from 21% to 13% FWHM, was measured for coupons cerammed for 8 hours at 850°C. Coupons cerammed for 8 hours at 1000°C became completely opaque, indicating extensive crystal growth. Primary crystal phases identified include CsBr and BaGdF5. Heat treatment studies are ongoing to identify the threshold dwell period required to grow crystallites to the 30nm target size.

Keywords: composite scintillators, light output, heat treatment, crystal growth
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(face) ID: 248

Poster Number:

Scintillation and Dosimetric Properties of Cerium-doped Lithium Aluminum Phosphate Glasses (#1190)

N. Kawaguchi1, H. Masai2, N. Kawano1, G. Okada1, T. Yanagida1

1 Nara Institute of Science and Technology (NAIST), Graduate School of Materials Science, Ikoma, Nara, Japan
2 National Institute of Advanced Industrial Science and Technology (AIST), Department of Materials and Chemistry, Ikeda, Osaka, Japan


In this study, we prepared Li3PO4-Al(PO3)3 glasses doped with different concentrations (0, 0.1, 0.2, 0.5 and 1.0 %) of Ce and studied the optical, scintillation and dosimetric properties. The scintillation and photoluminescence (PL) emissions showed an intense emission due to the 5d-4f transitions of Ce3+. In addition, the scintillation decay times and PL decay times of Ce3+ were obtained for 25-32 ns and 26-29 ns, respectively. These results were typical for Ce-doped scintillator. Moreover, as a dosimeter property, 0, 0.1, 0.5 and 1.0% Ce-doped glass samples showed thermally stimulated luminescence (TSL) around 150-200 °C and 350-400 °C with a good liner response over 0.5-10 Gy.

Keywords: scintillator, glass, cerium, fast decay
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(face) ID: 250

Poster Number:

Vacuum-ultra-violet Scintillation Properties of Thulium-doped Calcium Fluoride Crystals (#1192)

N. Kawaguchi1, N. Kawano1, G. Okada1, T. Yanagida1

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


Luminescence and scintillation properties of Tm3+ 0.1-15% doped CaF2 crystals were systematically investigated. The crystals were grown by a simple solidification method which allowed us to obtain crystals conveniently. In X-ray induced radio luminescence spectra, the luminosity of the self-trapped-exciton (STE) emission of CaF2 at 270 nm decreased with increasing of Tm3+ concentration. The 5d-4f transition base emission lines appeared at 175 nm (4f115d high spin state (HS) -> 3H6) and at 165 nm (low spin state (LS) to 3H6). Pulse height spectra were measured under a-ray irradiation by using vacuum ultra-violet (VUV) sensitive photomultiplier tube (PMT) R8778 and Tm3+ 0.1% doped specimen exhibited the highest light yield.

Keywords: VUV, STE, VUV scintillator
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(face) ID: 252

Poster Number:

Scintillation Properties of New Tl-based Single Crystals (#1199)

R. Hawrami1, E. Ariesanti1, H. Wei1, J. Finkelstein1, J. Glodo1, K. S. Shah1

1 Radiation Monitoring Devices, Inc., Watertown, Massachusetts, United States of America


We have investigated three new Tl-based scintillators: TlMgCl3, TlCaI3 and Tl2LaCl5:Ce. The crystals were successfully grown by Bridgman method in Øinner 10 mm ampoules, and all resulting in transparent crystal boules. Among these, TlMgCl3 and TlCaI3 are intrinsic scintillators. The scintillation light yield of TlMgCl3 and TlCaI3 are approximately 30,000 ph/MeV and 19,400 ph/MeV, respectively. The energy resolutions at 662 keV are 3.7% for TlMgCl3 and 6.2% for TlCaI3. For TlMgCl3, the scintillation decay is composed of three components: 46 ns, 166 ns, and 449 ns, while for TlCaI3, the scintillation decay time components are 62 ns, 200 ns, and 1440 ns. Both TlMgCl3 and TlCaI3 have broad radioluminescence emission peak between 300 mm and 540 mm, which matches well with commercial PMT’s. In addition, TlMgCl3 is not hygroscopic, which is beneficial for many applications as it can be used without sophisticated hermetic packaging. Moreover, these intrinsic scintillators do not need dopants which should improve the crystal homogeneity. Ce-doped Tl2LaCl5 is also reported. Tl2LaCl5:Ce has an exceptionally high scintillation light yield of 76,000 ph/MeV, along with an excellent energy resolution of 3.4% at 662 keV. Its major scintillation decay time is 39 ns. The radioluminescence emission peak of Tl2LaCl5:Ce occurs at 415 nm. With improvements in material purification and growth techniques, further improvements in their scintillation performance can be expected.

Keywords: Gamma-ray detectors, Scintillators, Tl-based compounds
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(face) ID: 254

Poster Number:

Temperature dependence of scintillation properties of La-GPS(Ce) for well-logging (#1320)

J. Iwanowska-Hanke1, M. Moszyński1, K. Brylew1, P. Sibczynski1, A. Dziedzic1, A. Yoshikawa2, K. Kamada2

1 National Centre for Nuclear Research, Otwock, Poland
2 C&A corporation, Sendai, Japan


In this work, we report the scintillation response of novel rare-earth pyrosilicate scintillator La-GPS(Ce). The study was undertaken with the expectation of the applicability of La-GPS(Ce) for well-logging. The basic properties, such as light output and energy resolution in temperatures up to 150 ˚C are reported. We tested two samples with dimension of 10×10×5 mm. We also tested basic properties of this scintillator in a room temperature. The La-GPS(Ce) is a non-hygroscopic, high-resolution (4.4% for 662-keV gamma-rays measured with Hamamatsu R6231-100 PMT), proportional, and bright scintillator (light output of about 25000 photons/MeV) with decay time similar to orthosilicate GSO(Ce). Additionally, the rZ4eff of La-GPS(Ce) is approximately two times larger than NaI(Tl), therefore it is a promising scintillator for gamma-ray spectrometry in a wide range of applications.

Temperature dependence on light output and energy resolution of La-GPS(Ce) samples is measured using a 9110V02 ET Enterprises PMT fitted to a high temperature measurements. The energy resolution of 662-keV gamma-ray line measured with the ET high-temperature PMT is 7.2%. The temperature measurements are done in an Genviro climate chamber giving the temperature between -70˚C and + 180˚C.

Keywords: novel scintillator, well-logging, high-temperature, gamma-ray spectrometry, La-GPS(Ce)
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(face) ID: 256

Poster Number:

Temperature Dependence of CsI:Tl Scintillation Pulse Shapes from -183°C to +90°C Measured with a SiPM Readout (#1562)

L. Swiderski1, M. Moszyński1, W. Czarnacki1, Z. Mianowska1, T. Sworobowicz1, T. Szczęśniak1, A. Syntfeld-Każuch1, W. Klamra2, R. T. Williams3, S. Gridin3, X. Lu3, M. R. Mayhugh4, A. Gektin5, S. Vasyukov5, C. Piemonte6, A. Ferri6, A. Gola6

1 National Centre for Nuclear Research (NCBJ), Otwock, Poland
2 Royal Institute of Technology, Stockholm, Sweden
3 Wake Forest University, Department of Physics, Winston Salem, North Carolina, United States of America
4 Faceted Development, LLC, Shaker Heights, Ohio, United States of America
5 Institute for Scintillation Materials, Kharkov, Ukraine
6 Fondazione Bruno Kessler (FBK), Trento, Italy


A custom designed cryostat was modified in order to measure the response of a CsI:Tl scintillator in temperature range from -183°C up to +90°C. The light readout was realized using a SiPM developed by FBK in near ultraviolet high density (NUV-HD) technology. The photodetector size was 4×4 mm2 with 25×25 µm2 cell pitch. The crystal and the SiPM were installed on separated copper frames. The crystal was cooled down by liquid nitrogen, while the SiPM was kept at temperature close to room temperature. A separation of 1 mm was kept between the crystal and the photodetector to ensure thermal isolation. Two voltage regulators were placed on the scintillator frame as heaters to allow for varying the temperature of the sample in the range of interest. The temperature of the crystal was continuously monitored using a coil shaped resistance thermometer. The crystal size was 5×6×7 mm3. All surfaces except the one facing the SiPM were covered with Teflon tape to enhance light collection by the photodetector. Thanks to good quality of the spectroscopic response of the CsI:Tl crystal coupled to the SiPM this experimental setup allowed for measuring the relative light yield and its nonproportionality as a function of temperature in the energy range between 14 keV and 662 keV. The CsI:Tl scintillation decay profiles were also recorded in entire temperature range provided by the cryostat. Recorded pulses will be fitted to extract the information about the intensity of scintillation decay components as a function of temperature of the scintillator. The results will be presented with effort to point out correlation between parameters describing scintillation performance of the tested sample. We expect that the outcome of this experiment will be a valuable source of information that can be used in the development of models predicting scintillators response to gamma-rays.

Keywords: CsI:Tl scintillation performnce, temperature dependence, relative light yield, nonproportionality, decay profiles
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(face) ID: 258

Poster Number:

Dosimeter properties of Ce-doped strontium aluminoborate glasses (#1637)

N. Kawano1, N. Kawaguchi1, G. Okada1, T. Yanagida1

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


We evaluate scintillation and dosimeter properties of Ce-doped strontium aluminoborate glass. The samples were fabricated by the conventional melt-quenching technique using an alumina crucible under ambient atmosphere. After polishing, all the samples show good transparency. Scintillation peak around 300-500 nm due to the 5d-4f transitions of Ce3+ was observed under X-ray irradiation. The scintillation from the sample (Ce:0.05%) had a lifetime of 22.5 ns. TL glow curves are characterized as a single peak at 80°C, and the TL intensity decreased with increasing Ce concentration.

Keywords: glass, Ce, borate
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(face) ID: 260

Poster Number:

Gamma-ray Detection Capabilities of Organic–Inorganic Layered Perovskite-type Compounds (#1639)

N. Kawano1, M. Koshimizu2, T. Yanagida1, G. Okada1, Y. Fujimoto2, N. Kawaguchi1, K. Asai2

1 Nara Institute of Science and Technology, Graduate School of Materials Science, Ikoma, Nara, Japan
2 Tohoku Univsersity, Graduate School of Engineering, Sendai, Miyagi, Japan


We investigated scintillation properties of organic–inorganic layered perovskite-type compounds. A single crystal of the hybrid compounds with phenethyl amine (17×23×4 mm) was fabricated by poor-solvent diffusion method. The scintillation light yield of the single crystal was about 1.5 time higher than that of GSO:Ce under gamma-ray irradiation from 137Cs and 57Co sources. The scintillation yield of the single crystal was estimated to be 13,500 photons per MeV. Moreover, the first component of scintillation from the single crystal had a lifetime of 8.2 ns which was much faster than that of GSO:Ce (48 ns) under X-ray irradiation. These results indicate that organic–inorganic layered perovskite-type compounds are promising scintillator for gamma-ray detection.

Keywords: excitons, quantum confinement effect, GSO
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(face) ID: 262

Poster Number:

Radio-photoluminescence (RPL) in Sm:BaAlBO3F2 Embedded in Glass Matrix (#1770)

G. Okada1, K. Shinozaki2, T. Komatsu3, S. Kasap4, N. Kawano1, N. Kawaguchi1, T. Yanagida1

1 Nara Institute of Science and Technology, Graduate School of Materials Science, Ikoma, Nara, Japan
2 National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka, Japan
3 Nagaoka Institute of Technology, Department of Materials Science and Technology, Nagaoka, Niigata, Japan
4 University of Saskatchewan, Electrical and Computer Engineering, Saskatoon, SK, Canada


Sm:BaAlBO3F2 show radio-photoluminescence (RPL) properties. RPL is a phenomenon that new luminescent centres are generated by irradiation. Before X-ray irradiation, the photoluminescence (PL) emission is only due to the 4f-4f transitions of Sm3+ observed around 600 nm; however, after X-ray irradiation it shows additional PL emissions due to the 4f-4f transitions of Sm2+; therefore, new luminescent centre as Sm2+ is generated by irradiation, indicating RPL. The glass ceramic sample includes BaAlBO3F2 crystallites in the glass matrix, and the RPL is only valid for Sm included in the crystalline phase since the precursor glass (without the crystalline phase) does not show RPL. The RPL response is so stable that it does not show any indication of fading even by heating at high temperatures up to 400 °C. For radiation sensing applications, we have confirmed that it shows a monotonically increasing response with X-ray dose at least over the 10 – 10,000 mGy; and it has been demonstrated for 2D dosimetry applications.

Keywords: Radio-photoluminescence (RPL), Sm, BaAlBO3F2, Glass-Ceramic
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(face) ID: 264

Poster Number:

Radio-photoluminescence (RPL) in Non-doped Mg2SiO4 (#1773)

G. Okada1, T. Kojima2, J. Ushizawa2, N. Kawano1, N. Kawaguchi1, T. Yanagida1

1 Nara Institute of Science and Technology, Graduate School of Materials Science, Ikoma, Nara, Japan
2 Oxide Corp, Hokuto, Yamanashi, Japan


Radiation-induced luminescence of non-doped Mg2SiO4 single crystal was studied. The Mg2SiO4 single crystals were synthesized by the Czochralski process. The obtained crystal samples were studied to characterize the radio-photoluminescence (RPL), radio-luminescence (RL), and thermally-stimulated luminescence (TSL) properties. A non-irradiated (or as-prepared) sample shows no particular PL features whereas X-ray treated sample shows a broad PL emission around 630 nm under excitation at 270 nm. The latter observation indicates that RPL centre has been generated by X-ray irradiation. The X-ray induced RL can be observed due to the RPL centre around 630 nm, and the intensity monotonically increases with accumulating the incident radiation dose. TSL glow curve consists of three peaks at 160, 260, and 390 °C, and the initial rise method derived the activation energies of 1.33, 1.47, and 1.85 eV, respectively. The first two TSL are associated with some shallow trapping centres, and annealing at this temperature range builds up the RPL response. On the other hand, annealing at higher temperatures supresses the RPL response; thus, the RPL centre is located at deeper site.

Keywords: Radio-photoluminescence (RPL), Mg2SiO4
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(face) ID: 266

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Defect Engineering in KCaI3:Eu2+ Single Crystal Scintillators by Codoping: A Combined Experimental and Theoretical Study (#1805)

Y. Wu1, 2, Q. Li3, 4, S. Jones5, S. Hu6, M. Zhuravleva1, 2, A. C. Lindsey1, 2, L. Stand1, 2, M. Loyd1, 2, M. Koschan2, J. D. Auxier II5, H. L. Hall5, C. L. Melcher1, 2

1 University of Tennessee, Materials Science and Engineering Department, Knoxville, Tennessee, United States of America
2 University of Tennessee, Scintillation Materials Research Center, Knoxville, Tennessee, United States of America
3 IBM TJ Watson Research Center, Physical Science Division, Yorktown Heights, New York, United States of America
4 University of Illinois at Urbana-Champaign, Department of Computer Science, Urbana, Illinois, United States of America
5 University of Tennessee, Department of Nuclear Engineering, Knoxville, Tennessee, United States of America
6 University of Tennessee, Department of Mechanical, Aerospace, and Biomedical Engineering, Knoxville, Tennessee, United States of America


Eu2+ doped alkali or alkali earth iodide scintillators with energy resolutions ≤3% at 662 keV promise the excellent discrimination ability for radioactive isotopes required for homeland security and nuclear non-proliferation applications. To extend their applications to X-ray imaging, such as computed tomography scans, the intense afterglow which delays the response time of such material is an obstacle need to be overcome. However, a clear understanding of the origin of the afterglow and feasible solutions are still lacking. In this work, we present an experimental and theoretical combined investigation of the physical insights of codoping-based defect engineering which can reduce the afterglow effectively in KCaI3:Eu2+ single crystal scintillators. We illustrate that Sc3+ codoping greatly suppresses the afterglow, whereas Y3+, Gd3+, or La3+ codoping enhances the afterglow. Meanwhile, a light yield of 57,000 photons/MeV and an energy resolution of 3.4% at 662 keV can be maintained with the appropriate concentration of Sc3+ codoping, which makes the material promising for medical imaging applications. Through our thermoluminescence techniques and density functional theory calculations, we are able to identify the defect structures and understand the mechanism by which codoping affects the scintillation performance of KCaI3:Eu2+ crystals.

Keywords: Scintillator, Halides, Afterglow, Defects
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(face) ID: 268

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Comparison of performances between Ce:LYSO and Ce:GAGG for Si-PM based gamma camera for ultrahigh resolution SPECT (#1844)

K. Nakanishi1, S. Yamamoto1, J. Kataoka2

1 Nagoya University, Graduate School of Medicine, Nagoya, Japan
2 Waseda University, Research Institute for Science and Engineering, Tokyo, Japan


Although Lu-based scintillator including Ce-doped Lu1.8Y0.2SiO5 (Ce:LYSO) is most frequently used for PET detector, it is not common to use for gamma camera for SPECT because the self-luminescence due to 176Lu deteriorates the image contrast. However, several studies insist that deterioration of image contrast due to 176Lu is not crucial, and Ce:LYSO is promising for SPECT. Consequently, we compared the performance of Ce:LYSO with that of Gd3Al2Ga3O12 (Ce:GAGG) to determine which one is more adequate for silicon photomultiplier (Si-PM) based gamma camera for ultrahigh resolution SPECT. We used finely pixelated Ce:LYSO and Ce:GAGG plates to obtain high spatial resolution. We optically coupled the finely pixelated Ce:LYSO or the Ce:GAGG plate to Si-PM array and measured the basic performances of them using 57Co (122keV). The energy resolutions of the Ce:LYSO and the Ce:GAGG were 29.5 and 23.3 %FWHM, respectively. The intrinsic spatial resolution of the Ce:GAGG (~0.5 mmFWHM) was better than that of the Ce:LYSO (0.6 mmFWHM). The background counts of Ce:LYSO was 15 times larger than that of Ce:GAGG. From the performance, we conclude that Ce:GAGG is more adequate for Si-PM based gamma camera than Ce:LYSO for ultrahigh resolution SPECT.

Keywords: LYSO, GAGG, SPECT, Si-PM, high resolution
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(face) ID: 270

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Investigation of scintillation properties of Ce:CaGdAl3O7 (#1857)

T. Yanagida1, D. Nakauchi1, G. Okada1, Y. Fujimoto2, M. Koshimizu2, N. Kawano1, N. Kawaguchi1

1 Nara Institute of Science and Technology, Ikoma, Japan
2 Tohoku University, Department of Applied Chemistry, Sendai, Japan


Inorganic scintillators are luminescent materials which convert the absorbed energy of the incident ionizing radiation to thousands of UV-VIS photons immediately. Scintillators have been used in ionizing radiation detectors, and they have played important roles in various applications such as medical imaging and security. In general, Ce-doped luminescent materials with heavy elements in their chemical composition show good properties to detect γ-rays (e.g., Yanagida, Opt. Mater., 35 1987 2013). Although rare-earth-doped CaGdAl3O7 (CGAM; M=Melilite) single crystals were studied as laser materials (J. Petit, et al., J. Appl. Phys 108 123108 2010), scintillation properties have not been reported. In this work, we synthesized Ce-doped CGAM single crystals with different Ce concentration from 0.3 to 2% by Floating Zone (FZ) method, and investigated their scintillation and optical properties.

In the scintillation emission spectra of Ce:CGAM, an intense emission peak appeared around 390-520 nm due to the 5d-4f transitions of Ce3+. Then, we evaluated the pulse height spectra of Ce:CGAM under 137Cs exposure, and the light yiled is 3500 ph/MeV. Because a photoabsorpton peak is observed, this sample can be applicable for the photon counting type scintillation detectors. The light yields depend on the Ce concentrations, and Ce 2% doping showed the best performance among the samples prepared for this work. In the conference, we will report and discuss in more detail with the optical and scintillation properties for Ce differently doped CGAM samples.

Keywords: scintillator
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(face) ID: 272

Poster Number:

Scintillation and dosimeter properties of LiSrAlF6 Crystals (#1859)

T. Yanagida3, G. Okada3, K. Fukuda1, K. Watanabe2, N. Kawano3, N. Kawaguchi3

1 Tokuyama Corp., Shunan, Japan
2 Nagoya University, Division of Quantum Science and Energy Engineering, Nagoya, Japan
3 Nara Institute of Science and Technology, Sensing device group, Nara, Japan


Optically (OSL) and thermally (TSL) stimulated luminescence are used to evaluate the radiation dose in individual dosimeters. Recently, we evaluated OSL and TSL properties of Ce- or Eu-doped LiCaAlF6 crystal scintillators, and they showed good dosimeter properties. In this study, we investigate dosimeter properties of Ce- or Eu-doped LiSrAlF6 crystalline scintillators which we could expect OSL and TSL based on the analogy with LiCaAlF6.

In the experimental procedures, Ce or Eu nominally 0.5% doped LiSrAlF6 crystals were prepared by Tokuyama Corp. using the micro-pulling down method. Optical properties including transmittance, photoluminescence (PL) spectra and quantum yields and decay time profiles were studied. Then, scintillation properties such as X-ray induced radioluminescence spectra, scintillation decay times and neutron induced pulse height spectra were investigated. Finally, we evaluated OSL spectra and TSL glow curves. Dose response functions from 0.1 to 1000 mGy were also measured.

When we focused on dosimeter properties, in OSL spectra, emission wavelengths of Ce- or Eu-doped LiSrAlF6 were same with those in PL or scintillation. Therefore the emission origin of them were Ce3+ or Eu2+ 5d-4f transitions. In OSL, both samples showed a linear response from 1 to 1000 mGy. When we observed TSL glow curves, the glow peak of Ce-doped LiSrAlF6 was around 300 oC while that of Eu-doped LiSrAlF6 was 180 oC . Unlike Ce- or Eu-doped LiCaAlF6, the glow peak was a single peak which is an advantage in practical applications. TSL dose response function was linear from 0.1 to 1000 mGy. Throughout this work, we confirm that Ce and Eu doped LiSrAlF6 have dosimeter properties as well as the scintillation properties.

Keywords: scintillator, neutron, dosimeter, TSL, OSL
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(face) ID: 274

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Development and Characterization of a Composite Scintillator Sensitive to Gammas, Fast, and Thermal Neutrons (#1930)

M. Sharma1, J. Nattress1, K. Wilhelm2, I. Jovanovic1

1 University of Michigan, Ann Arbor, Michigan, United States of America
2 The Pennsylvania State University, State College, Pennsylvania, United States of America


We present the development and characterization of a composite heterogeneous scintillation detector sensitive to gammas, fast, and thermal neutrons. The detector consists of a 2 in x 2 in cylindrical pulse shape discriminating plastic wrapped with a 320μm thick 6LiF:ZnS(Ag) inorganic scintillator on the side and one face of the plastic scintillator. The performance characteristics of this detector such as intrinsic capture and recoil efficiencies, gamma rejection, and figure of merit are presented. The detector demonstrates high gamma rejection with respect to neutron captures and the gamma rejection with respect to neutron recoils that is typical of a pulse shape discriminating plastic. We also conducted Geant4 simulations of the capture and recoil processes, showing a good agreement with the experimental results. This design could find applications in homeland security, nonproliferation, security-related assessments, as well as in basic research where discrimination of multiple particle types is essential.

Keywords: neutron and gamma discrimination, pulse shape discrimination, composite scintillation detector
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(face) ID: 276

Poster Number:

Scintillation properties of a 2-inch diameter KCa0.8Sr0.2I3:Eu2+ single crystal (#2092)

Y. Wu1, 2, A. C. Lindsey1, 2, M. Loyd1, 2, L. Stand1, 2, M. Zhuravleva1, 2, M. Koschan1, C. L. Melcher1, 2

1 University of Tennessee, Scintillation Materials Research Center, Knoxville, Tennessee, United States of America
2 University of Tennessee, Materials Science and Engineering Department, Knoxville, Tennessee, United States of America


Inch-sized scintillating crystals are required for practical radiation detectors such as hand-held radio-isotope identification devices. In this work, a transparent and colorless 2-inch diameter KCa0.8Sr0.2I3:0.5 mo%Eu2+ single crystal was grown by the vertical Bridgman method, and the scintillation properties of a 50 mm diameter and  45 mm long sample were evaluated. The Eu2+ 5d1-4f emission under X-ray excitation centers at 472 nm. Its scintillation decay time under 137Cs source irradiation is 2.37 ms, and the absolute light yield is 51,000±3000 photons/MeV. The energy resolution at 662 keV was evaluated by using a technique of coupling the crystal to the photomultiplier tube (PMT) in different directions and was also estimated based on the 40K background subtracted spectrum. The performance of the packaged crystal was also investigated.

Keywords: Scintillator, Halides, Inch-sized, Energy resolution
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(face) ID: 278

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Physical and Scintillation Degradation of PVT Scintillators (#2175)

M. Zhuravleva1, 2, L. Stand1, M. Loyd1, 2, C. Hurlbut3, K. Shipp3, L. Sideropoulos4, M. Koschan1, C. L. Melcher1, 2

1 University of Tennessee, Scintillation Materials Research Center, Knoxville, Tennessee, United States of America
2 University of Tennessee, Department of Materials Science and Engineering, Knoxville, Tennessee, United States of America
3 Eljen Technology, Sweetwater, Texas, United States of America
4 Nucsafe, Oak Ridge, Tennessee, United States of America


Plastic scintillation detectors based on polyvinyl toluene (PVT) have been successfully used in numerous radiation portal monitors for several decades. Recent studies have shown that exposure to environmental conditions such as repeated cycles of extreme temperature and humidity results in loss of detection sensitivity and limits the useful lifetime of these detectors. At present, it is not fully understood why the internal fogging, discoloration, and surface crazing affect some detectors, but not all of them.

This study investigates the nature of both surface and bulk defects that are responsible for physical and scintillation deterioration of PVT-based scintillators. We used accelerated aging experiments via temperature and humidity cycling in laboratory conditions to create observable defects in small samples (<1 in3). Samples for the study were obtained from Eljen Technology and Nucsafe. We used a Dynamic Vapor Sorption instrument and a previously developed procedure to measure the water absorption rate using gravimetric analysis. We monitored the time evolution of the induced defects and correlated them with optical and scintillation properties. Our observations revealed that accelerated sample aging could produce measurable differences in gamma-ray and alpha-ray spectra. A detailed understanding of the characteristics and root cause of detector degradation is expected to enable control of defect formation and thus lead to improved detection sensitivity and reliability.

Keywords: plastic scintillator, PVT
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(face) ID: 280

Poster Number:

The Scintillation Properties of BaF2 Crystal Produced by Non-Vacuum Bridgman Method in Air Atmosphere (#2185)

H. Ni1, R. Mao1, C. Wu2

1 Shanghai Institute of Ceramics, CAS, JiaDing, Shanghai, China
2 Suzhou JT Crystal Technology, SuZhou, JIanSu, China


We present in this work the optical and scintillation properties of Barium Fluoride (BaF2) crystal by Non-vacuum Bridgman method in air atmosphere. A mixture of tetrafluoroethylene (PTFE) and activated carbon was used as oxygen scavenger to produce BaF2 single crystal in air atmosphere in a sealed platinum crucible. The as grown BaF2 crystal show good optical transmittance within wavelength interested. The fast component of the BaF2 crystals was found about 850 ps. The influence of the oxygen scavenger on the optical and scintillation properties will also be discussed.

Keywords: Barium Fluoride, Non-vacuum, Bridgman Method, SCintillation, Decay
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(face) ID: 282

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Full-energy peak efficiency for cylindrical lanthanum bromide scintillation detector (#2201)

M. I. Abbas1

1 Alexandria university, Faculty of Science, Physics, Alexandria, Egypt


Analytical formula for the total and full-energy peak efficiencies for cylindrical lanthanum bromide (LaBr3:Ce) scintillation detectors is derived. This approach depends on the accurate analytical calculation of two important factors; the path length d, the photon traverses within the active volume of a gamma detector, and the geometrical solid angle, subtended by the source to the detector at the point of entrance. The cerium-doped lanthanum halide crystals have gained special interest due to their high density and atomic number, which results in excellent scintillation properties and higher detection efficiencies in comparison to NaI(Tl). The comparisons with the experimental and Monte Carlo method data reported in the literature indicate that the present method is useful in the efficiency calibration of the cylindrical lanthanum bromide scintillation detectors.

Keywords: Cylindrical lanthanum bromide scintillation detectors; total and full-energy peak efficiencies; point and disk sources
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(face) ID: 284

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Determination of the Birks' Law constants for the fast and slow scintillation components of barium fluoride (#2259)

A. Hasse1, H. Gestsson1, D. Hitlin1, J. H. Kim1, J. Trevor1

1 California Institute of Technology, Physics, Pasadena, United States of America


Barium fluoride has two principle scintillation components, centered at 220 and 310 nm, produced by distinct scintillation mechanisms. The 200nm component, with a decay time less than one nanosecond, is of particular interest. Using trace alpha radioactivity in a barium fluoride crystal, with the scintillation light detected by photomultiplier tubes having different quantum efficiencies as a function of wavelength, we have measured the Birks' Law coefficients for the separate fast and slow components for alpha particles in the 4 to 8 MeV energy range.

Keywords: scintillator
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(face) ID: 286

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Development of LuAG Ceramic Scintillator for Future HEP Experiments (#2287)

C. Hu1, J. Li2, F. Yang3, L. Zhang1, R. - Y. Zhu1

1 California Institute of Technology, HEP, Pasadena, United States of America
2 Shanghai Institute of Ceramics, Shanghai, China
3 Nankai University, Tianjin, China


Because of its bright and fast scintillation rare earth doped Lu3Al5O12 (LuAG) ceramics has attracted interest in the HEP community. Compared to single crystals fabrication of ceramics is featured at a lower temperature and a more effective use of raw materials, and thus promises a cost-effective scintillator. Our investigations on LuAG:Ce ceramics show excellent radiation hardness against ionization dose up to 200 Mrad and proton fluences up to 3×1014 p/cm2. Current status of the LuAG ceramic scintillator and future plan are discussed.

Keywords: Scintillators, Transparent Ceramics, LuAG, Radiation Hardness
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(face) ID: 288

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Pre-Production of PWO-II Crystals for the PANDA-EMC (#2400)

R. W. Novotny1, K. T. Brinkmann1, V. I. Dormenev1, J. Houzvicka2, M. Korjik3, S. Ochesanu2, D. Petrydes2, H. - G. Zaunick1

1 Justus-Liebig-University Giessen, 2nd Physics Institute, Giessen, Germany
2 CRYTUR spol. s.r.o., Turnov, Czech Republic
3 Institute for Nuclear Problems, Minsk, Belarus


There is a strong demand for high quality lead tungstate crystals (PbWO4, PWO) to complete in particular the barrel part of the electromagnetic calorimeter of target spectrometer of the PANDA detector at FAIR. However, after bankruptcy of the Bogoroditsk Technical Chemical Plant in Russia as the major producer so far, a new manufacturer had to be found. Due to the necessary sensitivity of the PANDA-EMC to photon energies even far below 1 GeV and the operation at low temperatures of -25oC radiation hardness achieved by a low concentration of defects becomes the dominating quality requirement. The company CRYTUR (Turnov, Czech Republic) with good experience in the development and production of different types of inorganic oxide crystals has re-started end of 2014 as a common effort the development of lead tungstate for the mass production based on the Czochralski method. An impressive progress of the R&D has been already achieved. The growing technology including the technical modification of the furnaces were optimized to produce full size samples in a reproducible manner to meet the specifications for PWO-II. After the successful production of 200 mm long rectangular prototypes and the confirmation of the required quality parameters tapered crystals (type 11L/R) in PANDA geometry have been manufactured. The presentation will give a detailed progress report on the started pre-production of more than 130 crystals. The obtained results with respect to optical performance, light yield, kinetics, temperature dependence and radiation hardness will be shown in comparison to the data collected for the crystals produced by BTCP and SICCAS in the past.

Keywords: Szintillator, Electromagnetic Calorimetry, PbWO4
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(face) ID: 290

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Modeled Response of CsI:Tl from -183°C to +90°C (#2464)

M. R. Mayhugh1, X. Lu2, S. Gridin2, R. T. Williams2, L. Swiderski3, M. Moszyński3, W. Czarnacki3, Z. Mianowska3, T. Sworobowicz3, T. Szczęśniak3, A. Syntfeld-Każuch3, W. Klamra4, A. Gektin5, S. Vasyukov5, C. Piemonte6, A. Ferri6, A. Gola6

1 Faceted Development, LLC, Shaker Heights, Ohio, United States of America
2 Wake Forest University, Department of Physics, Winston Salem, North Carolina, United States of America
3 National Centre for Nuclear Research (NCBJ), Otwock, Poland
4 Royal Institute of Technology, Stockholm, Sweden
5 Institute for Scintillation Materials,, 61001 Kharkov, Ukraine
6 Fondazione Bruno Kessler (FBK), Trento, Italy


The scintillation process in CsI has previously been modeled with a system of coupled differential equations and applied to nonproportionality at l00 K and room temperature using three equations for the pure material and adding four more for the Tl doped case also treated at room temperature. The same set of equations was refined and applied successfully to modeling pulses, light output vs. time, in the doped material at room temperature. The model incorporates all transport and rate coefficients thought to be relevant to determining scintillation response. Some are known from published measurements, some are estimated and some like Tl content and deep electron trapping vary from sample to sample. In this work the model is extended to calculating pulse shape as a function of temperature. This is done first by comparing to experimental data sets in the literature for CsI:Tl taken from +50 C to -70 C. Initial results show considerable similarity between experiment and model, namely falling pulse height and increasing time to peak as temperature drops but not yet with a detailed match to the shape and rate. The calculated results show appearance of an emission attributed to self-trapped excitions when temperature falls for certain doping levels as was seen experimentally in one case. Further, the pulse shape - time to peak and decay rate - changes with Tl content in a way consistent with differences between two experiments. Data extending the experimental temperature range up to 90 C and down to -183 C has been submitted to this conference and we will compare model to experiment for this case also. Describing STE emission vs. temperature is required because emission at Tl sites turns off with falling temperature. With rising temperature a decrease in decay rate is also to be taken in account.

Keywords: CsI:Tl Scintillation Model
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(face) ID: 292

Poster Number:

Improvements in Energy Resolution using a Stilbene Crystal in Conical Geometry (#2487)

C. S. Sosa1, D. L. Chichester2, S. J. Thompson2, S. D. Clarke1, S. A. Pozzi1

1 University of Michigan, Nuclear Engineering and Radiological Sciences, Ann Arbor, New York, United States of America
2 Idaho National Laboratory, Nuclear Nonproliferation Division, Idaho Falls, Idaho, United States of America


The objective of this work is to quantify changes in detector performance for stilbene crystals having cylindrical and conical geometries of equal height and base area. To maintain a fair comparison, experiments were performed with the same stilbene material (Inrad Optics), photomultiplier tube (ETL 9214A), voltage setting, gamma-ray source (Cs-137), and data-acquisition system (CAEN DT5730). Results demonstrate that the energy resolution for conical stilbene at 478 keVee outperforms cylindrical stilbene by approximately 10%. Geant4 simulations demonstrate how optical photons reflect less in the cone than the cylinder, thus increasing their chance of detection.

Keywords: Organic scintillators, Stilbene, Radiation detectors, Energy resolution
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(face) ID: 294

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ZnO:Ga nanorods grown by hydrothermal method as scintillators (#2503)

S. V. Kurudirek1, 2, M. Kurudirek1, 2, B. D. B. Klein2, C. J. Summers2, N. E. Hertel2

1 Ataturk University, Erzurum, Turkey
2 Georgia Institute of Technology, Atlanta, Georgia, United States of America


With its superior properties such as sub-nanosecond decay time, medium density (5.6 g/cm3) and high light output efficiency, ZnO has become a promising scintillator material. Its direct bandgap (3.37 eV) and large exciton binding energy (60 meV) makes it a very efficient emitter. Ga doped ZnO nanorods were synthesized by the low temperature hydrothermal method which has advantages over other growth techniques such as a low growth temperature (<350 °C), use of low cost and simple equipment, large area growth capability. ZnO:Ga nanorods were characterized by SEM, photoluminescence (PL) and alpha particle measurements. Samples were also annealed at a forming gas atmosphere resulting in significantly enhanced near-band gap PL emission. Results revealed that ZnO:Ga nanorods have superior photoluminescence and alpha particle responses when compared to undoped ZnO nanorods. Therefore, low temperature hydrothermal method was found to be a promising growth technique for high quality ZnO:Ga nanorod scintillators for possible use in alpha particle detectors.

Keywords: Scintillator, Hydrothermal synthesis, ZnO Nanorod, Ga doping
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(face) ID: 296

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Scintillation and dosimetric properties in Eu:(Ba,Sr)Al2O4 crystals (#2554)

D. Nakauchi1, G. Okada1, N. Kawano1, N. Kawaguchi1, T. Yanagida1

1 Nara Institute of Science and Technology, Ikoma, Nara, Japan


We have recently shown that Eu-doped SrAl2O4 crystal exhibits notably high scintillation light yield (46,000 ph/MeV), which is comparable to Ce:GAGG crystalline scintillator. Then, to extend the study, the aim of this research to improve scintillation properties of SrAl2O4 crystals by partially Ba-substitution. In all samples, an intense radioluminescence peak appeared around 520 nm, and the decay time constants are 400-700 nsec which are the typical values of the 5d-4f transitions of Eu2+. We also evaluated the pulse height spectroscopy and thermoluminescence properties.

Keywords: scintillator, dosimetry, thermoluminescence, radioluminescence
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(face) ID: 298

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Scintillation properties of SrF2 transparent ceramics and single crystal (#2556)

T. Kato1, G. Okada1, N. Kawano1, N. Kawaguchi1, T. Yanagida1

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


The interest in new scintillation materials is promoted by an increasing number of new applications in medical, security, environmental monitoring and particle physics. Today, almost all the scintillators used in practice are bulk single crystals due to the outstanding properties such as high transparency, and high light yield. However, recent studies have opened up a new possibility of using transparent ceramics as scintillators material thanks to the recent advancement of improved ceramic synthesis technologies developed in the laser field. In this study, to extend our previous research, we developed SrF2 transparent ceramic and characterized scintillation properties. The synthesis of SrF2 transparent ceramic was made by the spark plasma sintering method, and the scintillation property was investigated. Further, we have characterized the thermally stimulated luminescence glow curve in order to study relatively shallow trapping centers.

In X-ray induced scintillation spectra of SrF2 ceramic and single crystal samples, an emission peak at 300 nm was observed in both the samples. Similar emission peak was also reported by the earlier work, in which the origin of this mission was ascribed to self-trapped excitation (STE). Then, we measured the X-ray induced scintillation decay time profiles of SrF2 ceramic and single crystal samples. The decay curves were approximated by a second order exponential decay function. The derived decay time constants were 310 and 1113 ns for the ceramic sample, 348 and 1175 ns for the single crystal sample. These components are consistent with the previously reported, so the origins of these components are attributed to STE.

Keywords: Scintillator
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(face) ID: 300

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Scintillation and dosimeter properties of CaO and MgO transparent ceramic (#2559)

T. Kato1, G. Okada1, N. Kawano1, N. Kawaguchi1, T. Yanagida1

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


When dosimeter materials absorbs the energy of ionizing radiation, they emit light under the stimulation by low energy photons or thermal heat. The radiation detector using this phenomenon is mainly utilized as an individual radiation monitor, so called the dosimeter. These dosimeters are classified to three types in relation to the mechanisms involved: thermally stimulated luminescence (TSL), optically stimulated luminescence (OSL) and radiophotoluminescence (RPL).

For dosimeter applications, MgO have been studied for a long time. We reported that MgO transparent ceramic showed TSL spectra due to F+ center and highly sensitive dosimeter properties than the single crystal counterpart. On the other hand, in CaO, the similarly was revealed that the F and F+ center exhibited photoluminescence emission at 630 and 380 nm, respectively. To the best of our knowledge, a study example is few, and especially dosimeter properties of CaO have not yet been revealed. In this study, we have synthesized CaO and MgO transparent ceramics by the spark plasma sintering method and then characterized the dosimeter properties after X-ray irradiations and some basic luminescence properties such as photoluminescence and scintillation.

When TSL glow curve of CaO was measured immediately after irradiation, glow peaks were observed at 170 and 330 °C for CaO while MgO showed glow peaks at 140, 240 and 370 °C. It is suggested that the TSL trapping sites in CaO, which are typically some kinds of defects, are the same, or at least similar, to those in MgO since the TSL glow peaks, peak intensities and crystal structures are similar.

Keywords: scintillator
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(face) ID: 302

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Estimation of gamma-ray activity applying energy-weighting algorithm on the spectrum measured with a stilbene scintillator (#2690)

C. Kim1, V. B. Le2, J. - Y. Yeom1, 3, G. Kim2

1 Korea University, Department of Bio-Convergence Engineering, Seoul, Republic of Korea
2 Sejong University, Department of Nuclear Engineering, Seoul, Republic of Korea
3 Korea University, School of Biomedical Engineering, Seoul, Republic of Korea


Stilbene scintillators are known to show an excellent Pulse Shape Discrimination (PSD) performance in distinguishing neutrons from gamma rays in measurement. However, due to the inherent limitation as an organic scintillator, it is difficult to obtain a useful gamma-ray energy spectrum with stilbene, which can give us information about the type and activity of radionuclides.

In this study, we measured neutrons and gamma rays using a stilbene scintillator, a photomultiplier tube(PMT) and a fast digitizer. We applied PSD to distinguish neutrons from gamma ray signals and applied energy-weighting algorithm on the gamma-ray spectra to produce a “peak-like” feature for each radionuclide. We also simulated gamma-ray spectra for each source measured using MCNP6 and calculated absolute peak efficiencies as we defined in this study. We, then, compared APE’s obtained from the simulated spectra with ones from measurement experiments. The results show promises of estimating the gamma ray source activity based on the relation between the gamma-ray energy and the efficiency value obtained for the respective Compton edge region.

Keywords: PSD, Energy-weighted algorithm, efficiency, stilbene, Compton edge. activity
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(face) ID: 304

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The effects of radiation damage on CLYC performance (#3070)

K. E. Mesick1, D. D. S. Coupland1, S. F. Nowicki1, L. C. Stonehill2

1 Los Alamos National Laboratory, ISR-1: Space Science and Applications, Los Alamos, New Mexico, United States of America
2 Los Alamos National Laboratory, GS-IET, Los Alamos, New Mexico, United States of America


Cs2LiYCl6:Ce3+ (CLYC) is a new scintillator that is an attractive option for applications requiring the ability to detect both gamma rays and neutrons within a single volume. It is therefore of interest in applications that require low size, weight, or power, such as space applications. The radiation environment in space can over time damage the crystal structure of CLYC, leading to reduced performance. We have exposed 2 CLYC samples to the 800 MeV proton beam available at the Los Alamos Neutron Science Center (LANSCE). The samples were irradiated to approximately 10 kRad and 100 kRad and we measured the pulse shapes and amplitudes, energy resolution, and the ability to cleanly discriminate between gamma and neutron events before and after irradiation. We have also studied the effects of room-temperature annealing and recovery and high-temperature annealing and recovery. The results from these measurements on the impact of radiation damage on CLYC performance will be presented.

Keywords: CLYC, elpasolite, scintillator, radiation damage, neutron, gamma-ray, space
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(face) ID: 306

Poster Number:

Characterizing the Electron Response and Position Sensitivity for Radiation in Plastic Scintillators (#3206)

N. N. T. Tran1, S. Sasaki1, 2, T. Sanami1, 2, Y. Kishimoto1, 2, E. Shibamura3

1 The Graduate University for Advanced Studies (SOKENDAI), Department of Accelerator Science, Kanagawa, Japan
2 The High Energy Accelerator Research Organization (KEK), Ibaraki, Japan
3 Waseda University, Tokyo, Japan


To develop a space dosimeter based on LET measurement, we examine the characteristics of a candidate material, plastic scintillators. In this study, the electron responses of three plastic scintillators EJ-200, EJ-212, and EJ-252, defined as relative light output per unit energy, are determined via deposited energy measured by Compton Coincidence Technique using gamma rays. The position sensitivity characteristic is examined by using four square-aligned plastic scintillator rods (EJ-212), multi-segmented photomultiplier tubes are attached to the both ends of the respective rods, and the positions of radiation incidence in the rod are evaluated by using signals from the photomultiplier tubes. The radiation incidence is used to determined the path length of the radiation in the detector. By employing deposited energy and path length in the dosimeter, evaluation of LET can be obtained.

Keywords: plastic scintillator, electron response, position sensitivity
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(face) ID: 308

Poster Number:

Tests of 3x3 undoped CsI matrix with an extremely low intensity electron beam (#3248)

A. Artikov1, H. Ayvazyan2, A. Babayan2, V. Baranov1, J. Budagov1, D. Chokheli1, Y. I. Davydov1, V. Glagolev1, A. Hakobyan2, H. Hakobyan2, D. G. Hitlin3, S. Miscetti4, A. Simonenko1, A. Sirunyan2, A. Shalyugin1, V. Tereschenko1, H. Torosyan1, Z. Usubov1, H. Zohrabyan2

1 Joint Institute for Nuclear Research, Dubna, Russian Federation
2 A.Alikhanyan National Laboratory, Yerevan, Armenia
3 California Institute of Technology, Pasadena, United States of America
4 Laboratori Nazionali di Frascati dell’INFN, Frascati, Italy


We report measurements of energy resolution of a 3x3 matrix made of 30x30x200 mm3 undoped CsI crystals. The measurements have been performed using the electron beam of the linear accelerator of the Yerevan Physics Institute (Yerevan, Armenia) in the energy range of 15-35 MeV. The accelerator operated at extremely low beam intensity (10-50 electrons per second). That operation mode was achieved by decreasing the photo cathode temperature and lowering applied high voltage. Energy resolution and linearity of the matrix response have been studied during the tests. The matrix demonstrated good linearity of energy response in the 15-35 MeV range. The measured energy resolution is σE/E=6.4% at E=35 MeV. That result is consistent with our previous measurements of similar matrix at the energy range of 80-120 MeV.

Keywords: Mu2e, undoped CsI crystal, calorimeter, electron beam, energy resolution
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(face) ID: 310

Poster Number:

Sensitivity to initial track radius and hole self-trapping range in a transport and rate equation model of scintillation (#3269)

S. Gridin1, X. Lu1, S. Upadhya1, R. T. Williams1, M. Mayhugh2

1 Wake Forest University, Department of Physics, Winston-Salem, North Carolina, United States of America
2 Faceted Development, LLC, Shaker Heights, Ohio, United States of America


A scintillation model we developed earlier is predicated on including all physical interactions of carriers in a track that can reasonably be expected to influence performance properties of scintillators including pulse shape, nonproportionality, and total light yield.  The physical interactions built into the model are mostly governed by well-known rate and transport relations that comprise the system of coupled equations for evolution of carriers in the so-called “local light yield” part of the model that calculates light emission, quenching, trapping, etc. as functions of some “initial” distribution of carrier density in a track.  A second part of the model uses simulations of energy deposition from an incident particle of specified energy to provide a probability distribution of initial carrier densities in the track.  We have used GEANT4 simulations for this part in much of our past work, but have recently begun comparing results obtained using NWEGRIM (PNNL), which follows the energy deposition to low energy in better detail. The purpose of this study is to investigate how performance characteristics of CsI:Tl (with the other parameters fixed) change in response to variations in three stages of track radius.  Specifically, the values of "initial energy deposition radius", r0, initial STH radius, rSTH, before hopping transport sets in, the mean radius of electron thermalization, and the mobilities of thermalized electrons and holes are varied.

Keywords: scintillator, model, CsI:Tl
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(face) ID: 312

Poster Number:

Alkali-Free Ce-Doped and Co-Doped Fluorophosphate Glasses for Future HEP Experiments (#3384)

C. Hu1, A. Margaryan2, A. Margaryan2, F. Yang1, 3, L. Zhang1, R. - Y. Zhu1

1 California Institure of Technology, 256-48, HEP, Pasadena, California, United States of America
2 AFO Research Inc, Glendale, California, United States of America
3 Nankai University, Tianjin, China


We report current status of alkali-free cerium-doped and co-doped fluorophosphate glasses as a potential inorganic scintillator for future HEP experiments. Optical and scintillation properties, such as emission, transmittance, light output, decay time and their degradation after γ-ray irradiations, are measured for glass samples produced at AFO Research Inc. Further developments are needed for this potential cost-effective glass scintillator to be used for the HHCAL detector concept.

Keywords: scintillating glasses HHCAL HEP
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(face) ID: 314

Poster Number:

Kinetic Monte Carlo Model of Scintillation Mechanisms in Organic Scintillator Radiation Detectors (#3429)

P. Schuster1

1 University of Michigan, Nuclear Engineering, Ann Arbor, Michigan, United States of America


Although organic scintillator materials are widely used as radiation detectors, an understanding of the light production mechanisms remains incomplete.  No quantitative tool exists for simulating the dynamics of the molecular excitations produced by radiation interactions that are responsible for light emission. To build such a tool, a kinetic Monte Carlo technique has been implemented for modeling the scintillation mechanisms in organic scintillators in response to radiation interactions. The initial distribution of excited states is produced based on the physics of a neutron or gamma-ray interaction. A simple cubic lattice has been implemented with theoretical time constants typical of those observed in existing organic scintillator materials. The model serves as a mathematical proof-of-concept to illustrate that the kinetic Monte Carlo technique can capture the complexities of these systems. Work remains to incorporate correct time constants and a monoclinic crystal structure to make the model represent real materials such as anthracene or stilbene.  

Keywords: organic scintillator; simulation; kinetic Monte Carlo;
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(face) ID: 316

Poster Number:

Method for Post Processing of Digitized Events for Accurate Characterization, Application to Scintillation Decay Analysis (#3585)

O. Philip1, I. Shestakova1

1 Schlumberger, Sugar Land, Texas, United States of America


Precise quantification of events is often essential to understand phenomena, to be able to process the signals correctly and to identify abnormalities.  A method is proposed to process a large number of digitized statistical events, or samples, to produce a representation of the population with a high level of accuracy.  In the case of scintillation signals, we want to have a representation of the signal that is accurate and has good statistical precision so that all relevant features can be quantified accurately.  A common difficulty lies in the large dynamic range necessary to acquire the signal accurately.  For example, some complex scintillation signals can have a rise time of a few nano seconds and multiple decay constants ranging from several nanoseconds to hundreds of nanoseconds or longer.  Additionally, the nature of the signal is statistical, and single acquisition traces are not sufficient to characterize some features such as long time decay constants with small amplitude.  Similarly, a single trace acquisition is not sufficient for such analysis.  A simple stacking of digitized traces can provide useful information, however, the stacked result will be affected by differences in sample amplitudes, baseline levels, acquisition artefacts including noise or parasitic events such as multiple pulses, and imperfect trigger.   The proposed method is designed to greatly reduce the influence of the parameters that are unrelated to the statistics of the phenomenon being studied.  The signals are processed to eliminate the effect of varying baseline levels, imperfect triggers, signal artefacts such as noise and multiple events to produce a statistically accurate representation of the population. The entire population is analyzed to derive a preliminary model of the statistical population and produce acceptance criteria against which non-conforming signals will be rejected. Example analysis for scintillator decay (LaBr3, YAP, GSO, GYGAGG) will be presented.

Keywords: scintillation signal, time decay characterization, multiple decay analysis, statistical method
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(face) ID: 318

Poster Number:

Scintillation properties of KSr2I5 activated with Na+, In+, Yb2+ and Ce3+ (#3721)

L. M. Stand1, 4, M. Zhuravleva1, 2, J. Johnson1, 2, M. Koschan1, E. D. Lukosi3, C. Melcher1, 2

1 University of Tennessee, Scintillation Materials Research Center, Knoxville, Tennessee, United States of America
2 University of Tennessee, Department of Materials Science and Engineering, Knoxville, Tennessee, United States of America
3 University of Tennessee, Department of Nuclear Engineering, Knoxville, Tennessee, United States of America
4 University of Tennessee, Bredesen Center, Knoxville, Tennessee, United States of America


Potassium strontium iodide (KSr2I5) scintillators are typically activated by populating a few per cent of the divalent lattice sites with Eu2+ luminescent centers; however, other activators offer the potential to modify certain scintillation properties such as decay time and emission wavelength.  Consequently, we grew single crystals of KSr2I5 activated with Na+, In+, Yb2+ and Ce3+ via the Bridgman technique at 1 mm/h using a two-zone transparent furnace. Samples with dimensions of approximately 5 x 5 x 5 mm were cut from the grown crystals.  Through a series of characterization techniques, we found that the luminescence centers proposed in this study are suitable activators in the KSI matrix. Each activator displayed characteristic luminescence with the peak emission wavelength under X-ray irradiation ranging from 420 nm to 590 nm while the primary scintillation decay constant under gamma-ray excitation ranged from 90 ns to 2,000 ns.  The scintillation light yields measured were 15,200 ph/MeV for KSI:Na 0.5%, 23,100 ph/MeV for KSI:In 0.5%, 50,500 ph/MeV for KSI:Yb 0.5% and 55,800 ph/MeV for KSI:Ce 0.5%, with energy resolutions at 662 keV of 10.5%, 7.6%, 3.8% and 4.0% respectively.  Further work will focus on optimization of the activator concentration and investigation of the scintillation mechanisms.

Keywords: Single crystal growth, Bridgman technique, Metal Halides, Scintillators
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(face) ID: 320

Poster Number:

New Eu2+ doped metal halide scintillators: Cs4-×A×CaI6 and Cs4-×A×SrI6 (#3902)

L. Stand1, 3, M. Zhuravleva1, 2, B. Chakoumakos4, J. Johnson1, 2, M. Loyd1, 2, M. Koschan1, C. L. Melcher1, 2

1 University of Tennessee, Scintillation Materials Research Center, Knoxville, Tennessee, United States of America
2 University of Tennessee, Department of Materials Science and Engineering, Knoxville, Tennessee, United States of America
3 University of Tennessee, Bredesen Center, Knoxville, Tennessee, United States of America
4 Oak Ridge National Laboratory, Quantum Condensed Matter Division, Oak Ridge, Tennessee, United States of America


In this work we present the crystal growth and scintillation properties of new of Eu2+ doped metal halide scintillators belonging to the Cs4-xAxCaI6 and Cs4-xAxSrI6 compositional families (A = Li, Na, K and Rb and 0 ≤ × ≤ 1).  Single crystals up to one inch diameter were grown in evacuated quartz ampoules via the vertical Bridgman technique using a two-zone transparent furnace. These crystals belong to K4CdCl6 structure-type, trigonal space group R-3c with density of ~4 g/cm3. Typical luminescence properties due to the 5d-4f radiative transitions in Eu2+ were observed, with emission centered at ~460 nm. At this early stage of development Cs4-xAxCaI6:Eu and Cs4-xAxSrI6:Eu have shown very promising scintillation properties, measuring light yield up to 65,000 ph/MeV and energy resolutions as low as 3.3% at 662 keV, with microsecond long decay times.  The crystals studied showed a proportional response that deviated less than 5% from the ideal.

Keywords: New Scintillators, metal halide, single crystal growth, Bridgman technique
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(face) ID: 322

Poster Number:

Directionally solidified Tb3+-doped GdAlO3/α-Al2O3 eutectic scintillators (#4088)

A. Yoshikawa1, 2, K. Kamada2, 3, S. Kurosawa2, A. Yamaji1, Y. Ohashi2, Y. Yokota2, N. Yasui4, Y. Ohashi4, T. Den4

1 IMR, Tohoku Univ., Sendai, Japan
2 NICHe, Tohoku Univ., Sendai, Japan
3 C&A Corp., Sendai, Japan
4 Canon Inc., Tokyo, Japan


The sub-micron diameter Tb:GAP eutectic scintillator fibers surrounded with a-Al2O3 matrix from directionally solidified eutectics were fabricated. In this crystal, the length of longest fiber of GAP along the growth direction was at least about few mm or so. As shown in Fig.2(a), the lines under GAP/a-Al2O3 were emerged at the surface of GAP /a-Al2O3. This proves that it has wave-guiding properties. Scintillation light will be guided along the GAP scintillator fiber.

Scintillation properties of eutectic scintillator is measured carefully taking composition and transparency into consideration. In the presentation, relation between chemical composition of starting materials, growth rate, volume ratio of eutectic, diameter of GAP rod phase will be discussed. In addition, other scintillation properties such as light yield and scintillation decay time will be reported. Imaging result using GAP/a-Al2O3 will also be shown.

Keywords: directionally solidified eutectic, phase-separated scintillator fibers, high-resolution radiation imaging
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(face) ID: 324

Poster Number:

Analytical Solutions of Transient Drift-Diffusion in P-N Junction Pixel Sensors (#1187)

G. Blaj1, G. Haller1, C. J. Kenney1, J. Segal1

1 SLAC National Accelerator Laboratory, TID\AIR, Menlo Park, California, United States of America


Radiation detection in applications ranging from high energy physics to medical imaging rely on solid state detectors, often hybrid pixel detectors with (1) reverse biased p-n junction pixel sensors and (2) readout ASICs, attached by flip-chip-bonding. Transient signals characteristics are important in, e.g., matching ASIC and sensor design, modeling and optimizing detector parameters and describing timing and charge sharing properties. Currently, analytical forms of transient signals are available for only a few limited cases (e.g., drift or diffusion) or for the steady state (which is not relevant for high energy radiation detection). Tools are available for (relatively slow) numerical evaluation of the transient charge transport. We present here the first analytical solutions of partial differential equations describing drift-diffusion-recombination charge transport in planar p-n junction sensors in a variety of conditions: (1) undepleted, (2) fully depleted, (3) taking into account the gradual velocity saturation, and (4) overdepleted. We deduce the Green's functions which can be applied to any detection problem through simple convolution with the initial conditions. We compare the analytical solutions with Monte Carlo simulations and industry standard simulations (Synopsys Sentaurus), demonstrating good agreement. Using the analytical equations enables fast modeling of the influence of various detector parameters on tracking, imaging and timing performance, describing performance and enabling optimizations for different applications. Finally, we illustrate this model with applications in 3D+T (x,y,z,time) photon tracking and 4D+T (x,y,theta,phi,time) relativistic charged particle tracking.

Keywords: Hybrid pixel detectors, p-n junction sensors, transient signals, charge sharing, drift-diffusion-recombination model, partial differential equations
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(face) ID: 326

Poster Number:

Investigating Artefacts Associated with α Particle Interactions in Charge Coupled Devices (#1381)

R. Newton1, M. J. Scott2, M. J. Joyce1

1 Lancaster University, Engineering Department, Lancaster, United Kingdom, United Kingdom of Great Britain and Northern Ireland
2 BIC Technology Ltd., Liverpool, United Kingdom, United Kingdom of Great Britain and Northern Ireland


The response of charge coupled devices (CCDs) to α radiation has been investigated to assess the potential of using these devices to perform α-particle detection and measurement. Previous research indicates that α radiation leaves distinctive patterns in the images produced by CCDs when compared with other types of radiation. In this research, CCD responses to α and β radiation have been compared to highlight these differences. The CCD used was a Sony ICX825AL interline transfer CCD with an 8.98 × 6.71 mm imaging area consisting of 1392 × 1040 pixels, each of size 6.45 × 6.45 µm, covered with a thin aluminised Mylar film to stop exposure to light. Images have been taken of exposures to a 210Po source and horizontal streaks have been observed. It is thought the horizontal streaks are caused by the charge produced by the α particles being read out over several cycles. The average length of the streaks was found to be 14±2.65 pixels. When the α particles are attenuated from 5.30 MeV to 3.93±0.05 MeV, the average streak length remains similar at 13±3 pixels, but with significantly fewer total counts. Future research will be done to further assess streaks produced by different energy α particles to investigate the potential of using CCDs for spectroscopy.

Keywords: alpha detection, charge coupled device, CCD
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(face) ID: 328

Poster Number:

Strip detector for the ATLAS detector upgrade for the High-Luminosity LHC (#2036)

D. Madaffari2

2 IFIC Valencia, Valencia, Spain


The planned HL-LHC (High Luminosity LHC) in 2025 is being designed to maximise the physics potential of the LHC through a sizeable increase in the luminosity, reaching 1x1035cm-2s-1 after 10 years of operation [1]. A consequence of this increased luminosity is the expected radiation damage at an integrated luminosity of 3000 fb-1, requiring the tracking detectors to withstand hadron fluencies to over 1x1016 1 MeV neutron equivalent per cm2. With the addition of increased readout rates, a complete re-design of the current ATLAS Inner Detector (ID) is being developed as the Inner Tracker (ITk), which will consist of both strip and pixelated silicon detectors.

The physics motivations, required performance characteristics and basic design of the proposed upgrade of the strip detector will be a subject of this talk. Present ideas and solutions for the strip detector and current research and development program will be discussed.

Keywords: silicon detectors, tracking ATLAS, LHC
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(face) ID: 330

Poster Number:

A three-dimensional gated diode structure for surface parameter characterization in a 3D sensor technology (#2229)

D. Sultan1, 2, M. Boscardin3, 2, R. Mendicino1, 2, S. Ronchin3, 2, N. Zorzi3, 2, G. - F. Dalla Betta1, 2

1 University of Trento, Department of Industrial Engineering, Trento, Italy
2 TIFPA INFN, Trento, Italy
3 Fondazione Bruno Kessler (FBK), Center for Materials and Microsystems, Trento, Italy


We report on a three-dimensional gated diode test structure compatible with the latest fabrication technology developed at FBK for 3D pixel sensors oriented to the Phase 2 Upgrades at the High-Luminosity LHC (HL-LHC). Since this technology does not feature any implanted region at the surface, standard gated diode structures cannot be implemented, thus hindering the extraction of surface parameters, in particular the surface generation velocity (s0). The proposed three-dimensional device is potentially suitable to this purpose, although some design constraints dictated by the fabrication process result in non-ideal current-voltage characteristics. Experimental results from the characterization of the first prototypes will be presented and discussed with the aid of TCAD simulations. Modified geometries aimed to improve the accuracy of the extracted s0 values were also designed and implemented in a second batch of 3D sensors, currently being fabricated at FBK. Preliminary results from their characterization will also be presented.

Keywords: Silicon radiation sensors, Gated diode, 3D sensor technology
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(face) ID: 332

Poster Number:

Recent advances in DEPFET technology (#3152)

A. Bähr1, P. Lechner1, J. Müller-Seidlitz2, J. Ninkovic1, R. Richter1, W. Treberspurg2, J. Treis1

1 Semiconductor Laboratory of the Max-Planck-Societey – MPG-HLL, Munich, Bavaria, Germany
2 Max-Planck-Institute for Extraterrestrial Physics – MPE, Garching, Bavaria, Germany


The DEPFET is a combined sensor-amplifier, which allows the implementation of a wide variety of functions already on pixel level. Here, we will introduce four examples of recent advances in DEPFET technology that have been developed and produced at the MPG-HLL and are currently being tested.

One of the latest achievements was the introduction of DEPFETs with linear gate geometry in X-ray spectroscopy. In contrast to circular gates previously used, linear gates can be scaled easily. The first prototype matrices with smaller feature sizes are available und currently under test. With a pixel size of 130x130 µm² and a bulk thickness of 450µm, these prototypes provide lower noise and improved energy resolution.

An application calling for a completely different set of requirements is direct electron detection in electron microscopes, for which sensors with a pixel size of 60x60 µm² built on 50 µm and on 30 µm thick substrates were recently finalized. These are capable to store signals larger than 106 e-, provide in-pixel signal compression and frame readout rates of up to 80 kHz for a 1MPixel detector. Prototypes have been finished and results from the first measurements will be reported.

Furthermore, we developed DEPFET devices with multiple in-situ storage regions. The first devices of this kind, the so-called Infinipix DEPFETs, provide two storage nodes and were proposed for applications requiring both, high time resolution and high throughput. They are fully functional, exhibit a read noise of the order of 3 e- ENC and are unaffected from readout artifacts (out of time events) or dead time.

A consequent advancement of the Infinipix is the Quadropix DEPFET. This novel concept provides four storage nodes and is proposed as sensor for the high precision polarimetric camera currently developed for the EST. First prototypes are available and test results will be reported and compared to device simulations.

Keywords: DEPFET, X-ray Detector, Radiation Imaging, Silicon Detector, Electron Detector, Polarimetry
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(face) ID: 334

Poster Number:

Commissioning of a Si(Li) Compton polarimeter with improved energy resolution (#3191)

M. Vockert1, 2, G. Weber2, 3, U. Spillmann3, T. Krings4, T. Stöhlker1, 3

1 Friedrich Schiller University Jena, Institute of Optics and Quantum Electronics, Jena, Germany
2 Helmholtz Institute Jena, Jena, Germany
3 GSI Helmholtzzentrum, Darmstadt, Germany
4 Forschungszentrum Jülich GmbH, Institut für Kernphysik, Jülich, North Rhine-Westphalia, Germany


On the basis of a double-side segmented Si(Li) crystal a new Compton polarimeter was developed within the SPARC collaboration of FAIR. The new detector is equipped with a cryogenic first stage of the preamplifiers to improve the energy resolution and reduce the electronic noise, compared to previous detectors with preamplifiers operating at roomtemperature. We present first results from a commissioning measurement of the new instrument at the ESR storage ring of GSI in Darmstadt, Germany and contrast it with the performance of an older polarimeter system.

Keywords: x-ray spectroscopy, Compton polarimetry, heavy ion, REC radiation
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(face) ID: 336

Poster Number:

Characterization and analysis of cross-talk on monolithic SDD arrays for the SIDDHARTA experiment (#3469)

A. Amirkhani1, 2, G. Bellotti1, 2, A. D. Butt1, 2, M. Carminati1, 2, D. Ferrari1, C. Fiorini1, 2, G. Borghi3, C. Piemonte3, N. Zorzi3

1 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
2 INFN, Sezione di Milano, Milano, Italy
3 Fondazione Bruno Kessler (FBK), Trento, Italy


This work is mainly focused on cross-talk analysis and characterization of a detection module for X-ray spectroscopy which is developed under the scope of SIDDHARTA experiment. The SIDDHARTA experiment is designed to investigate strong nuclear interactions using exotic atoms in the field of nuclear physics. Silicon Drift Detectors (SDDs) used in this experiment, are arranged in arrays of 2 × 4 elements with total area of 612 mm2. At the final stage of SIDDHARTA experiment, 48 SDD arrays are needed to be utilized in a gantry structure to perform X-ray spectroscopy of exotic nuclei, like kaonic deuterium. Each single SDD unit in 2 ×4 formation of arrays is coupled to a charge sensitive preamplifier, namely CUBE, which is followed by shaping amplifier, and consequent analog and digital electronics that are all integrated on a custom developed multichannel chip called SFERA. This work aims to emulate and measure the effect of charge sharing on SDD channels upon absorption of X-rays and MIPs (Minimum Ionizing Particle) on SDD to investigate the performances of such devices when expected to be irradiated with X-rays signals and with a large background of the accelerator.

Keywords: SDD, kaonic atoms, cross-talk, x-ray spectroscopy
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(face) ID: 338

Poster Number:

Silicon PhotoMultiplier (SiPM) Temperature Measurement using Direct Bias (#3693)

A. Abba1, V. Arosio1, M. Caccia2, F. Caponio1, R. Santoro2

1 Nuclear Instruments, Lambrugo, Italy
2 Università degli Studi dell’Insubria, Dipartimento di Scienza e alta Tecnologia, Como, Italy


Silicon Photomultipliers (SiPM) are solid-state photodetectors sensitive to single-photon. They mainly consist of a matrix of reversed bias diodes connected in parallel to a single output through quenching resistors. They are operated in Geiger Müller regime providing an output signal proportional to the number of fired cells. Each cell has a typical gain of about 106 that depends on the overvoltage setting. Since the breakdown voltage changes with the temperature, the latter also affects the intrinsic gain. A calibrated system needs to monitor the temperature to adjust the overvoltage setting. It is common practice to achieve this purpose by using a temperature sensor placed close to the SiPM. In this contribution, a novel method that uses the SiPM itself to monitor the temperature when it is directly biased is proposed. This measurement can be regularly performed when the sensor is not in acquisition (i.e. operated synchronously with other devices or operated at low rates) allowing to achieve a precision higher than 0.1°C. This method is definitely of interest for compact systems where the space and the gain stabilization are critical (i.e. portable devices subjected to temperature variation) or for large area detectors where an accurate temperature measurement for the single SiPM could be beneficial.

Keywords: SiPM, temperature measurement, bias
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(face) ID: 340

Poster Number:

Robust Pixel Gain Calibration with Limited Statistics (#1338)

G. Blaj1, G. Haller1, C. J. Kenney1

1 SLAC National Accelerator Laboratory, TID \ AIR, Menlo Park, California, United States of America


Pixel detectors typically display pixel-to-pixel gain variation of a few percent which result in reduced spectroscopic performance. Integrating pixel detectors provide spectroscopic information directly, and photon counting detectors through threshold scans. Gain maps are used to rectify pixel-to-pixel gain variation. Ideally, the pixel gain is calibrated with monochromatic radiation (e.g., from a synchrotron or free electron laser beamline, or laboratory x-ray sources with monochromators). However, beam time is usually valuable, and monochromatic sources are not always available; x-ray tubes and radioactive sources produce complex spectra. For calibration of ePix100A cameras, we used a Mo x-ray tube with Zr and Al filters (to optimize the Mo Ka line) and acquired limited statistics (50 to 250 photons), sampled from a complex spectrum (where accurate fitting of a peak with charge sharing would require 1000 photons per pixel). We developed a calibration method which relies on cross-correlating histograms of many pixel pairs and obtaining large sets of relative shifts. These were subsequently used to calculate absolute pixel shifts and corresponding pixel gains. We demonstrate that this method yields stable gain calibration maps with an order of magnitude less statistics than required by typical approaches. Finally, we demonstrate the accuracy of the method by comparing with gain maps obtained with good statistics and monochromatic radiation at a synchrotron beamline. The robust gain calibration method presented here can be used for any pixel detector with minimal effort and assumptions on calibration spectrum. It is particularly useful when the quantity and/or quality of calibration data is limited and repeated measurements could be difficult (e.g., previous experiments at synchrotron or free electron laser sources, FEL).

Keywords: Gain calibration, Pixel detectors, Limited statistics
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(face) ID: 342

Poster Number:

Sub-ns Response GaAs X-Ray Detectors for Pulsed Power Applications (#1802)

Q. Looker1, M. G. Wood1, D. K. Serkland1, J. K. Kim1, G. A. Keeler1

1 Sandia National Laboratories, Albuquerque, United States of America


For pulsed power applications, such as experiments at Sandia’s Z-machine, the National Ignition Facility, or the OMEGA facility at Rochester, detectors with fast (often sub-nanosecond) response are required to capture the rapidly changing signals of interest.  Historically, Si diodes or diamond photoconductors have been widely utilized for time-resolved x-ray detection in these applications, but the x-ray absorption efficiency of these detectors decreases rapidly for energies above 10 keV.  Furthermore, a tradeoff with detector size and speed places a limit on sub-ns detection efficiency with Si.  Given the strong dependence of x-ray absorption efficiency on atomic number, GaAs detectors provide a method of significantly increasing detector efficiency with the same geometry and similar response time.  We have fabricated GaAs detectors with a 20 μm absorber thickness and <1 mm cross-sectional area which are capable of sub-ns x-ray response and 13x stronger absorption at 15 keV than an equivalent Si detector.  As a comparison to available Si diodes, we present x-ray absorption data, pulsed x-ray data, and relevant material properties along with potential impacts on pulsed power experiments.

Keywords: Pulsed Power, GaAs Detectors, Nanosecond X-Ray Detectors, X-Ray Diodes
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(face) ID: 344

Poster Number:

A Compton Spectroscopy Array for Extreme Pileup Measurements (#2653)

A. S. Wilhelm1, I. Jovanovic1

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


We propose a method of gamma ray spectroscopy suitable for extreme pileup situations, wherein traditional pulse-height spectroscopy is not feasible. One example of such application is spectral characterization of intense laser-based radiation sources that employ laser wakefield acceleration, in which a large number of photons can be produced in a well-collimated beam on a sub-ps timescale. The method relies on the measurement of the angular distribution of Compton scattering in which an integrated energy measurement is sufficient. The probability that a photon will undergo Compton scattering into a given solid angle is a function of the photon's initial energy. By first Compton-scattering a beam of photons and then analyzing the total energy deposited in an array of detectors at various angles of scatter, it is possible to reconstruct incident beam energy characteristics without the need to resolve individual photon interactions. We demonstrate a successful simulation reconstruction for a monochromatic, dichromatic, and Gaussian beam. In each case, all parameters are fitted within uncertainty of the simulated values.  Additionally, we demonstrate the technique experimentally with a monochromatic beam of 662 keV gamma rays, which is resolved as 660 +/- 20 keV.

Keywords: Gamma-ray detection, Spectroscopy, Inverse Problems
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(face) ID: 346

Poster Number:

New developments for the EIGER single photon counting detector (#2965)

E. Fröjdh1, M. Andrä1, A. Bergamaschi1, M. Brückner1, R. Dinapoli1, T. Grüne1, D. Greiffenberg1, F. - K. Leonarski1, C. Lopez-Cuenca1, D. Mezza1, M. Ramilli1, A. Mozzanica1, S. Redford1, M. Ruat1, C. Ruder1, B. Schmitt1, X. Shi1, G. Tinti1, D. Tattil1, E. van Genderen1, S. Vetter1, M. Wang1, J. Zhang1

1 Paul Scherrer Institute, Villigen, Aargau, Switzerland


The EIGER is a single photon counting detector developed at the Paul Scherrer Institut in Switzerland. Designed in UMC 0.25 um it has one global threshold and a configurable counter depth of either 4, 8 or 12 bit. This can be extended to 32 bit in the readout system using the dead time free read out mode and summing of frames. Two main features of the EIGER detector is a parallel design, allowing for large area detectors, and a very high frame rate of 23kHz. Detectors ranging from 250k to 9M pixels have been produced and are in operation at beamlines at PSI and ESRF.  While EIGER is mainly developed for synchrotron applications it is also used for electron detection, in electron diffraction and PEEM. This paper focuses on the recent developments for EIGER in terms of electron detection, higher continuous frame rate due to data compression in the readout system, and looks at the data backend for the larger area detectors. Also important for photon counting detectors is the lost signal close to the pixel corners, for which we present detailed measurements using a pencil beam and a comparison to simulations using Geant4. We also show how this problem is mitigated using charge integrating detectors.

Keywords: photon counting, hybrid pixel detector, synchrotron
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(face) ID: 348

Poster Number:

New generation Electrically-Cooled HPGe Detector Array for X-ray Spectroscopy (#3583)

V. Marian1, M. Ginsz1, B. Pirard1, P. Quirin1, J. Flamanc1, M. - O. Lampert1

1 Mirion Technologies, Lingolsheim, France


This paper presents the performance of a new generation HPGe x-ray detector array, exhibiting greatly improved energy resolution and throughput characteristics. The detector consists of a multichannel HPGe sensor (monolithic or individual elements) cooled using a state-of-the-art electrical cryocooler with active vibration cancellation. The system is capable of resolving several million counts per second and per channel, with energy resolution similar or better that state of the art Silicon Drift Detectors (SDD), while covering a much wider energy range.

Keywords: HPGe, X-ray, XAFS, electrical cooler
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(face) ID: 350

Poster Number:

Calibration of the pixel response of a 64x64 pixel DSSC imager over a wide energy range by means of X-rays, IR laser and mono-energetic protons (#3854)

A. Castoldi1, C. Guazzoni1, S. Maffessanti1, M. Porro2, S. Schlee2, G. Weidenspointner2, J. Soldat3, L. Carraresi4

1 Politecnico di Milano and INFN, Milano, Italy
2 European X-Ray Free-Electron Laser Facility GmbH, Schenefeld, Germany
3 University of Heidelberg, Institute for Computer Engineering, Mannheim, Germany
4 Università degli Studi di Firenze and INFN, Sesto Fiorentino (FI), Italy


The DSSC (DEPFET Sensor with Signal Compression) is one of three ultra-fast, large area imaging detector systems presently being developed for the European XFEL. The demanding XFEL conditions of high dynamic range (up to 10,000 X-ray photons) and single photon resolution require the qualification of the full response matrix of each individual pixel, which makes calibration of large-format detectors a further challenge in itself due to the large number of parameters per channel involved.

The availability of sources able to accurately probe the X-ray imaging detectors in conditions close to the experiments foreseen at the European XFEL is therefore a key issue for a twofold reason: i) to guide optimization of the final architecture of sensor and readout electronics, ii) to implement appropriate strategies aiming at the calibration of each individual pixel channel with the required degree of accuracy.

Bunches of mono-energetic protons (1-6 MeV) can probe in a unique way the impact of the simultaneous high charge deposition expected in the “bright” pixels. We carried out a beam time at the DEFEL beam line (LaBEC, Sesto Fiorentino) where we used bunches of mono-energetic protons (n=1, 2, 3, …) as an absolute reference to validate the energy calibration of the DSSC pixel response over a wide energy range, normally achieved by means of electrical pulsing, x-ray reference lines and/or optical injection (705nm IR laser).

The experimental points corresponding to protons energies (778.9 keV and 843.9 keV) showed very good agreement with the pixel response (deviation of about 10 keV). Non linearity errors between the internal pixel injection circuit and the reference IR laser curve can be appreciated starting at energies >1MeV.

The results of these measurements will be critically summarized and calibration strategies will be discussed.

Keywords: XFEL, DSSC, calibration, proton bunches, X-ray imager
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(face) ID: 352

Poster Number:

Multi-Element Silicon Drift Detectors for UltraHigh Speed X-ray Spectroscopy (#4191)

Y. J. Wang1, S. Barkan1, V. Saveliev1, L. Feng1, M. Zhang1, E. Damron1

1 Hitachi High-Technologies Science America, Inc, Chatsworth, California, United States of America


Silicon drift detector (SDD) with improved high count rate performance is developed for advanced X-ray spectroscopy, such as x-ray fluorescence micro imaging, fluorescence computed microtomography (fCMT), XANES (x-ray absorption near-edge structure) and EXAFS (extended x-ray absorption fine structure). The key parameter for high count rate is the signal rise time. This study will discuss the  rise time of SDD spectrometers by comparing detectors with various thickness and active area. The SDDs are integrated with advanced front-end ASIC preamplifiers and feature superior energy resolution at very short shaping times. For each channel, output count rate is even higher than 3Mcps with the latest adaptive pulse processing electronics. The option of 1 mm thick SDDs provides significant increased quantum efficiency for high energy X-ray. The superior result has been achieved in multiple synchrotron light sources.

Keywords: SDD, silicon drift detector, spectroscopy