2019 IEEE Nuclear Science Symposium and Medical Imaging Conference
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NSS Poster Session II

Session chair: Bohm, Christian, (Stockholm, Physics, Stockholm, Sweden); Woody, Craig, (Brookhaven National Laboratorty, Physics Department, Upton, USA)
 
Shortcut: N-19
Date: Wednesday, 30 October, 2019, 10:20 AM
Room: Central 1
Session type: NSS Session

Contents

Click on an contribution to preview the abstract content.

Poster panel: 2

Poster Number:
N-19-002

Front-end-Electronics for the SiPM-readout gaseous TPC for neutrino-less double beta decay search (#1077)

K. Z. Nakamura1

1 Kyoto university, High Energy Physics Group, Department of Physics, Faculty of Science, Kyoto, Japan

On behalf of the AXEL-Collaboration

Content

We are developing a high pressure xenon gas TPC (time projection chamber), AXEL, for neutrino less double beta decay search. Ionization electrons are accelerated with high electric field at the readout plan to produce electroluminescence photons.
Those photons are detected by SiPM's. Currently, we are constructing a 180L-size prototype detector with 1,512 channels and have developed a dedicated front-end electronics board(FEB).
One board readouts 56 channels of SiPM's.  It provides bias voltage to each SiPM.  A special configuration is adopted to enable the adjustment of bias voltage for each channel while keeping the DC-coupling readout. The waveform of each channel is recorded with a 14-bit dynamic range and 5-Msps. Multiplexed readout at 40-Msps with higher gain is available to monitor the SiPM dark current.
In this talk, the performance of the FEB when used to readout the 180L detector will be presented.

Keywords: DAQ, front end electronics, SiPM, Double-beta decay, Time projection chamber
Poster panel: 4

Poster Number:
N-19-004

MERCURY: An ASIC for High-Rate High-Energy X-ray Spectroscopy  (#1279)

P. Seller1, S. J. - M. Bell1, T. C. Gardiner1, M. D. Hart1, L. L. Jones1, M. L. Prydderech1, M. C. Veale1, M. D. Wilson1

1 Rutherford Appleton Laboratory, Didcot, United Kingdom

Content

MERCURY is a new ASIC that can measure single X-rays up to 160keV on each pixel and operates at up to 1MHz frame rate with 1keV FWHM energy resolution and a count rate limit ~108 photons/s/cm2. MERCURY has 80x80 pixels of 250 µm x 250µm and is intended for the readout of electron signals from conversion materials such as CdTe, CZT, GaAs, Ge and p-type silicon. Recent results using these semiconductor pixel detectors have shown that larger conventional electron signals are often accompanied by smaller positive signals induced on the neighboring pixel caused by internal weighting potential effects. Improved spatial and spectroscopic resolution can be achieved by simultaneously detecting these positive events. The analogue pixel circuitry of MERCURY is designed to capture both the electron and positive signals and uses 12-bit time to digital converters shared between eight pixels to digitize the data. Every 1 µs the ASIC digitizes 6400 analogue signals and encodes the digital data into a 64b66b Aurora protocol which is output on 20 CML lanes each at 4.1Gbps. The ASIC architecture to measure the energy of each individual X-ray and export this extreme 82Gbps continuous data is explained and simulated performance is presented.

Keywords: Pixel detector, readout ASIC, X-ray detector
Poster panel: 6

Poster Number:
N-19-006

Validation and Characterization of the TRACE Silicon Detector Array Demonstrator (#1638)

S. Capra1, 2, A. Goasduff3, 4, G. Benzoni2, D. Mengoni3, 4, A. Pullia1, 2

1 University of Milan, Dpt. of Physics, Milan, Italy
2 INFN, Milan, Milan, Italy
3 University of Padua, Dpt. of Physics and Astronomy, Padua, Italy
4 INFN, Padua, Padua, Italy

Content

The preliminary results of the TRACE (TRacking Array for Charged Ejectiles) demonstrator are reported. TRACE is an array of Silicon PAD detectors for particle spectroscopy and discrimination to be employed in low-energy nuclear physics experiments with stable and radioactive beams at the Legnaro National Laboratories (LNL, Italy). The readout is perfomed with multi-channel, VLSI preamplifiers realized in AMS 350 nm technology, directly wire-bonded on the PCB. These preamplifiers have a resolution of 125 electrons rms and a risetime of 10 ns with a 4 pF capacitance referred to the input. The preamplifiers have a spectroscopic dynamic energy range of 40 MeV. This value is boosted by more than one order of magnitude by an innovative fast-reset device that allows for 40-700 MeV spectroscopy with a resolution of less than 0.3% FWHM. After preamplifier test-bench characterization, a full validation of a TRACE demonstrator including detector, front-end electronics, single-ended to differential converters and digitalization system has been performed. The resolution of the 60 active channels, evaluated at the 5486 MeV 241Am alpha peak, is 34 +/- 4.8 keV.

Keywords: Analog Electronics, Front-End Electronics, Low-Noise Preamplifier, Silicon Detector, Particle Spectroscopy
Poster panel: 8

Poster Number:
N-19-008

A CMOS Front-End for Timing and Charge Readout of Silicon Photomultipliers (#1841)

P. A. P. Calò1, S. Petrignani1, C. Marzocca1, B. Markovic2, A. Dragone2

1 Politecnico di Bari, Department of Electric and Informatic Engineering, Bari, Italy
2 SLAC National Accelerator Laboratory, SLAC TID-AIR research group, Menlo Park, California, United States of America

On behalf of SLAC-Collaboration

Content

The main purpose of this paper is to show, by means of reliable simulations, how the choice of a current mode approach can be the key for designing an effective CMOS front-end suitable for Silicon Photomultipliers (SiPM), where the goal is preserving the fast timing required at single photon level while accommodating the large dynamic range of the detector. In fact, commercial SiPMs provide excellent energy resolution in applications with intense photon blasts, but when it comes to time resolution, the performance of a SiPM-based detection system, already plagued by the large equivalent capacitance of the detector, strongly depends on the front-end electronics and can be further spoiled by process defects and interconnection parasitic effects. The results predicted by transistor level simulations reported in the present work can rely on an accurate electrical model of the whole detection chain including the SiPM and the front-end. The design of the front-end has been based on both the model of the detector MPPC S10931-050P by Hamamatsu and a realistic parasitic inductance of 10 nH whose adverse impact on the slope of the timing signal produced by the detector should never be overlooked at high frequencies. A differential structure has been chosen for the current mode preamplifier, since it can inherently guarantee a high degree of common mode noise immunity, thus improving the reliability of the results achieved in simulation, especially for ToF-PET applications; moreover, ad hoc design techniques have been used to enlarge the dynamic range of the circuit while preserving its timing performance. The SiPM analog channel can provide charge measurements up to 1280 pC of input charge and is equipped with a TDC to pick off the arrival time of a valid single photon with a simulated time jitter of 31 ps rms. The circuit, that is crafted in a standard 130-nm CMOS technology, has a power consumption of 10 mW with 1.2 V supply voltage and can sustain an event rate of 100 kHz.

Keywords: SiPM, front-end electronics, single photon time resolution, TDC
Poster panel: 10

Poster Number:
N-19-010

Very High‑Performance 24‑Channels Time‑to‑Digital Converter in Xilinx 20‑nm Kintex UltraScale FPGA (#2031)

N. Lusardi1, F. Garzetti1, N. Corna1, R. De Marco1, A. Geraci1

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

Content

In this contribution, we present the implementation of a resource-saving, 24-channels, high-performance, Tapped Delay-Line (TDL) based, Time-to-Digital Converter (TDC) implemented in a Xilinx 20-nm Kintex UltraScale (XCKU040-2FFVA1156E) Field Programmable Gate Array (FPGA) device hosted in a general purpose evaluation board (EVB) KCU105.
The term high-performance is not only referred to high-resolution, which is equal to 305 fs over full-scale range of 10.24 μs and single-shot precision below 8.5 ps r.m.s. with maximum operative rate up to 50 MHz per channel, but high-performance also means design flexibility, modularity and, last but not least, low time-to-market and implementation costs.
High-resolution over a so wide dynamic-range is provided by Nutt interpolation. In this way, each one of the 24-channels produces a 25-bit wide timestamp, with LSB of 305 fs, obtained merging a coarse and a fine measure. The coarse contribution is obtained by sampling a 12-bit counter clocked at 400 MHz, whereas the fine part of the measure is returned by the sub-interpolation of eight 512 taps long TDLs by means of a Super Wave Union (SuperWU) algorithm. This choice allows to achieve resolution, in average, sixteen times better than the propagation delay characteristic of the technology in use.
The TDLs are implemented with the carry-chains, i.e. the CARRY8 primitive, available into the fabric of the XCKU040 device. Moreover, each channel is equipped with a decoder and a “bin-by-bin” dynamic calibrator able to compensate at best the non-linearity due to the difference among propagation delays of the CARRY8 blocks and the relative temperature drifts.
Thanks to the configurability and the modularity provided by the FPGA structure, the presented architecture can be easily migrated on different families of Xilinx UltraScale and UltraScale+ FPGAs and System-on-Chips (SoCs).
The read-out is performed via USB 3.0.

Keywords: Time-to-Digital Converter, Tapped Delay-Line, Field Programmable Gate Array, Bubble Error, Calibration
Poster panel: 12

Poster Number:
N-19-012

Kerberos: a 48-Channel Analog Processing Platform for Scalable Readout of Large SDD Arrays (#2048)

P. King1, 2, G. Torrisi1, M. Gugiatti1, 2, M. Carminati1, 2, C. E. Fiorini1, 2

1 Politecnico di Milano, DEIB, Milan, Italy
2 INFN, Sezione di Milano, Milan, Italy

Content

The readout of large pixelated detectors with good spectroscopic quality represents a challenge for both front-end and back-end electronics. For instance, the TRISTAN project for the search of the Sterile neutrino in the keV-scale envisions the operation of 21 detection modules equipped with a monolithic array of 166 SDDs each, for β-decay spectroscopy in the KATRIN experiment. Since the trace of the sterile neutrino existence would manifest as kink of <1ppm in the continuous spectrum, high accuracy in the acquisition is required. Within this framework, we present the design of a multichannel scalable analog processing and DAQ system named Kerberos. It is based on three 16-channel integrated and programmable analog processors (SFERA ASICs), high linearity ADCs, and an FPGA. The platform is able to acquire data from up to 48 pixels in parallel, providing also different readout and multiplexing strategies. In addition, we present a preliminary MPSoC-based aggregator that will concentrate the data streams coming from up to four Kerberos, allowing the system to read up to 192 pixels. The use of an analog ASIC-based solution instead of a Digital Pulse Processor, represents a viable and scalable processing solution at the price of slightly limited versatility and count rate.

Keywords: analog digital processing, multichannel readout, beta spectroscopy, neutrino, sterile neutrino
Poster panel: 14

Poster Number:
N-19-014

Development of Multi-channel Programmable SiPM Driver Board (#2057)

S. Qian1, P. Chen1, 2, Z. Wang1

1 Chinese Academy of Sciences (CAS), The Institute of the High Energy Physics, Beijing, China
2 North China University of Technology, Beijing, China

Content

General commercial SiPM driver boards are only available for certain models of SiPM. And this kind of driver board is only suitable for single-channel testing in the laboratory. This obviously does not apply to batch testing in large scientific engineering. So, we developed a new type of SiPM drive board that can realized the multi-channel test of SiPM. After detailed test, our SiPM driver board has the same test performances with the commercial one in voltage output, power ripple and temperature compensation function. We also conducted a small batch of driver board testing and compared it to the single board test.

Keywords: MPPC,, driver boards
Poster panel: 16

Poster Number:
N-19-016

SENSROC13: A Mixed-Signal Binary-Output Front-End Readout ASIC with Automatic Feedback Reset for CZT/Si-PIN Detectors (#2066)

W. Gao1, Z. Li1, Y. Yao1, J. Zhou1, B. Wang1, P. Huang2, Y. Hu1

1 Northwestern Polytechnical University, Instite of Microelectronics, Xi'an, China
2 National Institute of Measurement and Testing Technology, Chengdu, China

Content

This paper presents a novel low-power low-noise mixed-signal front-end readout application-specified integrated circuit (ASIC) with the automatic feedback reset function for cadmium-zinc-telluride (CZT) and Silicon PIN detectors. The ASIC includes four-channel analog front-ends with a digital interface. Two dummy channels, bias circuits, and band-gap circuit are integrated as well.  Each readout chain consists of a charge sensitive amplifier, a CR-RC pulse shaper followed by a Sallen-Key low-pass filter, a discriminator, an automatic-feedback-reset circuit, and a digital-to-analog (DAC) converter. The digital part of this ASIC mainly includes I2C interface, data multiplexer and shift registers. Low-noise design under the conditions of ultra-low power dissipation and high-count rate is critical for the proposed ASIC. The proposed automatic-feedback-reset circuit maintains low noise performance while significantly increasing the counting rate. A prototype ASIC is implemented in TSMC 0.35 μm CMOS mixed-signal 3.3 V process. The die size is 2.4 mm × 2.4 mm. The preliminary tested results have been obtained. The input charge is 0.2 ~ 15 fC. The equivalent noise charge is 55 e- + 35 e- / pF. The power dissipation is about 1.2 mW/channel. And the maximum count rate is up to 1 Mcps. The proposed ASIC is a good solution of front-end electronics for personal dosimeters and photon-count X-ray imaging applications.

Keywords: ASIC, Front-End Readout, Automatic Feedback Reset, Si-PIN, CZT
Poster panel: 18

Poster Number:
N-19-018

High Resolution Electronics for a Position Sensitive MCP Delay-line Detector (#2099)

W. Dong1, C. Feng1, Y. Shi2, X. Song2, S. Liu1

1 University of Science and Technology of China, State Key Laboratory of Particle Detection and Electronics, Hefei, China
2 Shandong Institute of Space Electronic Technology, Yantai, China

Content

This paper presents a readout electronics getting high position resolution of the photon hit on the Micro-Channel Plate (MCP) Delay-line detector using FPGA-based Time to Digital Converters(TDC). The time measurement electronics obtain high performance of (RMS) resolution better than 40 ps. And it has ten channels divided to two modules which can deal with two detectors input signals at the same time. With large dynamic range of 1.32 second the readout system provides the hit time sequence – the arriving times of phonon. To reconstruct these multi-hit events –more than one hit signal transmitting on the delay line- the dead time of the TDCs is shorter than 20 ns. In view of the number of input channels and event rate, the tradeoff must be weighed between performance and cost. The TDC readout system is implemented in Xilinx low-end Artix-7 FPGA. We measure the signal arriving time using system clock and carry-chain in FPGA. The delay time of carry logic cell called CARRY4 in Artix-7 FPGA is less than 100ps, as a result we can get high resolution. The digitized time data of all TDCs and channel number are gathered and then transmitted by USB3.0 interface. The speed of the interface is up to 1.6Gb/s and it also transmit commands from master PC to the TDC module.

Keywords: Micro-Channel Plate detector, TDC, FPGA, Position Reconstruction
Poster panel: 20

Poster Number:
N-19-020

Development of Frontend Electronics for Hyper-Kamiokande Experiment (#2131)

Y. Kataoka1, Y. Hayato1, Y. Takemoto1, S. Izumiyama2

1 The Unifersity of Tokyo, Hida-city, Japan
2 Tokyo Institute of Technology, Beguro-ku, Japan

On behalf of Hyper-Kamiokande-proto collaboration

Content

The next generation of neutrino experiment Hyper-Kamiokande (HK) is based on the largest ever water Cherenkov detector with 70m height water tank. It requires various challenges on frontend electronics currently under development.
 High performance of signal digitizer is required to extract timing and charge information from photomultiplier tube (PMT). New signal digitizer consists of two components, Charge to Time converter (QTC) and TDC. TDC is newly developed and implemented on FPGA instead of predefined hardware. This approach brings us great advantages on flexibility, cost and time of the development. Various types of TDC are tried, and some techniques are introduced to overcome differential nonlinearity (DNL) which comes from propagation delay in FPGA. As a result, 100ps of time resolution is achieved without any calibration.
The most critical requirement in HK is not to lose supernova events, which could be tens of millions events per second in case of Vetelgyus. Therefore the post-processing after digitizer is carefully designed to have large buffer and high speed transmission.
The other aspect is synchronization. The system has 1000 frontend boards connected to 20000 PMTs. In order to take a clear picture of Chrenkov ring, these boards must be synchronized to the level of time resolution. Furthermore, the detector is a part of long baseline neutrino experiment and has to be synchronized with neutrino injector in JParc 300km far from Kamioka. Therefore, clock distribution system based on GPS is designed and prototype is evaluated.
 The other challenge is the frontend electronics under water to minimize length of analog cable to PMT. It brings various requirement such as water tight case/connector, precise control of heat exchange, and long durability of electronics. The prototypes are developed and evaluated.
These results are promising and combined into a system. Then the whole DAQ system will be established on top of that.

Keywords: Hyper-Kamiokande, Frontend Electronics, Digitizer, TDC, FPGA
Poster panel: 22

Poster Number:
N-19-022

SEL-oriented Rad-hard Strategy and Hardness Assurance Test Results of XCR4C ASIC for X-ray CCD Applications (#2294)

B. Lu1, 2, B. Li3, J. Huo1, Y. Chen1, W. Wei2, J. Gao3, C. Wang3, H. Liu3, Y. Zhou3, 4

1 Chinese Academy of Sicences (CAS), Institute of High Energy Physics, Beijing, China
2 State Key Laboratory of Particle Detection and Electronics, Beijing, China
3 Institute of Microelectronics, Beijing, China
4 University of Chinese Academy of Sciences, Beijing, China

Content

We report in this work the SEL hardness assurance test (HAT) for XCR4C ASIC, which is a fully customized four-channel rad-hard correlated double sampling (CDS) ASIC targeting the readout of X-ray CCDs for applications in the fields of X-ray spectroscopy, imaging and timing observations. The ASIC is implemented in a novel differential switched-capacitor architecture, which makes it high linear, low power, immune to commom-mode noise and interferences as well as easy configurable. Some SEL-oriented rad-hard by design techniques are used to combat the harsh low-earth-orbit (LEO) space environment, among which we describe in detail the double guard ring (DGR) layout technique and the process hardness. XCR4C ASIC was fabricated with AMS 0.35 μm 2P4M bulk CMOS with an epitaxial layer and occupies a chip area of 3.47 × 1.84 mm mm². The HAT was carried out at the Heavy Ion Research Facility in Lanzhou (HIRFL), where the ASIC was irradiated by 181Ta31+ ions with a linear energy transfer (LET) in silicon of 81.35 MeV-cm2/mg. The results showed that with a total fluence as high as 1.68 × 107 ions/cm2, not a single latchup was monitored, and the performance degradations after irradiation were negligible.

Keywords: X-ray CCD, CDS, ASIC, rad-hard, SEL
Poster panel: 24

Poster Number:
N-19-024

GAMMA: High Dynamic Range 16-Ch. ASIC for Large Scintillator Readout with SiPM Arrays (#2330)

L. Buonanno1, 2, G. L. Montagnani1, D. Di Vita1, 2, F. Castelli1, M. Carminati1, 2, C. E. Fiorini1, 2

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

Content

A 16-channel ASIC for SiPM-based gamma detection with automatic gain control (AGC) is presented. Its experimental characterization has shown compatibility with large input capacitances (above 50 nF thanks to a weakly-positive feedback input stage), low-noise performance (0.5 photoelectron noise rms thanks to low-noise design and gated-integrator configuration), good linearity and high dynamic range (85 dB, thanks to AGC). The circuit provides also a timing operating mode for the discrimination of neutron and gamma photons when using CLYC scintillators.

Keywords: SiPM, ASIC, CLYC, LaBr
Poster panel: 26

Poster Number:
N-19-026

Multi-channel front end readout electronics based on linear discharge method for PET application (#2438)

K. Hu1, X. Cheng1, D. Yang1, Y. Wang2, Y. Shao1

1 UT Southwestern, Department of radiation oncology, Dallas, Texas, United States of America
2 USTC, Department of Modern Physics, Hefei, China

Content

The objective of this study is to develop and evaluate a compact, scalable, cost-effective and practical front-end readout electronics for a Silicon Photomultiplier (SiPM) based PET detector system. The circuit design applies FPGA-controlled charge integration and fast linear discharge method to convert input charge signals into digital signals (QDC), and a simple yet effective approach to extend the input signal polarity from negative only to both positive and negative polarities without changing the circuit configuration or inverting signals.  We have developed and evaluated initial prototype front-end readout electronics that includes a 96-ch analog board and a digital FPGA board. The gain non-uniformities of all the positive and negative channels are 0.1 % and 0.15 % respectively; Single-channel RMS noise is <1.0 mv; the intrinsic timing resolution of the circuit with leading edge discrimination for timing pickoff is ~75 ps. The readout electronics has also been evaluated with an advanced PET detector panel with total 64 channel signal outputs. The detector consists of a 30×30 array of 1×1×20 mm3 LYSO scintillators optically coupled to four 8×8 arrays of 2×2 mm2 SiPMs one each end of the crystal array. Excellent crystal identification was achieved. The single crystal energy resolution (FWHM) measured from the detector was around 18% - 28%. Overall, the prototype electronics system demonstrated its good performance for PET detector applications, and will be applied for the PET system construction and imaging studies.

Keywords: PET, SiPM, FPGA, Front End Electronics
Poster panel: 28

Poster Number:
N-19-028

Measurement results for AARDVARC: Waveform Sampling System On Chip with Picosecond Timing Resolution (#2532)

L. Macchiarulo1, B. Rotter1, G. Varner2, I. Mostafanezhad1, D. Uehara1, C. Chock1

1 Nalu Scientific, LLC, Honolulu, Hawaii, United States of America
2 University of Hawaii at Manoa, Physics and Astronomy, Honolulu, Hawaii, United States of America

Content

In this article we describe the measurement results on an “AARDVARC” prototype in 130 nm. AARDVARC is a multi-channel waveform digitizing and processing Application Specific Integrated Circuit (ASIC) front-end. We report on various performance metrics: fast sampling (10-14 Gsa/s), deep storage (32K samples), timing resolution (better than 5ps), low power consumption (<100mW/channel).

Keywords: System-on-chip, Data acquisition, front-end electronics, waveform digitization, picosecond timing
Poster panel: 30

Poster Number:
N-19-030

A low-jitter low-power front-end for 4D vertex detectors in 28-nm CMOS technology (#2658)

L. Piccolo1

1 Politeecnico di Torino, DET, Turin, Italy

Timespot

Content

This work describes the design of a low-power low- jitter, analog front-end for timing-pixel radiations sensors. The circuit will provide the input stage for the front-end ASIC proposed for the TimeSpOT project that will be manufactured in a commercial 28 nm CMOS process. This front-end is designed to be part of 4D tracking detectors for future high data rate high energy physics experiments. This research aims to realize a 55 μm × 55 μm pixels with sub 100 ps resolution within less then 10 μW power consumption. The whole system needs to sustain an average signal rate of 75 kHz per channel. Analog solutions has been adopted to both compensate sensor leakage current and minimize the effect of channel mismatch and process variation on the timing measure with minimal external control. A first prototype of this circuit has been manufactured and will be tested in order to the measure its performance a verify the feasibility of the proposed compensation technique.

Keywords: CMOS, ASIC, Front-End, Pixel Sensor, Timing
Poster panel: 32

Poster Number:
N-19-032

A Pixel Read-Out Front-End in 28 nm CMOS with Time and Space Resolution (#2685)

M. Barbaro1, 2, S. Cadeddu2, L. Casu2, L. Frontini3, A. Lai2, V. Liberali4, 3, C. Napoli1, 2, L. Piccolo5, 6, A. Rivetti6, J. Shojaii7, S. Sonedda1, 2, A. Stabile4, 3

1 Università degli Studi di Cagliari, Cagliari, Italy
2 INFN Cagliari, Cagliari, Italy
3 INFN Milano, Milano, Italy
4 Università degli Studi di Milano, Milano, Italy
5 Politecnico di Torino, Torino, Italy
6 INFN Torino, Torino, Italy
7 University of Melbourne, Melbourne, Australia

Content

Future High Luminosity colliders will require front-end electronics with unprecedented performance, both in space and time resolution (tens of micrometers and tens of picoseconds) and in radiation hardness (tens of megagray). Moreover, the high number of events will generate an enormous quantity of data (some terabits per second), and the limited bandwidth requires to perform data selection as close as possible to the front-end stage, to reduce the amount of data transmitted and stored for off-line analysis.
The TIMESPOT (TIME and SPace real-time Operating Tracker) project, financed by INFN, is developing a complete demonstrator of a tracking device including all the features needed for future high luminosity experiments.
In this presentation, we describe the first prototype of the read-out electronics in 28 nm CMOS technology. The modules of the front-end circuitry have been designed and integrated in a test chip, which will allow us to characterize each block separately, and to connect them in a processing chain to evaluate the overall performance.

Keywords: Pixel detector, tracking, time resolution
Poster panel: 34

Poster Number:
N-19-034

Evaluation of waveform digitizing ASICs for Silicon Photomultiplier-based photon-counting cameras (#2697)

C. Duffy1, J. S. Lapington1, S. A. Leach1

1 University of Leicester, Space Research Centre, Department of Physics and Astronomy, Leicester, United Kingdom

Content

Detectors for applications in particle physics, astroparticle physics and medical imaging often require a combination of high time resolution with waveform capture, to allow pulse shape analysis. One way to achieve this is using multi-channel waveform capture ASICs, several of which have become available over recent years. These devices commonly utilise an analogue ring buffer to capture the waveform within a fixed number of samples at very high sample rate following an event trigger. The captured waveform samples are then digitised at lower rate with a high-resolution analogue to digital converter. These devices are ideally suited to applications requiring simultaneous event capture across multiple channels at relatively low rates. We describe the application of the waveform capture technique to the Cherenkov High Energy Camera (CHEC) developed for imaging air Cherenkov telescopes (IACTs). and characterize and compare the performance and practicality of the currently utilised TARGET chipset with alternatives, such as the SAMPIC and DRS4 ASICs. We present performance comparisons in terms of time resolution, linearity, and rate handling capability and discuss the practical considerations such as power dissipation, accommodation and cost.

Keywords: waveform digitizer, photon-counting, ASIC, detector, multi-channel
Poster panel: 36

Poster Number:
N-19-036

Development of a Low Background Front End ASIC for HPGe Detectors (#2757)

P. J. Barton1, D. Gnani1, A. Drobizhev1

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

Content

Very low radioactive backgrounds are required by the next generation of neutrinoless double beta decay experiments.  Following the successful low-background results from the Ge-based GERDA and Majorana Demonstrator experiments, a new collaboration LEGEND has been formed to demonstrate even lower backgrounds in a ton-scale Ge experiment.  The close proximity of the existing front end electronics to each detector poses a unique challenge for the radiopurity of the electronics. A low mass front end (LMFE) was successfully employed in Majorana. The next step in scaling up the experimental detector mass is to develop a dedicated application specific integrated circuit (ASIC) preamplifier.  Features include a high dynamic range (9 MeV) with low enough noise to provide a suitably low triggering threshold (<1 keV). A single power supply alleviates the need for additional background-containing cables. A differential output maintains signal integrity on the 10 m span to the data acquisition electronics. Dedicated on-chip regulators obviate the need for radioactive external bypass capacitors.  Results will be presented from the first fabrication run of this low noise low background preamplifier ASIC.

Keywords: HPGe, PPC, Front End, ASIC, Preamplifier
Poster panel: 38

Poster Number:
N-19-038

A high Speed Programmable Analog-to-Digital Conversion System Based on System in Package (#1196)

R. Jin1, J. Hu1, X. Jiang1

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

Content

The nEXO project is designed to continue the search for the 0vββ process of 136Xe, and it requires high reliability and small volume in the readout electronic system. The purpose of this research is to improve the integration and the reliability of the circuit design based on SIP technology. The core chip of the system is a highly integrated programmable chip based on System in Package which include two high-speed Analog-to-Digital Converter (ADC) dies and a Field Programmable Gate Array (FPGA) die. With this chip as a core, a complete front-end data sampling system can be constructed by adding the Front-End amplifier Chip (FEC), the back-end serial communication network port and the corresponding power supply module. The system has the functions of dual-channel high-speed data sampling, data assembly, serial communication, on-line control and real time data processing. Two channels can simultaneously sample two analog signals at a very high sampling rate, complete data assembly, process the data and communicate with back-end equipment. From this research, first we provide a new design way of the readout system for nEXO, and second we can get a highly integrated high speed programmable ADC chip which can be used in any other situations.

Keywords: System in Package(SIP), High speed ADC, FPGA, Readout electronic system
Poster panel: 40

Poster Number:
N-19-040

Development of Front-end and Back-end FPGA DAQ Systems Using Comparator-less Gated QTC and Gigabit Transceiver for the MR-Compatible Long Axial FOV Brain PET Inserts (#1361)

J. Y. Won1, H. Park1, J. - W. Son2, J. S. Lee1, 2

1 Seoul National University, Department of Biomedical Sciences, Seoul, Republic of Korea
2 Brightonix Imaging Inc., Seoul, Republic of Korea

Content

We have developed the front-end and back-end FPGA DAQ systems for long axial field-of-view (FOV) brain PET inserts for 7T MRI scanners. The developed front-end FPGA DAQ system was MR-compatible and had a compact dimension of 20×6 cm2. It consisted of a low-power FPGA (Artix-7, Xilinx) and 64 comparator-less gated charge-to-time converters (QTCs). 16 time-to-digital converters (TDCs) and gigabit transceivers (GTs) were implemented in the FPGA. A new time-based energy measurement method of comparator-less gated QTC was developed to digitize the energy signals of the block detector with light sharing and charge division circuit. Gated QTC provided the dual-slope pulse of which pulse width was proportional to the gated input charge. The FPGA-only digitizer using the single-ended memory interface (SeMI) input receiver directly digitized the dual-slope pulse and measured the pulse width.
18 front-end FPGA DAQ systems were located inside the MRI bore and digitized all detector signals in the early stages. In addition, the digitized signal was transmitted to the back-end FPGA DAQ system using the GT with a line rate of 3.2 Gbps through an HDMI cable. The back-end FPGA DAQ system located in the MRI control room 20 meters apart from the scanner received data and synchronized all front-end FPGA DAQ systems via 20 m HDMI cables.
The pulse width measured using the comparator-less gated QTC changed linearly with respect to the input charge. The FWHM value of the pulse width was less than 2%. All high-resolution crystals of the block detector with a crystal pitch of 2.17 mm were clearly distinguished in the flood map obtained using four comparator-less QTCs. The energy resolution values for the upper and lower layers were 9.2±0.7% and 10.2±1.5%, respectively. The system-level timing uncertainty of TDC was 17.0 ps, including the TDC timing uncertainty of the front-end FPGA DAQ systems and the clock jitter from the back-end FPGA DAQ system via 20 m HDMI cables.

Keywords: DAQ, FPGA digitizer, TDC, Clock distribution, Brain PET
Poster panel: 42

Poster Number:
N-19-042

A high-resolution Vernier delay generator using delay-adjustable carry chains on FPGAs (#1385)

K. Cui1, X. Li2, Z. Ren1, R. Zhu1

1 Nanjing University of Science and Technology, the MIIT Key Laboratory of Advanced Solid Laser, Nanjing, China
2 Nanjing University of Science and Technology, the School of Computer Science and Engineering, Nanjing, China

Content

Delay generator (DG) generating a digitally programmed time interval acts as the core component in various modern nuclear or physical experiments. Most traditional designs are based on application specific integrated circuit (ASIC) platform causing long development period and high cost. This work presents a high-resolution Vernier DG architecture based on field programmable gate array (FPGA) platform, which utilizes a novel delay line structure built on multiplexed carry chain. The carry chain structure guarantees the resolution rather small. The multiplexer laid next to the carry chain makes the actual delay of the delay line dynamically adjustable. This structure can be automatically compiled by PC without manual intervene while maintaining very high resolution. A DG prototype circuit was implemented on a Stratix III FPGA and experimental tests were conducted to evaluate the performance. The obtained resolution is 23.9 ps, the differential nonlinearity (DNL) lies in the range of -0.62 least significant bit (LSB) ~ 0.59 LSB and the integral nonlinearity (INL) lies in the range of -0.14 LSB ~ 0.01 LSB. All the performances show state-of-the-art quality. This work can help to expand FPGA applications further into the analog field, and can play an important role in any nuclear instruments that require high-precise synchronization or trigger. 

Keywords: delay generator, FPGA, Vernier delay line, carry chain
Poster panel: 44

Poster Number:
N-19-044

Poster panel: 46

Poster Number:
N-19-046

Real-time data display and storage device for pulsed neutron scattering experiment (#1604)

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

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

Content

A real-time data display and storage device was developed for pulsed neutron scattering experiments using the time-of-flight method. The device contains two sets of field programmable gate arrays and on-board microcomputers for data display and storage. The experimental data are displayed on a commercially available monitor through the HDMI connector and saved in the storage device that has a USB connector. The device has a 68-pin connector and ERA00-type connector for receiving the position data from the two-dimensional neutron detector and the T0 signal that indicate the time when the pulsed neutron is generated in the experimental facility, respectively. The developed device can determine the time-of-flight and time-resolved neutron position data with a time range from 0 to 40 ms using a beam of pulsed neutrons at 25 Hz from an experimental facility. Operation tests were performed using test signals that simulate the neutron detector output signals. It was found that the device could separate signal pulses with a time interval of 1 μs by the evaluation of the time response using double pulses with various time intervals; furthermore, it could measure the continuous pulses with a frequency of 1 MHz by the evaluation of a counting rate using continuous pulses with various frequencies. Consequently, it was confirmed that the developed device demonstrated a counting rate capability of beyond 1 Mcps.

Keywords: Neutron detectors, data acquisition, pulsed neutron, time of flight
Poster panel: 48

Poster Number:
N-19-048

Streaming Readout of the sPHENIX Tracking System (#1741)

M. L. Purschke1

1 Brookhaven National Laboratory, Physics Dept., Upton, New York, United States of America

Content

The sPHENIX apparatus is a significant upgrade of the PHENIX detector at the Relativistic Heavy Ion Collider at the Brookhaven National Laboratory. It will enable a comprehensive measurement of jets and upsilons in relativistic heavy ion collisions. Different from the previous PHENIX detector, the upgrade will give the experiment full azimuthal coverage within a pseudorapidity range of -1.1 < η < 1.1.
The Data Acquisition System of sPHENIX is designed for event rates of 15 KHz. The largest data volume is produced by the TPC. In order to achieve the design event rate, the tracking system will be read out in continuous, or streaming, mode. The resulting continuously sampled signals from the tracking system must then be processed and correlated with the actually triggered data from the calorimeter system. Due to budget constraints, it is not possible to update the entire readout, including the calorimeter systems, to a streaming-based one.
The chosen technology for the streaming readout systems is a FPGA card designed for the ATLAS experiment, called "FELIX". The card is PCIe-based and has a large number (up to 48 pairs) of fiber inputs to connect to the front-end cards. The board has a powerful FPGA for data processing, zero-suppression, and data compression.
We currently use close-to-final prototypes of the TPC front-end cards with 8 SAMPA ASICs and 256 readout channels that we use for our firmware development and tests. Our MAPS-based vertex detector (MVTX) is using near-final hardware as well.
Focusing on the tracking system, we will describe the goals and design of the sPHENIX experiment. We will present the envisioned design of the streaming readout, and explain the challenges with the high data rates generated by this readout method, which could reach as much as 135 GBit/s. We will show the design of our data acquisition and timing system to cope with those data rates, and present the status of the ongoing R&D with our prototype setups.

Keywords: DAQ, Streaming Readout
Poster panel: 50

Poster Number:
N-19-050

Controlled linear discharge of photodetector signal integration for charge measurement in (S)PE(C)T (#1785)

N. Chevillon1, 2, F. Boisson1, 2, C. Fuchs1, 2, V. Bekaert1, 2, D. Brasse1, 2

1 Université de Strasbourg, Institut Pluridisciplinaire Hubert Curien (IPHC), Strasbourg, France
2 IPHC - CNRS/IN2P3, Strasbourg, France

Content

In the context of preclinical (S)PE(C)T developments, we propose a FPGA-based charge and time measurement system to readout photo-detector signals. The integration of charges from crystal scintillation on a capacitor offers the most accurate way to perform the charge measurement. To obtain the totale charge, we apply a controlled discharge current on the capacitor and we measure the time of complete discharge. This method allows a measure on the fly with the superposition of the charge and discharge times and a minimization of the dead time. Indeed, according to the exponential decay of the charge production by the photo-detector coupled to a scintillation crystal, the charge rate of the capacitor is maximum at the beginning, and decreases exponentially. Applying a constant moderate discharge rate as soon as the capacitor voltage exceeds a threshold set low, the discharge can start almost from the beginning of the scintillation. One threshold compares the charge integral through the capacitor voltage. A FPGA performs a time over threshold allowing totale charge calculation and time tagging at the same time. We implemented an integration circuit with a discret operational amplifier, a capacitor and two resistors. A Zynq-7020 Xilinx System-on-Chip on a ZedBoard (Avnet) realizes the comparator and time measurement functions with the use respectively of a LVDS buffer and two ISERDES resources in oversampling mode. So we propose a charge and time measurement system with standard components only. We use a home-made standard gigabit data transmission to send the measures to an acquisition computer.

Keywords: FPGA, DAQ, charge measurement, PET, SPECT
Poster panel: 52

Poster Number:
N-19-052

First performance evaluation of MexSiC - a readout ASIC for analog SiPM based Cherenkov detectors (#1885)

A. I. Bautista-Castillo1, 2, S. Rosales-Nuñez2, D. Durini2, V. R. Gonzalez-Diaz3, A. Díaz-Sánchez2, J. M. Rocha-Pérez2, 3, J. Rangel-Magdaleno2, J. R. Alfaro Molina1, A. Iriarte-Valverde4

1 Universidad Nacional Autónoma de México, Physics, CDMX, Mexico
2 Instituto Nacional de Astrofísica, Óptica y Electrónica, Electronics, Puebla, Mexico
3 Benemérita Universidad Autónoma de Puebla, Electronics, Puebla, Mexico
4 Universidad Nacional Autónoma de México, Astrophysics, CDMX, Mexico

Content

Silicon Photomultipliers (SiPMs) are currently an excellent option to replace the traditional photomultiplier tubes (PMTs) in several fields ranging from astrophysics to medical applications. SiPMs are reliable photodetectors enabling near single-photon counting capability alongside nanosecond time resolutions. The latter opens the possibility of using this technology for detecting Cherenkov light bursts of visible (blue) light. This paper describes a data acquisition (DAQ) system that is currently being developed for a series of nine SiPMs of ON-Semiconductor. The system detects Cherenkov light using an application specific integrated circuit (ASIC) fabricated in a 180 nm standard CMOS technology. The ASIC has the trans-impedance amplifier (TIA) as its input stage used to amplify and convert the SiPM output current pulses into voltage signals. We implement an event-driven Triggering Logic Unit (TLU) to discriminate between detected events based on fully programmable individual threshold reference voltages for each SiPM input signal. The TLU defines if one SiPM input signal is valid and compares this decision with the other eight neighboring SiPM signals to take the final decision. The time resolution is defined by the implemented phase-locked loop (PLL) stage. The time spent by the input signals above the defined threshold voltage, using the Time-over-Threshold (ToT) principle, will be defined based on the amount of PLL frequency defined time intervals counted by a 10-bit digital counter, forming the so-called time-to-digital converter (TDC) stage. Additionally, the system will send the information concerning the start time of the first, and each consecutive SiPM activated. Finally, in order to determine the amount of charge generated during the event of interest, a charge-to-digital converter (QDC) is implemented using at its core a sigma-delta (Σ − Λ) modulator generating a single output time-modulated pulse to be digitized by an accompanying FPGA module.

Keywords: Silicon Photomultipliers, detects Cherenkov light, Triggering Logic Unit, time-to-digital converter, charge-to-digital converter
Poster panel: 54

Poster Number:
N-19-054

Readout board validation setup for the ALICE Time Of Flight detector upgrade (#1985)

D. Falchieri1, P. Antonioli1, C. Baldanza1, M. Giacalone1, A. Mati2

1 INFN, Section of Bologna, BOLOGNA, Italy
2 CAEN, Viareggio, Italy

Content

The new Digital Readout Module, named DRM2, for the readout of the ALICE TOF detector at CERN, has been produced and is ready to face the commissioning stage. It is a narrow 9U VME card (16 cm x 33 cm) with the goal to read out the TDC (Time to Digital Converter) chips on 9 or 10 VME boards, named TRMs (TDC Readout Module). A test setup for the DRM2 production cards validation has been designed and built, to check and validate the correct behavior of the produced boards. The test setup and related performances will be described in detail in this paper.

Keywords: High energy physics, printed circuits, data acquisition.
Poster panel: 56

Poster Number:
N-19-056

Synchronization in Networks of Time‑to‑Digital Converters based on Field Programmable Gate Arrays (#2040)

F. Garzetti1, N. Lusardi1, N. Corna1, A. Geraci1

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

Content

Nowadays, in many high technological fields of research the classical Time-to-Digital-Converter (TDC) structure is no more satisfactory, since the architecture of one measuring unit connected to many sensors is no more feasible because the not sufficient number of channels, the lack of flexibility or both. This is the case, for instance, of Positron Emission Tomography (PET) facilities of last generation.
In the Nuclear Science Symposium 2018 we presented a “All-Digital Fully-Configurable Instrument for Multi-Channel Time Measurements at High Performance”. The present contribution deals with the implementation of a distributed architecture of TDCs, i.e. an instrument that allows measuring timestamps on different devices but with the same relative time reference. This allows managing measures performed by different TDCs like if they were collected by a unique device, so providing a huge flexibility that opens the way for new advanced applications like PET network detectors.
The realization of a network for TDCs poses two main issues: a high-performance data transfer mechanism in addition to a precise and reliable synchronization methodology. This contribution focuses on the latter issue that is the most critical and complex to address.
The analysis is carried out both from theoretical and implementation point of view.

Keywords: Time-to-Digital Converter, Field Programmable Gate Array, System-on-Chip, Network, Delay-Line
Poster panel: 58

Poster Number:
N-19-058

Position Encoding Readout Electronics of Large Area Micromegas Detectors aiming for Cosmic Ray Muon Imaging (#2109)

J. Pan1, C. Feng1, Z. Zhang1, J. Wang1, D. Zhu1, J. Wang1, J. Feng1, S. Liu1

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

Content

A large area Micromegas telescope system consisting of several 40x40cm2 4-layers detector modules is designed to achieve muon imaging. Due to the high spatial resolution, low cost and the convenience of large area imaging, Micromegas detectors have good application prospects in muon imaging. In order to achieve position resolution on the order of 100 micrometers, the spacing between the anode strips is 0.4 mm. A single detector has 2000 strips in two dimensions. For the large number of readout requirements, position encoding readout is adopted to reduce the number of readout channels, which is demonstrated by the Eulerian path of graph theory. For the 40x40cm2 Micromegas detector used in this paper, every 250 strips as a group, eventually encoded into 32 channels. By using this encoding method, only 256 channels of electronic channels are required for a Micromegas detector. Compared with the 2000 strips, the number of electronic channels is greatly reduced. In addition, an optical fiber-based readout system composed of several front-end cards (FECs) and a data acquisition card (DAQ) is adopted. The FEC exploits the capability of an existing 64-channel generic TPC readout ASIC chip, named AGET, to implement 256 channels readout. Each Micromegas detector requires one FEC. The electronics system have been jointly tested with a 15x15cm2 Micromegas detector.

Keywords: Muon imaging, Large area Micromegas detector, Position encoding
Poster panel: 60

Poster Number:
N-19-060

PGP3: A Pretty Good Protocol for 10+ Gbit FPGA to FPGA Communication (#2285)

B. Reese1, R. T. Herbst1, L. Ruckman1

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

Content

PGP3 is a 64b/66b encoded high-speed serial protocol intended for 10+ Gigabit point-to-point communication between FPGAs. The protocol provides a simple flow model and up to 16 independent Virtual Channels. Access to each Virtual Channel is provided by individual AXI-Stream interfaces. Internally, the protocol multiplexes the channels together and breaks long frames into Cells of up to 128 64-bit words each. Each transmitted cell indicates the receive buffers state for each of the Virtual Channels in the Cell header, thus providing flow control. If no cells are available to transmit, and IDLE word is sent that contains the same flow control information. A running CRC is included in the tail of each cell, to verify the integrity of the Cell and its overall frame. A single clock-compensation word is sent every 5000 words to mitigate the effect of drift between oscillators on either side of the connection. An additional sideband interface allows 48-bit opcodes to be sent over 8 opcode channels. The protocol word efficiency is 98.4%, with 64b/66b encoding bringing the overall efficiency to 95.4%. The VHDL code is open source, and reference implementation code is provided for several different FPGAs, including Xilinx Artix7, Kintex7, and Kintex UltraScale, each at several different data rates, from 3.125 Gbps to 10 Gbps. It has been successfully deployed in hardware for all of these examples. The protocol is intended as a free, open-source, cross-platform alternative to the Aurora 64b/66b protocol owned by Xilinx.

Keywords: Data Acquisition, Field Programmable Gate Array, VHDL
Poster panel: 62

Poster Number:
N-19-062

SURF: A Full Featured VHDL Component Library for Accelerating FPGA Firmware Development (#2473)

B. Reese1, R. T. Herbst1, L. Ruckman1

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

Content

We present the SLAC Unified RTL Firmware (SURF) library. SURF is a full-featured development library written in VHDL, with synthesizable components that perform a wide range of common firmware functions, from low level functions like clock synchronization to high level bus protocols like AXI. SURF contains a full Ethernet stack with support for IPv4, DHCP, UDP and several PHYs, for 1 Gigabit and 10 Gigabit Ethernet communication. It also has modules for many common peripheral protocols including SPI, I2C, JESD204b and JTAG. The AXI protocol modules are particularly useful for constructing firmware designs with common busses for register access and streaming data. All totaled, the library contains over 700 VHDL modules, all of which are well tested and have been used by SLAC on FPGA-based Data Acquisition systems on projects such as LCLS, ATLAS, protoDUNE, Belle2, LSST, Heavy Photon Search and others. It is also cross-platform, with modules that will synthesize for Xilinx, Altera, and other FPGA device families. Some vendor-specific components are also in the library to aid in the setup of complex device features such as high-speed transceivers. All modules in the library adhere to a novel coding style that enhances maintainability and readability. The SURF library is free and open source, available under a permissive BSD style license.

Keywords: Data Acquisition, Field Programmable Gate Array
Poster panel: 66

Poster Number:
N-19-066

Pushing dark matter axion detectors to higher frequencies with quantum sensors and microwave cavity networks (#1293)

C. R. Boutan1

1 Pacific Northwest National Laboratory, Radiation Detection & Nuclear Sciences, Richland, Washington, United States of America

Content

The discovery of a hypothetical elementary particle called the axion could simultaneously solve deep mysteries in quantum chromodynamics and cosmology. As direct-detection microwave cavity searches like the Axion Dark Matter eXperiment (ADMX) continue to look for yocto-watt power excess from axion-to-photon conversion at exceedingly higher axion masses, two losses in signal-to-noise need to be combatted: 1) the loss in signal power from decreasing detector volumes and 2) the increase in the quantum noise limit imposed by the uncertainty principal. I will motivate the axion as an excellent dark matter candidate, present an overview of ADMX, outline the challenges ahead and discuss the need for quantum information science solutions.

Keywords: axions, dark matter, quantum information science, quantum sensing, axion dark matter experiment (ADMX)
Poster panel: 68

Poster Number:
N-19-068

An analytical method for optimizing charge transfer inefficiency in CCDs for the SMILE mission. (#1536)

T. W. Buggey1, M. R. Soman1, N. Bush1, D. J. Hall1, A. D. Holland1

1 The Open University, STEM, Milton Keynes, United Kingdom

Content

SMILE is an S-class ESA mission that will observe the dynamic relationship between the solar wind and the Earth’s Magnetosphere in a highly elliptical orbit over a period of 3 years. Over time, the CCDs on the Soft X-ray Imager (SXI) will be bombarded by highly energetic protons, causing performance degradation and increasing Charge Transfer Inefficiency. Previous space missions have suffered from this damage, attempting to optimize performance by altering operating conditions, such as the speed of the charge transfer process or operating temperature. To optimize this charge transfer process for SMILE SXI, a new analytical approach is utilized which adopts the latest measurements of the defect landscape in CCDs exposed to proton environments to predict the magnitudes of improvements following changes in each aspect of the frame transfer and image readout timing. The analytical model is presented and nominal timings of the SMILE SXI CCD370 described. The effects of varying the operational timings, a non-zero background signal and charge injection rows are explored. In the summary, the plans for validating the model in future CCD370 testing, and the power of this analytical method for predicting the performance of future CCD-based instruments is presented.

Keywords: CCD, CTE, CTI, SMILE, SXI
Poster panel: 70

Poster Number:
N-19-070

The High Energy Particle Detector for the 2nd Chinese Seismo Electromagnetic Satellite (#1980)

G. Masciantonio1

1 INFN, sezione Roma Tor Vergata, ROMA, Italy

On behalf CSES-Limadou Collaboration

Content

In this paper, we describe the new architecture and main characteristics of the High Energy Particle Detector (HEPD) for the second Chinese Seismo Electromagnetic Satellite (CSES). We present the characteristics of the detector and electronics, highlighting the improvements with respect to HEPD-01, the first instrument currently flying on board CSES-01 launched on February 2, 2018. The two CSES satellites will form the basis for the construction of the satellite constellation planned for the future. The HEPD-02 instrument, developed by the Italian "Limadou" collaboration, consists of the following subsystems: detector, electronics, power supplies and mechanics. The detector comprises the following subsystems: a Tracker, a Trigger, an Energy and Veto detector; the electronic subsystem consists of the following boards: Trigger, the Tracker Data Acquisition (T-DAQ) and the Data Processing and Control Unit (DPCU). HEPD-02 will be able to work in different configurations depending on the orbital position, in order to manage the different particle fluxes encountered in space.

Keywords: Astrophysics, Low earth orbit satellites, Space technology, Earth Observing System
Poster panel: 72

Poster Number:
N-19-072

Poster panel: 74

Poster Number:
N-19-074

The design and development of prototype cold-atom gravimeter electronics for space (#2091)

T. Valenzuela1, M. Clapp1, M. Salter1, N. Waltham1, E. - M. Butroid1, A. Giatzoglou1, J. King1, W. Li1, A. Marshall1, L. McCaul1, C. Parmenter1, G. Patel1, B. Pierobon1, K. Stick1, S. Woodward1

1 UKRI - STFC, RAL Space, Didcot, United Kingdom

Content

Space-based high precision gravimetry as offered by cold atom approaches is an emerging key-enabling technology for a range of markets dependent on Earth Observation. Furthermore, gravimetry has a broad range of terrestrial applications from underground surveying to locating oil and mineral deposits. Although the levels of precision of cold atom gravimetry have been demonstrated, in comparison to current gravimeters, the most prominent drawback is the systems size weight and power (SWaP) characteristics. SWaP requirements are seen as the key roadblock in the wider adoption of cold atom gravimeters, despite having a multitude of advantages over existing solutions. In this paper, we describe the modular PXI-based prototype electronics that RAL Space have developed, we present the initial results and describe the next steps for future work. We also provide an overview of an application specific integrated circuit (ASIC) that we have developed to help minimise the SWaP characteristics of a high-performance direct digital synthesis (DDS) system for future space-based gravimeters. This work identifies the key challenges for each of the modules developed by comparing the results achieved with the target specifications. The modules presented include a spectroscopy lock, offset lock, RF function generator and acoustic optical module (AOM) drive, magnetic coil drive, laser drive and a timing card for sequencing the overall experiment.

This work at RAL Space has been funded by EPSRC and carried out as part of the Miniature Cold Atom Gravimeter for Space Applications (MCLAREN) project led by M Squared Lasers for Innovate UK.

Keywords: gravimeter, space-qualified, spectroscopy lock, offset lock, laser drive
Poster panel: 76

Poster Number:
N-19-076

The Penetrating particle ANalyzer (PAN) instrument (#2187)

G. Ambrosi1, P. Azzarello2, B. Bergmann3, B. Bertucci1, 4, F. Cadoux2, M. Duranti1, M. Ionica1, M. R. Kole2, M. Paniccia2, C. Plainaki5, S. Pospisil3, P. A. Thonet6, N. Tomassetti1, 4, A. Thykhonov2, V. Vagelli5, 1, X. Wu2

1 Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, Perugia, Italy
2 University of Geneva, Department of Nuclear and Particle Physics, Geneva, Switzerland
3 Czech Technical University in Prague, Institute of Experimental and Applied Physics, Prague, Czech Republic
4 University of Perugia, Department of Physics and Geology, Perugia, Italy
5 Italian Space Agency (ASI), Roma, Italy
6 European Organization for Nuclear Research (CERN), Geneva, Switzerland

Content

PAN is an instrument designed to precisely measure and monitor the flux, composition, and direction of highly penetrating particles (>100 MeV/nucleon) in deep space and interplanetary missions. The detector design is based on the well-known magnetic spectrometer detection principle, with novel layout and detection concept. In order to reach an energy resolution better than 10% for nuclei from H to Fe at 1 GeV/n, the spectrometer has been designed by dipole magnet sectors built from high field permanent magnet Halbach arrays, instrumented with high resolution silicon strip detectors. The particle charge will be determined by scintillating detectors and silicon strip detectors, with readout ASICs capable of large dynamic range. Silicon pixel detectors used in a low power setting will maintain the detection capabilities for high rate periods due to the strongest solar events. The fast scintillator system will be readout using SiPMs to determine the entering direction of the particle, provide timing information and perform high rate particle counts. The overall instrument will be limited to about 20 kg in mass and 20 W in power consumption. PAN will fill an observation gap of galactic cosmic rays in the GeV region, and provide precise information on the spectrum, composition and emission time of energetic particles originated from the Sun. The precise measurement and monitoring of the energetic particles are also a unique contribution to space weather studies.

Keywords: Cosmic rays, Space Weather, Space radiation, Magnetic spectrometer, Silicon tracker
Poster panel: 78

Poster Number:
N-19-078

Initial results from the Advanced Scintillator Compton Telescope (ASCOT) Balloon Flight (#2425)

T. Sharma1, P. F. Bloser2, J. Legere1, C. Bancroft1, C. Frost1, M. McConnell1, 3, J. Ryan1

1 University of New Hampshire, Space Science Center, Durham, New Hampshire, United States of America
2 Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
3 Southwest Research Institute, Dept. of Earth, Oceans & Space, Durham, New Hampshire, United States of America

Content

A medium-energy gamma-ray Compton telescope called the Advanced Scintillator Compton Telescope (ASCOT) was designed to address the existing need for observations in the gamma-ray energy range of 0.4 - 20 MeV. Built on the legacy of COMPTEL instrument onboard NASA’s CGRO, ASCOT uses commercially available high-performance scintillators, such as Cerium Bromide (CeBr3) and p-terphenyl in conjunction with Silicon Photomultipliers (SiPM) as compact readout devices to improve the instrument response. ASCOT also makes use of the Time-of-Flight background rejection technique along with the hardware advancement, an important tool for effective imaging in this energy range. ASCOT was developed with the goal of imaging the Crab Nebula at MeV energies during a high-altitude balloon flight. The instrument was successfully launched by NASA from Palestine (TX) on 5th July 2018. It operated stably and observed the Crab for ~5 hours from an altitude of 120,000 ft. Based on pre-flight calibrations and simulations results we expect a ~4.5 sigma detection of the Crab in the 0.2 - 2 MeV band. We present here the calibrated flight data along with preliminary results. The findings from ASCOT will demonstrate an improvement in the energy, timing, and position resolution using this advanced technology.

Keywords: Astrophysics, Silicon devices, Telescopes, gamma ray detection, photomultipliers
Poster panel: 80

Poster Number:
N-19-080

Poster panel: 82

Poster Number:
N-19-082

Simulation of EMP interference radiated by pulsed X-rays (#1100)

Z. Xu1, 2, C. Meng1, 2, Y. Jiang1, 2, P. Wu1, 2

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

Content

In some accelerators or medical imaging equipment, pulsed X-rays could cause significant cavity system-generated electromagnetic pulse (SGEMP) interference. Based on the finite-difference time-domain (FDTD) and particle-in-cell (PIC) method, the charge-conserving assignment, time-biased algorithm and conformal mesh technique are introduced to implement 2D calculations and develop a three-dimensional electromagnetic particle simulation method. The electric field waveform inside a 0.5-meter-diameter, 0.5-meter-long cylindrical cavity is obtained by 2D simulation, with a peak value of 70.77kV/m for the cavity SGEMP main pulse. Since metal cavity walls would reflect electromagnetic wave, resonance phenomenon is observed, which determines the main frequency component to be 456 MHz and 548 MHz for cavity SGEMP. The spatial distribution is demonstrated that the maximum electric field decreases from 208 kV/m to 15.96 kV/m when increasing the distance from emitting plate. The 3D calculation result is compared with 2D simulation: the waveforms are quite similar and only differ by 2.98% for the peak value of cavity SGEMP main pulse. The three-dimensional electromagnetic particle simulation method is verified and can be applied to the X-ray radiation hardness.

Keywords: Conformal mesh, Finite-difference time-domain, System-generated electromagnetic pulse, Time-biased algorithm, X-rays
Poster panel: 84

Poster Number:
N-19-084

The cross-section measurement of (n,lcp) reactions based on a silicon-detector array and silicon carbide detectors at Back-n white neutron source (#1229)

W. Jiang1, 2, R. R. Fan1, 3, H. Yi1, 2, K. Sun1, 2, C. Ning1, 2, J. Tang1, 2, G. Zhang4, Z. Sun1, 2, Q. An3, 5, P. Cao3, 5, Z. Tan1, 2, Q. Li1, 2, Y. Chen1, 2, H. Y. Bai4, H. Jiang4, Z. Q. Cui4

1 Institute of High Energy Physics, Institute of High Energy Physics, Beijing, China
2 Dongguan Neutron Science Center, Dongguan, China
3 Sate Key Laboratory of Particle Detection and Electronics, Beijing Hefei, China
4 Peking University, State Key Laboratory of Nuclear Physics and Technology, School of Physics, Beijing, China
5 University of Science and Technology of China, Department of Modern Physics, Hefei, China

Content

Back-n white neutron source at China Spallation Neutron Source (CSNS) was put into operation in 2018, providing a good platform for measuring cross sections of neutron induced light charged particle (lcp) emission (n,lcp) reactions. Currently, in order to detect and identify the light charged particles produced in (n, lcp) reactions at Back-n, a silicon-detector array(SDA) is set up in light partilce detector array(LPDA) spectrometer. The SDA is composed of 15 PIN silicon detectors, with thickness of 500 μm. The active area of each detector is 20 mm×25 mm. The SDA was placed 200 mm away from the center of the target and could detect the emerging particles from 18 degree to 160 degree. Adopting the SDA, 6Li(n, t)α and 10B(n, α) 7Li experiments were carried out at Back-n.  The SDA shown good performance in experiments. Double-differential cross sections of 80 energy points are extracted. Nevertheless, silicon detector suffers from the effect of irradiation damage and needs to be away from the beam center. Thus, the detectors cover a small spatial solid angle and it takes a long time to measure the reaction cross section during experiments. Taking advantage of a good anti-radiation performance, Silicon Carbide (SiC) detectors are suitable for cross-section measurements of (n, lcp) reactions at 0° angle. In this work, a SiC detector was placed in the beam for the cross-section measurement of 6Li(n, t) reaction. The experiments has been completed and data analysis is going on.

Keywords: Silicon detector, Silicon carbide detector, White neutron source
Poster panel: 86

Poster Number:
N-19-086

Simulation System for Planar Aperiodic Cavity Imager Based on Compressed Sensing (#1586)

C. He1, Y. Liu1

1 Beijing Normal University, College of Nuclear Science and Technology, Beijing, China

Content

By acquiring compressed information directly, the compressed sensing theory provides a method to reconstruct signals from few sampled data. Based on this theory, a microwave imaging simulation system working at K-band frequencies (18-26.5GHz) was designed. The system consists of a planar cavity transmit aperture with aperiodic radiating circular irises and a set of low-gain horn receive antennas. Hardware in the loop (HIL) simulation was applied to design and optimize the imaging system by using the computational electromagnetics software FEKO. In addition, the sparsity adaptive matching pursuit (SAMP) algorithm was used to reconstruct signals from the compressive sampled data, and highly resolution result was obtained. Primary results demonstrated that the system is effective to perform imaging at the scene.

Keywords: Aperiodic radiating irises, compressed sensing, HIL simulation, microwave imaging, planar cavity aperture
Poster panel: 88

Poster Number:
N-19-088

Restricted Boltzmann Spectrum Deconvolution (#1879)

M. J. Neuer1, 2

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

Content

A machine learning method is shown that deconvolves spectra in a single step procedure. This method is based on special neural network, a Bernoulli type restricted Boltzmann machine (RBM). Using a sophisticated Geant4 simulation to produce monoenergetic line response vectors of a Sodium Iodide detector, this RBM is trained to learn the detector response and apply the corresponding inversion to each spectrum that is inserted in the visible layer of the neural net. Although the training is time intensive and requires several different response matrices, the evaluation of the RBM at runtime is fast. The method does not require the same amount of memory than other techniques, such as the Maximum-Likelihood deconvolution. 
This Restricted Boltzmann Spectrum Deconvolver (RBSD) was test on a series of real-world spectra including NORM, innocent and SNM sources with extremely low statistics and weak peak structures. The RBSD was able to reconstruct the peaks well, although some amount of noise remained in the reconstructed spectra. Peak height ratios are being preserved by the technique.

Keywords: deconvolution, restricted Boltzmann machine, machine learning, neural network, spectroscopy
Poster panel: 90

Poster Number:
N-19-090

Simulation of a High Granulation Quartz-based Cherenkov Calorimeter (#1946)

Y. Onel1, J. Wetzel1, 2, B. Bilki1, 3, T. Simmons1, R. DeFano1

1 University of Iowa, Department of Physics, Iowa City, Iowa, United States of America
2 Augustana College, Department of Physics, Rock Island, Illinois, United States of America
3 Beykent University, Department of Physics, Istanbul, Turkey

Content

The search for new physics requires ever more radiation tolerant detectors and ever faster readout systems to handle the increased event-density caused by high luminosity beams.  Most scintillators are not radiation tolerant, and most scintillators have long decay times which creates a challenge known as pileup.  We present a solution to both problems, using quartz and Cherenkov radiation, rather than plastic and scintillation as the active media for a SiPM based sampling calorimeter.  Quartz is extremely radiation tolerant, and the Cherenkov radiation process is so fast that light production stops almost immediately after the instigating particle leaves the medium.  This simulation models the published photon response of a common Hamamatsu SiPM.  We present results for muons, electrons, and pions from 1 GeV to 1000 GeV and find that this detector can do tracking, and function as both an ECAL and HCAL.  The simulated detector is 45 x 45 x 80 cubes, each 1 cm on edge, with 1 radiation length of iron, along with a separate run using 1 radiation length of tungsten between each XY layer of quartz.  The detector is large enough to fully contain electromagnetic and hadronic showers, and the segmentation of the cube/SiPM elements allows tracking of the particle.

Keywords: calorimetry, quartz, sipm, high energy physics, Cherenkov Radiation
Poster panel: 92

Poster Number:
N-19-092

GEANT4 Systematic Study of the FRACAS Apparatus for Hadrontherapy Cross Section Measurements (#2118)

E. Barlerin1, D. Cussol1, M. Labalme1, S. Salvador1

1 LPC Caen, CNRS, IN2P3, Caen, France

Content

During a hadrontherapy treatment heavy ions can fragment in the tissues causing a loss of primary beam ions and the creation of lighter elements resulting in a mixed radiation field. By knowing the fragmentation cross sections of heavy ions in the human tissues the deposited dose can be more precisely controlled during the treatment planning phase. FRACAS as a large acceptance mass spectrometer, will be used to measure the fragmentation cross sections of 12C ions on thin targets of medical interest. It will be composed of a beam monitor giving the time reference for the time-of-flight measurements and beam particle position, up- and downstream trackers giving fragment trajectory before and after the magnet, which will provide mass separation of the fragment of the same charge, and a time-of-flight (ToF) wall giving the energy and arrival time of the fragments to extract their charge using a ΔE-ToF method. As the mass will be obtained by evaluating the deviation of the fragments in the magnet, trajectory reconstruction will be needed.  In the development phase of FRACAS it is necessary to know which configuration, in terms of detectors positions and spatial resolutions, will allow to identify as accurately as possible the charge and the mass of each fragments produced in the target. Geant4 simulations of the whole system were made and used alongside in-house developed algorithms for fragment identification and trajectory reconstruction to evaluate the trajectory and mass reconstruction efficiency. This gave an overview of the optimal configuration needed in terms of detector positions as well as restrictions on the detector spatial resolutions.

Keywords: Hadrontherapy, Geant4
Poster panel: 94

Poster Number:
N-19-094

Software Defect Prediction on Unlabelled Dataset with Machine Learning Techniques (#2684)

E. Ronchieri1, M. Canaparo1, D. Salomoni1

1 INFN - Istituto Nazionale di Fisica Nucleare, CNAF, Bologna, Italy

Content

Being able to predict defective module is an essential goal in the field of software engineering. This would lead to a more efficient allocation of resources for software testing and an increased awareness of software quality. In the last decades, Machine Learning techniques have been employed for this purpose with both supervised and unsupervised methods. These techniques require datasets that are composed of software metrics for each software module. Supervised defect prediction models rely on label datasets, i.e. datasets in which, for each module, is provided the defective information. Unfortunately, most of the software datasets do not contain the defective data because it is a time and resource consuming activity. Therefore, software metrics datasets usually belong to the unlabelled category.
In this work, we are going to focus on the various approaches that allow software engineers to apply supervised machine learning techniques to unlabelled datasets in order to create a defect prediction model. We also explain the way Machine Learning techniques is complementary to the traditional software development process. Furthermore, we are going to describe pros and cons of the different Machine Learning frameworks in terms of resource eploitation.

Keywords: Software Defect Prediction, Unlabelled Datasets, Unsupervised Machine Learning Techniques
Poster panel: 96

Poster Number:
N-19-096

Interfacing the "Boltzmann-Langevin One Body” nuclear interaction model with Geant4 (#2716)

C. Mancini Terracciano1, 2, M. Asai3, B. Caccia4, G. A. P. Cirrone5, A. Dotti3, R. Faccini1, 2, P. Napolitani6, L. Pandola4, E. Solfaroli Camillocci1, 2, D. H. Wright3, M. Colonna5

1 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Rome, Italy
2 Sapienza Univ. di Roma, Dip. di Fisica, Rome, Italy
3 SLAC National Accelerator Laboratory, Menlo Park, California, United States of America
4 Istituto Superiore di Sanità, National Center for Radiation Protection and Computational Physics, Rome, Italy
5 INFN - Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania, Italy
6 CNRS/IN2P3, IPN, Orsay Cedex, France

Content

Geant4 is one of the most widely used MC toolkit, also in medical applications; however, recent literature has shown the limitations of the Geant4 models in reproducing the secondaries yields measured in ions interaction below 100 MeV/n. To improve the Geant4 capabilities in simulating nuclear reactions below 100MeV/n, we interfaced it with a dedicated model for such kind of reactions: BLOB (“Boltzmann-Langevin One Body”). It is a self-consistent one-body approach to solve the Boltzmann- Langevin equation based on the description of the time evolution of the nucleon density distribution in a semi-classical way, i.e. taking into account the Pauli principle. It includes the treatment of the mean-field propagation, on the basis of an effective interaction and fluctuations are included in full phase space through a collision term where nucleon-nucleon correlations are explicitly involved.
We already showed in preliminary works the potentialities of BLOB in describing 12C fragmentation, comparing the relative total yields predicted by it with experimental data. In this work, we present a more extended benchmark with the data-set by De Napoli et al., i.e. experimentally measured double differential cross sections of fragments production in the interaction of a 12C beam at 62MeV/n with a thin carbon target. We coupled BLOB with Geant4 and its de-excitation phase, foreseen its porting in the Geant4 toolkit.

Keywords: Monte Carlo simulazion, Nuclear interaction
Poster panel: 98

Poster Number:
N-19-098

Analysis Declarative Languages for the HL-LHC (#2793)

G. Watts1, E. Torró-Pastor1, M. L. Proffitt1

1 University of Washington, Seattle, Washington, United States of America

Content

The Large Hadron Collider, located at the CERN laboratory just outside Geneva, will commence its longest data collection period in 2026. Called the High Luminosity LHC, this run will collect 100 times more data than the dataset collected for the discovery of the Higgs boson. The increase in the size of the data demands a comparable improvement in software and processing infrastructure. The computing environment is also shifting from the homogeneous x86 architecture most experimental particle physicists are used to, to a heterogeneous environment where the bulk of the processing power is often located in coprocessors like GPUs. The particle physics community, which traditionally uses homegrown tools to analyze the data, is exploring bringing new tools, especially from industry, into its workflow, extending both the industry tools and the homegrown tools. Concepts and techniques include declarative languages to specify hierarchical data selection and transformation, cluster systems to manage processing the data, Machine Learning integration at the most basic levels, statistical analysis techniques, etc. This talk will cover the forces driving this change, and concentrate on recent work in developing Analysis Languages, domain specific languages to aid the physicist in extracting the physics from these large datasets in an efficient way.

Keywords: High energy physics computing, Particle collisions, Software algorithms
Poster panel: 100

Poster Number:
N-19-100

R&D on Pico-second Timing TOF Counter (#1145)

Z. Li1, X. Li1, Q. Cao1, C. Li1, Y. Wang1

1 University of Science and Teconology of China, Department of Modern Physics, Hefei, China

Content

The final state of particle and the range of phase space are increasing with the increasing of energy and luminosity of the new generation particle accelerator, the identification of high density and high momentum particle becomes the key problem in the experiment of nucleus and particle. An experimental prototype of pico-seconds timing TOF (Time-of–Flight) counter was developed. The detector was composed of a Cherenkov radiator connected to fast micro-channel plate PMTs (MCP-PMT), and and a full readout electronics chain. The timing performance of the prototype has been tested on the H4 beam line at CERN. The beam test demonstrates that it can achieve an excellent time resolution of less than 10ps after deduction of the electronics' contribution. We also developed a GEANT4 based simulation framework as a reference to study its operation mechanism. With its compact structure, fast timing performance, and relatively low material budget, it is a promising candidate of the trigger and timing detector in high-luminosity physic experiments.

Keywords: Multi-threshold differential discriminator(MDD), Beam test, Geant4 simulation, Pico-second timing TOF (Time of Flight) counter, micro-channel plate (MCP-PMT)
Poster panel: 102

Poster Number:
N-19-102

Ultra-Fast Read-Out Trough Transmission Lines for TOF PET detectors and ClearMind Project (#1325)

M. Follin1, 3, D. Yvon1, 3, V. Sharyy1, 3, J. P. Bard1, 3, D. Breton2, 3, J. Maalmi2, 3

1 CEA, IRFU, Gif-sur-Yvette, France
2 CNRS, LAL, IN2P3, Orsay , France
3 Université Paris-Saclay, Orsay, France

Content

ClearMind project aims to develop a fast detection module for TOF-PET. We propose a position-sensitive detector consisting of a PbWO4 scintillating crystal on which is directly deposited a bialkali photo-electric layer. This detector optimizes the transmission of scintillation photons and Cherenkov light photons to the photoelectric layer. To fully exploit the potential of this detector, an ultra-fast read-out is needed. It optimizes the time and the spatial resolution of the detection chain. The use of transmission lines and of the SAMPIC waveform digitization module enables fast acquisition of signal shapes. We tested such read-out scheme using the commercial Planacon MCP-PMT and a pulsed 20 ps laser. We present the first promising results for x and y spatial resolution. In particular, we measured the difference of the signal time from both ends of the line with a precision of 20 ps (FWHM) resulting in a spatial resolution along the line down to 1.5 mm. We measured a single-photon time resolution correspond- ing to PMT TTS of 70 ps (FWHM) as well. We also study the possibility of multi-photon reconstruction on a same line. We will present the first promising results for x and y spatial resolution using the commercial Planacon MCP-PMT as well as study of multi-photon reconstruction in such detector obtained thanks to this ultra-fast read-out. A companion paper (D.Yvon et al.) will be devoted to the entire detector concept and foreseen timing performances as calculated by simulation of the current available PbWO4 scintillator technologies.

Keywords: Gamma Detector, SAMPIC, MCP-PMT, Planacon, Transmission Line Read Out
Poster panel: 104

Poster Number:
N-19-104

Methods to compensate the time walk errors in conicedence timing measurements between PET detectors (#1724)

S. Xie1, X. Zhang1, 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 (LBNL), Berkeley, California, United States of America

Content

The purpose of this study is to investigate the effects of signal walk in timing measurements and the methods to compensate this error when leading edge discriminator (LED) triggering is used in positron emission tomography (PET). Three pairs of crystals (6 mm LaBr3 cubes, 6 mm LYSO cubes, and LYSO rectangular prisms) coupled to 6 mm SensL photodetectors were tested for coincidence timing resolution (CTR) to evaluate four compensation methods: Linear 1D, Logarithm 1D, Polynomial 2D, and Artificial Neural Network (ANN) 2D.
The experimental results show that: (1) The signal walk causes a logarithmic relation between energy and measured time, so a logarithm operation needs to be applied to the energy before the linear correction can be applied. (2) The signal walk dramatically affects the timing performance of the PET detectors at a wide energy window. The measured FWHM CTR increased by a factor of 7.2, from 92.7 ps to 670 ps, when the lower cut of the energy window decreased from 440 keV to 110 keV. (3) The logarithm 1D compensation can dramatically improve the timing performance. The FWHM CTRs increased by 69.9% (from 101.3 ps to 326.8 ps) with an energy window of 300 keV –550 keV and by 12.5% (from 85.1 ps to 97.2 ps) with an energy window of 410 keV – 550 keV for the LaBr3 cube crystals. The FWHM CTRs were promoted by 26.9% (204.4 ps to 279.7 ps) for a 300 keV – 550keV energy window and by 10% (171.8ps to 189.5 ps) for 410 keV – 550 keV for the LYSO rectangular prism crystal. The results show that the logarithm 1D, polynomial 2D, and ANN 2D compensations work well, achieving at least 10% improvement in timing performance.
It is essential to apply Logarithm 1D or Polynomial 2D compensation when constructing high-performance time-of-flight (TOF) PET systems with dual-end readout detectors, monolithic scintillators, or scintillator with a low photofraction rate.

Keywords: Coincidence timing resolution, Leading edge discriminator, Time-of-flight, Time-walk correction
Poster panel: 106

Poster Number:
N-19-106

Positron Annihilation Lifetime Spectroscopy Using Fast Scintillators and Digital Electronics (#1926)

M. Fang1, N. Bartholomew1, A. Di Fulvio1

1 University of Illinois at Urbana-Champaign, Department of Nuclear, Plasma, and Radiological Engineering, Urbana, Illinois, United States of America

Content

Positron Annihilation Lifetime Spectroscopy (PALS) is a non-destructive radiological technique widely used in material science studies. PALS typically relies on an analog coincidence measurement setup and allows the estimate of the positron lifetime in a material sample under investigation. The positronium trapping at vacancies in the material results in an increased lifetime. In this work, we have developed and optimized a PALS experimental setup using organic scintillators, fast digitizers, and advanced pulse processing algorithms. We tested three pairs of different organic scintillation detectors: EJ- 309 liquid, EJ-276 newly developed plastic, and BC418 plastic, and optimized the data processing parameters for each pair separately. Our high-throughput data analysis method is based on single-pulse interpolation and a constant fraction discrimination (CFD) algorithm. The setup based on the BC418 detector achieved the best time resolution of 195.7 ± 0.4 ps. We used such optimized setup to analyze a single-crystal quartz sample and found lifetimes of 145.1 ± 2.4 ps and 347.8 ± 6.4 ps, as expected for this material. The proposed experimental set up and data processing methods achieve an excellent time resolution, which makes it possible to accurately characterize material vacancies by discriminating between the lifetimes of either the spin singlet or triplet states of positronium.

Keywords: Positron lifetime, organic scintillator, digitizer, CFD
Poster panel: 108

Poster Number:
N-19-108

Optimal design of single-photon sensor front-end electronics for fast-timing applications (#2296)

J. M. Fernández-Tenllado Arribas1, 2, R. Ballabriga Suñe1, D. Gascón Fora2, M. Campbell1, S. Gómez Fernández2, J. Mauricio Ferré2

1 CERN, EP-ESE-ME, Geneva, Switzerland
2 University of Barcelona, ICCUB, Barcelona, Spain

Content

The readout of Silicon Photomultipliers or Photomultiplier Tubes present a challenge in the design of front-end electronics in view of achieving competitive time jitter results. In this paper we analyze the impact of parameters such as detector capacitance, parasitic inductance, input impedance, bandwidth of the front-end, input sensing approach (current or voltage mode), noise and power consumption, from an analytical point of view, in order to provide a set of guidelines and simple expressions to tackle the design of analog front-ends for fast-timing applications. Optimum values for input impedance and bandwidth depending on the sensor are obtained by means of analytical calculations and circuit simulations. Global criteria for the design of fast-timing front-ends are identified: minimum impedance of 5 Ω for open-loop preamplifiers (roughly 15 Ω in closed-loop configuration), and a maximum bandwidth of 1 GHz, on multichannel front-ends. Hybrid interconnection may surpass such bandwidth limitation.
Furthermore, we address the benefit of area segmentation of large area detectors by means of active analog summation, highlighting the time jitter improvement and power consumption trade-offs. Optimum segmentation factors are related to series and parallel noise contributions, and to the impact of the reduction of the detector capacitance in the signal shape.

Keywords: Silicon photomultipliers, Photomultiplier tubes, Front-end electronics, Fast timing, Time jitter
Poster panel: 110

Poster Number:
N-19-110

A digital-analog SiPM approach: a story of electronic and excess noise (#2182)

S. M. Decker3, M. Pizzichemi1, A. Polesel2, 1, M. Paganoni2, E. Auffray1, S. Gundacker2, 1

1 CERN, Meyrin, Genève, Switzerland
2 University of Milano-Bicocca, Milano, Italy
3 Boston University, Boston, Massachusetts, United States of America

Content

Modern PET detectors rely on fast and accurate timing performances in order to provide improved lesion detectability and reduced patient scan times. Optimizing the coincidence timing resolution (CTR) is an important facet that helps achieve high performance. Research on all detector components, including the scintillator, photodetector, and electronic readout, is necessary to improve the CTR to sub-100ps, and ultimately 10ps. The digital SiPM, where each single photon avalanche diode (SPAD) is connected to its own readout, has gained a lot of attention as the ultimate photodetector. However, extended power consumption and the enormous number of channels makes the realization challenging. In this contribution we investigate a semi-digital approach, realized with the pixelation of an analog SiPM. We tested a single SiPM from HPK (S13360-6075V), compared to a 3x3 SiPMs array (S13361-2075N-03) readout by our in-house developed acquisition system, employing NINO as front-end ASIC. Preliminary results show a minimum CTR value of 117±5ps coupling a 6x6x3mm3 LYSO:Ce crystal (CPI) to a single 6x6mm2 SiPM with 75um SPAD size (S13360-6075V). In contrast, if we use the exact same crystal on the 3x3 SiPMs array reading each of the 9 SiPMs independently, correcting for time walk and properly combining the time-stamps, we obtain a minimum CTR of 136±5ps. This result is surprising, because the lower capacitance of the smaller SiPMs should lead to a reduced electronic noise, and therefore better timing. The most probable explanation for this counter-intuitive result is the 9 times lower number of scintillation photons generating each SiPM signal. That, in combination with correlated noise sources (e.g. optical crosstalk), leads to excess noise, especially in the applied leading edge time discrimination. Further Monte-Carlo simulations and measurements will be presented, investigating this digital-analog approach in depth, with a special view on the gamma interaction time estimator.

Keywords: SiPMs
Poster panel: 112

Poster Number:
N-19-112

FAST: a front-end readout ASIC for high flux and high time resolution applications with UFSD (#2724)

E. J. Olave1, F. Fausti1, N. Cartiglia1, R. Arcidiacono1, 3, A. Staiano1

1 INFN section of Torino, Turin, Italy
2 Universita' del Piemonte Orientale, Turin, Italy

Content

The research of a few tens of pico-seconds accuracy in timing measurements is currently a hot topic not only in the field of high energy physics but also in several applied physics branches. The Ultra Fast Silicon Detector group of the Turin section of the INFN is involved in this challenge, developing fast silicon sensors. This group spent the recent years developing UFSD devices, a particular type of Low Gain Avalanche Diodes optimized for timing application. The development of fast detecting systems requires furthermore a high-performance front-end electronics to be coupled with the sensors. For this reason, the microelectronics department of the Turin section of INFN started a UFSD-dedicated development plan through which the group produced two ASIC prototypes that have been successfully tested in both our laboratories and particle accelerator facilities.
From the know-how raised in those projects, a new custom low power front-end chip, called FAST, has been designed to fulfill the 30ps time resolution, nowadays required by the HL-LHC community for the next upgrade phase. In addition to this, FAST aims to cope also with additional requirements coming from other applications like particle therapy where UFSD sensors are currently employed. In this field, the Turin medical physics group is collaborating in a national INFN project aiming to replace gas detectors with solid state ones. Due to the high rate of therapeutic beams (up to 10^9 cm^-2s^-1) used in this field, dedicated R&D for sensors and electronics is required.
In order to be suitable also for this applications, FAST has been designed with an additional care oriented to implement the single ion detection capability at high-rates and with a wide input charge range. FAST has been submitted to the foundry in May 2019 and an extensive characterization campaign is going to start in the next autumn. The description of FAST with first experimental results will be presented in the conference.

Keywords: ASIC, front-end electronics, UFSD sensors, high flux particle counting, particle therapy
Poster panel: 114

Poster Number:
N-19-114

SiPM-based detector for high resolution measurements in pulsed radiation fields: preliminary findings (#1174)

L. Pavelic1, I. Lackovic2, M. S. Mihic1, I. Prlic1

1 Institute for Medical Research and Occupational Health, Radiation Dosimetry and Radiobiology Unit, Zagreb, Croatia
2 University of Zagreb, Faculty of Electrical Engineering and Computing, Zagreb, Croatia

Content

Ten years ago, it became evident that commercially available dose and dose rate meters do not measure correctly in pulsed radiation fields. Pulsed fields have become mainstream technology in medical imaging and they are present in nondestructive testing, accelerators, etc. Today, some modern dosimeters perform better with only a slight underestimation in pulsed fields of higher dose rates, but dose rate measurements during the pulse still remain a challenge, especially for scattered radiation. This can also be extended to short exposures, dominant in the medical sector. We developed a detector consisting of a silicon photomultiplier coupled to a 10x10x10 mm3 scintillator. For the current stage of research, a NaI(Tl) scintillation crystal was chosen due to its high light yield and capability to detect low energy X-rays. Signals from the detector are digitized using a digital storage oscilloscope and recorded for offline analysis. Analysis was based on signal integration, which remained invariant to pulse pileup and thus allowed measurements from low to high dose rates several times higher than IEC 61526 requirements. Preliminary results promise a sufficient time and dose (H*(10)) resolution for measurement of scattered radiation pulses down to several ms in width.

Keywords: dosimeter, pulsed fields, silicon photomultiplier, scintillator
Poster panel: 116

Poster Number:
N-19-116

Multi-anode MCP-PMT Characterisation with high-channel count sampling ASICs (#1762)

T. M. Conneely1, J. S. Milnes1, A. T. Duran1, 2, P. L. Hink1

1 Photek LTD, St. Leonards-on-sea, United Kingdom
2 University of Nottingham, Physical Chemistry, Nottingham, United Kingdom

Content

We will present results characterising the performance of two Multi-Anode Microchannel Plate Photomultiplier Tubes (MCP-PMT) when coupled with waveform digitising sampling electronics such as the SAMPIC ASIC. Both MCP-PMTs offer two-dimensional multi-anode arrays at 0.828 mm pitch with single photon gain (>106) in two different form factors. The MAPMT253 has a square form factor for close packing applications with 53 mm x 53 mm active area in a 60 mm x 60 mm outer envelope and a 64 x 64 anode array. The MAPMT228 has a 26.5 mm x 26.5 mm active area in a 60 mm diameter round outer envelope and a 32 x 32 anode array. Both MCP-PMTs use Anisotropic Conductive Film for ease of customisation by grouping anodes to form alternate anode arrays such as a 16 x 16 array of 1.656 mm pitch anodes or an 8 x 8 array of 6.624 mm pitch anodes. Basic performance characteristics are measured for each MAPMT in several anode configurations using waveform digitising sampling readout electronics, including crosstalk (multi-photon and single photon counting), correlated noise and single photon timing. In addition, the charge measurement capabilities of the waveform digitising sampling readout electronics will be determined. Further discussion will address modelling of relative contributions to the total cross talk introduced due to the photocathode to MCP gap, MCP to anode gap and capacitive coupling between individual anodes for various readout configurations.

Keywords: Photodetectors, Photomultipliers, Application Specific Integrated Circuits, Fast timing
Poster panel: 118

Poster Number:
N-19-118

Towards a low cost lead assay technique for drinking water using CMOS sensors (#2523)

A. Deisting1

1 Royal Holloway, University of London, Egham, United Kingdom

This contribution is on behalf of working-groups and researches of the following institutions: Centro Atomico Bariloche, Argentina; Boulby Underground Laboratory, Whitby, UK; Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de México, Mexico; Royal Holloway, University of London, UK; University College London, UK; University of Sussex, UK

Content

We are working on methods for measuring lead contamination in drinking water with commercial, off-the-shelf CMOS sensors. It is estimated that globally 26 million people in low- and middle-income countries are at risk of lead exposure. Therefore a low cost and easy to use sensor could have a huge impact to reduce lead ingestion in at-risk regions.
Lead occurs together with traces of radioisotopes including the radioactive lead isotope 210Pb. Pb decay energies cover the range of 10 to several 100 keV, which is easily accessible in silicon sensors. Measuring lead concentrations at, and below, the World Health Organisation (WHO) limit for drinking water of 0.87 ppb can be done with methods developed for Dark Matter (DM) searches. DM experiment techniques have reached sensitivities down to 10-10 ppb of 210Pb in acrylic, or 10-8 ppb of 210Pb in water. A low cost sensor will have an orders of magnitude less sensitivity, which would however potentially still be enough to measure Pb at the WHO limit.
We will report on radiation measurements a scientific CMOS sensor exposed to radioisotopes of different energies and address: (i) the minimum Pb source activity the sensor can reliably identify; and, (ii) the achievable decay energy resolution via calorimetric reconstruction in the sensor data. We will report the results of similar measurements done with a phone camera CMOS sensor to establish the capabilities of smart-phones for lead assay. Furthermore we will report the results of volume-reduction techniques for water assay in the field. To quantify the efficiency which (radio)isotopes are retained in water when the volume is reduced by boiling, volume-reduced samples have been assayed with high-sensitivity γ-counters.

Keywords: CMOS image sensors, Dosimetry, Gamma-ray detectors, Lead isotopes, Water pollution
Poster panel: 120

Poster Number:
N-19-120

Study of the Effects of Radiation at the CERN Gamma Irradiation Facility on the CMS Drift Tubes Muon Detector for the HL-LHC (#1328)

B. Alvarez Gonzalez2, A. Sharma1

1 RWTH Aachen Univ., III. Physik. Inst. A,Aachen, Physics, Aachen, Germany
2 Universidad de Oviedo, Physics, Oviedo, Spain

On behalf of the CMS Muon Group

Content

The CMS drift tubes (DT) muon detector, built for standing up the LHC expected integrated and instantaneous luminosities, will be used also in the High Luminosity LHC (HL-LHC) at a 5 times larger instantaneous luminosity and, consequently, much higher levels of radiation, reaching about 10 times the LHC integrated luminosity. Initial irradiation tests of a spare DT chamber at the CERN gamma irradiation facility (GIF++), at large (~O(100)) acceleration factor, showed aging effects resulting in a degradation of the DT cell performance; however, full CMS simulations have shown almost no impact in the muon reconstruction efficiency over the full barrel acceptance and for the full integrated luminosity. A second spare DT chamber was moved inside the GIF++ bunker in October 2017. The chamber was being irradiated at lower acceleration factors, and only 2 out of the 12 layers of the chamber are switched at working voltage when the radioactive source is active, being the other layers in standby. In this way the other non-aged layers are used as reference and as a precise and unbiased telescope of muon tracks for the efficiency computation of the aged layers of the chamber, when set at working voltage for measurements. An integrated dose equivalent to two times the expected integrated luminosity of the HL-LHC run has been absorbed by this second spare DT chamber and the final impact on the muon reconstruction efficiency is under study. Direct inspection of some extracted aged anode wires presented a melted resistive deposition of materials. Investigation on the outgassing of cell materials and of the gas components used at the GIF++ are underway. Strategies to mitigate the aging effects are also being developed. From the long irradiation measurements of the second spare DT chamber, the effects of radiation in the performance of the DTs expected during the HL-LHC run will be presented.

Keywords: HL-LHC, drift tubes, cms cern, aging
Poster panel: 122

Poster Number:
N-19-122

Impurity Effect on Ionization Yield in Helium by Alpha-Particles (#1574)

A. Takeuchi1, K. Saito1, 2, Y. Kishimoto1, 2, T. Oyama2, T. Sanami1, 2

1 The Graduate University for Advanced Studies, Tsukuba, Japan
2 High Energy Accelerator Research Organization, Tsukuba, Japan

Content

The ionization efficiency is characterized by W-value, which is defined as the average energy required to produce an ion pair by a charged particle in gases. W-value has been measured in many gases and these results have reproducibility. However, the various experimental results of W-value in Helium (42.2-46.0 eV) are shown by many researchers. It is assumed that one of causes of the different results is due to the Penning effect. The excited helium atom ionizes the impurities atom or molecule in Helium by the collision, which results in the increase of ionization yield because of the production of additional ion pairs. To measure ionization yield without the influence of impurities, it is important to keep purity of the gas high during measurement because impurities are released from a measurement chamber continuously. We applied two types of purifiers: Ni compound and Zr-Ba-Fe getters. Water vapor pressure in a helium as impurities was measured using a dew point meter. The ionization yield has been measured with a gridded ionization chamber. An 241Am was used as α-particles source. We measured a variation of ionization yield and water vapor pressure in helium simultaneously. In the case of using purifier, the ionization yield and the water vapor pressure increased with time, finally it became a constant value. The increasing of ionization yield with purification was less than without one. That is due to inhibiting from increasing impurities by purification. We obtained W-value in Helium by making clear an association of the ionization yields with the impurity concentration.

Keywords: ionization, W-value, helium
Poster panel: 124

Poster Number:
N-19-124

Gas Drift Detector for X-Ray Applications (#1693)

H. Sipila1, A. Niemela1, J. - M. Perkkio1, J. Laurila1

1 Fenno-Aurum Oy Ltd, Espoo, Finland

Content

The phenomenon of Gas Amplification has been widely and successfully used for many decades in gas-filled radiation detectors, e.g. proportional counters. However, the use of gas amplification has several disadvantages; the signal is induced by positive ions drifting from the amplification region towards the cathode, the positive ions drift velocity is typically three orders of magnitude slower than that of electrons, and the gas amplification process is a statistical process decreasing the spectroscopic properties of gas-filled detectors.
During the last decade, integrated MOSFET preamplifier chips have developed rapidly to have much lower noise than traditional JFET-input preamplifiers. For instance, MOSFET preamplifiers have improved silicon drift detector (SDD) properties significantly.
In this work, a low-noise, low-capacitance integrated MOSFET preamplifier was used for the first time with a gas-filled detector. The signal was collected on a small golden anode sphere with low capacitance. Because of the favourable weighting function used, the signal is almost independent of the location of the X-ray photon absorption. With the help of the low-noise preamplifier, no gas amplification was needed, and the detector was operated in the ion-chamber region instead.
In this “proof-of-principle” type of study, Ar-CH4(10%) gas mixture (a.k.a. P-10) was used and an energy resolution of 9.8% was measured at the 5.9 keV line of Fe-55. To our knowledge, this is the best ever energy resolution measured using this gas mixture. The gas drift detector (GDD) used in this study is also very fast because only electron signal is read out. Space charge accumulation is minimal, and the detector ageing effects are significantly reduced because there is no gas amplification. In the next phase of GDD development, the noise level can be further reduced, and by using various Penning mixtures the energy resolution can still be significantly improved.

Keywords: X-ray detector, Gas-filled detector, Gaseous detector
Poster panel: 126

Poster Number:
N-19-126

Upgrade of the CMS Muon Spectrometer in the forward region with the Triple-GEM technology  (#1778)

A. Irshad1

1 Université libre de Bruxelles, Service de Physique des Particules, Brussels, Belgium

Content

The Large Hadron Collider (LHC) will be upgraded in several phases to significantly expand its physics program. After the long shutdown of 2019 and 2020 (LS2) the accelerator luminosity will be increased to 2 − 3 * 10^34cm−2s−1 exceeding the design value of 1 * 10^34cm−2s−1 allowing the CMS experiment to collect approximately 100 fb−1/year. A subsequent upgrade in 2022-23 will increase the luminosity up to 5 * 10^34cm−2s−1. The CMS muon system must be able to sustain a physics program after the LS2 shutdown that maintains sensitivity to electroweak scale physics and for TeV scale searches similar to what was achieved up to now. To cope with the corresponding increase in background rates and trigger requirements the installation of additional sets of muon detectors, referred to as GE1/1, GE2/1 and ME0 that use Triple-GEM (Gas Electron Multiplier) technology has been planned. The installation and commissioning of the GE1/1 chambers is starting now and will continue through 2019 and 2020, while the GE2/1 and ME0 detectors are expected to be installed after 2022. In this contribution we present an overview of the muon spectrometer upgrade using the Triple-GEM technology, the ongoing GE1/1 chambers production with the first results of the quality assurance tests performed in a large test bench that can host up to 30 GE1/1 chambers and where each GE1/1 detector is recording cosmic muons during several weeks before being installed in CMS. We will also present the status of the detector and electronics designs as well as the technical solutions adopted for the foreseen GE2/1 and ME0 upgrade, with a summary of the R&D activities ongoing. Namely we will present recent results obtained with a first GE2/1 chamber equipped with the new front-end electronics prototype.

Keywords: CMS, HL-LHC, Muon, Triple-GEM
Poster panel: 128

Poster Number:
N-19-128

The study of boron-lined honeycomb neutron detector with a multi-wire proportional chamber readout (#1955)

L. Liu1, 2, Y. Yu1, 2, Z. Fang1, 2, C. Deng3, Y. Yang1, 2

1 Tsinghua University, Department of Engineering Physics, Beijing, China
2 Tsinghua University, Key Laboratory of Particle & Radiation Imaging, Beijing, China
3 China Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang, China

Content

Boron-lined honeycomb convertor neutron detector (BHCND) exhibits high detection efficiencies, good spatial resolution and is a potential alternative to 3He detectors for the application of neutron scattering. However, due to the unsatisfactory electrons migration efficiencies, the neutron detection efficiency is lower than the simulated result. A new design of the BHCND using a multi-wire proportional chamber (MWPC) readout is proposed in this paper. Unlike the gas electron multiplier (GEM) used in the former work, the MWPC can collect and multiply electrons from both its upper and lower sides, thus the honeycomb neutron converter can be separated into two parts or even more, with the MWPC readout placed between them. As a result, the electrons migration distance is shortened by half. The Garfield++ simulations show that the electron’s migration efficiencies are significantly improved. The equivalent energy deposition of the neutron signal is enlarged. Finally, the neutron detection efficiencies of the new BHCND increase to 38.8%, with a 93keV threshold set to discriminate noises and gamma-rays.

Keywords: electrons migration efficiencies, honeycomb, MWPC, neutron
Poster panel: 130

Poster Number:
N-19-130

Studies of ecological gas mixtures in GEM based detectors with optical readout (#2372)

F. Iacoangeli1

1 LNF , INFN, Frascati, Italy

on behalf of Cygno Collaboration

Content

Modern imaging sensors can be used to detect the scintillation light produced in MPGDs during electron avalanche multiplication. Using gas mixtures with scintillation light spectra compatible with the quantum efficiency of CCD or CMOS cameras, optical readout can be used to build 2D images with a mechanism stable against electronic noise. In The Cygno project , a TPC for directional dark matter  searches and neutrino scattering measurements,  a three GEM layers detector is used as amplification device and the light produced during the multiplication process is detected by a sCMOS camera. The TPC is operated with a mixture of Helium and CF4.  Recently many freon gases, as the CF4, have been banned by the European community due to their high pollution impact to the atmosphere. Our group has started a study to use eco-friendly gases to replace the CF4 in such kind of applications. The setup used to collect data and preliminary results obtained in terms of amplification factors and of light production will be presented with some of the more interesting ecological gas mixtures selected on the market.

Keywords: MPGD, GEM, Dark Matter, Optical Readout
Poster panel: 132

Poster Number:
N-19-132

Elemental mapping distribution studies with MPGDs (#2456)

A. L. Silva1, P. M. S. Carvalho2, L. F. N. Carramate1, M. L. Carvalho2, J. P. Santos2, J. F. Veloso1

1 I3N -University of Aveiro, Physics Dpt., Aveiro, Portugal
2 LIBPhys-UNL, School of Science and Technology, NOVA University of Lisbon, Lisboa, Portugal

Content

X-rays are a very powerful tool in analytical techniques and widely used in fields ranging from medicine, art history, geology, industry, etc. Some of these techniques are still limited by the lack of detection technologies able to fully use the information obtained from the X-rays. When large areas of detection with position and energy resolution are needed, micropatterned gaseous detectors (MPGDs) become a very interesting solution. These detectors are widely used in fundamental physics experiments and applications, with a solid history of success. A large area 10x10 cmsystem for X-ray fluorescence imaging applications, based on 2D-THCOBRA device of, high detection efficiency (e.., 75% at 5.9 keV), energy resolution of about ~ 1 keV (full width at half maximum - FWHM at 5.9keV), and intrinsic imaging capability (resolution<300 µm FWHM) was developed. The detector was applied for elemental identification of samples for analysis of the elements spatial distribution using energy dispersive X-ray fluorescence techniques. 

Keywords: THCOBRA; MPGD; EDXRF; X-ray imaging; gaseous detectors
Poster panel: 134

Poster Number:
N-19-134

A light charged particle detector array for the“Back-n“ (#1187)

R. R. Fan1, 2, W. Jiang1, 3, H. Yi1, 3, L. Zhou1, 3, C. J. Ning1, 3, Y. C. He1, 3, Y. F. Wang1, 3, K. Sun1, K. Q. Gao1, G. H. Zhang4, H. Y. Bai4, H. Y. Jiang4, Z. Q. Cui4, Z. J. Sun1, 2

1 Chinese Academy of Sicences (CAS), Institute of High Energy Physics, Beijing, China
2 State Key Laboratory of Particle Detection and Electronics, Beijing, China
3 Dongguan Neutron Science Center, Dongguan, China
4 Peking University, School of Physics, Beijing, China

Back-n Collaboration

Content

“Back-n” is a high luminosity white neutron source at the China Spallation Neutron Source (CSNS). A Lighted charged Particle Detector Array (LPDA) is designed for general (n, x) reaction experiment, including three different detectors and some support system. The LPDA finished first experiment of 6Li (n, α) measurement while the “Back-n” first running. From the preliminary results, the detectors give an excellent particle identification. A series of precise double differential cross sections of 6Li (n, α) reaction is achieved.

Keywords: Charged Particle, Nuclear Data
Poster panel: 136

Poster Number:
N-19-136

Operation and Calibration of a Highly Granular Hadron Calorimeter with SiPM-on-Tile Read-out (#1318)

F. Simon1, O. Pinto2

1 Max-Planck-Institut für Physik, München, Bavaria, Germany
2 DESY - Deutsches Elektronen-Synchrotron, Hamburg, Hamburg, Germany

On behalf of the CALICE Collaboration

Content

The Analogue Hadron Calorimeter (AHCAL) technological prototype, developed and recently constructed by the CALICE collaboration, is a scalable engineering prototype for energy-frontier electron collider experiments. The calorimeter is based on layers of plastic scintillator tiles individually read out by silicon photomultipliers (SiPM-on-tile) between stainless steel absorber plates. The front-end ASICs are integrated into the active layers of the calorimeter and are designed for minimizing power consumption by rapidly cycling the power according to the beam structure of a linear collider. The front-end electronics provide channel-by-channel self-triggering and time stamping on the few nanosecond to sub-nanosecond level, depending on operation mode. The full prototype consists of 38 layers with a total of 22\,000 channels, followed by a tail catcher using the same active elements but with a coarser sampling structure to ensure full longitudinal containment of hadronic showers. The calorimeter has been extensively tested in particle beams at the CERN SPS, providing a wealth of data for a detailed studies of the detector performance and to investigate the spatial and time structure of hadronic showers. The contribution will discuss the calibration of the detector using built-in systems and particle beams, highlight first results with beam as well as aspects of the detector operation, basic features such as uniformity and stability, and touch on key elements of the detector construction.

Keywords: Calorimetry, Silicon Photomultipliers, Detector calibration, Imaging Calorimetry
Poster panel: 138

Poster Number:
N-19-138

Detector Response of Timepix3 with a 300 μm Silicon Sensor in Relativistic Charged Particle Beams (#1395)

B. Bergmann1, P. Burian1, 2, P. Broulim2, L. Meduna1, M. Petro1, S. Pospisil1, P. Azzarello3, M. Paniccia3, C. Perrina3, X. Wu3

1 Institute of Experimental and Applied Physics at CTU in Prague, Praha, Czech Republic
2 Faculty of Electrical Engineering of the University of West Bohemia, Pilsen, Czech Republic
3 Departement de Physique Nucleaire at Corpusculaire, Universite de Geneve, Geneva, Switzerland

Content

This contribution describes the application of a Timepix3 detector with a 300 µm thick silicon sensor layer for measurement in relativistic charged particle beams. Therefore, the detector was placed in a 400 GeV/c primary proton beam and a mixed ion beam created after 330 GeV/c impact on target. The detector response in the form of particle tracks and energy spectra as measured at different impact angles are presented. With the proton data it is shown, that a relative energy resolution ΔE/E of approximately 9 % can be achieved. Further research to determine the detector's capability of decomposing the mixed beam by energy spectrum deconvolution, iterative Landau curve fitting or separating ion species utilizing track features (δ-rays, halo properties, ...) has been started.

Keywords: Hybrid pixel detectors, Timepix3, Particle beams
Poster panel: 140

Poster Number:
N-19-140

Development of an Aerogel Cherenkov Counter for π+ and K+ identification in γd → K+(Λn) reaction (#1697)

T. Yuzawa1, H. Kawai1, M. Tabata1, A. Kobayashi1, K. Okuhata1

1 Chiba University Graduate School of Science and Engineering, Division of Advanced Science and Engineer, Physics course, Chiba, Japan

Content

In the FOREST/BLC experiment, which is being performed at the Research Center for Electron Photon Science (ELPH) at Tohoku University, Japan, photon beams are irradiated to the deuteron target, and hadron interactions are studied by detecting charged particles emitted in 0° direction in addition to γ-rays generated in multiple directions. Although nucleon interactions have been studied through only protons and neutrons for many years, it is important to investigate unified baryon interactions by adding hyperons. Therefore, the FOREST/BLC experiment focuses on the interaction γd → K+(Λn). A large amount of e+ and π+ are generated in the experiment. We have been developing a threshold-type Cherenkov counter that identifies K+ and π+. The momentum of K+ ranges from 0.7 to 1.0 GeV/c, and we use a silica aerogel with a refractive index of 1.12 as a radiator. A π+ veto rate of 99% or more is required. Thus far, we have been tested prototype counters using e+ beams of 675 MeV/c at ELPH. There were two types of prototypes; one was a specular reflection type that uses aluminized mylar sheets as a reflector, and the other was a diffuse reflection type that uses teflon sheets as a reflector. In the test beam experiment, both the types achieved a detection efficiency of 98% with respect to e+ at the center of the sensitive area of the counters. Considering the fake detection rate, the specular reflection type is promising, and further improvements in the detection efficiency can be expected by optimizing the internal structure with mirror surfaces. Results from the previous and coming June 2019 test experiments: i.e., the number of detected photoelectrons, its positional dependences, and expected particle identification efficiency will be presented.

Keywords: Silica aerogel radiator, Cherenkov Counter, Threshold-type Cherenkov Counter, particle identification
Poster panel: 142

Poster Number:
N-19-142

Independent confirmation of the MARS fast neutron spectrum by the WATCHBOY detector (#1797)

F. Sutanto1, 2

1 University of Michigan, Nuclear Engineering and Radiological Sciences Department, Ann Arbor, Michigan, United States of America
2 Lawrence Livermore National Laboratory, Physical Life Sciences Division, Livermore, California, United States of America

On behalf of the AIT-WATCHMAN Collaboration

Content

We present a measurement of the rate of correlated neutron captures in the WATCHBOY detector target at a depth of 390 meters water equivalent (m.w.e.) in the Kimballton Underground Research Facility (KURF). The WATCHBOY detector consisted of a cylindrical 2 ton water target doped with 0.1% gadolinium, surrounded by a 40 ton pure water hermetic shield. WATCHBOY was designed to measure or set limits on the rate of muogenic radionuclides in water, by looking for a characteristic pair of energy depositions, correlated on tens of microsecond time scale, generated by the radionuclide decay. The main background in WATCHBOY was expected to be correlated pairs of neutrons, arising from external muon interactions in nearby rock. We present a comparison of our results with the expected rate of correlated neutron captures from a hybrid FLUKA/Geant4-based simulation. The fast neutron energy distribution incident on the outside of the WATCHBOY shield was measured by the MARS detector at the same depth and used as an input to the simulation. We find that the measured and simulated neutron multiplicity distributions are consistent, providing an independent confirmation of the fast neutron energy spectra measured by MARS at 390 m.w.e. This in turn, increases confidence in the fast neutron spectra measured by MARS at different overburdens. Confirmation of the fast neutron spectrum is important as it places constraints on the scaling models used to extrapolate fast neutron flux between different overburdens.

Keywords: Antineutrino detection, fast neutron, nonproliferation
Poster panel: 144

Poster Number:
N-19-144

The FARCOS detection system: the first application in a real experiment (#1898)

L. Acosta1, 2, L. Auditore3, 2, C. Boiano4, G. Cardella2, F. Fichera2, A. Castoldi5, 4, M. D'Andrea2, F. De Benedetti4, A. Grimaldi2, E. De Filippo2, S. De Luca6, 2, F. Favela2, E. Geraci6, 2, N. Giudice6, B. Gnoffo6, 2, C. Guazzoni5, 4, G. Lanzalone7, 8, F. Librizzi2, C. Maiolino8, S. Maffessanti5, 4, N. S. Martorana3, 2, S. Pirrone2, S. Norella3, 2, A. Pagano2, E. V. Pagano8, M. Papa2, T. Parsani5, 4, G. Passaro8, G. Politi6, 2, L. Quattrocchi6, 2, F. Rizzo6, 8, P. Russotto8, G. Sacca'2, G. Salemi2, D. Sciliberto2, V. L. Sicari5, 4, A. Trifiro'3, 2, M. Trimarchi3, 2

1 Universidad Nacional Autónoma de México, Instituto de Fisica, Mexico City, Mexico
2 INFN, Sezione di Catania, Catania, Italy
3 Universita' degli Studi di Messina, Dip. di Scienze MIFT, Messina, Italy
4 INFN, Sezione di Milano, Milano, Italy
5 Politecnico di Milano and INFN, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
6 Universita' degli Studi di Catania, Dipartimento di Fisica e Astronomia, Catania, Italy
7 Universita' KORE, Facolta’ di Ingegneria e Architettura, Enna, Italy
8 INFN, Laboratori Nazionali del Sud, Catania, Italy

Content

FARCOS (Femtoscope Array for Correlation and Spectroscopy) is a modular detection system intended to extend the capacity of 4p detectors to perform correlation measurements. The final FARCOS system is composed of 20 telescopes, each formed by two Si layers (300 μm and 1500 μm thick) of 32-ch orthogonal Double Sided Silicon Strip Detectors and one calorimeter stage composed by 4 CsI(Tl) tronco-pyramidal scintillator crystals 6cm-thick readout by a Si photodiode. Now the first half of the FARCOS detection system are used in a real experiment at Laboratori Nazionali del Sud, INFN, Catania Italy. 10 FARCOS telescope units are coupled to the 4π CHIMERA detection system in the ChiFAR (Chimera/FARCOS) experiment. The ChiFAR experiment aims at studying dynamical processes in projectile break-up and Intermediate Mass Fragments production at 20 MeV per nucleon beam incident energy with the CHIMERA and FARCOS devices. The contribution will focus on the structure and performance of the final FARCOS detection array and will highlight the main instrumental features relevant for the experiments and the measured performance.

This work is supported by INFN, Istituto Nazionale di Fisica Nucleare in the framework of the NEWCHIM experiment.

Keywords: FARCOS, particle identification, pulse shape analysis
Poster panel: 146

Poster Number:
N-19-146

A measurement of (e,xn) cross sections of 181Ta with 100MeV electrons (#1941)

Y. Yang1, 2, Y. Yu1, 2, X. Weng3, Y. Yang1, 2

1 Tsinghua University, Department of Engineering Physics, Beijing, China
2 Tsinghua University, Key Laboratory of Particle & Radiation Imaging, Beijing, China
3 Northwest Institute of Nuclear Technology, State Key Lab. Of Intense Pulsed Radiation Simulation and Effect, Xi’an, China

Content

By directly exchanging the virtual photons, energetic electrons can transmit energy to the target nuclei and induce the emission of neutrons, which is termed (e,n) neutrons. As a one-step reaction, in which the real bremsstrahlung photons are not needed to be involved, the (e,n) reaction can generate neutrons when high energy electrons penetrates a thin foil, resulting in a small point neutron source with ultra-short pulse-width, which would be useful for the fast neutron resonant analysis. In our previous research, the (e,n) cross section of 100 MeV electrons with 181Ta has been measured. In this research, the detailed information in the electro-disintegration are analyzed, and the cross sections of (e,xn) reactions, in which x is the number of emitted neutrons are measured. The results show that (e,xn) reactions will be even more important than the (γ,xn) reactions with an enlarged x, indicating that the (e,xn) reactions can be used to generate proton-rich nuclides, being beneficial to the proton-drip line research. Both the experimental results and the preliminary interpretation will be presented.

Keywords: neutron source, (e xn)reaction, cross section, proton-drip line nuclides
Poster panel: 148

Poster Number:
N-19-148

Analysis of Mixed Radiation Fields in ATLAS with Timepix Hodoscopes (#2229)

T. Billoud1, 2, C. Leroy2, S. Pospisil1, B. Bergmann1

1 IEAP, Prague 1, Czech Republic
2 University of Montreal, Department of Physics, Montreal, Québec, Canada

Content

During the LHC Run 2 (2015-2018), a network of pixelated detectors (ATLAS-TPX) has been monitoring radiation in the ATLAS experiment. Each detector of the network is an hodoscope, made of two Timepix chips facing each other, with neutron converters placed in-between. This design allows for the detection of ionizing particles, photons and neutrons on a track- by-track basis. Moreover, the TOT mode of the Timepix chip has permitted the combined measurement of dE/dx and trajectory of energetic charged particles. We present here a comparison of the measured trajectories and dE/dX with predictions obtained from Monte Carlo simulations of the radiation field in ATLAS. Other detection capabilities of the ATLAS-TPX network will be investigated separately.

Keywords: Pixel detectors, particle tracking, radiation monitoring
Poster panel: 150

Poster Number:
N-19-150

Poster panel: 152

Poster Number:
N-19-152

ATLAS LAr Calorimeter Performance in LHC Run-2 (#2810)

K. E. Kennedy2

1 Columbia University, New York, New York, United States of America

On behalf of ATLAS LAr collaboration

Content

The ATLAS detector was designed and built to study proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and instantaneous luminosities up to 1034 cm−2s−1. Liquid argon (LAr) sampling calorimeters are employed for all electromagnetic calorimetry in the pseudo-rapidity region |η| < 3.2, and for hadronic calorimetry in the region from |η| = 1.5 to |η| = 4.9. In the first LHC run a total luminosity of 27 fb−1has been collected at center-of-mass energies of 7-8 TeV between year of 2010 to 2012. Following a period of detector consolidation during a long shutdown, Run-2 started with approximately 3.9 fb-1and 35.6 fb-1of data at a center-of-mass energy of 13 TeV recorded in 2015 and 2016, respectively. In order to realize the level-1 acceptance rate of 100 kHz in Run-2 data taking, number of read-out samples for the energy and the time measurement has been modified from five to four with keeping the expected performance. The well calibrated and highly granular Liquid Argon Calorimeter achieved its design values both in energy measurement as well as in direction resolution, which was a main ingredient for the successful discovery of a Higgs boson in the di-photon decay channel. This contribution will give an overview of the detector operation, hardware improvements, changes in the monitoring and data quality procedures, to cope with increased pileup, as well as the achieved performance, including the calibration and stability of the electromagnetic scale, noise level, response uniformity and time resolution.

Keywords: calorimetry, particle detectors
Poster panel: 154

Poster Number:
N-19-154

Studies and validation of a CMS Drift Tube trigger algorithm for HL-LHC (#2405)

C. Carrillo1

1 CIEMAT, Madrid, Spain

On behalf of the CMS Collaboration

Content

The electronics of the CMS (Compact Muon Solenoid) DT (Drift Tubes) chambers will need to be replaced for the HL-LHC (High Luminosity Large Hadron Collider) operation due to the increase of occupancy and trigger rates in the detector, which cannot be sustained by present system. A new system is being designed that will forward asynchronously the totality of the chambers signals to the control room, at full resolution. A new backend system will be in charge of building the trigger primitives of each chamber out of this asynchronous information, aiming at achieving resolutions comparable to the ones that the offline High Level Trigger can obtain nowadays. In this way, the new system will provide improved functionality with respect to present system, allowing to improve the resilience to potential aging situations. An algorithm has been designed for this new backend system following a simplified, hardware-oriented procedure optimizing the FPGA resources. The performance of this algorithm has been validated through different methods: from a software emulation approach to hardware implementation tests. The performance obtained is very good, with optimal timing and position resolutions, close to the ultimate performance of the DT chamber system. One important validation step has included the implementation of this algorithm in a prototype chain of the HL-LHC electronics, which has been operated with real DT chambers under cosmic data taking campaigns. The new trigger primitive generation has been implemented in spare uTCA boards from present DT system which host Xilinx Virtex 7 FPGAs. The performance of this prototyping system has been verified and will be presented in this contribution, showing the goodness of the design for the expected functionality during HL-LHC.

Keywords: Compact Muon Solenoid, Drift Tubes upgrade, FPGAs, High Luminosity Large Hadron Collider, trigger systems
Poster panel: 156

Poster Number:
N-19-156

Design and performance of the LHCb detector and full real-time reconstruction in Run 2 of the LHC (#2480)

M. Alexander1, 4, M. Borsato4, A. Poluektov4, G. Zunica5, 4

1 University of Glasgow, School of Physics and Astronomy,, Glasgow, United Kingdom
2 The LHCb collaboration, CERN, Switzerland
3 University of Manchester, Physics and Astronomy, Manchester, United Kingdom

On behalf of the LHCb collaboration.

Content

The LHCb collaboration has redesigned its trigger to enable the full offline detector reconstruction to be performed in real time. Together with the real-time alignment and calibration of the detector, and a software infrastructure for persisting the high-level physics objects produced during real-time processing. This redesign enabled the widespread deployment of real-time analysis during Run 2. Furthermore, the widening of the LHCb physics program and the higher precision made possible by the large dataset collected in Run 2 prompted the development of several new techniques for precise calibration of the detector performance. We will describe the design of the Run 2 trigger and real-time reconstruction, and present data-driven performance measurements for a representative sample of LHCb's physics programme.

Keywords: High energy physics instrumentation computing
Poster panel: 158

Poster Number:
N-19-158

Performance Evaluation of a Clock Synchronization over Fiber Data links for Large Experiments (#2551)

Y. Hu1, Y. Wang1, J. Kuang1

1 University of Science and Technology of China, Department of Modern Physics, hefei, China

Content

Most large experiments for high energy particle physics are time measurement related, which requires a network supporting the broadcast communication in order to distribute the central clock to all endpoints. In addition to conventional solutions using a dedicated network just for time synchronization, several groups have proposed to embed the clock distribution network into the data stream network. Using only a single bidirectional fiber link for all network abilities, some special demands for these experiments, for example, limited space for hardware and long distance connection, can be satisfied. As the time resolution of detectors is constant increasing, the performance requirement for time synchronization based on this unified network is challenged. In this paper, we propose to use the state-of-art techniques on field programmable gate arrays (FPGA) and optical circulator based fiber connections to implement the unified network. By constructing a prototype system with three levels of hierarchical structure, the time synchronization performance is experimentally measured. Benefitting from the single wavelength fiber connection, high precision time-to-digital convertors (TDC), and phase interpolator (PI) components in FPGA SerDes transceivers, the clock offset of the distribution can be precisely measured and automatically compensated. Through multiple times of power-on and reset operation test, the clock synchronization accuracy over 5 km fiber connection is measured less than 40 ps. By employing the jitter cleaner devices in clock recovered endpoints, the recovered clock in different levels have independent jitter less than 4 ps. In addition, the achieved high performance is also proved to be insensitive to operation temperature and the connection distance. The test results show that the proposed implementation is a straight-forward and practical method with the high performance that can meet the requirements of most current large-scale experiments.

Keywords: Clock synchronization, SerDes, Optical circulator, TDC
Poster panel: 160

Poster Number:
N-19-160

Testing highly integrated components for the technological prototype of the CALICE silicon tungsten electromagnetic calorimeter (#2645)

A. Irles1

1 LAL Orsay, Orsay, France

CALICE Collaboration

Content

A highly granular silicon-tungsten electromagnetic calorimeter (SiW-ECAL) is the reference design of the ECAL for International Large Detector (ILD) concept, one of the two detector concepts for the detector(s) at the future International Linear Collider. Prototypes for this type of detector are developed within the CALICE Collaboration. The final detector will comprise about 10^8 calorimeter cells that have to be integrated in a volume of maximal 20 cm in depth. Detector components that in terms of size and channel density come already close to the specifications for future large scale experiments are progressively developed. This contribution will report on the performance of a new 1.2 mm thick 9-layer PCB with wirebonded ASICs and comparisons with PCBs with BGA packaged ASICs will be presented. A volume of about 6x18x0.2 cm^3 is available for the digital readout and the power supply of the individual detector layers that feature up to 10000 calorimeter cells. We will present newly developed electronic cards that meet these constraints.

Keywords: granular calorimeters, compact readout
Poster panel: 162

Poster Number:
N-19-162

Towards reactor antineutrino directional detection – observation of PSD in a 64-segment plastic-scintillator detector using SiPM arrays (#2742)

S. Dazeley1, V. Li1, F. Sutanto2, 1, I. Jovanovic2, A. Maybe1, T. Classen1

1 Lawrence Livermore National Laboratory (LLNL), Nuclear and Chemical Sciences Division, Livermore, California, United States of America
2 University of Michgan, Nuclear Engineering, Ann Arbor, Michigan, United States of America

Content

Reactor antineutrino detection generally requires a proton rich organic scintillator doped with a neutron capturing agent such as gadolinium or 6Li. The resulting detector signal is therefore a ~few MeV positron followed a few 10’s of microseconds later 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 backgrounds 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. We are investigating an alternative approach – 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 by a form of 6Li-doped plastic PSD organic scintillator, which can be machined into thin rods and coupled with position sensitive silicon-photomultiplier (SiPM) arrays, 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. Our group is building a detector with the aim of testing sensitivity to direction 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-773893.

Keywords: Inverse beta decay, Reactor monitoring, Pulse shape discrimination, neutron capture, directionality
Poster panel: 164

Poster Number:
N-19-164

Deployment of the First Photofission Measurement System Dedicated to SNM Detection in Europe: Outcomes and Future Prospects (#1055)

A. Sari1, F. Carrel1, A. Grabowski1, F. Lainé1, B. Espinosa1, J. - P. Poli1, P. Sibczyński2, I. Della-Rocca3, M. Foster3, A. Etilé4, O. Roig4, S. Maitrejean5, S. Rogerat5, T. Berthelier5, E. Gasser5, M. Slegt6, R. de Goede6, J. Groeneveld6, H. de Wilde6, M. Heerschop6

1 CEA List, Gif-sur-Yvette, France
2 National Centre for Nuclear Research, Radiation Detectors Division, Otwock, Poland
3 Symetrica Security Ltd, Southampton, United Kingdom
4 CEA DAM, Arpajon, France
5 Smiths Detection, Vitry sur Seine, France
6 Dutch Customs Administration, Rotterdam, Netherlands

Content

Special Nuclear Material (SNM) such as uranium and plutonium isotopes could be potentially used to make a nuclear bomb involved in a terrorist attack. To prevent illicit trafficking of SNM in Europe, inspection of cargo containers at borders is required. X-ray scanning is widely used by customs to control suspect containers. However, this technology is not the most adapted to bring to light SNM signature. Therefore, a second line technology based on the photofission reaction could enable to detect SNM in a non-destructive manner. In the frame of the C-BORD European project, several teams specialized in photofission have joined forces to design an active photon interrogation system enabling to detect SNM hidden in cargo containers. The system is based on the use of a linear electron accelerator (linac). First, high-energy photons generated by Bremsstrahlung in the conversion target of the linac irradiate a suspect area of the cargo container. Secondly, prompt and delayed particles emitted following photofission reactions are detected if SNM is present. The largest seaport in Europe (Maasvlakte, in the suburbs of Rotterdam, Netherlands), where 9 MeV linacs are used by Dutch customs for X-ray scanning, has been chosen as test site. In order to deploy a full system taking advantage of all photofission signatures, different subsystems have been developed. In this paper, first, we give an overview of the photofission system. Then, we show how the system has been deployed at the Rotterdam seaport in September and October 2018 and tested on mock-ups of cargo containers. Finally, we show that setting up a photon interrogation system on an industrial facility initially designed for X-ray scanning is a challenge which has been successfully met in the frame of the C-BORD project to deploy the first photofission measurement system on an industrial site in Europe. The outcomes of this first deployment will be exposed and the future challenges to be addressed will be discussed.

Keywords: Active photon interrogation, cargo containers, linear electron accelerator (linac), photofission, uranium
Poster panel: 166

Poster Number:
N-19-166

Improvement of detection limit in differential die-away analysis system for nuclear non-proliferation and nuclear security (#1149)

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

1 Japan Atomic Energy Agency, Nuclear Science and Engineering Center, ibaraki, Japan

Content

In the fields of safeguards, nuclear non-proliferation, and nuclear security, non-destructive analysis (NDA) techniques useful for highly radioactive nuclear materials (NMs) are not established yet because there are so many technical difficulties to measure the amount of the highly radioactive NMs. A novel NDA system with a pulsed neutron source as the method for determining the composition of mixed NMs has been developing in the Japan Atomic Energy Agency (JAEA). In the NDA system, a differential die-away analysis (DDA) technique is used to quantify the amount of fissile materials. The detection limit of fissile materials in DDA system is determined by the signal to noise ratio in fast neutron counting. A method to reduce the noise signal by using neutron absorber (B4C rubber) sheets mounted on the inner entire surface in the sample cavity is proposed. The effect of the sheets on the reduction of noise signal in the fast neutron counting was investigated in both experimental test and simulation. The experimental results show that it is possible to detect a nuclear fissile material (239Pu) of as low as 1 mg in a vial bottle when the absorber sheets with a thickness of 3 mm is used. The comparison between experimental data and simulation results is presented

Keywords: NDA, NM, Differential die-away, Nuclear non-proliferation, nuclear security
Poster panel: 168

Poster Number:
N-19-168

Development of a Field Deployable Imaging Neutron Detector (FIND) for SNM (#1204)

J. S. Legere1, P. F. Bloser2, M. L. McConnell1, J. M. Ryan1

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

Content

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. This paper describes the development and testing of a Field-Deployable Imaging Neutron Detector (FIND). The FIND instrument is based on modern, commercially available detector technology that is compact, low-power, low-mass, and rugged. Individual detector cells are composed of stilbene organic scintillators that are read out by arrays of silicon photomultipliers (SiPMs). Two layers of such detector cells form a double-scatter neutron camera.  The compactness, ruggedness, and low weight of this technology allow these layers to be easily transported in a single standard portable container for rapid deployment in the field.  Gamma-ray imaging and low-resolution spectroscopy can be achieved as well. We describe the FIND instrument in detail and present imaging and spectroscopy results from laboratory and field measurements.

Keywords: Neutron Imaging, Neutron Spectroscopy, SNM Detection
Poster panel: 170

Poster Number:
N-19-170

A Novel Approach to Determining the Distance From a Source with a Single Measurement and no Prior Knowledge of Source Activity (#1261)

C. Cooke1, J. J. Velthuis1, 2, L. Beck1

1 University of Bristol, HH Wills Physics Laboratory, Bristol, United Kingdom
2 University of South China, School of Nuclear Science and Technology, Hengyang, China

Content

This paper describes a technique to find the distance between a stationary gamma source and a detector using a single measurement with no prior knowledge of the source’s activity. To do this, the percentage of detected counts in a radiation detector under the photopeak is used. This method has been tested using Geant4 simulations for 235U, 137Cs and 60Co for distances of up to 6 m. The percentage counts below the photo peak compared to the total counts was plotted against the distance, then these curves were fitted and used to reconstruct the distance for new data samples. Three different energy cuts for the percentage counts were tested for each source. A very strong correlation between the true and reconstructed distance was found. The most accurate 60Co reconstruction used a cut at 1.10 MeV, where the graph of the reconstructed distance vs the true distance had a gradient of 1.01±0.04. For 137Cs, the best cut was at 0.66 MeV with a gradient of 0.96±0.04, and for 235U the best cut was at 0.15 MeV with a gradient of 0.93±0.02. High and low air pressure simulations were also tested for 137Cs and found to retain good distance resolution.

Keywords: radiation detectors, homeland security
Poster panel: 172

Poster Number:
N-19-172

GAGG-based gamma-ray detector for in-situ ocean radiation monitoring (#1356)

S. Lee1, J. S. Lee1, 2, G. B. Ko2, S. Baek3, J. - M. Seo3, S. M. Kim3

1 Seoul National University, Department of Biomedical Sciences, Seoul, Republic of Korea
2 Brightonix Imaging Inc., Seoul, Republic of Korea
3 Korea Institute of Ocean Science and Technology, Maritime ICT R&D Center, Busan, Republic of Korea

Content

Frequent monitoring of ocean radiation level in desired sites is required to manage the safety of nuclear power plant operation and rapidly deal with radiation discharge into the ocean. We developed a gamma-ray detector consisted of a large-sized monolithic GAGG crystal and silicon multipliers. The detector was carried by an unmanned surface vehicle for in-situ radiation detection and the data was transferred via ultra-high field communication to the laboratory PC. We first performed energy and temperature calibrations of the detector and the multichannel analyzer. The detector showed acceptable energy linearity and energy resolution of 8.4% for Cs-137 detection. We also performed water tank experiments to investigate underwater detectability. Differing the depth of Cs-137 point source, we obtained energy spectra and measured 662-keV peak count rate. The count rate was sufficiently high when the Cs-137 source was placed within 1 m from the detector. High attenuation of gamma-rays in the water contributed to the limitation in the detectable distance, but the superior mobility of the system is able to overcome the limitation. To measure natural ocean activity concentration, the future work will be focused on the sensitvity improvement of the detector and conversion of count rate to activity concentration.

Keywords: Ocean radiation, Radiation protection, GAGG
Poster panel: 174

Poster Number:
N-19-174

Radiological characteristics of CANDU spent fuel stacks using optical fiber probe (#1383)

S. Park1, Y. Kim1, S. Joung2

1 Korea Institue of Nuclear Non-proliferation and Control (KINAC), Daejeon, Republic of Korea
2 Korea Atomic Energy Research Institute, Daejeon, Republic of Korea

Content

The Optical Fiber Probe System (OFPS) was developed for Physical Inventory Verification (PIV) of CANDU spent fuel pool. OFPS is consisted with an optical fiber with scintillator to react just gamma-ray from spent fuels. In this study, a couple of types of scintillation material are evaluated to be appropriate sensor for the physical inventory verification considering detection efficiency, resolution and also cost effectiveness and handling. The peaks from the plastic scintillator (BC-400) are higher compared to those of lithium-7 (Li-7) scintillator due to higher light yields, reduced decay time and larger volume. The sensibility of the plastic scintillators has ability to find hidden peaks between high peaks. BC-400 can be considered appropriate sensor substituting Li-7.

Keywords: Spent fuel, Optical fiber Probe System, Plastic Scintillator, Li-7
Poster panel: 176

Poster Number:
N-19-176

4π Spectrometric Gamma-Ray Scanner with Anti-Collimator (#1527)

O. P. Ivanov1, V. N. Potapov1, I. A. Semin1, S. M. Ignatov1

1 National Research Centre Kurchatov Institute, Rehabilitation, Moscow, Russian Federation

Content

Decommissioning of nuclear facilities requires the instrumentation for full and precise characterization of radioactive contamination of premises and installations. Because of different conditions of measurements the devices with different characteristics- sensitivity, weight, and angular resolution are needed. The paper presents the development of a low weight spectrometric system with a wide scanning field (up to 4π) , a wide range of dose rate, and with an angular resolution about 5o. The anti-collimator principle is used to obtain spatial modulation of the signal. When scanning a scene, the system rotates in such a way that anti-collimator blocks the radiation flux to the detector from a certain spatial area. During the scanning of all directions, a primary image is obtained, which is then reconstructed by an iterative procedure using the angular apparatus function of the system. The apparatus function can be measured using point gamma-ray source or calculated on base of Monte-Carlo simulation of the system. The Monte-Carlo simulation was carried out to optimize parameters of system with CsI(Tl) scintillator placed behind anti-collimator. The crystal volume of the detector was chosen for examination of premises with a dose rate about 1 mR/h and is 6 cm3. As a result of the optimization, a cylindrical lead shutter (anti-collimator), D 3.2 cm x L 4 cm was selected, the distance between the anti-collimator and the detector should be 15 cm. A prototype of the system with spectrometric detector based on a 6 cm3 CsI(Tl) scintillator crystal with silicon photomultipliers (SiPM) was manufactured. The dependence of the detector energy resolution on the number of SiPMs has been studied. When using 4 SiPMs, the energy resolution of Cs-137 was 12.1%. First images of the scenes consisting of different gamma sources were obtained and reconstructed. Results of measurements present angular distribution of partial dose rate of different nuclides in the location of the system.

Keywords: Gamma-ray imaging, Anticollimator
Poster panel: 178

Poster Number:
N-19-178

Commercialization of the Li Foil Multi-Wire Proportional Counter Neutron Detector, a Backpack Radiation Detector Design (#1549)

B. W. Montag1, S. L. Bellinger1, N. S. Edwards2, L. C. Henson1, J. Lage2, D. S. McGregor2, T. R. Ochs2, J. Terrel2, L. M. Whitmore1, B. Willis1

1 Radiation Detection Technologies, Manhattan, Kansas, United States of America
2 Kansas State University, Mechanical and Nuclear Engineering, Manhattan, Kansas, United States of America

Content

The Li foil multi-wire proportional counter (Li Foil MWPC) neutron detectors have shown promise as a 3He replacement technology and are currently being developed into a commercialized product. Large area Li Foil MWPCs with five layers of 75-µm thick 6Li foils have been built and characterized, yielding over 55% thermal neutron detection efficiency, with the possibility of increasing the efficiency above 70% with ten 96% enriched 6Li foil layers. Most recently, a modular design is being commercialized to be included in a backpack radiation detector (BRD) configuration. The simulated device intrinsic thermal neutron detection was determined at 39.2%, for a four-foil device (two wall foils, and two suspended foils). These Gen3 devices were fabricated with advancements from prior prototype devices including an on-board custom electronics package, a new electrical feedthrough, and advanced anode wires. The custom electronics package is being evaluated at the moment that incorporates pulse shape discrimination where all microphonic noise is removed from the measured signal. Four of the new Gen3 devices are currently being evaluated in a BRD configuration that has approximately 1000 cm2 of active neutron-sensitive area. The Li Foil BRD continues to undergo radiological evaluations to various neutron sources (252Cf, AmBe, AmLi, WGPu) and gamma-ray rejection to 60Co. At 1.5 meters in the horizontal source plane, the BRD responses with 0.36cps/ng of 252Cf and has a gamma-ray rejection ratio of 10-14 at 60mR/Hr of 60Co. In addition, vibration tests are under way to confirm all false positive signals (microphonic interruptions) are discriminated from the collected signal. The Li Foil MWPC latest generation devices are currently being integrated into BRDs provided by NucSafe, Inc., including the Guardian Surveyor, Guardian Patriot and Guardian Predator. A current status of the technology readiness of the Li Foil MWPC and commercial availability will be presented here.

Keywords: Neutron Detector, Lithium, Large-area, Portable, Backpack
Poster panel: 180

Poster Number:
N-19-180

Demonstration of Isotope CT Using NRF Absorption Method in UVSOR-BL1U (#1590)

K. Ali1, H. Ohgaki1, H. Zen1, T. Kii1, T. Hayakawa2, T. Shizuma2, H. Toyokawa3, Y. Taira3, V. Iancu4, G. Turturica4, M. Fujimoto5, M. Katoh5

1 Institute of Advanced Energy, Kyoto University, Kyoto 611-0011, Japan
2 Tokai Quantum Beam Science Center, National Institutes for Quantum and Radiological Science and Technology (QST), Ibaraki 319-1106, Japan
3 National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2-4, IBARAKI 3058568, Japan
4 Extreme Light Infrastructure - Nuclear Physics, s/ Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, Bucharest-Magurele, Judet Ilfov, RO-077125, Romania
5 UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan

Content

Nuclear resonance fluorescence (NRF) absorption method could have an ability to identify the shielded isotopic contents such as special nuclear materials inside the spent nuclear fuel canisters, nuclear wastes, or those surrounded by massive materials for the non-destructive inspection. This method could provide its distribution image. Taking into account the gamma-ray transmission factor with both effects of the atomic and nuclear resonant attenuation, a Computed Tomography (CT) image of the enriched 208Pb isotope distribution has been obtained in UVSOR-BL1U where a Laser Compton Scattering (LCS) gamma-ray beam has been available. In March 2019, we have introduced a new laser system and have upgraded the energy and intensity of the LCS gamma-ray beam to be 5.52 MeV with a total flux of 1×107 photons/s before the collimator to excite a level with Jπ=1- at 5.512 MeV in 208Pb. A lead collimator of 1 mm diameter was used to define the incident gamma-ray beam diameter on the CT target. For the detection system, a Plastic Scintillation detector was used to measure the incident LCS gamma-ray beam flux, and also a LaBr3(Ce) detector was used to measure the flux of the transmitted gamma-ray beam. For measuring the NRF gamma-rays scattered from the witness target (enriched 208Pb) two High Purity Germanium detectors were used. The CT target consisted of three cylindrical rods (206Pb, 208Pb, and natural lead) of which individual diameters were 6.1 mm. The rods were implanted in a Bismuth cylinder holder (99.99% purity) with a 25-mm diameter and a 20-mm height. The CT target was placed on a two-axis movable stage whose position was changed in the horizontal dimension in steps of 2 mm from 0 to 26 mm, and the target rotation angle was changed in steps of 30 degrees from 0 to 150 degree. The NRF-CT reconstruction image of 208Pb will be discussed.

Keywords: Nuclear resonance fluorescence (NRF), Computed Tomography (CT), Laser Compton Gamma-ray Beam, Isotope Distribution
Poster panel: 182

Poster Number:
N-19-182

Reliably Implemented Non-destructive Spectrometric Method for the Characterization of the Volume Radioactive Contamination of Objects at Nuclear Industry. (#1681)

V. N. Potapov1, E. A. Stepanov1, O. P. Ivanov1

1 National Research Centre Kurchatov Institute, Rehabilitation, Moscow, Russian Federation

Content

A method for characterization of a volumetric radionuclide source of pollution in the environment without prior information on the distribution of radionuclides in the objects is presented. The method was originally developed to characterize radioactive fallout after the Chernobyl accident. The method is based on determining the count rates in the region of the peak of total absorption for a particular nuclide and the Compton region to the left of the peak, in gamma-ray spectrum of nuclide. The ratio of these rates is determined by the surface activity and the depth of contamination. The method is implemented using a spectrometer with a gamma detector of sufficient volume placed in the collimator. Two measurements are made with an open and closed collimator. The size of the detector depends on the required sensitivity. Instruments implementing the method are used in the decommissioning of nuclear facilities during the preliminary assessment of radioactive substances in the premises, as well as in the final assessment of the premises after decontamination operations at complex dose conditions and for the certification of radioactive waste containers. The method has obvious advantages: efficiency, information content, safety of use, non-destructive nature, variability and determination of the penetration depth of radioactive contamination. As development of method we consider a new approach based the deconvolution of spectrum for search of exact profile of contamination. The procedure of deconvolution uses the apparatus function of the system measured (or calculated) as set of spectra of the source in the form of an infinitely thin layer with uniform activity at different depth z in object. The measured spectrum is considered as the convolution of the apparatus function with the actual source distribution. The results of measurement with method at different conditions are presented.

Keywords: Gamma contamination, Spectrometric detector, in-situ measurement
Poster panel: 184

Poster Number:
N-19-184

Pulse shape analysis of plastic scintillator with pulse shape discrimination capabilities using optical photon tracking within Geant4. (#1771)

M. W. J. Hubbard1, M. P. Taggart1, P. J. Sellin1

1 University of Surrey, Department of Physics, Guildford, United Kingdom

Content

Plastic scintillators which exhibit pulse shape discrimination (PSD) properties for neutron and gamma radiation have been developed by companies such as Eljen Technologies (EJ-299, EJ-276) and Amcrys (UPS-113NG). When these materials have been scaled up to large sizes their PSD performance is observed to decrease. Utilising Geant4, the individual optical photons generated in scintillation events have been tracked, when these photons arrive at a detecting region their time distribution makes up the pulses. Typically the pulses have a rising edge and multiple decay time constants related to the scintillation mechanism from the initial radiation interaction. Further time constants can be convoluted onto the pulse signals to simulate photomultiplier tube or silicon photomultiplier readout. Analysing each stage of the pulse shape generation process has enabled sources to be identified that lead to convolutions within the decay time of the pulse shapes thus impacting PSD performance of the system. The work presented will show how pulse shape artefacts due to the directionality of emission and scintillator geometry impact the pulse decay times and PSD performance of plastic scintillators.

Keywords: Pulse Shape Discrimination, Plastic Scintillators, Geant4, Optical Simulation
Poster panel: 186

Poster Number:
N-19-186

Multiple Source Localization by Sensor Fusion of Digital Magnetic Compass Data with Spectroscopic Data (#1819)

E. Jacobs1, M. J. Neuer1, 2, C. Henke1, N. Teofilov1, W. Schykowski1

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

Content

A technique is shown to estimate the location of a source with a single detector. The method exploits an angular histogram of counts calculated by the fusion of the digital compass data with spectroscopic quantities like the count rate. The perimeter around the user is divided into N discrete segments. Storing the count rate in dependency of the angle towards north allows to calculate a count rate per segment, thus indicating from which direction the radiation comes from. This approach builds upon former works conducted with a gyroscope, showing that the compass is a more robust tool for the localisation. Additionally, it extends the perspective from finding a single source to the localisation of multiple sources.
Considering the application to a handheld radioisotope identification device, different hand motions are investigated and compared, where waving apparently has the best angular detection rates. The method also uses a graphical visualisation to guide the user towards the source. This tool is a compass rose combined with a segmented display of the angular count distribution. A single source and two sources are resolved by technique and graphical examples of the visualisation interface are presented. Also the aspect of moving towards or away from a source is covered. Here, segments to the front and segments to the rear are filled, based on the response of an additional gyroscope.
Test setup and test results are described. Crucial for resolving the position of a source is the ratio between motion radius and distance to the source. Distant sources do not vary enough to be resolved by waving motions. In such cases, full circle rotations are recommended, using the body of the user a temporary shield to increase the performance of position determination.

Keywords: source localization, detection algorithm, perimeter search, homeland security, nuclear security
Poster panel: 188

Poster Number:
N-19-188

Wireless and Robust Radioactivity Detector for Environmental Monitoring (#1844)

M. Carminati1, 2, G. L. Montagnani1, 2, L. Lorusso2, E. Lavelli2, G. Morandi3, P. Rizzacasa3, C. E. Fiorini1, 2

1 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milano, Italy
2 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
3 TNE SpA, Cassina de' Pecchi, Italy

Content

Within consolidating scenarios of wireless sensors networks and Internet-of-things for pervasive urban and environmental monitoring, we present a compact gamma-ray spectrometer based on 4 SiPMs coupled to a 2” NaI scintillator. This microcontroller-based system represents the evolution of an initial prototype to be embedded in lifting electromagnets to screen scrap metal for radioactive sources and, thus, tolerant to large magnetic fields. With the addition of wireless communication, plastic and rugged metallic cases, auxiliary inertial and magnetic sensors, and improved light collection, it offers 11% energy resolution at 662 keV, suitable for the majority of environmental safety applications, and a convenient 2” form factor. Operation on board of a drone is also demonstrated.

Keywords: SiPM, gamma-ray detection, NaI scintillator, scrap metal, waste
Poster panel: 190

Poster Number:
N-19-190

Development of a SiPM based coded aperture gamma camera (#1967)

X. Huang1, J. Zhai1, 2, L. Shuai1, Y. Liu1, W. He1, 2, X. Liang1, 2, Z. Zhang1, C. Wei1, L. Wei1

1 Chinese Academy of Sciences, Institute of High Energy Physics, Beijing Engineering Research Center of Radiographic Techniques and Equipment, Beijing, China
2 University of Chinese Academy of Sciences, School of Nuclear Science and Technology, Beijing, China

Content

Coded aperture imaging performs better in term of improving the detection efficiency, shortening the imaging time and improving the detecting sensitivity by a high opening ratio. In this paper, an imaging system of coded aperture gamma camera based on a 19×19 MURA collimator and latest silicon photomultiplier tubes (SiPM) was developed. The detector consisted of a 19×19 BGO array with the pixel size of 2.2mm×2.2mm×10mm. An 8×8 SiPM array was constructed using SensL’s J60035 sensors. The 64 channel SiPM signals were readout and digitized by one Maroc3 ASIC chip. Energy and position information of gamma rays were processed and calculated in FPGA. The performances of the imaging system were preliminarily evaluated. The results indicated that the system had a FOV of about 44.65° and an angular resolution of 2.56°. In low activity condition, the imaging of radioactive source also achieved good results.

Keywords: MURA, coded aperture, gamma camera, SiPM, ASIC
Poster panel: 192

Poster Number:
N-19-192

A Compact, High Resolution Radioxenon Detection System Using SrI2(Eu)+SiPMs and a Silicon Beta Cell (#2010)

S. A. Czyz1, A. T. Farsoni1, H. R. Gadey1, K. D. McGee1

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

Content

The release of several radioxenon isotopes (131mXe, 133Xe, 133mXe, 135Xe) in certain ratios is characteristic of a nuclear weapon detonation and acts as a “smoking gun” whereby the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) can identify clandestine nuclear testing activities. The detectors currently employed for this purpose in the International Monitoring System (IMS), though effective, have various drawbacks associated with them including cost, memory effect, lackluster energy resolution, and cumbersome readout electronics. To address some of these concerns, a new beta-gamma coincidence radioxenon detection system has been developed and characterized at Oregon State University. A PIPSBox, constructed from two parallel passively implanted planar silicon wafers, provides high resolution for electrons at room temperature, low background sensitivity, and a memory effect over an order of magnitude less than commonly employed plastic scintillators. A pair of ultra-bright D-shaped SrI2(Eu) scintillator crystals, each coupled to an array of silicon photomultipliers (SiPMs), are placed upon the outside faces of the PIPSBox. These detectors provide improved energy resolution for photons compared to the frequently employed NaI(Tl), while also providing a more rapid response time than high resolution solid state detectors such as coplanar CZT. Four independent signals, one from each detecting body, are digitized using a custom multi-channel digital pulse processor. An onboard high-performance FPGA identifies coincidence events between detectors in real-time. The design and characterization of the system, including evaluation using radioxenon samples, calculation of MDC, determination of memory effect, and comparison to other state-of-the-art radioxenon detection systems, will be discussed.

Keywords: Radioxenon, PIPSBox, Strontium Iodide, SiPM, CTBTO
Poster panel: 194

Poster Number:
N-19-194

Novel gamma tracker for rapid radiation direction detection for UAV drone use  (#2074)

R. Pani1, F. Camera2, A. Pergola2, C. Polito3, 4, R. Falconi3, G. Franciosini5, M. Longo6, 7, M. Bettiol6, 8, V. Frantellizzi9, G. De Vincentis10, L. Indovina11, A. Pani12

1 Sapienza University of Rome, Department of Medico-Surgical Science and Biotechnologies, Rome, Italy
2 NGdetector s.r.l., Rome, Italy
3 Sapienza University of Rome, Specialty School in Medical Physics, Department of Medico-Surgical Science and Biotechnologies, Rome, Italy
4 IRCCS Bambino Gesù Children’s Hospital, Medical Physics Unit, Rome, Italy
5 Sapienza University of Rome, Department of Physics, Rome, Italy
6 Sapienza University of Rome, Ph.D. Program in Morphogenesis & Tissue Engineering, Rome, Italy
7 Arcispedale Sant’Anna Hospital, Medical Physics Unit , Ferrara, Italy
8 IRCCS Istituto Tumori “Giovanni Paolo II”, Department of Medical Physics, Bari, Italy
9 Sapienza University of Rome, Department of Molecular Medicine, Rome, Italy
10 Sapienza University of Rome, Department of Radiologocal Sciences, Oncology and Antomical Patology, Rome, Italy
11 Università Cattolica del Sacro Cuore, Department of Physics, Rome, Italy
12 University of Milan Statale, Post Graduate School of Clinical Pharmacology and Toxicology, Milan, Italy

Content

The localization of radioactivity is an increasing topic of interest, both in the field of nuclear medicine and for environmental monitoring. We developed a gamma tracker prototype that is a small and handy object that can identify the direction of a radioactive source; it consists in more than one scintillation detecting elements with a cylindrical symmetry (40 mm height and 25 mm large) coupled with a position sensitive photo detecting matrix of SiPM; external crystals (LYSO, attenuation coefficient at 511 keV=0.86 cm-1) surround an internal one acting like an active collimation that shield the central detector (LaBr3:Ce or GAGG) and giving information about the radioactive source position. We firstly investigated spectrometric characteristics of the prototype detecting elements, irradiating the crystals with collimated 133Ba and 57Co sources; LaBr3:Ce crystal show an excellent Energy Resolution (RE) (6.4% at 122 keV), while external detectors show a good shielding property and a good RE, adequate to reduce the diffuse radiation background. Finally, we explored the properties of whole detecting system (scintillating crystals + SiPM matrix); we found that the spectrometric properties are not compromised by the crystals coupling with the photo detecting means and that the identification of the radioactive source direction is possible with an accuracy of 0.5°.

Keywords: gamma tracker, GAGG, SiPM, radioactive source direction
Poster panel: 196

Poster Number:
N-19-196

Potassium-40 Background Suppression in KSr2I5:Eu2+ (#2176)

H. Davis1, 2, A. Goluoglu1, 2, L. Stand3, 4, C. Goetz1, C. Melcher3, 4, E. Lukosi1, 2

1 The University of Tennessee, Nuclear Engineering , Knoxville , Tennessee, United States of America
2 The university of Tennessee, Joint Institute for Advanced Materials , Knoxville, Tennessee, United States of America
3 The University of Tennessee, Material Science Engineering , Knoxville, Tennessee, United States of America
4 The University of Tennessee, Scintillation Materials Research Center, Knoxville, Tennessee, United States of America

Content

KSr2I5:Eu2+(KSI) is an inorganic scintillator that demonstrates good energy resolution and potential low-cost growth. However, the presence of 40K, which emits both a 1.46 MeV gamma ray and a 1.31 MeV end-point energy beta, results in ~6.5 Bq/cm3intrinsic background. In addition, the scintillator exhibits a variable ballistic deficit due to the Eu2+activator, which results in a reduced energy resolution for short shaping times. The basis of this research is to take advantage of the challenges of 40K and the Eu2+activator to provide intrinsic background suppression and some measure of source localization. Because of the Eu2+ activator, transient responses of gamma interactions are dependent on the interaction location. Using pulse-shape discrimination (PSD), it is possible to determine where in the scintillator an incident gamma ray interacts for certain detector-source orientations. This information is then used to reject the intrinsic background in parts of the scintillator where the gamma rays do not interact. Further, PSD enables corrective measures to enhance the energy resolution while using faster shaping times. Finally, based upon the gamma ray energy and interaction profile within the crystal, it is possible to gain some directionality information about the source. Current results in applying PSD to enhance the efficacy of KSI for source detection, identification, and/or localization will be presented.

Keywords: Nuclear Security, Scintillator Detectors, Nuclear Engineering
Poster panel: 198

Poster Number:
N-19-198

Design and Development of a 3D Position-Sensitive Detector for 4π View Gamma Imager Based on Dual-Ended Readout Technique (#2258)

P. Fan1, 2, Z. Lyu3, T. Xu4, Y. Hu3, Q. Wei5, C. Zhu1, L. Jiang1, 2, Y. Xia1, 2, Y. Liu3, T. Ma3

1 China Academy of Space Technology, Beijing Institute of Spacecraft Environment Engineering, Beijing, China
2 Beijing Institute of Spacecraft Environment Engineering, Science and Technology on Reliability and Environmental Engineering Laboratory, Beijing, China
3 Tsinghua University, Department of Engineering Physics, Beijing, China
4 Beijing NOVEL MEDICAL Equipment Ltd, Beijing, China
5 University of Science and Technology Beijing, School of Automation and Electrical Engineering, Beijing, China

Content

Gamma imager capable of monitoring, detection and localization of radioactive sources is of critical importance for nuclear safety and homeland security with the increasing use of radioactive sources in applications of nuclear technology. A 4π view gamma imager based on gamma ray occlusion technique is under development in our lab. The key component of the gamma imager is a 3D position-sensitive detector, which enables 4π field of view of the imager. In this work, we propose a 3D position-sensitive detector design for the 4π view gamma imager based on dual-ended readout (DER) technique. The detector was composed of a 16 × 16 GAGG block coupled to an 8 × 8 SiPM array at both crystal ends. DOI calibration was conducted with a collimated fan beam 18F source and DOI resolution was evaluated. Energy calibration was performed for each 3D position region of the detector by incorporating 3D position information to correct for the energy response inconsistency in different 3D position regions inside the detector. Various radioisotopes including 99mTc, 131I, 137Cs and 22Na were tested. An exponential factor was applied to compensate for energy response non-linearity due to SiPM saturation effect at higher gamma energy. The measured average DOI resolution was 1.96 ± 0.21 mm for all the four DER detector modules, indicating excellent 3D positioning accuracy of the detector design. With the proposed energy calibration approach, characteristic photopeaks of each radioisotope can be clearly identified at the correct energy position on the measured energy spectra. The achieved energy resolution was 9.76% at 662 keV, demonstrating good energy performance of the detector design, which could benefit radioisotope identification capability of the gamma imager. To conclude, the proposed 3D position-sensitive detector design based on DER technique features good 3D positioning and energy performance and is feasible for the 4π view gamma imager.

Keywords: Gamma imager, 4π view, 3D position-sensitive detector, Dual-ended readout
Poster panel: 200

Poster Number:
N-19-200

A Compact and Low-Cost Radioxenon Detection System with Near-Zero Memory Effect (#2298)

H. R. Gadey1, A. T. Farsoni1, S. A. Czyz1, K. D. McGee1

1 Oregon State University, Corvallis, Oregon, United States of America

Content

Monitoring of atmospheric radioxenon concentrations and determining the ratios of 131mXe, 133/133mXe, and 135Xe is widely used by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) for the purpose of identifying clandestine weapon testing activities. Radioxenon detection systems that employ plastic scintillators in the capacity of a gas cell and an electron detector have been shown to exhibit a high memory effect. In this work, the design of a prototype electron-photon coincidence detection system using an organic stilbene scintillator coupled to SiPMs for light readout and solid-state coplanar grid CdZnTe is presented. Coincidence identification is carried out in real-time using an onboard Field Programmable Gate Array (FPGA) and pulses are transferred to the PC user interface for amplitude identification and generating the energy histogram. Detector calibration and characterization were carried out using lab check sources and high purity stable xenon isotope samples were irradiated in the Oregon State TRIGA reactor and injected in the gas cell to record detector response. All signatures from the decay of the four radioxenon isotopes of interest were uniquely identified. A 48-hour coincidence background was recorded and using the Regions of Interest (ROI) approach the Minimum Detectable Concentration (MDC) of all but 135Xe was found to be below the 1 mBq/m3 threshold set by the CTBTO. Using 131mXe the memory effect of the gas cell was found to be 0.045 ± 0.017%, this is almost a two orders of magnitude reduction compared to plastic scintillators. The use of high-resolution detector material coupled with negligible memory effect of the stilbene gas cell enabled this detection system to perform respectably compared to the state-of-the-art.

Keywords: CdZnTe, Coincidence detection, Nuclear weapon testing, Radioxenon, Stilbene
Poster panel: 202

Poster Number:
N-19-202

Evolution of Boron-Coated Straw Structures and Applications (#2440)

J. L. Lacy1, S. Davenport1, A. Athanasiades1, C. S. Martin1, H. Phung1

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

Content

An array of boron-coated rectangular channels offers the same detection efficiency in a more compact shape, and is significantly easier to manufacture and operate, compared to an array of tubular straws. Channels in the array are fabricated by squashing round boron-coated straws into rectangles. A wire tensioned at the center of each channel acts as the anode, and all channels share a common gas volume. The proposed squashed straw array (SSA) structure is an ideal solution for personnel security applications requiring compact, lightweight detectors. We present performance measurements for a prototype detector, formed as a 5x12 array of channels, each 1 mm deep x 5 mm wide x 100 mm long. The prototype can achieve the same neutron response as a 2-deep array of 31 pie12 straws, previously employed in a pocket-sized personal radiation monitor.

Keywords: Boron-Coated Straw, Neutron Detector, Wearable
Poster panel: 204

Poster Number:
N-19-204

Benchmarking Algorithm for RadioNuclide Identification (#2499)

M. Monterial1, A. Morton2, K. Nelson1, S. Labov1, A. Hecht2, S. Sangiorgio1

1 Lawrence Livermore National Laboratory, Nuclear and Chemical Sciences Division, Livermore, California, United States of America
2 University of New Mexico, Nuclear Engineering, Albuqurque, New Mexico, United States of America

Content

Benchmark Algorithm for Radio-Nuclide Identification (BARNI), an open-source radionuclide identification software package has been developed for use with a wide range of gamma-ray detectors. BARNI is designed to serve as a comparative tool against which all other vendor algorithms, found in RadioIsotope Identification Devices (RIID), could be compared against. The core identification algorithms follow a typical peak search and match strategy, leveraging machine learning to generate an expert system customized for a specific detector. Initial results for single and mixture radionuclide testing are presented, sampled from a library of 81 radionuclides under a wide range of shielding configurations.

Keywords: open-source, gamma-ray spectroscopy, machine learning, radionuclide identification
Poster panel: 206

Poster Number:
N-19-206

The AIT-WATCHMAN Project for Remote Monitoring of Nuclear Reactors (#2507)

C. Metelko2, F. J. R. Dalnoki-Veress1, W. C. On Behalf of1

1 MIIS, Monterey, California, United States of America
2 University of Liverpool, Physics Dept,, Liverpool, United Kingdom

This submission is on behalf of the AIT-WATCHMAN collaboration. We have not identified a speaker yet (I am chair of the Speaker Board for the collaboration) so it is possible I may not be the one to present.

Content

Antineutrino detectors could complement conventional safeguards methods to determine the power and fissile content of reactors under safeguards independent of knowledge of reactor operations, or even exclude the existence of reactors in wide geographical regions. In this presentation, we describe a new initiative known as the Antineutrino Instrumentation Testbed (AIT). AIT is a joint United States and United Kingdom project to test and demonstrate a range of antineutrino-based monitoring technologies for detecting nuclear reactors. The first project of AIT is an antineutrino detector located in the North-East England in the Boulby Underground Laboratory with a 1.1 km overburden shielding the detector from cosmic ray interactions. The detector will be located at 25 km standoff distance from the Hartlepool Reactor Complex housing two operational 1.5 GWth reactors. The detector will use 6,000 tons of gadolinium doped water as its antineutrino target and detection medium, and will be instrumented with several thousand light detectors known as photomultiplier tubes. When an antineutrino from the reactor interacts with the medium, it will produce a telltale signature of a prompt flash of light when the antineutrino hits a proton, separated within about 30 microseconds from another flash of light when the neutron released from the original interaction is absorbed on a gadolinium atom. This signal can be easily distinguished from most background signals. The goals of the experiment will be to determine the sensitivity for determining that any reactor is present, and when one, or both of the reactors are shutdown. By measuring signal efficiencies and backgrounds in a controlled but realistic real-world environment, AIT will help explore the prospect of detecting and monitoring smaller reactors at greater standoffs using a scalable water-based technology.

Keywords: antineutrinos, safeguards, reactor
Poster panel: 208

Poster Number:
N-19-208

Optimization of SPECT detectors for spent fuel inspection (#2547)

M. K. Baek1, H. J. Choi1, K. B. Kim1, J. J. Ahn2, C. H. Min1, Y. H. Chung1

1 Yonsei, Radiation Convergence Engineering, Wonju, Republic of Korea
2 Yonsei, Information and Statistics, Wonju, Republic of Korea

Content

Single photon emission computed tomography(SPECT) system has being developed for the structural evaluation of spent fuel assemblies in the water storage pool. The detector module uses an 1D array of pixelated scintillators coupled to 3x3 mm2 silicon photomultipliers(SiPMs) to achieve 3 mm and 40 mm spatial resolution in the trans-axial and axial directions, respectively. To maximize the light collection efficiency, the effect of the shape(rectangle, trapezoid) and surface condition (polish, rough) of the scintillator, and reflector materials(Teflon, paint, mirror film) on the light transfer characteristics were investigated. GATE optical simulation was performed and its results were verified experimentally. The trapezoid scintillator with rough surfaces and teflon wrapping showed the best light yield in the simulation and experiment. Further study will be conducted to develop a spent fuel inspection SPECT system based on this detector module.

Keywords: SPECT, collection efficiency, trapezoid scintillator, spent fuel assemblies, GATE optical simulation
Poster panel: 210

Poster Number:
N-19-210

Development of de-noised image reconstruction technique using Convolutional AutoEncoder for fast monitoring of spent fuel assemblies (#2605)

J. Y. Lim1, S. H. Choi1, S. J. Park1, H. J. Choi2, J. W. Jang2, C. H. Min2, Y. H. Chung2, J. J. Ahn1

1 Yonsei University, Applied statistics, Wonju, Republic of Korea
2 Yonsei University, Radiation Convergence Engineering, Wonju, Republic of Korea

Content

Spent nuclear fuels requires internal radioactivity measurements because it can cause radiation damage to people. A tomography method is used as a method for measuring this. The data obtained by the tomography is converted into an image, that can confirm the cross-section internal radioactivity distribution inside the spent nuclear fuels, by using the mathmetical image reconstruction method. However, there is a problem of low quality of image caused by noise and the time reqiured for complicated calculation when the image is obtained by the mathematical method used in the existing tomography. In order to overcome these problems, we propose an image processing method through deep learning. In this paper, we proposed convolutional autoencoder (CAE), one of the deep learning algorithm, which learns the reconstruction method both monte carlo simulated image and mathematically calculated image. The structure of the CAE consists largely of an encoder and a decoder. The encoder consists of two convolution layers and two max-pulling layers, and the decoder consists of two convolution layers and two up-sampling layers. Through the learning of such a deep learning structure, it is possible to obtain an image of improved image quality in addition to a fast operation.

Keywords: GATE, Single photon emission tomography, Filtered back-projection, Spent fuel assembly, Convolutional AutoEncoder
Poster panel: 212

Poster Number:
N-19-212

192Ir Source Localization via Gamma Ray Skyshine using Large Volume Pixelated CdZnTe (#1024)

D. I. Goodman1, D. L. Chichester2, Z. He1

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

Content

The direct line-of-sight between a detector and strong gamma-ray source can be heavily shielded in urban environments. In optically opaque scenarios, such as measuring a gamma-ray source through several buildings, little-to-no gamma-ray flux streams from directions around the source due to building attenuation. This unknown, non-spatially-smooth attenuation from buildings hinders traditional 1/r2-based localization in urban environments. Air-scattered gamma rays, known as skyshine, offer a complimentary signal that is a weak function of unknown ground-based shielding between the source and detector. Skyshine can be leveraged to localize strong gamma-ray sources, without the use of count rates, in attenuation heavy scenarios. Skyshine-based localization was demonstrated for a 83 Ci 192Ir source in a silo geometry using a H3D H420 CdZnTe detector. Source directionality was successfully estimated from coded aperture reconstructions of skyshine gamma rays at distances ranging from 25-150 m.

Keywords: CdZnTe, skyshine, compton imaging, rdd, scatter
Poster panel: 214

Poster Number:
N-19-214

Neutron/Gamma-ray Pulse Shape Discrimination with a Cs2LiYCl6:Ce3+ Scintillator (#1049)

Q. Nie1, J. Zhu1, H. Ma1, Z. Zeng1, J. Li1, H. Zhang1, J. Cheng1

1 Tsinghua, Department of Engineering Physics , Beijing, China

Content

Cs2LiYCl6-Ce3+ (CLYC) is a promising new inorganic scintillator for its ability to perform neutron detection and distinguish Neutron/Gamma-ray Pulse, which makes it a potential 3He gas replacement material. In this work, special integrated PMT digitizer was designed for a 1’’×1’’ CLYC scintillator enriched 95% 6Li. Differences on the rising time between n/γ pulses collected by 500 MSPS/12-Bit Analog-to-Digital Converter (ADC) and its effect on the traditional charge integration method were analyzed. A pulse shape discrimination (PSD) method based on Fisher linear discriminant was used to discriminate n/γ pulses with different parts of waveform. The results show that positive effect on n/γPSD appears when the integral window is well set according the rising time of n/γ pulses. Fisher classification achieves better figure-of-merit (FOM) of 4.6± 0.1 compared to charge integration method. This method also shows a reliable screening ability with short length waveform whose distinctions are mainly from the rising part. When the waveform length is 80 ns, the FOM is 2.3±0.1. This benefits the applications of CLYC at some situations with high count rates and short recording waveforms.

Keywords: Cs2LiYCl6:Ce3+ (CLYC) crystal, n/γ pulse shape discrimination, Fisher linear discriminant
Poster panel: 216

Poster Number:
N-19-216

Alternatives neutron detection systems for nuclear well logging application. (#1131)

A. Bala1, D. Jenkins1, P. Worthington​2

1 University of York, Department of Physics, York, United Kingdom
2 Robertson Geologging Ltd, Engineering & Development Section, Deganwy, Conwy , United Kingdom

Content

The need for an effective and efficient neutron detection systems in National security and safeguards, Neutron scattering science, Nuclear waste repositories, Neutron imaging, Nuclear physics research, Petroleum and gas exploration can not be overemphasized. He3 tube has been the most widely used detection systems which is as a result of their high neutron cross-section, insensitivity to gamma-ray, robustness for deployment and above all high thermal neutron detection efficiency. However, due to the increasing cost as a result of high demand and shortage of He3 gas, there has been many efforts put into research to find an alternative thermal neutron detection system with comparable performance to He3 tube. In this work we present the response of the thermal neutron detectors as used in neutron porosity tool during nuclear well logging. We compare the performance of He3 tube to Boron-coated straw tube (BCST), Lithium Aluminosilicate glass (GS20) and Lithium Calcium Aluminium Fluoride (Eu:LiCAF) from simulation. An experimental result obtained with BCST using AmBe neutron source was also compared with the BCST simulated result.

Keywords: BCST, GS20, Eu:LiCAF
Poster panel: 218

Poster Number:
N-19-218

Development of GEM-based neutron detector (#1227)

S. Yoo1, D. Song1, I. Park1, J. S. Lee1, K. Choi1, Y. Kang1, Y. Jung1

1 University of Seoul, Physics, Seoul, Republic of Korea

Content

GEM technology has the high-rate capability, fast timing and nice position resolution. A GEM-based detector with Gadolinium converter is a viable option for the replacement of 3He neutron detector. We studied various configurations such as the drift volume of the triple GEM chamber, the placement of Gadolinium converter and the energy of the neutron. The result using the AmBe source and neutron beam will be presented.

Keywords: GEM, neutron, gadolinium, Gas Electron Multiplier
Poster panel: 220

Poster Number:
N-19-220

Development of spectroscopic Compton imaging of prompt and delayed fission gamma-rays toward active interrogation of nuclear materials (#1300)

H. Tomita1, K. Kanamori1, A. Mukai1, T. Shimoyama2, J. Kawarabayashi3, E. Takada4, J. Hori5, T. Matsumoto6, K. Tsuchiya7, T. Iguchi1

1 Nagoya University, Department of Energy Engineering, Nagoya, Japan
2 Nagoya University, Facility for Nuclear Materials, Nagoya, Japan
3 Tokyo City Univ., Department of Nuclear Safety Engineering, Tokyo, Japan
4 Toyama College, National Institute of Technology, Toyama, Japan
5 Kyoto University, Institute for Integrated Radiation and Nuclear Science, Osaka, Japan
6 National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
7 National Research Institute of Police Science, Chiba, Japan

Content

In active interrogation methods to identify nuclear materials, spatial localization of the target leads to a high signal to background ratio detection. For identification of nuclear materials based on based on a combination of active neutron interrogation with imaging of neutron/gamma-ray caused by neutron irradiation, it is important to consider attenuation of neutron/gamma-ray by shielding around the target. Therefore, we propose a spectroscopic Compton imaging of prompt and delayed fission gamma-rays to obtain information of both the target and its surrounding materials toward active interrogation of nuclear materials. We have demonstrated a localization and quantitative activity measurement of a hidden gamma source using a 4π direction sensitive Compton image. Here we report prompt gamma-ray imaging of 10B and results from spectroscopy of delayed fission gamma-ray using an electron LINAC based pulsed neutron source at Kyoto University Institute for Integrated Radiation and Nuclear Science by the prototype imager. Effect of thermal neutron shielding and spatial selection to the 10B prompt gamma image were investigated. Further detailed analysis of prompt gamma-ray imaging and delated fission gamma-ray spectroscopy will be presented with future prospects of a combination of prompt gamma- and delated fission gamma- imaging as an advanced active interrogation method.

Keywords: Compton imaging, prompt gamma-ray, delayed fission gamma-ray, active interrogation
Poster panel: 222

Poster Number:
N-19-222

Can Ce:Gd3Al2Ga3O12scintillators detect thermal neutrons? (#1373)

C. L. Wang1

1 Songshan Lake Materials Laboratory, Neutron Science Group, Dongguan, China

Content

Alternative neutron detectors are actively being searched to replace 3He gas detectors for neutron scattering and homeland security. Neutron scintillators for this purpose must have high light output, short decay time, low sensitivity to gamma-rays, and possibly be non-hygroscopic. Gd-containing oxide scintillators are excellent in detecting gamma-rays, but their thermal-neutron detectability has not been proven yet, because of similar pulse-shapes generated under thermal neutron and gamma irradiation. Here we show that a non-negative matrix factorization (NMF) algorithm for digital signal processing greatly improves neutron-gamma discrimination ratio (the ratio of neutron and gamma detection efficiencies) of a Gd-containing scintillator, Ce:Gd3Al2Ga3O12(Ce:GAGG). In the case of Ce:GAGG as a gamma detector, an excellent discrimination between gamma and ambient background events was also observed. Therefore, Gd-containing scintillators are potentially applicable in not only neutron detection but also in gamma detection with high signal-to-noise ratio. This result would open new venues for neutron/X-ray scattering science, nuclear medical imaging, and homeland security applications.

Keywords: Gd-containing scintillator, neutron-gamma discrimination, neutron and gamma detectors, digital signal processing, high signal-to-noise ratio
Poster panel: 224

Poster Number:
N-19-224

Portable Timepix3 Compton Camera for Real-time Gamma Imaging (#1488)

P. Mánek1, B. Bergmann1, M. Pichotka2, 1, F. Zavoral3

1 Czech Technical University, Institute of Experimental and Applied Physics, Prague, Czech Republic
2 University Hospital Freiburg, Department of Nuclear Medicine, Freiburg, Baden-Württemberg, Germany
3 Charles University, Faculty of Mathematics and Physics, Department of Software Engineering, Prague, Czech Republic

Content

Compton cameras localize γ-ray sources in 3D space by observing scattering and absorbtion of photons with pixel detectors. This work presents a new portable Compton camera designed for real-time γ-imaging applications. The principal component of the camera is a telescope comprised of synchronized Timepix3 hybrid pixel detectors, here a 300 μm thick silicon scattering layer and a 2 mm thick CdTe absorber. Observed clusters of events then correspond to conic surfaces in 3D space, from which the γ-ray source is reconstructed by back projection. Due to the improved performance of Timepix3 ASIC over its predecessors, reconstruction offers increased angular accuracy, and permits for continuous data-driven data acquisition, conveniently combined with online data processing. To ensure high performance in possibly harsh environments, the reconstruction software is implemented as a chain of vectorizable algorithms, relying on data structures of low worst-case asymptotic complexity. In addition, the most computationally intensive stage was fully offloaded to a multi-GPU pipeline, achieving average speedups of 2-3K compared to single-threaded CPU implementation. Results of the first experimental measurements are consistent with Geant4 simulation, indicating that the presented device constitutes a viable method of 3D γ-ray source localization.

Keywords: Timepix3, Compton camera, Katherine, back projection, gamma imaging
Poster panel: 226

Poster Number:
N-19-226

Optimization of a Multi-Layered Scintillator for Neutron Detection and Spectroscopy Applications (#1540)

A. Osovizky1, 2, Y. Yehuda-Zada2, D. Ginzburg1, Y. Ifergan2, R. Seif2, T. Edvabsky2, R. Harn2, Y. Knafo2, M. Ghelman2, Y. Kadmon2

1 Rotem Industries Ltd., Beer Sheva, Israel
2 Nuclear Research Center Negev, Beer Sheva, Israel

Content

This work presents a multi-layered detection (MLND) approach as a possible utilization of a neutron detector. An optimization study and its advantages for neutron spectroscopy and as an alternative for He-3 gas is discussed.
The MLND approach is based on several sequenced layers of thin tile LiF-ZnS(Ag) optically coupled to a few millimeters of acrylic sheet. The acrylic sheet functions as both, a transparent moderator and a light guide for the scintillation light towards a silicon photomultiplier (SiPM) light sensor. Such configuration provides high neutron sensitivity along with the benefit of approximate neutron spectroscopy.  This feature is required in neutron detection applications, such as health physics or material studies, which require the assessment of the neutron's flux at different energy ranges.
This study presents an optimization of the MLND configuration. The width of the acrylic sheet, number of layers and the dimension of the SiPM were optimized by utilizing an advanced simulation tool.
Our results present the different count rate of each of the layers based on interacting neutron energy. An analytical algorithm based on the layers count rate ratios supports the feasibility of this configuration for approximate neutron spectroscopy. However, it is yet to improve the detection sensitivity that is noticeably reduced due to poor light guiding in the direction of the light sensor.
So Due to this reason, we evaluated the light collection efficiency when using a wavelength shifting plate (WLSP), instead of the acrylic moderator. The WLSP was specifically developed for the MLND configuration. Therefore, this WLSP has optimal separation between the absorption and transmission wavelengths curves. This optimization was achieved by matching the scintillator emission spectra to the SiPM quantum efficiency. In addition, the width of the WLSP and the die concentration were also optimized to achieve light absorption and transparency to the emitted wavelength.

Keywords: Neutron Detection, Spectroscopy
Poster panel: 228

Poster Number:
N-19-228

Experimental study of material identification inside concrete drums via a DECT technique (#1625)

L. Tamagno1, N. Estre1, D. Tisseur1, M. Kistler1, E. Payan1, D. Eck1

1 CEA Cadarache, DTN/SMTA/LMN, Saint-Paul-Lez-Durance, France

Content

In view of material characterization inside concrete drums, the combined information on the density (ρ) and the effective atomic number (Zeff) is required to distinguish between pre-defined groups of materials (solvents, plastics, pulverulent, pyrophoric, etc.), with a target uncertainty of the order of one on the Zeff. The information on Zeff allows discriminating between materials having close densities but different natures (water and plastics, powdered materials, etc.). The Dual-Energy Computed Tomography (DECT) technique, which consists in two distinct tomographic acquisitions of the same object using two X-ray sources with different energy spectra, gives both ρ and Zeff. Such a method has been investigated with simulation software, using high-energy X-ray sources of 9 MeV and 15 MeV. This study gave very promising results about material discrimination in a (ρ,Zeff) diagram. In this article, we show an experimental validation of the method on the CINPHONIE high-energy X-ray tomography facility of CEA Cadarache. The source is a LINAC which can deliver different output energies. In order to test the method, various materials will be placed inside a concrete disk of diameter 60 cm. In particular, water versus typical chemical solvents will be measured. Light organic materials (plastics) and intermediate Z materials will be measured. The Zeff and ρ measurement for each material will be presented and the discrimination inside the (ρ,Zeff) diagram will be discussed. The influence of the radial position of the material inside the drum, as well as the influence of beam filtration between the source and the object on the accuracy of the reconstruction, will be shown.

Keywords: DECT, Effective atomic number, material identification, CINPHONIE, Beam hardening
Poster panel: 230

Poster Number:
N-19-230

Poster panel: 232

Poster Number:
N-19-232

Position and Timing Resolution Measurements of Organic-Glass scintillator bars for the Optically Segmented Single-Volume Scatter Camera (#1810)

M. Sweany1

1 Sandia National Laboratories, Livermore, California, United States of America

on behalf of the SVSC Collaboration

Content

The Single Volume Scatter Camera (SVSC) Collaboration is a multi-institution effort led by Sandia National Laboratories to develop portable neutron imaging systems for a variety of applications in non-proliferation and arms control. Current state-of-the-art kinematic neutron imaging systems consist of distributed scintillator volumes in which the position, time, and energy of multiple interactions are used to reconstruct a neutron’s incoming direction. Such systems suffer from poor geometrical efficiency and are ultimately limited in performance by the size of the individual scintillator cells. The SVSC project aims to improve geometrical efficiency by up to an order of magnitude by reconstructing multiple neutron interactions within the same scintillator volume. The size reduction also enables closer inspection, further improving detection rates. In addition, the imaging performance is no longer limited by the size of individual cells, but by how well two interactions in the volume can be reconstructed: component-level improvements such as improved light output of the scintillator or timing properties of the photo-detector could lead to overall imaging performance improvements without a full-scale re-design of the system. Several detector design concepts are being explored with different methods to reconstruct the event. One is an optically segmented approach in which only the spatial position along the bar is reconstructed. Recently published results explored the timing, position, and energy resolution of interactions with commercially available scintillators and easily obtained reflective materials. To further improve reconstruction parameters, we are exploring custom scintillator formulations based on organic glass, which have the benefit of improved light output, rise times, and pulse-shape discrimination capabilities compared to commercially available plastics. We will present results on single bar studies, and how these improvements affect imaging metrics.

Keywords: fast neutron imaging, special nuclear material detection
Poster panel: 234

Poster Number:
N-19-234

Development and Optimization of the Tb3+/Ce3+ co-doped Gd2O3 Scintillation Glass Fiber Faceplate for Cold Neutron Microscope  (#1916)

D. Li1, H. Li1, M. Niu1, P. Qiao1, J. Lv1, H. Li1, X. Zhang1, 2

1 https://www.eventclass.org/contxt_ieee2018/profile, China insititue for radiation protection, Taiyuan, China
2 University, North China Electric Power University, Beijing, China

Content

Novel Tb3+/Ce3+ co-doped Gd2O3 scintillation glass fiber faceplates had been developed and successfully used for cold neutron imaging. In order to achieve the best imaging results, some optimizations were proceeded. The scintillation efficiency or scintillation light yield of the Gd2O3 scintillation glass fiber was optimized through its composition adjustment. The optimum compositions of sensitizers Tb3+ and Ce3+ are 17% and 2% (mass percent), respectively. The diameters of the glass fiber and the thickness of the faceplate were optimized through the experiments and Monte Carlo Simulation. The optimum thickness of the faceplate is 0.4mm and the diameter of glass fiber is 6μm. The imaging system made of such scintillation glass fiber faceplate achieve a spatial resolution of 35.1lp/mm and a detection efficiency of 55.3%.

Keywords: Tb3+/Ce3+ co-doped Gd2O3 glass, high spatial resolution, high detection efficiency
Poster panel: 236

Poster Number:
N-19-236

A Large Area Position-Sensitive Scintillation Neutron Detector For Upgrading SENJU Diffractometer (#1940)

T. Nakamura1, K. Toh1, M. Ebine1, A. Birumachi2, K. Sakasai1

1 Japan Atomic Energy Agency, J-PARC, Tokai, Ibaraki, Japan
2 Japan Atomic Energy Agency, Nuclear Science Directorate, Tokai, Ibaraki, Japan

Content

A large area, position-sensitive scintillation neutron detector was developed for upgrading the SENJU, time-of-flight Laue single crystal neutron diffractometer, in J-PARC MLF. The detector has a neutron-sensitive area of 512 x 512 mm with a pixel size of 4 x 4 mm. The detector was developed for upgrading of the SENJU instrument. The large area detector is to be installed below the vacuum tank to enlarge a covering solid angle. A 6Li:ZnS (Ag) scintillator and wavelength-shifting fiber technologies are employed. Each fiber channel is read out individually with photon counting mode. The electronics boards are implemented at the backside of the detector, enabling the detector depth as short as 20 cm. The detector exhibited a detection efficiency of 45% for thermal neutron. No degradation in fiber position and in neutron sensitivity has been observed over one year after production. In this paper, detector design and detector performances are presented.

Keywords: Position-sensitive neutron detector, Scintillation detector, Neutron diffractometer, Large area, Wavelength-shifting fiber
Poster panel: 238

Poster Number:
N-19-238

Comparative study of neutron/gamma identification in different scintillators (#2265)

Y. Zhu1, 2, Z. Wang2, S. Qian2

1 Harbin Institute of Technology, Department of Electronic Science and Technology, Harbin, China
2 Chinese Academy of Sciences, Institute of High Energy Physics, Beijing, China

Content

This paper describes some scintillators that identifies neutrons and gamma by coupled detector. The ceramic scintillators of Gd3Al2Ga3O12: Ce (GAGG) were grown successfully. The GAGG has high light yield and fast decay time. A cylindrical or cubic GAGG was processed and polished. The Gd isotopes has the largest thermal neutron capture cross section. We establish a test system to detect thermal neutron with the neutron detector based on GAGG. The detector can detect thermal neutrons by testing energy spectrum of internal conversion electrons. We find the energy peak at about 71 keV successfully. In addition, we use BC501A liquid scintillator detector for neutron/gamma (n/γ) identification with the method of pulse shape discrimination (PSD). The method of PSD is also used to Cs2LiYCl6 (CLYC) scintillator. The results show that CLYC offers good energy resolution and n/γ discrimination capability.

Keywords: neutron detector, neutron/gamma identification, scintillator, pulse shape discrimination
Poster panel: 240

Poster Number:
N-19-240

Experimental Demonstration of Additive Point Source Localization (#2333)

T. H. Y. Joshi1, D. Hellfeld2, M. S. Bandstra1, W. J. Vanderlip2, K. Meehan1, J. W. Cates1, R. T. Pavlovsky1, B. J. Quiter1, R. J. Cooper1, K. Vetter1, 2

1 Lawrence Berkeley National Laboratory (LBNL), Applied Nuclear Physics, Berkeley, California, United States of America
2 University of California Berkeley, Nuclear Engineering, Berkeley, California, United States of America

Content

In applications ranging from medical imaging to nuclear security, gamma-ray imaging attempts to estimate the spatial and intensity distribution of radionuclides that gave rise to a set of Poisson-distributed measurements. The image reconstruction problem in gamma-ray imaging is often solved using spatial discretization and application of Maximum Likelihood (ML) or Maximum A Posteriori (MAP) methods. While both powerful and general, these approaches are susceptible to over-fitting in sparse scenarios, e.g. radiological source search, and limited in resolution by the spatial discretization. In previous work Additive Point Source Localization (APSL), an alternative approach, was proposed for sparse parametric image reconstruction. APSL was demonstrated using simulated data and found to yield improved accuracy and computational performance relative to ML and MAP methods. In this work we present the first experimental demonstration of APSL, radiological search scenarios, and compare and contrast the performance with ML and MAP methods.

Keywords: radiological source search, source localization, poisson likelihood, maximum likelihood, gamma-ray imaging
Poster panel: 242

Poster Number:
N-19-242

Squashed Straw Array for High-Resolution Neutron Science Applications (#2468)

J. L. Lacy1, A. Athanasiades1, C. S. Martin1, S. Davenport1, H. Phung1

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

Content

A modified boron-coated straw (BCS) structure is introduced, aimed at neutron science instruments that require very high spatial resolution in small sensitive areas. The proposed structure is a close-packed array of rectangular channels, each fabricated by squashing a round BCS into a rectangular shape, lined on all 4 sides with enriched boron carbide (10B4C). Channel dimensions can be as small as 0.5 mm x 2.5 mm, with an optimal ratio of 1-to-5, to ensure adequate ionization collection, and to minimize the number of channels in the direction of irradiation. A resistive wire tensioned at the center of each channel acts as the anode, and all channels share a common gas volume. Charge division is used to decode the event position along the length of the wire. The array can achieve sub-millimeter level resolution, a thermal neutron detection efficiency as high as 50% in only 2 layers, and excellent gamma rejection. It also offers minimal neutron scattering due to its thin aluminum structure (25 μm walls) and has a very high count rate capability.

Keywords: Neutron Detector, Neutron Imaging, Boron-Coated Straw, Neutron Science, Squashed Straw Array (SSA)
Poster panel: 244

Poster Number:
N-19-244

Development of an optimized converter layer for silicon carbide based neutron sensor for the detection of fissionable materials (#2253)

S. D. Monk1, S. P. Platt1, M. Anderson1, D. Cheneler1

1 Lancaster University, Engineering, Lancaster, United Kingdom

Content

Here, we describe the early stage design, construction and testing of a miniature silicon carbide diode neutron sensing instrument. It is intended that a more mature version of this instrument will be used as part of a robotic manipulator to investigate various parts of the stricken Fukushima nuclear power plant. Here, three such silicon carbide based proto-type sensors have been created, two of which have differing thicknesses of boron-10 deposited on, with the final one left bare. The thicknesses and materials chosen have been informed via Monte Carlo software (MCNP 6.2) which was also used to assess the suitability of two other potential converter materials – Lithium-6 and gadolinium-157. The work goes on to describe the design, construction and testing of the prototype device at two sites around the UK. The project is part of a UK/Japanese collaboration between Lancaster University and Kyoto University and is supported by an EPSRC grant via the UK Japan Civil nuclear research program.

Keywords: Fukushima NPP, Miniature Neutron Sensor, Monte Carlo, Silicon Carbide
Poster panel: 246

Poster Number:
N-19-246

Coded-Aperture Imaging using the Polaris-LAMP Platform  (#2560)

J. J. Hecla1

1 University of California, Berkeley, Nuclear Engineering, Berkeley, California, United States of America

Content

The Polaris-LAMP detector system is a compact, free-moving radiation mapping and imaging platform which fuses radiation data with information from contextual sensors such as LIDAR and cameras. In this work, we discuss upgrades enabling 3D reconstruction of radiation sources using a coded-aperture imaging modality and scene data fusion (SDF). Coding is performed using a tungsten rank-17 modified uniformly redundant array (MURA) mask in front of the pixelated CZT detector volume (H3D Technologies, Ann Arbor MI). High-fidelity, far-field angular response functions were generated for the detector system over  using MCNPX. List-mode maximum-likelihood expectation maximization (List-mode MLEM) is used to perform reconstruction over a voxel space created using LIDAR data. A variety of event-cut criteria and point-cloud cleaning tools are used to minimize the size of the voxel space and remove events which do not contribute to source localization. The coded-aperture imaging capability of the detector allows imaging of photon sources in the range of 40-200keV, which complements the existing Compton-imaging mode which is optimized for in the 300keV-1MeV energy range.  The combination of these two imaging modalities drastically improves the versatility of the detector system, and allows detection and mapping of a variety of proliferation-relevant sources.  Further, the low-energy imaging capability allows imaging of downscattered high-energy photons, improving the ability of the system to locate and image shielded sources.

Keywords: Coded aperture, Compton imaging, 3D Mapping, LIDAR, Gamma Rays
Poster panel: 248

Poster Number:
N-19-248

Non-destructive Studies of Iron and Stony Meteorite Materials by Energy Resolved Neutron Imaging (#2577)

A. S. Tremsin1, S. C. Vogel2, A. S. Losko2, 3, C. T. Olinger2, W. Kockelmann4

1 University of California, Berkeley, Space Sciences Laboratory, Berkeley, California, United States of America
2 Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
3 Technical University Munich, Garching, Germany
4 Rutherford Appleton Laboratory, Didcot, United Kingdom

Content

The unique capabilities of neutrons to penetrate samples opaque to other more conventional non-destructive methods are demonstrated in the present study of meteorite samples. The internal structure of metallic and stony meteorites is investigated by energy-resolved neutron imaging, where the neutron transmission spectrum is measured for each pixel of the image. This relatively novel technique is enabled by recent developments of bright pulsed neutron spallation sources and high resolution neutron counting detectors capable of operation at high counting rates. This paper demonstrates how the analysis of neutron transmission spectra in thermal and cold neutron energy ranges can be used to study the uniformity of the bulk microstructure within meteorites, which are opaque to X-rays and electrons. At the same time, maps of elemental composition (for a limited set of elements, which have large enough resonance absorption cross section) can be reconstructed through the analysis of neutron resonance absorption in the epithermal range of energies. This relatively novel and at the present time somewhat exotic non-destructive technique can provide complementary information and can be very attractive for the studies of rare or precious samples when other methods fail due to their opacity.
The near future possibilities of energy resolved neutron imaging and diffraction for non-destructive characterization of materials will also be discussed.

Keywords: Non-destructive testing, Neutron imaging, High resolution
Poster panel: 250

Poster Number:
N-19-250

Development of a real-time neutron detector for measurement at whole body position in BNCT (#2636)

H. Tanaka1, T. Takata1, K. Okazaki1, N. Hu2, M. Sato1, Y. Sakurai1, S. Kawabata2, S. - I. Masunaga1, M. Suzuki1

1 Kyoto University, Institute for Integrated Radiation and Nuclear Science, Osaka, Japan
2 Osaka Medical College, Osaka, Japan

Content

Since fast neutrons have high relative biological effectiveness, real-time fast neutron monitor at the whole body is desired in BNCT irradiation.
Thermal neutrons can be measured with the LiCAF scintillator, but fast neutrons can not be directly measured.
In this study, we optimized polyethylene moderator for the measurement of fast neutrons that can be adapted to the whole body position in BNCT irradiation.
The produced polyethylene moderator was combined with a LiCAF scintillator to conduct a characteristic test of fast neutron measurements.
It has been confirmed that fast neutrons can be measured in real time at the position of the neck, chest and abdomen of a water phantom that simulates the human body.

Keywords: boron neutron capture therapy, neutron monitor, real-time, LiCAF
Poster panel: 252

Poster Number:
N-19-252

High Sensitivity Gamma-ray Imaging With Compressed Sensing (#2680)

J. Ilter1, A. Flynn1, M. Guenette1, L. Chartier1, J. Barnes1, N. Karantonis1, G. Watt1, L. Petkovic1, D. A. Boardman1

1 ANSTO, Nuclear Stewardship, Sydney, Australia

Content

A compressive gamma-ray imager has been developed that consists of a single non-position sensitive detector in the center of two nested, counter rotating, cylindrical tungsten masks. This imaging technique has previously been demonstrated with small detector geometries that are equivalent to the mask aperture size. Utilizing larger detector geometries will increase the sensitivity but also introduce blurring in the reconstructed image. The imaging performance of a small volume (1 cm3) and a large volume (~43 cm3) Cs2LiLa(Br,Cl)6 (CLLBC) detector was compared. The signal-to-noise ratio (SNR) and angular resolution of the reconstructed images are used as the metric of comparison for the two detector geometries. The point spread function of the large detector has been simulated and this response is then removed during the compressed sensing reconstruction process. The larger detector volume has shown significant improvement in the image SNR for low count scenarios, which is due to the increased sensitivity.

Keywords: gamma-ray imaging, compressed sensing, deconvolution, SNR, angular resolution
Poster panel: 254

Poster Number:
N-19-254

The mechanisms of dark current passage and the influence of the crystal electro-physical parameters on the detecting properties of the Ме/CdMnTe/Ме, Ме/CdZnTe/Ме, Ме/CdTe/Ме structures (#1369)

V. Sklyarchuk1, P. Fochuk1, S. Solodin1, A. Rarenko1, Z. Zakharuk1, R. B. James2

1 Yuriy Fedkovych Chernivtsi National University, Institute of Biology of Chemistry and Bioresources, Chernivtsi, Ukraine
2 Savannah River National Laboratory, Aiken, South Carolina, United States of America

Content

CdTe, Cd(Zn)Te and Cd(Mn)Te solid solutions attract an attention of many scientists, who study their detector properties. The goal of these investigations is the improvement of detector quality.
CdTe, Cd(Zn)Te, Cd(Mn)Te crystals were grown by Bridgman method. The ingots were purified before the growth by the Te zone. The optical measurements allowed to determine the band gap; it was equal to 1.5 eV for CdTe, 1.56 eV for Cd1-xZnxTe and 1.68 eV for Cd1-xMnxTe, which corresponds to x=0.1 and x = 0.14, respectively. Structures with both ohmic and rectifying contacts were fabricated and investigated. Mechanisms of charge passage in these structures were analyzed and explained, their basic electro-physical parameters have been investigated.
For a structure with rectifying contact at ~1-100 V with reverse switching, the main mechanisms of charge transport are: generation-recombination in the space-charge region, charge transport in conditions where the width of the space-charge region exceeds the crystal’s thickness at higher voltages and at last, SCLC at high voltages.
The structures with a rectifying contact had substantially less dark currents at high voltages, they possessed significantly better detecting properties than structures with ohmic contacts.
From the comparison of calculation results and measured ratio of the 241Am isotope photo-peak height for detector irradiated from the side of ohmic contact and the Schottky contact, the concentration of uncompensated impurities in the crystals is determined. It is shown that the detecting capability is better for detectors, fabricated on crystals with a lower concentration of uncompensated impurities.
From the measurements of the temperature dependence of resistivity and SCLC, the degree of compensation in studied crystals is determined. Detectors fabricated on crystals, in which the degree of compensation is less, had the better detecting properties.

Keywords: metal-semiconductor contact, generation-recombination currents, space-charge limited currents.
Poster panel: 256

Poster Number:
N-19-256

Fabrication and Evaluation of ZnS(Ag) Fast Neutron Scintillators for the TREAT Fuel Motion Monitoring System (#1599)

S. M. Watson1, J. T. Johnson1, S. J. Thompson1, J. D. Hix1, D. L. Chichester1

1 Idaho National Laboratory, Radiochemistry and Nuclear Measurements, Idaho Falls, Idaho, United States of America

Content

The Fuel Motion Monitoring System at the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory uses ZnS(Ag) proton recoil scintillators (PRS) to detect fast neutrons emitted from fuel undergoing transient testing. These detectors exhibit excellent neutron-photon discrimination, quick signal decay, and good linearity across wide-dynamic-range reactor transients reaching 19,000 MW in time frames of a few seconds. Recent work has explored the measurement performance of legacy PRS buttons made ~40 years ago in order to develop a capability to build new buttons. The design effort evaluated the relationship between total light output and pulse-shape discrimination performance in newly-made buttons as a function of ZnS(Ag) loading (5%-20% by weight) and two different suspension materials (EJ-500 and Clear-Lite Casting Resin (acrylic)). The mixture with 20%-loaded ZnS(Ag) in EJ-500 was observed to have the best performance characteristics for deployment at TREAT in terms of total light output, PSD, and manufacturability.

Keywords: TREAT, ZnS(Ag), Fast Neutron, Transient
Poster panel: 258

Poster Number:
N-19-258

An In Situ alpha and beta spectrometer for D&S activities  (#2117)

O. R. Evrard1, C. Theroine2, S. Thys1, J. Elseviers1, S. Put1, R. Abou-Khalil2, S. Dogny2

1 Mirion Technologies, R&D department, Olen, Belgium
2 ORANO, Corporate, Paris, France

Content

In collaboration with Mirion, ORANO has developed a transportable In Situ glove box into which several analyses can be carried out on swabs taken in facilities in dismantling. This glove box includes a BeGe HPGe [EJ1] detector [3], a 1700 mm 2 PIPS A-series [EJ2] detector for alpha spectroscopy [3] as well a  telescope of four 450 mm2 PD[EJ3] PIPS detectors [3] and a segmented silicon drift detector[EJ4] (SSDD) [1] for  in situ beta spectroscopy.
Direct In situ alpha spectroscopy carried out in vacuum on surfaces or on swabs can be of help to identify basic families of nuclides such as
Group 1: 4.1-4.7 MeV range with 234,234,238-U  /Group 2: 4.7-5.25 MeV range with 239,240-Pu/Group3: 5.25-5.6 MeV range with 238Pu, 241-Am/Group4: 5.6-5.9 MeV range 244Cm /Group6: 5.9-7 MeV: 212-Bi,243-Cm
In these regions, an inaccuracy of 25% is allowed on the extracted activity of a given nuclide, provided that the estimator of the minimal activity is reliable, this will ensure the D&D operator that a given element is not minimized.   After this first diagnosis, the decision can be taken to direct some swabs to a more accurate alpha spectrometry process. The telescope of PD detectors is appropriate for carrying out beta spectroscopy analysis.  In complex mixes of beta emitters, a Fermi Kurie transform allows the spectral deconvolution of each beta component by linearizing the beta response. The SSDD has low energy thresholds (6-8 keV) allowing the spectral identification of  very low energy beta emitters,  such as tritium, under vacuum.

Keywords: Segmented Silicon Drift detectors, PIPS detectors
Poster panel: 260

Poster Number:
N-19-260

Performance of Boron-Coated Straws for Spent Nuclear Fuel Emission Tomography  (#2419)

J. L. Lacy1, S. Davenport1, A. Athanasiades1, C. S. Martin1, H. Phung1, L. Fabris2, P. Hausladen2, A. S. Iyengar2

1 Proportional Technologies, Inc., Houston, Texas, United States of America
2 Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America

Content

A tomographic technique to image spent nuclear fuel assemblies, employing an annular neutron detector and collimator, has been developed at ORNL. Given sufficient resolution, the technique can resolve individual pins within the assembly, and thus determine whether pins have been diverted. The proposed neutron detector, employing an 8x288 array of boron-coated straws distributed in an annular high-density polyethylene moderator, must have high detection efficiency for fission neutrons, uniform response, excellent gamma rejection, high count rate capability, and good position resolution. We present initial measurements of detection efficiency and uniformity of the recently completed half-scale (semicircular) counter, employing 1152 straws, distributed in an 8x144 array. Straws were read out in groups of 8, for a total of 144 channels. A 409 ng 252Cf source (emitting 940,000 n/s) was located at the center of the semicircle, 57.8 cm away from the detector face. The measured absolute detection efficiency was 5.86%, and the intrinsic detection efficiency was 13.5%, assuming a detector active area of 18,200 cm2 (100x182 cm2). The average rate per channel was 383 cps, with a statistical error of ±1.13 cps. The variation observed among channels was at best about ±5 cps, attributed to an inherent variation of sensitivity, among the 8-straw groups. We estimate that the counter can achieve rates up to 106 cps per channel (288x106 cps in the full-scale counter), and a gamma rejection orders of magnitude lower than 10-9, assuming operation at a low voltage of 600 V, possible through reduction of the full instrument EMI noise to a small fraction of the 3 mV RMS white noise of the amplifier. Initial measurements and estimates of performance are consistent with design objectives.

Keywords: fast neutrons, spent fuel, boron-coated straw, tomography, safeguards
Poster panel: 262

Poster Number:
N-19-262

Investigation of Gamma-ray and Fast Neutron Shielding Properties of Bismuth Modified Calcium-Potassium-Phosphate Glass System (#2801)

P. Kaur1, K. J. Singh1, S. Thakur2

1 Guru Nanak Dev University, Department of Physics, Amritsar, India
2 Guru Nanak Dev University College Verka, Department of Physics, Amritsar, India

Content

Bismuth modified phosphate glass system containing calcium and potassium was prepared and assessed for its applicability as transparent viewing windows for shielding against gamma-rays and neutrons in nuclear reactors. The structure of the glasses was studied by density, XRD techniques. The gamma-ray shielding properties were studied at energies 356 and 662 keV both experimentally and theoretically (by XCOM and XMuDat programs) and compared with commonly used barite concrete. Exposure buildup factor was also investigated. The neutron shielding properties were studied and compared with some common neutron shielding materials (Boron Carbide, Polyethylene grains and ordinary concrete). Results indicate that the studied glasses with 0.2, 0.25, 0.3 wt. fraction Bi2O3 are potential candidates for gamma-ray and neutron shielding applications.   

Keywords: Gamma-rays, Glass, Neutrons, Shielding
Poster panel: 264

Poster Number:
N-19-264

Preliminary Study of Plastic Scintillation based Detector for 85Kr Analysis (#1099)

J. Lee1, H. Song1, Y. G. Ko1, H. Kim1, J. - M. Lim1, W. Lee1

1 Korea Atomic Energy Research Institute, Environmental Radioactivity Assessment Team, Daejeon, Republic of Korea

Content

One of the anthropogenic source of the radioactive noble gas 85Kr (beta emitter, Emax: 687 keV, half-life: 10.76 years) is nuclear-fuel reprocessing. Therefore, monitoring of radioactivity of 85Kr in the atmosphere is a significant and reliable method to detect the nuclear activities of neighboring countries such as clandestine separation of plutonium for the preparation of nuclear weapons owing to chemically stable property of gas. To determine the radioactivity of 85Kr in the atmosphere, the optimized gas proportional counter has been used. However it has limit on the in-situ long term monitoring of nuclear activities caused by use of P-10 gas. In this study, we developed the scintillation based beta detectors for in-situ monitoring of 85Kr radioisotope. Optimized size and shape of the plastic scintillator were designed using Monte Carlo MCNP6 simulation, and demonstrated experimentally using 2-in diameter photomultiplier tube and multi-channel analyzer and the BC-404 plastic scintillator fabricated with simulated size and shape. A BC-630 silicone optical grease and an enhanced specular reflector (ESR) film were used to join the ends of the plastic scintillator and the photomultiplier tube. The 85Kr beta energy spectrum from Monte Carlo simulation matched well with it from experiment, showing error in low energy at the measurement of a 70 mol% of stable Kr contained plastic bag. We believe that our research results from the simulation and experiment will be a cornerstone to select a quantitative analysis method for 85Kr in the development of the automatic 85Kr analysis system.

Keywords: Krypton analysis, Beta ray detection, Plastic scintillator.
Poster panel: 266

Poster Number:
N-19-266

Effect of Al to Ga ratio and Mo co-doping on scintillation properties of Ce:Gd3(Ga, Al)5O12 single crystal scintillators (#1112)

K. J. Kim1, K. Kamada2, 3, M. Yoshino1, Y. Shoji3, V. V. Kochurikhin3, 4, A. Yamaji1, S. Kurosawa2, 5, Y. Yokota2, Y. Ohashi2, A. Yoshikawa1

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

Content

The Cerium doped Gadolinium Aluminum Gallium Garnet (Ce:Gd3(Ga,Al)5O12, Ce:GAGG) presented by Kamada et al. is the most attractive scintillator material from the point of view of light output, decay time, energy resolution, density and absence of intrinsic radioactivity. Many studies have been continued on the effects of rare earth doping and/or co-doping with various cations in GAGG crystal structure, multicomponent garnet based on Y3Al5O12 (YAG) crystal with an admixture of Ga and Gd, to improve its properties. In this study, the performance of Mo co-doped Ce0.5%:Gd3GaxAl5−xO12 single crystal scintillators with different ratio of Al and Ga (x=2.4, 2.7, 3.0) was investigated. All these crystals were prepared by the micro-pulling (m-PD) down method and also have a wide concentration range of the Mo co-dopant. We have investigated the relationship between the effects of reducing Ga content in Ce:GAGG and the effects of co-doping with Mo ion in Ce:GAGG. The scintillation properties of the grown crystals such as light yield and energy resolution and non-proportionality in scintillation response were evaluated. Light output was increased in a sample with the small amount of Mo concentration and maximum light output of 112% compared to the non co-doped Ce:GAGG was obtained in the Mo 300 ppm co-doped crystal with x=3.0. The scintillation decay was also accelerated to 57.2 ns by Mo 500 ppm co-doping with x=3.0. The Mo co-doped crystals with x=3.0 showed a higher light yield and faster decay time than those with x=2.4 and 2.7.

Keywords: Scintillators, Single crystal growth, GAGG, Co-doping
Poster panel: 268

Poster Number:
N-19-268

First measurements with a plastic scintillation dosimeter for MRI-LINAC dosimetry (#1128)

L. J. Madden1, J. I. Archer1, E. Li1, U. Jelen2, A. Rosenfeld1

1 University of Wollongong, Centre for Medical Radiation Physics, University of Wollongong, Australia
2 Ingham Institute for Applied Physics Research, Medical Physics, Liverpool, Australia

Content

MRI-LINACs present the opportunity for adaptive radiotherapy with optimal soft tissue contrast by combining MRI and LINAC technologies. The presence of an MRIs magnetic field alters the trajectories of secondary electrons traversing through a dosimeters sensitive volume; this effect can complicate MRI-LINAC dosimetry for dosimeters that possess angular dependencies. Plastic scintillation dosimeters possess many desirable qualities that make them suitable for MRI-LINAC dosimetry, including water equivalence and a dose response that is not affected by magnetic fields. However, plastic scintillation dosimeters have not yet been applied for MRI-LINAC dosimetry. An in-house plastic scintillation dosimeter and a Scanditronix/Wellhofer FC65G ionisation chamber were applied to measure output factors and a percent depth dose distribution. The plastic scintillation had a reproducibility of 0.97% calculated from the standard deviation of measured responses. The plastic scintillation dosimeter and ionisation chamber differed on average by 0.84%. This closeness to agreement demonstrates that plastic scintillation dosimeters are effective for relative MRI-LINAC dosimetry.

Keywords: Dosimetry, Linear Accelerator, Magnetic Resonance Imaging, Optical Fiber, Plastic scintillator
Poster panel: 270

Poster Number:
N-19-270

High-efficient gamma detector for radiation portal monitors (#1165)

A. Boyarintsev1, T. Nepokupnaya1, Y. Onufriyev1, T. Sibilieva1, O. A. Bobovnikov1

1 National Academy of Sciences of Ukraine, Institute for Scintillation Materials, Kharkov, Ukraine

Content

The goal of this paper is development of efficient large area gamma detector with high sensitivity to low-energy gamma radiation. Plastics are the cheapest scintillators for radiation portal monitors, but have some drawbacks. It is low registration efficiency of gamma rays with energies less than 100 keV. Other problem is degradation of plastics (as indicated by lower light output) due to internal “fogging” when exposed to certain outdoor environmental conditions over long periods of time  So in order to exclude “fogging” factor sealed housing must be used in detector design.
In this paper high-efficient gamma detector for radiation portal monitors was developed. Low gamma registration efficiency of large area plastics was improved in two ways: 1- covering of plastic by crystal layer, 2 – optimizing of reflective coating. Aluminum housing was select for environment protection of scintillators.
 Plastic scintillators (UPS-923A type) with dimensions 50x250x1000 mm3 and 50x500x1000 mm3 were used for detector development. High gamma efficient NaI(Tl) and CsI(Tl) with thickness 4 mm and 0.5 mm, respectively, were used for fabrication of low-gamma sensitive layers. Diffuse and mirror reflectors were selected. Aluminum (0.5-1 mm thick) was used as protective housing. Amplitude spectra of were measured by Canberra test stand using 137Cs (33 keV) and 241Am (59.6 keV) gamma sources. R1306 PMT was used in measurements and in detector design.
Registration efficiency of  plastic increased near two times after covering by NaI(Tl). Sensitivity and minimal detectable activity to 137Cs and 241Am were improved when CsI(Tl)  was applied onto plastic. CsI(Tl) absorbs low energy gamma radiation and emits light which passes through transparent plastic to photodetector. Scintillation parameters get worse when aluminum housing is used, but parameters remain still much better than ones of plastics without any coverings. Count rate of plastic get higher when mirror reflector was used.

Keywords: Gamma detector, polystyrene, halide cystal, large area
Poster panel: 272

Poster Number:
N-19-272

Absolute measurement of gain and quantum efficiency for avalanche photodiode (#1253)

J. Jegal1, H. W. Park1, H. J. Kim1

1 Kyungpook national university, Department of Physics, Daegu, Republic of Korea

Content

Dependence of the gain and dark current on bias voltage has been studied for the 5 mm × 5 mm S8664-55 avalanche photodiode produced by Hamamatsu Photonics at room temperature. In this study, the gain and quantum efficiency of the APD was measured using 650 nm red LED in order to expect a similar effect to the combination with scintillators. The gain was measured using both method the ratio of the dark current and the photocurrent and ADC measurement of the LED power. In addition, the quantum efficiency at 650 nm was absolutely calculated to be 82 ± 8 % using the measured gain and 1.2 ADC/fC by charge injection. This absolute measurement method is good tool to confirm the experimental parameters characterizing detector and expected to contribute to single photon detection at low temperature which is based on low electronic level.

Keywords: Avalanche photodiode, gain, quantum efficiency
Poster panel: 274

Poster Number:
N-19-274

Scintillating Fiber based Beta Spectrometer: Principle and Proof of Concept (#1283)

N. Dufour1, A. Sari1, F. Carrel1, G. H. V. Bertrand1, J. Dumazert1

1 CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, Gif-sur-Yvette, France

Content

Nuclear decommissioning and dismantling is a long, complex, and costly process, which requires radiological characterization in order to declassify a nuclear facility. The drawbacks cited above may come from different reasons: large area to characterize, uneven surfaces of measurement, or low count rates. Therefore, the study of new detectors, or new methods of measurement using classic detectors, has become a central area of research. We present an innovative concept of a beta spectrometer using scintillating fibers with different geometries. This system is composed of multiple fibers (or types of fibers) which have different cladding thicknesses and core diameters, resulting in different responses. In fact, thicker cladding blocks signals coming from low energy beta sources, like 14C or 90Sr, whereas high-energy beta sources, like 90Y or 212Bi, would still be detected. Thus, we can construct an accurate inference on the measured spectrum with thin cladding, allowing a more robust deconvolution in the case of a mixed beta source. This spectrometer concept has been validated using the MCNP6 simulation code, and the deconvolution step of the process was tested with a Maximum Likelihood – Expectation Maximization (ML-EM) algorithm. A scintillating fiber-based beta spectrometer is well adapted to large measurement area and rough surface, being deformable. In addition, such a spectrometer has a low sensitivity to alpha particles and photons. Finally, the detector can accurately localize the source, using a time-of-flight method.

Keywords: Beta spectrometry, scintillating fiber, spectra deconvolution, nuclear decommissioning and dismantling
Poster panel: 276

Poster Number:
N-19-276

High-Light-Yield and Radiation Tolerant Scintillation Materials for Future High Luminosity Experiments (#1396)

E. Auffray1, M. Korjik2, D. Kozlov2, N. Kratochwil1, M. Lucchini3, V. Mechinsky2, S. Nargelas4, J. Talochka2, G. Tamulaitis4, A. Vaitkevicius4

1 CERN, EP_CMX, Geneva, Genève, Switzerland
2 Nuclear Problems of Belarus State University, Minsk, Belarus
3 Princeton university, Princeton, United States of America
4 Vilnius University, Vilnius, Lithuania

Content

Multicomponent oxide scintillators are currently the material of choice for designing sampling electromagnetic calorimeters and fast timing detectors for operation in harsh irradiation environments of high energy physics experiments such as the high luminosity HL-LHC and the forthcoming FCC, where the total fluence of charged and neutral hadrons up to 5x1015p/cm2in the forward regions of the detectors is expected. To avoid the volumetric factor of the damage effects in the scintillator elements, a “spaghetti”-like layout, consisting of detecting elements in form of crystal bars or crystal fibers packed in grooves of heavy metal composite absorber, is considered to be a promising detector design geometry for this application. Moreover, to avoid pileup effects, the scintillation materials have to exhibit a fast luminescence response. In this study, we focused on the investigation of the timing properties of two scintillators: Gd3Al2Ga3O12and (Lu1-xYx)2SiO5single crystals doped with Ce and co-doped with aliovalent ions to improve their timing properties. Both materials enable designing SiPM-based detecting elements with coincidence time resolution (CTR) better than 40 ps for MIP detection. To investigate the difference in timing properties of the scintillation materials before and after irradiation, we combined the CTR measurements with the study of nonequilibrium carrier dynamics by using optical pump and probe technique in sub-picosecond domain and exploiting selective excitation of Ce ions. The impact of the irradiation on the materials timing properties and the ways for their possible improvement will be discussed.

Keywords: Scintillator, radiation hardness, fast timing, high energy physics experiments, radiation detectors
Poster panel: 278

Poster Number:
N-19-278

Bright scintillation of cryogenic detector based on doped GaAs crystal (#1406)

S. Vasiukov (Vasyukov)1, 2, F. Chiossi1, 2, G. Carugno1, 2, F. Moretti3, E. Bourret-Courchesne3, S. Derenzo4

1 University of Padua , Department of Physics and Astronomy, Padova , Italy
2 Istituto Nazionale Fisica Nucleare, Padova Division, Padova, Italy
3 Lawrence Berkeley National Laboratory, Materials Sciences Division, Berkeley, California, United States of America
4 Lawrence Berkeley National Laboratory, Molecular Biophysics and Integrated Bioimaging Division, Berkeley, California, United States of America

The research is sponsored by Istituto Nazionale di Fisica Nucleare (INFN) within the AXIOMA project and the Office of Basic Energy Sciences of the U.S. Department of Energy at the Lawrence Berkeley National Laboratory under UC-DOE Contract No. DE-AC02-05CH11231

Content

The radioluminescence features and scintillation efficiency of pure and doped gallium arsenide (GaAs) crystals at low temperature are presented in this work.
Features of emission centers of doped GaAs in 800-1700 nm are discussed. Using the example of a GaAs:(Si, B) crystal, the importance of donor and acceptor activation as a way to improve the scintillation efficiency is demonstrated.
By Si (360-1140 nm range) and InGaAs (900-1700 nm range) PIN photodiodes the light yield was estimated. High light output of 125 photons/keV and 71 photons/keV are reported in GaAs:(Si, B) and GaAs:Si, respectively.
With this, we re-opened low band gap materials as bright scintillators. This is significant because the doped GaAs crystal is a promising material for a cryogenic scintillator for the dark matter detection or searching of rare events.
Obtained data demonstrate the great potential of scintillation applications of low band gap materials materials (like GaAs, InP, InGaAs, etc.).
Additional measurements using a Ge PIN photodiode as light detector are currently being performed in order to estimate GaAs light yield and energy resolution of under alpha radiation excitation.

Keywords: Gallium arsenide, Inorganic Scintillators, Radioluminescence, Semiconductor materials, Cryogenic Scintillatros
Poster panel: 280

Poster Number:
N-19-280

A simple identification of multiple-hit events to improve the image quality of fine-pixel scintillation detector  (#1439)

S. Sato1, J. Kataoka1, S. Mochizuki1, K. Fujieda1, F. Nishi1

1 Waseda University, Research Institute for Science and Engineering, Tokyo, Japan

Content

Scintillation detectors are widely used in various imaging techniques in the fields of medicine, astronomy, and environment. In general, large-area and fine-pixel scintillation arrays are needed to improve the sensitivity and image quality of detectors. However, a large scintillation array requires a huge number of read-out channels, which makes the detector system complex and expensive. The use of a resistive charge-division network can effectively reduce the number of readout channels. However, the disadvantage is that such detectors are insensitive to “multiple-hit” events, in which gamma rays interact multiple times within the same scintillator array. In this paper, we propose a simple method to identify multiple-hit events to improve the image quality of fine-pixel scintillation detectors. As a first demonstration, we obtained the flood map of a 42 times 42 Ce:GAGG scintillator array coupled with 8 times 8 MPPC of 3 times 3mm2 pixels. Using a 2D charge division network, 64 ch signals from MPPCs are compiled into four analog signals from the corners, S0, S1, S2, and S3. Then, the centroid of X and Y can be calculated in two ways by different groupings of Si. We assume that mismatched position (either X or Y) may be due to multiple-hit events that occurred within the scintillator. By rejecting such multiple-hit events, which accounts for ~10% of the total, we confirmed that the peak-to-valley rate of the flood map improved from 6.00 to 8.79 at 350-550 keV with irradiated 137Cs.

Keywords: scintillation detector, multiple scattering, multiple-hit, MPPC, MAPMT
Poster panel: 282

Poster Number:
N-19-282

Parametric Optimization to Simulate Gamma Response of an Organic Plastic Scintillation Detector (#1608)

B. Jeon1, J. Kim1, M. Moon3

1 KAERI, Neutron Science Center, Daejeon, Republic of Korea
2 KAERI, the Radiation Equipment Research Division, Daejeon, Republic of Korea

Content

In this paper, we address an optimization technique to simulate gamma response function of an organic plastic scintillator. Despite of poor energy resolution of organic plastic scintillators, they have been used for security and dosimetry due to their unique characteristics. Because transport and use of radioactive materials are under controlled by national radiation safety regulations, we can’t use all kind of radioactive sources. Most of studies on radiation measurements have been conducted based on simulations and verified with several available sources. Therefore, it is important to simulate response function of organic scintillation detectors in these research activities. To simulate gamma response function using Monte Carlo simulations, Gaussian energy broadening (GEB) function is used. For organic plastic scintillation detectors, however, it is difficult to determine GEB parameters due to poor energy resolution and absence of full energy peak in measured spectra. To determine the parameters, we defines an optimization problem as a comparison of measured and simulated gamma spectra, and solved by an optimization solver. Simulated gamma spectra using calculated parameters show good agreement with measured spectra.

Keywords: Gamma response function, Genetic algorithm, Organic plastic scintillation detector, Parametric optimization
Poster panel: 284

Poster Number:
N-19-284

Light output uniformity of GAGG:Ce scintillation fibers for high energy physics applications (#1635)

D. Dobrovolskas1, G. Tamulaitis1, E. Gaubas1, M. Korjik2

1 Vilnius University, Institute of Photonics and Nanotechnology, Vilnius, Lithuania
2 Belarus State University, Institute for Nuclear Problems, Minsk, Belarus

Content

Radiation detectors based on multiple single crystalline scintillating fibers are promising for next generation of electromagnetic calorimeters to be exploited in high-luminosity high-energy physics experiments. These novel fiber-based detectors consist of long single crystalline rods, thus the light propagation conditions in these fiber-like structures are of crucial importance. Various scattering centers inside the crystal lead to a decrease in the optical transparency and light output of the crystal. Thus, microscopic-scale characterization of scintillating fibers is important for their efficient application in radiation detectors. In this work, the uniformity of Czochralski-grown cerium-doped gadolinium aluminum gallium garnet (GAGG:Ce) fibers was studied by employing confocal optical microscopy. The surface of the crystals was also studied using atomic force microscopy. All samples showed good large-scale homogeneity with no significant intensity variation along their length. On the micrometer scale, growth related defects were observed as alternating plains exhibiting photoluminescence intensity and band peak position variations. Light attenuation length was estimated and found to vary in nominally identical fibers. The influence of crystal growth defects and surface polishing quality on light propagation is revealed and discussed.

Keywords: Scintillators, GAGG, light attenuation length, confocal microscopy
Poster panel: 286

Poster Number:
N-19-286

Comparison of Back-thinned Detector Ultraviolet Quantum Efficiency for Two Commercially Available Passivation Treatments (#1733)

J. Heymes1, M. Soman1, G. Randall1, A. Gottwald2, I. Moody3, X. Meng1, A. D. Holland1

1 The Open University, Centre for Electronic Imaging, School of Physical Sciences, STEM Faculty, Milton Keynes, United Kingdom
2 Physikalisch-Technische Bundesanstalt, Berlin, Berlin, Germany
3 Teledyne-e2v, Chelmsford, United Kingdom

Content

Back-thinned silicon detectors offer a high response over a very broad spectrum for direct detection by removing the electronic and dead layers from the optical path. To ensure high quantum efficiency at wavelengths where the absorption length in silicon is short, such as ultraviolet radiation (absorption length less than 10 nm), the passivation layer of the back-illuminated sensors, made to reduce surface defects effects, must remain thin.
We have tested two CCDs with different back-surface shallow p+ implant thicknesses (basic and enhanced) using monochromatized Synchrotron radiation in  the UV spectral range at the M4 line at the Metrology Light Source of the Physikalisch-Technische Bundesanstalt. As the activation of the backside p+ layer is performed with UV laser pulses, the effect of further illumination in the UV spectrum on the surface during lifetime is of interest for many applications. Quantum  efficiency measurements have been carried out before and after exposures to quantify any change in behaviour.
The measured quantum efficiency of the standard backthinned CCD is low between 70 nm and 370 nm as expected from the absorption lengths. Nonetheless, an average additional 5 % efficiency is achieved in the enhanced device within the same range. At the limits of the measured spectrum, towards soft X-ray or towards the visible range, the QE increases and the discrepancy between the standard and the enhanced process is reduced as the photon absorption length  increases beyond the immediate back surface. The measured quantum efficiency after long high fluxes exposures at 200 nm shows remarkable improvement.

Keywords: CCD, CIS, QE, EUV, VUV
Poster panel: 288

Poster Number:
N-19-288

R&D of new high-performance scintillators including double beta decay nuclei (#1877)

T. Iida1, K. Kamada2, 4, M. Yoshino3, 4, K. J. Kim3, S. Kurosawa2, A. Yoshikawa3, 4

1 University of Tsukuba, Faculty of Pure and Applided Science, Tsukuba, Japan
2 Tohoku University, New Industry Creation Hatchery Center, Sendai, Japan
3 Tohoku University, Institute for Material Research, Sendai, Japan
4 C&A Corporation, Sendai, Japan

Content

Inorganic scintillators have been used for dark matter experiments and double beta decay experiments. We have developed CaI2 which has a large amount of luminescence and contains 48Ca from double beta decay nuclei. Half-inch CaI2 crystals were prepared by the Bridgman method in IMR, cut into several mm squares, and the scintillation characteristics were measured. The light emission amount was 107,000 ph / MeV, 2.7 times NaI (Tl) and 10 times undoped CaF2. The light emission wavelength was 410 nm, which was in agreement with sensitive wavelength of photomultiplier tubes. When the waveform discrimination characteristics were measured using alpha rays of 241Am and gamma rays of 137Cs, it was found that there was a large difference in the first 300 ns between the waveforms. CaI2 showed high potential for pulse shape discrimination. Detailed analysis is now underway. At present, the growth and processing of large crystals is difficult due to the strong deliquescence and cleavage of CaI2. Work is underway to develop better growth and processing method for CaI2 crystal. Cs2ZrCl6 (CZC) including 96Zr and Ce:(La, Gd)2Si2O7 (Ce:La-GPS) including 160Gd are also tried to be grown and will be measured by the IEEE-NSS conference.

Keywords: Double beta decay, Inorganic scintillator, Pulse shape discrimination, Radiation detector
Poster panel: 290

Poster Number:
N-19-290

The 20 inchMCP-PMT for Neutrino Detection (#1891)

S. Qian1

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

On behalf of MCP-PMT-Collaboration

Content

Researchers at IHEP have conceived a new concept of MCP-PMT several years ago. The small MCP units replace the bulky Dynode chain in the large PMTs. In addition the transmission and reflection photocathode in the same glass bulb to enhance the efficiency of photoelectron conversion. After several years R&D, the 20 inch MCP-PMT was successfully produced. This type of PMT has large sensitive area, high QE, and large P/V for good single photoelectron detection. Compensating the PMT performances, cost, radioactivity, the JUNO ordered 15000 pic 20-inch MCP-PMT from the NNVT in Dec.2015. The MCP-PMT collaboration group finished to build the mass production line and batch test facility in Nanjing in 2016. From 2017 to 2019, all the 20-inch PMTs will be produced and tested one by one in NNVT for JUNO.
This presentation will talk about the R&D, the mass production and batch test result of the 10K pieces of MCP-PMT prototypes for JUNO. Further more, the QE of this type of MCP-PMT is improved from 28% to 34%@410nm in 2018, and this new technology has already used on the PMT mass production. And also in 2018, another Flower-liked MCP-PMT was designed with the TTS less than 5ns, and this new type of 20 inch MCP-PMT has already evaluated by the PMT group in LHAASO and HyperK.

Keywords: Photon Detector, PMT, MCP
Poster panel: 292

Poster Number:
N-19-292

Spectrometer of Hard X-ray Imager payload on board the ASO-S Mission (#1914)

Z. Yan1, G. Jianhua1, Z. Yongqiang1

1 Purple Mountain Observatory, Key laboratory of Dark Matter and Space Astronomy, CAS, Nanjing, China

Content

A space-borne hard X-ray spectrometer with an array of 99 scintillation detectors and their readout electronics have been developed for the Hard X-ray Imager (HXI). The HXI is one of the three payloads on board of the Advanced Space-based Solar Observatory (ASO-S) that is scheduled to be launched early 2022 as the first Chinese solar satellite. LaBr3 scintillators and PMTs with Super Bi-Alkali cathode are used to achieve an energy resolution better than 20% at 30 keV. A new multi-channel charge sensitive readout ASIC guarantees high-frequency data acquisition with low power consumption. We will presents the design of the spectrometer for Engineering Model of the HXI with noise and linearity performance being discussed.

Keywords: Solar Radiation Detection, X-ray Spectrometer, Hard X-ray Imager, ASO-S
Poster panel: 294

Poster Number:
N-19-294

Poster panel: 296

Poster Number:
N-19-296

Optical and Scintillation Properties of BaMgF4 Crystals (#1977)

R. Mao1

1 SICCAS, Shanghai, China

Content

We present in this work the optical and scintillation properties of BaMgF4 (BMF) crystal. Single crystal was grown by Vacuum Bridgman method and a sample with dimension of 20X20X40 mm was made. Optical transmittance, X-ray excited luminescence (XEL), light output and scintillation kinetics were performed. The BMF shows excellent optical transmittance within wavelength interested. The XEL was found peaking at 220 and 300 nm. The light output was calculated to be 12000 photons/MeV. The time constant were determined to be 1.1 ns (97%) and 427 ns (3%).

Keywords: BaMgF4, Light output, Fast decay
Poster panel: 298

Poster Number:
N-19-298

From SiPM efficiency to the future perspective of photo-detection (#2087)

M. Salomoni1, 2, E. Auffray2, S. Enoch3, A. Gola4, S. Gundacker1, 2, P. Lecoq2, M. T. Lucchini5, A. Mazzi4, M. Paganoni1

1 University of Milano-Bicocca, Giuseppe Occhialini, Physics, Milano, Italy
2 European Organization for Nuclear Research, Meyrin, Valais, Switzerland
3 Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, Marseille, France
4 Fondazione Bruno Kessler, Trento, Italy
5 Princeton University, Princeton, New Jersey, United States of America

On behalf of the Photquant ATTRACT H2020 project

Content

The work presented investigates the use of a high refractive index optical coupling to be applied between inorganic scintillators and the photo-detectors. A Lu2(1-x)Y2xSiO5:Ce (LYSO) crystal was tested with two different Silicon Photo-multipliers (SiPM), one with a protective glass window of refractive index (RI) = 1.52, the other with only high refractive index optical coupling and the window being removed. The purpose was to improve the light transport efficiency from the scintillator to the SiPM active area and consequently demonstrate a gain in coincidence time resolution (CTR). Preliminary measurements confirmed the simulations with a gain of 11% in LY and 6% in CTR for an optical coupling with RI = 1.68. Several other configurations using different optical couplings, ranging from 1.3 to 1.75, for LYSO (RI = 1.82), Gd3Al2Ga3O12:Ce (GAGG, RI = 1.9) and Bi4Ge3O12 (BGO, RI = 2.1), are under study.
This research ultimately underlines the need for future technological advancement from both the scintillator and the SiPM technologies, outlining possible R&D&I investigations.

Keywords: Photo-detector, Time resolution, Scintillator, Medical physics, High energy physics
Poster panel: 300

Poster Number:
N-19-300

Bridgman Growth and Scintillation Performance of High Quality Cs2HfCl6 Crystals (#2186)

S. Lam1, C. Guguschev2, M. Hackett1, R. Hawrami3, A. Burger3, S. Motakef1

1 CapeSym, Inc., Natick, Massachusetts, United States of America
2 Leibniz Institute of Crystal Growth, Berlin, Germany
3 Fisk University, Nashville, Tennessee, United States of America

Content

Cesium hafnium chloride (CHC, Cs2HfCl6) is a scintillator with superior gamma detection capabilities. Advantages of CHC include: an energy resolution of 3%, no self-absorption, no self-radioactivity, and negligible hygroscopicity. However, Cs2HfCl6 tends to form secondary phases during crystal growth. Since CHC is a line compound flanked by two eutectics, an on-stoichiometric melt is essential to prevent the generation of secondary phases in the grown CHC crystal. Crystals grown by the Bridgman method material processed by traditional methods often result in formation of an undesired secondary phase which we have identified by micro-XRF to be Cs-rich.
More recently, we have developed a processing approach to suppress secondary phase formation, resulting in clear crystals. The processing approach includes improved handling to suppress hafnium chloride loss, purification of both hafnium chloride starting material as well as synthesized CHC, and improved growth conditions. Clear crystals of approximately 1-inch in diameter have been grown with the energy resolution in the range of 3.5-4%. Smaller samples have achieved closer to 3% energy resolution. We are currently fine-tuning our processing approach to improve crystal quality and energy resolution and scaling up growth towards 50 mm diameter.
This work has been supported by the U.S. Department of Department of Energy, Office of Science, under competitively awarded contract DE-SC0015733. This support does not constitute an express or implied endorsement on the part of the Government.

Keywords: scintillators, crystal growth, cesium hafnium chloride
Poster panel: 302

Poster Number:
N-19-302

Crucible-free bulk crystal growth of Ce doped Gd3(Ga,Al)5O12 single crystal from the melt; its optical and scintillation properties (#2228)

A. Yoshikawa1, 2, V. K. Kochurikhin2, Y. Shoji2, H. Sato4, 3, M. Yoshino1, 2, A. Yamaji1, K. Kamada3, 2, Y. Yokota3, S. Kurosawa3, Y. Ohashi3

1 Tohoku University, Institute for Materials Research, Sendai, Japan
2 C&A (Crystals and Applications) Corp., Sendai, Japan
3 Tohoku University, NICHe, Sendai, Japan
4 EXA, Sendai, Japan

Content

In this study, iridium crucible was NOT used and GAGG:Ce were grown in AIR. Cold crucible pulling (CCP) method is used for the single crystal growth. This method is the fusion of skull method and Czochralski method.
GAGG crystals were grown in air without use of precious metal crucible using pulling up from the cold container. The GAGG crystal during the growth are shown in the Fig. 1 and as grown GAGG crystal exited by UV light was shown in Fig. 2 respectively. Typical luminescence from Ce3+ 5d-4f transition was observed peaking around 550 nm by X-ray excitation (Fig. 3).
Such technique gives the opportunity to avoid growth problems typical for traditional Czochralski method. After further adjustment of growth technology, the pulling from the cold container technique can become the competitor of traditional Czochrlaski technique for the production of bulk GAGG scintillator crystals.

Keywords: Scintillator, single crystal growth, Skull method, Czochralski method
Poster panel: 304

Poster Number:
N-19-304

Poster panel: 306

Poster Number:
N-19-306

Spatial Calibration of Encapsulated LaBr3:Ce Scintillator Detectors (#2308)

V. Solovov1, 2, L. Buonanno3, 4, M. Carminati3, 4, C. E. Fiorini3, 4, A. Minerva3, 4, A. Morozov1, 2

1 LIP-Coimbra, Departamento de Física, Coimbra, Portugal
2 Universidade de Coimbra, Departamento de Física, Coimbra, Portugal
3 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
4 INFN, Sez. Milano, Milano, Italy

Content

Reconstruction of 3D position of the interaction vertex in scintillation detectors is of interest in several applications, such as spectroscopy measurements of short-lived isotopes in nuclear physics or medical imaging with Compton cameras. Cerium-doped Lanthanum Bromide (LaBr3:Ce) is considered a very attractive material for these applications due to its high gamma-ray detection efficiency and excellent energy resolution (3.2% at 662 keV). Previously, we demonstrated feasibility of reconstruction of a gamma-ray 3D interaction coordinates in an encapsulated cylindrical 3” × 3” LaBr3:Ce scintillator read out by a single planar array of SiPMs. However, practical implementation of this method requires knowledge of the efficiency of light collection as a function of coordinates for each SiPM (Light Response Function - LRF). In the present work, we have developed a technique that permits reconstruction of the LRFs from the data obtained by scanning the detector with a pencil beam of 662 keV gamma rays. The a priori unknown coordinate along the beam is reconstructed by means of k-nearest neighbour (kNN) method, after which the LRFs are obtained by fitting the SiPM response by a smooth function in 3 coordinates. To improve the quality of the LRF reconstruction, filtering by distance to the nearest neighbor event was implemented that allows to considerably reduce contamination of the scan datasets by multiple Compton scatters that would otherwise degrade the performance of kNN reconstruction. Monte Carlo simulations predict spatial resolution of better than 10 mm FWHM in the directions parallel to the SiPM plane and 15 mm FWHM for the depth of interaction for 662 keV gamma rays. The detailed results of Monte Carlo studies as well as preliminary experimental results with a 662 keV gamma-ray pencil beam will be presented.

Keywords: scintillation detectors, position sensitivity, light response functions, statistical event reconstruction
Poster panel: 308

Poster Number:
N-19-308

Improving the Cherenkov based PET performance using multi-layer detectors (#2318)

D. C. Rodríguez1, R. Dolenec2, 1, S. Korpar3, 1, P. Križan2, 1, R. Pestotnik1

1 Jožef Stefan Institute, Ljubljana, Slovenia
2 Faculty of Mathematics and Physics, Ljubljana, Slovenia
3 Faculty of Chemistry and Chemical Engineering, Maribor, Slovenia

Content

Positron emission tomography (PET) images can be improved by including measurement of time-of-flight (TOF) information in image reconstruction. The accuracy of the TOF measurement is currently limited by the time response of the crystal. One open possibility to develop new devices is to search for new materials with faster light emission mechanisms such as the Cherenkov light emitted by electrons moving in a material with velocities exceeding the speed of light in the material. This enables excellent time resolution. On the other hand, the travel time spread of photons inside crystals of sufficient length for PET application, represents a fundamental limitation for the TOF resolution. One possibility to improve the timing without affecting gamma stopping power is to use a multi- layer detector geometry. In this work we have explored how the multi-layer detector for Cherenkov PET can improve the TOF measurement and the efficiency using annihilation gammas from a sodium source and HRFlexToT electronics. When incorporating silicon photomultiplier (SiPM) photodetectors, Cherenkov PET detectors could be realized at a very competitive price. Due to their compact size, SiPMs also enable the construction of a multi- layer detector.

Keywords: Cherenkov radiation, TOF-PET, SiPMs, multi-layer detector
Poster panel: 310

Poster Number:
N-19-310

TOPS: New Organic Plastic Scintillators for Fast Timing Detectors (#2353)

M. Marafini1, 2, A. Belardini4, L. Mattiello4, R. Mirabelli3, 2, D. Rocco4, A. Sarti4, 2, A. Sciubba4, 1, G. Traini3, 2, V. Patera4, 1

1 Museo Storico della Fisica e Centro Studi e Ricerche E.Fermi, Rome, Italy
2 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Roma, Italy
3 Sapienza Università di Roma, Dipartimento di Fisica, Roma, Italy
4 Sapienza Università di Roma, Dipartimento di Scienze di Base e Applicate per l'Ingegneria, Roma, Italy

Content

Organic scintillators are largely exploited in a wide range of detectors due to their capability to obtain very good time resolutions. Plastic scintillators are also relatively cheap, easy to manipulate and light (low density) with respect to conventional crystal scintillators and are traditionally used to perform very precise measurements of particle Time of Flight (TOF).
The research and development on organic scintillators is always active and in this framework a collaboration between the physics, engineering and chemistry groups of University “Sapienza” of Rome and Centro Studi e Ricerche Enrico Fermi  started the TOPS project (Time Of flight Plastic Scintillators) focused on  the development of a new class of plastic scintillators. TOPS scintillators have been realized in liquid and solid samples and their intrinsic characteristics have been studied. The samples show light output up to $\sim 300 \%$ larger with respect to anthracene and good timing properties. \par
In order to improve the matching between the emission/absorption spectra of the scintillators, doping material have been added as  wave-shifter. The use of POPOP as doping improved the performances of a fraction of the  scintillator samples. Based on the comparison of the light output values obtained in measurements with cosmic rays, a selection of the most promising scintillators has been investigated also from the timing point of view. The scintillation time characteristics of the TOPS plastic samples have been analyzed with minimum ionizing particles and for two samples with protons at different energies ($70-220\ \mega\electronvolt$). The commercial plastic scintillator BC-412 has been used as a reference. The results of the preliminary test will be presented.

Keywords: Fast Advanced Scintillator Timing, Plastic Scintillators
Poster panel: 312

Poster Number:
N-19-312

Laser-processed hybrid LSO block detector for ToF PET  (#2358)

M. Kapusta1, J. Corbeil1, L. Byars1

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

Content

Hybrid scintillation block detectors for PET have been developed, where monolithic slabs are pixelated by means of a sub-surface laser engraving (SSLE) technique. Short duration pulses of a high intensity laser are focused into the bulk of the scintillation crystal, inducing micro-cracks inside that locally change the refractive index.  The resultant “virtual” pixelization is without inter-pixel gaps. We have fabricated segmented arrays using a Vitro laser system to engrave various patterns of micro-cracks inside of monolithic LSO slabs of the size of 16×20×3.2 mm3. The pixelization occurred from the side face of a 16×20 mm2 slab to minimize errors due to crystal uniformity dependence. Five such slabs where similarly patterned and stacked. For evaluation the 16×16 mm2 face of the assembled block was optically coupled to a size matched SiPM array of the format of 4×4 elements. The position histograms, light outputs, energy resolution and timing resolutions of such block detectors were measured and compared to a traditionally pixelated block detector. The results suggest that such fabricated arrays are of worse timing performance in comparison to air coupled separate pixels block detectors. This is likely due to the light transport differences in both types of block detectors.

Keywords: PET, scintillation detector, timing resolution, laser
Poster panel: 314

Poster Number:
N-19-314

Growth of CsI crystals with low afterglow for High Energy Physics applications  (#2377)

V. Taranyuk1, A. Gektin1, V. Cherginets1, T. Rebrova1, N. Shiran1, Y. Boiaryntseva1, V. Nesterkina1, Y. Onufriyev1

1 Institute for Scintillation Materials, NAS of Ukraine, Kharkiv, Ukraine

Content

Due to the excellent performance and high radiation hardness CsI single crystals are referred to the main detecting materials used in calorimeters for high-energy physics. However, in spite of the well-developed industrial technology of their production, obtaining crystals with high and stable functional characteristics remains a difficult task. The performance of CsI crystals is estimated by the main two parameters. The first one is the effective time of luminosity of the fast components (τeff), which have to be not more than 16 ns. The second one is the ratio of the integral luminescence during the first 200 ns of the light emission to the total intensity of luminescence for 3000 ns (Fast/Total, F/T). For high-quality CsI crystals, the F/T value should be above 0.75. However, contamination of CsI crystals with various impurities in the form of oxygen compounds and heavy metals deteriorate these characteristics significantly. To solve this problem, a method of in situ melt purification with scavengers during crystal growth can be applied. The goal of this research was to obtain large-sized CsI crystals with F/T > 0.9 from standard raw material with in situ melt purification with scavengers on industrial equipment by Kyropoulos and Continuous crystal growth techniques. Two series of crystal growth were carried out: without purification of raw material and melt, and with the application of the melt purification with a scavenger in situ. Crystals with a diameter of 460 mm and a height of up to 300 mm were obtained. To study the functional characteristics, 35х35х200 mm sized samples were used. It was showed that CsI crystals grown without melt purification were characterized by the F/T values 0.6 - 0.8. When using a scavenger, the F/T values for all samples were 0.85 – 0.95. At the same time, the effective time of luminosity of the fast components decreased from 16 ns to 14 ns.

Keywords: CsI, scintillator, crystal growth, scavenger, Fast/Total
Poster panel: 316

Poster Number:
N-19-316

Gamma-Ray Rejection of the SiPM-coupled Micro-Layered Fast-Neutron Detector (#2433)

P. Ghosh1, D. M. Nichols1, D. S. McGregor1

1 Kansas State University, Mechanical and Nuclear Engineering, Manhattan, Kansas, United States of America

Content

The Micro-Layered Fast-Neutron Detector (MLFD) is a proton-recoil fast-neutron scintillator that uses lucite as the hydrogen-rich neutron converter and silver-doped zinc sulfide (ZnS:Ag) as the inorganic scintillator medium. The MLFD is constructed by placing alternative layers of neutron converter and scintillation medium in order to maximize its light collection. A 43-mm long MLFD has previously shown a high detection efficiency of 9.2% for a bare 252Cf source, and exhibits acceptable gamma-ray suppression with pulse height discrimination. Pulse-shape discrimination of neutrons and gamma-rays yielded a figure-of-merit of 4.56. Modeling in Geant4 has shown that lengthening the MLFDs up to 200 mm can further increase the neutron detection efficiency. These results indicate that the MLFD can potentially be used in applications such as active and passive interrogation, and Special Nuclear Material searches. However, the light collection device used thus far has been photomultiplier tubes, which prove to be cumbersome at longer lengths of the MLFD. To construct a compact hand-held neutron detection system, the photomultiplier tubes would require to be replaced with silicon photomultipliers (SiPMs). This paper reports on the performance of an MLFD coupled to SiPMs when irradiated with neutrons and gamma-rays. The results show that the pulses from gamma-ray events are not distinct from electronic noise, rendering the MLFD-SiPM system insensitive to gamma-rays. Simply setting a threshold to reject electronic noise is sufficient to register only neutron events, and additional electronics for pulse-shape discrimination are not required. This result indicates that the MLFD-SiPM system would be a compact, highly efficient fast-neutron detector in a gamma-ray environment.

Keywords: proton recoil detector, scintillator, gamma discrimination, fast neutron detector, silicon photomultiplier
Poster panel: 318

Poster Number:
N-19-318

Investigation of SiPM performance stability for on-line PET imaging with pencil scanning proton beams  (#2542)

K. Hu1, X. Cheng1, X. R. Zhu2, Y. Shao1

1 UT Southwestern, Department of radiation oncology, Dallas, Texas, United States of America
2 The University of Texas MD Anderson Cancer Center, Department of Radiation Physics, Houston, Texas, United States of America

Content

The objective of this study was to evaluate the performance of Silicon Photomultiplier (SiPM) change by radiation of neutrons induced by pencil scanning proton beam radiotherapy. Both dark current and gain changes of SiPM arrays were measured as they are the primary SiPM performance parameters. The experiment setup included a pencil scanning proton beam irradiated a human head phantom with SiPM arrays being placed nearby. Multiple repeated radiations and dark current/gain measurements were conducted. The results have shown that the impact of neutron radiations was negligible, with SiPM array’s both dark current and gain changes less than around 1% to 2%, well within the experiment uncertainty, even for cumulated proton beam dose up to 12 Gy. In conclusion, for the specific pencil scanning proton beam with this study, there is no need to concern the impact of neutron radiations to SiPM’s performance that is a crucial question for on-line PET image-based proton beam range monitoring. This conclusion is likely to be true for other pencil scanning proton beam facilities as well.

Keywords: Proton beam, SiPM performance, neutron radiation
Poster panel: 320

Poster Number:
N-19-320

Position sensitivity in monolithic scintillator detectors (#2573)

F. A. Alsomali1, S. Paschallis1, J. Brown1, P. Joshi1, D. Jenkins1

1 University of York , physics, York, United Kingdom

Content

There is an increasing need for Ƴ ray scintillation detectors in many fields such as nuclear medicine, astronomy, nuclear physics research and nuclear security. Besides the detector performance in terms of energy and time resolution another important property, for all fields mentioned, is to obtain position sensitive detectors with the simplest possible configuration. We report on the development of a detector consisting of a 50 mm x 50 mm x 50 mm CsI:Tl crystal coupled 8 x 8 siliconPhotoMultiplier  (SiPM) arrays at two opposite faces of the crystal. Measurements were carried out using 662 keV Ƴ rays from a collimated 370MBq 137Cs source. The detector was placed on a computer controlled xy scanning station built at the University of York. The light distribution measured at each SiPM array was recorded at different depths of interaction with a multi-channel acquisition system. An optical simulation was performed in GEANT4  to simulate the light distribution obtained from such a configuration and to provide a better understanding of the data.

Keywords: depth of interaction (DOI), silicon photomultiplier (SiPM), Monte Carlo, GEANT4.
Poster panel: 322

Poster Number:
N-19-322

Study of the imaging properties of a SrI2:Eu-based gamma camera  (#2625)

G. Hull1, A. Fabbri2, M. Josselin1, L. Menard3, M. - A. Verdier3, C. Trigila3

1 Institut de Physique Nucleaire d'Orsay, CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, Orsay, France
2 Roma3 Section, INFN, Rome, Italy
3 Laboratory of Imaging and Modelisation in Neurobiology and Cancerology , CNRS-IN2P3, Orsay, France

Content

We will present our study on the detection properties of a SrI2:Eu crystal for possible application in a gamma camera for medical imaging. We tested a disc-shaped SrI2:Eu with dimensions of 38mm in diameter and 5mm thick, coupled to a Hamamatsu 10966 multi anode PMT (MAPMT). At the time, it was the largest size available for a disc-shaped SrI2:Eu crystal. We compared the obtained results to a slightly larger LaBr3:Ce, with the same shape (50 mm diameter x 5 mm thick).
Despite its long decay time constant, the SrI2:Eu scintillator has showed remarkable gamma-rays detection properties due to its high light yield (bigger than 80000 photons/keV) and reduced light yield non-proportionality effect, that lead to an energy resolution better than 3% at 662 keV. Anyway the self-absorption effect observed for the SrI2:Eu, represents a serious drawback for the use of large volume optics. As a matter of fact, the self-absorption causes severe energy resolution degradation when the thickness of the crystal increases.
For gamma imaging, the use of thin, high light yield scintillator materials is recommended and thus it represent an ideal application for SrI2:Eu.
In this communication we will present the complete characterisation of the tested disc-shaped SrI2:Eu prototype scintillator with a standard high quantum efficiency PMT and we will discuss the outcomes of a spot scanning measurement performed on the tested crystal coupled to a MAPMT. The SrI2:Eu mean spatial resolution measured in the central Field of View, obtained with a modified centre of gravity algorithm, will be compared to that of the LaBr3:Ce.

Keywords: SrI2:Eu, Gamma camera, gamma imaging
Poster panel: 324

Poster Number:
N-19-324

A Study on the Effect of Light Collection Efficiency on Spectral Responses of a Scintillation Detector.  (#2675)

J. Kim1, G. Kim1

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

Content

In the simulation of gamma-ray spectral response from a scintillation detector, the energy deposited in the detector is often calculated from the energy lost by each incident gamma ray due to the interaction, no matter where it happened. In reality, the light collection efficiency of the scintillator will not be uniform over the entire scintillator, which affects the spectral response that can actually be obtained by the scintillator. The energy resolution and peak efficiency, as well as overall shape of the gamma-ray spectrum can be changed. In this work, we simulated transport of optical photons generated from a specific region of a scintillator and obtained simulated spectra in which the light collection efficiency was considered . We compared these with the nominal simulated gamma-ray spectra  and studied how much the energy resolution and the peak efficiency can be affected when the light collection efficiency is considered.

Keywords: Optical Photon, Monte Carlo Simulation, Light Collection Efficiency, Scintillator, Gamma-ray Spectrum
Poster panel: 326

Poster Number:
N-19-326

Characterization of Retroreflective Tape Optical Properties for Use with Position-Sensitive Scintillator Detectors (#2561)

M. Folsom1, M. Febbraro2, P. Hausladen2, J. Hayward1, 2, J. Nattress2, K. Ziock2

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

Content

A retroreflector, or retroreflective surface, has a relatively high probability of reflecting an optical photon 180° relative to its incident direction. This type of surface is beneficial in applications where one wishes to reflect light back at or through its emission point, such as the lettering on road signage or in communications. A retroreflector can also be used to maximize the amount of detected scintillation light produced by ionizing radiation in a scintillator volume while preserving the light’s directional distribution where all scintillator surfaces are not instrumented. This usage is being investigated as part of a project to build a compact neutron scatter camera using fast plastic scintillators. In this application, proton recoils in a very fast but dim scintillator have an approximate threshold energy of 300 keV where only a few dozen optical photons are emitted. This work explores the reflective and retroreflective properties of five low-cost, commercially available retroreflective tapes. Measurements of the reflected intensity and spatial distribution using a blue LED and performance with ionizing radiation in a block of plastic scintillator are presented.

Keywords: scintillator, reflector, retroreflector, optics, imaging
Poster panel: 328

Poster Number:
N-19-328

Module Development for the Phase-2 ATLAS ITk Pixel Upgrade (#1694)

J. Weingarten1, C. Troncon2

1 TU Dortmund, Dortmund, Germany
2 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milano, Italy

Abstract submitted on behalf of the ATLAS Collaboration

Content

In the high luminosity era of the Large Hadron Collider, the instantaneous luminosity is expected to reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. To cope with the resultant increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk). The innermost part of ITk will consist of a state-of-the-art pixel detector, with an active area of about 14 m², which will provide tracking capability up to |η|=4. In order to cope with the changing requirements in terms of radiation hardness, power dissipation and production yield, several different silicon sensor technologies will be employed in the five barrel and endcap layers.
Based on first modules assembled using the RD53A prototype readout chip, numerous issues are being studied. These include production issues like bump bonding of large area, thin modules, encapsulation of wire bonds, and HV insulation between sensor and readout chip, as well as layout issues like optimization of the bandwidth usage through data encoding schemes and sharing of links between multiple chips and modules. The talk will present results of many of these studies, which directly impact the construction and assembly of modules using the first production version of the readout chip ITKpixV1, which will become available shortly

Keywords: Pixel detectors, High Luminosity, LHC
Poster panel: 330

Poster Number:
N-19-330

Development of the MYTHEN III microstrip detector (#1989)

M. Andrae1, A. Bergamaschi1, J. Zhang1, B. Schmitt1, N. Casati1, A. Cervellino1, S. Chiriotti-Alvarez1, R. Dinapoli1, E. Fröjdh1, D. Greiffenberg1, G. Tinti1, M. Meyer1, D. Mezza1, A. Mozzanica1, S. Redford1, X. Shi1, C. Lopez-Cuenca1, M. Brückner1, D. Thattil1, S. Vetter1, R. Barten1, C. Ruder1

1 Paul Scherrer Institut, Villigen PSI, Aargau, Switzerland

Content

The MYTHEN detector is a single photon counting microstrip detector with 50 μm pitch developed for powder diffraction experiments at the Swiss Light Source. After more than ten years of operation of MYTHEN II, a new readout chip MYTHEN III was designed in 110 nm UMC technology to upgrade the current detector and to improve all aspects, specifically noise performance, count rate capability, threshold dispersion and frame rate. Each readout channel of the MYTHEN III chip features a dual polarity front end consisting of a charge sensitive amplifier and a shaper with variable gain and shaping time, as well as three comparators and gateable 24-bit counters. The internal counting logic allows for different modes of operation: energy-windowing, charge sharing suppression, count rate improvement and pump-probe with multiple time slots. The first two prototypes have been characterised in the lab and at the synchrotron. The noise is reduced to 175 electrons and the untrimmed threshold dispersion was measured as 476 eV. Thanks to the three thresholds in the chip, we can detect pile-up of the analog signal in the shaper at high photon flux and thereby reach a count rate of 25 MHz. Based on these results, a full scale chip with 128 channels has been produced. The architectures of the chips, characterisation results of the final chip and module design of the new detector will be presented.

Keywords: DAQ, Front End, Powder diffraction, Silicon microstrip detector, Synchrotron radiation
Poster panel: 332

Poster Number:
N-19-332

32-Channel Detection Unit for Combined XRF-XRD in Mining Transportable Applications (#2171)

M. Carminati1, 2, A. Amirkhani1, 2, E. Ferrara2, C. E. Fiorini1, 2, E. Demenev3, G. Pepponi3, S. Ronchin3, F. Ficorella3, G. Borghi3, N. Zorzi3, L. Lutterotti4

1 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milano, Italy
2 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
3 Fondazione Bruno Kessler, Povo (TN), Italy
4 University of Trento, Dipartimento di Ingegneria Industriale, Povo (TN), Italy

Content

We present the design and characterization of a detection unit for simultaneous and combined XRF and XRD analysis of powder mineralogical samples. Silicon microstrips are coupled to 16-channel CUBE preamplifier ASICs targeting an energy resolution below 200 eV. The compact detection module will be mounted on a goniometer inside a suitcase-sized analyzer to be operated in mining sites.

Keywords: microstrips, portable spectrometer, multichannel preamplifer, combined analysis
Poster panel: 334

Poster Number:
N-19-334

The Design and Construction of LHCb VELO modules (#2401)

K. Akiba1, P. Svihra2

1 Nikhef, amsterdam, Netherlands
2 University of Manchester, physics department, manchester, United Kingdom

Content

The construction of the new LHCb Vertex Locator (VELO) detector is presented. The upgraded subsystem will play a crucial role in the tracking during data-taking runs starting in 2021, its main objective locating primary and secondary vertices. Compared to its predecessor, the main advantages are better resolution together with trigger-less readout at the maximal rate of 40 MHz. In total, VELO consists of 52 modules positioned in vacuum along the LHC beampipe, surrounding the interaction point. The modules are populated with 4 hybrid silicon pixel detectors with pixel pitch of 55 μm. Each of the sensors is read out by 3 VeloPix ASICs with 256x256 pixels. For experiment control and data propagation, sets of front-end hybrids and GBTx ASICs are utilized. The data are then sent through a vacuum feed-through board to an opto-and-power (OPB) board, which is connected to the rest of the experiment via optical fibres. Cooling of the whole module is achieved by phase transition of liquid CO2 using a custom-made silicon microchannel substrate. The assembly of modules at both University of Manchester (Manchester, UK) and Nikhef (Amsterdam, NL) requires high precision in many aspects, therefore extensive procedures for the large-scale construction and its quality assurance have been deployed. The information during each step is uploaded to the online database and automatically analyzed, providing instantaneous information about quality of both components, performed tasks and whole modules. Final assembly of the whole system then takes place at University of Liverpool (Liverpool, UK) and is then transported to CERN (Geneva, CH).

Keywords: LHC, hybrid pixel detectors, radiation resistant, tracking systems
Poster panel: 336

Poster Number:
N-19-336

Diamond Semiconductor-Based Alpha-Particle Detector for High Radiation Environment (#1110)

K. Ueno1, Y. Nagumo1, Y. Kometani2

1 Hitachi, Ltd., Research & Development Group, Hitachi, Japan
2 Hitachi GE Nuclear Energy, Ltd., Nuclear Engineering and Product Division, Hitachi, Japan

Content

As part of efforts for decommissioning of nuclear power plants, we have been developing an alpha-particle detector for use in a high radiation environment of 100 Gy/h. We selected a diamond semiconductor as a detector from the viewpoints of its low sensitivity to gamma-rays and its easy miniaturization. The detector using the 30-μm-thick diamond semiconductor was fabricated and the detection characteristics of alpha-particles from 241Am and gamma-rays from 60Co were evaluated by observing the time trend of the count and the pulse height. The count with time for alpha-particles decreased gradually; however, that by gamma-rays became stable. In order to evaluate the difference of the behaviors, the pulse height spectra with time at each source were compared. The pulse height for alpha-particles degraded with time; that led us to conclude a polarization effect occurred inside the semiconductor. On the other hand, the pulse heights for gamma-rays were stable. We thought that the difference in behaviors might originate from the combination of the polarization effect and the stopping power or the deposited energy of each radiation. The dose rate dependence of the count in the dose rate range from 0 Gy/h to 352 Gy/h was evaluated. We suggested a method to extract the count of alpha-particles by using an extrapolation curve. The count at 352 Gy/h was estimated as 1.5 times larger compared with that at 0 Gy/h; this indicated that the alpha-particle detection by using the detector and the method was reliable.

Keywords: Diamond semiconductor, Alpha-particle, Polarization, Nuclear fuel, Decommissioning
Poster panel: 338

Poster Number:
N-19-338

Development of neutron radiation damage model and comparison of the effects of neutron and proton irradiation on macroscopic properties of the silicon detectors (#1197)

C. Jain1, A. Bhardwaj1, K. Ranjan1, A. Messineo2, M. A. Ciocci3

1 University of Delhi, Department of physics and Astrophysics, New Delhi, India
2 Università di Pisa, Dipartimento di Fisica, Pisa, Italy
3 Universita' e Scuola Normale Superiore, P, INFN Sezione di Pisa, Pisa, Italy

Content

Silicon detectors are widely employed in the modern HEP experiments at particle colliders like LHC because of their excellent tracking and vertexing capabilities. However, the high irradiation levels of unprecedented luminosity of the HL-LHC physics programme of the CMS experiment, requires development of new generation of radiation hard silicon detectors. The radiation environment due to p-p collisions in HL-LHC would consist of both charged and uncharged particles (particularly protons and neutrons), which would reach fluence levels of about 1e16 neq cm-2 in tracker and endcap calorimeter regions. These high levels of incident fluence interact with the silicon detectors and cause radiation damage and hence affect the macroscopic properties of the detectors, viz. full depletion voltage (VFD), leakage current (ILEAK) and charge collection efficiency (CCE). In the present work, Technology Computer Aided Design (TCAD) simulation software - Silvaco, has been used to develop a radiation damage model for neutron irradiation. The effects of neutron and proton irradiation on macroscopic properties of the silicon detectors are also compared and presented in this work. For proton irradiation the already developed proton radiation damage model has been used. The simulation results related to those macroscopic properties are found to be in good agreement with the measurement results.

Keywords: Detector modelling and simulations, Radiation hard detectors, Proton and neutron irradiation
Poster panel: 340

Poster Number:
N-19-340

Damage effects in plastic scintillators under hadron and gamma irradiations (#1291)

V. Dormenev1, E. Auffray2, K. - T. Brinkmann1, A. Boyarintsev3, M. Korjik4, D. Kozlov4, M. T. Lucchini5, M. Moritz1, R. W. Novotny1, R. Pots2, H. - G. Zaunick1, P. Zhmurin3

1 Justus-Liebig Universität Giessen, 2nd Physics Institute, Giessen, Hesse, Germany
2 CERN, PH-CMX, Geneve , Genève, Switzerland
3 Institute for Scintillation Materials NAS of Ukraine, Kharkiv, Ukraine
4 Institute for Nuclear Problems, Minsk, Belarus
5 Princeton University, Princeton, New Jersey, United States of America

Content

Future detectors for high energy physics experiments will require an unique combination of the material properties, particularly in case of experiments based on accelerating facilities. Crucially important becomes a relatively low level of radiation damage effects under the electromagnetic part of the ionizing radiation and energetic hadrons as well: low deterioration of the optical transmission, low level of afterglow and low level of radioluminescence due to radio-nuclides to be generated by nuclear reaction in the material of the detector. Organic scintillation materials are widely used in high energy physics experiments and still considered for future detectors. There are presently several detector concepts in consideration being based on organic scintillator materials for fast timing of charged particles or sampling calorimeters. We have tested different types of organic plastic scintillators, having luminescence in a wide spectral range, from blue to red, which were produced by the Institute for Scintillation Materials (Kharkiv, Ukraine). The aim of the test was to justify a hypothesis that a shift of the spectrum of the plastic scintillator into the red region benefits for the smaller radiation damage. The ongoing activity has characterized the relevant parameters such as light output, luminescence/excitation spectra and the degradation of the optical transmittance. The study was focused on the change of performance after irradiation with 190 MeV and 24 GeV protons with an integral fluence of 5·1013 protons/cm2 as well as with a strong 60Co gamma-source accumulating an integral dose up to 20 kGy. Here we report the obtained results.

Acknowledgment: The work was done in frames of INTELUM and Crystal Clear Collaboration Projects and has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 654002.

Keywords: Plastic scintillators, radiation damage, calorimetry, high energy physics detectors
Poster panel: 344

Poster Number:
N-19-344

A portable test-bench for real-time radiation damage measurements in scintillating and wavelength-shifting fibres (#1696)

D. R. Smith1, P. R. Hobson1

1 Brunel University London, Department of Electronic and Computer Engineering, Uxbridge, United Kingdom

Content

A portable test-bench has been developed to enable the real-time measurement of radiation-induced absorption in scintillating and wavelength-shifting fibres. Such fibres are typically used in the readout of fibre calorimeters or scintillating tiles such as those used in some hadron calorimeters. The test-bench has been designed to be used in a range of facilities, such as 60Co irradiators or high-intensity test beam facilities, and can accommodate fibres with length up to 300 mm and diameter greater than 1.0 mm. The test fibres are illuminated using a combined deuterium and halogen light source focussed onto the end of the fibre with a 0.25 NA radiation-tolerant quartz lens. The light transmitted by the fibre is collected by an identical lens and measured as a function of wavelength with a linear charge-coupled device spectrometer covering a wavelength range of 190 to 850 nm. We present the design of the test-bench, and studies of the systematic errors arising from the components. We measured induced absorbance in the fibres tested and determined the major systematic error to be the stability of the light source. Planned enhancements to the test-bench are discussed.

Keywords: fibre, scintillator, radiation damage
Poster panel: 346

Poster Number:
N-19-346

Dark Count Rate and Energy Resolution of Proton Irradiated Silicon Photomultipliers  (#2003)

S. Mianowski1, D. Borowicz3, 2, K. Brylew1, A. Dziedzic1, M. Grodzicka-Kobylka1, A. Korgul4, M. Krakowiak4, Z. Mianowska1, A. G. Molokanov2, M. Moszynski1, G. Mytsin2, K. N. Shipulin2, T. Szczesniak1

1 National Centre for Nuclear Research (NCBJ), Radiation Detector Physics Division, Świerk (Otwock), Poland
2 Joint Institute for Nuclear Research (JINR), Dzhelepov Laboratory of Nuclear Problems, Dubna, Russian Federation
3 Greater Poland Cancer Centre, Department of Medical Physics, Poznan, Poland
4 University of Warsaw, Faculty of Physics, Warsaw, Poland

Content

This paper presents the results of proton irradiation of silicon photomultipliers by mono-energetic 170 MeV protons with fluence up to 4.4×108  particles/cm2. In our work, three types of silicon photodetectors from Hamamatsu with area 3x3 mm2 and different subpixel size: 25 μm, 50 μm and 75 μm were used. The changes in silicon photomultiplier properties before and after proton irradiation for temperature in the range of 20 °C to -65 °C are presented. Parameters such as dark count rate, dark count spectra and SiPM noise contribution to energy resolution of 662 keV gamma line from the 137Cs for a non-irradiated GAGG:Ce (1%) scintillator are investigated. SiPMs radiation hardness and energy resolution degradation must be taken into account in gamma spectroscopy measurements, whenever experiments are performed in environments with a high proton background.

Keywords: SiPM, proton irradiation, dark count rate, energy resolution, GAGG:Ce scintillator
Poster panel: 348

Poster Number:
N-19-348

Characterization of FBK Small-Pitch 3D Sensors after Irradiation up to 3.5×1016 neq /cm (#2299)

R. Mendicino1, M. Boscardin3, G. - F. Dalla Betta1, 2

1 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Trento, Trento, Italy
2 University of Trento, Department of Industrial Engineering, Trento, Italy
3 Fondazione Bruno Kessler, TRENTO, Italy

Content

3D pixel structures with very short distance between vertical electrodes are the most radiation-hard silicon detectors, and represent the best candidate technology for the innermost tracking layers of detectors at the High Luminosity LHC. Since a few years a joint R&D effort of INFN and FBK has developed a new generation of small-pitch 3D sensors meeting the challenging requirements of future experiments. These devices are fabricated using a single-sided technology on Si-Si Direct Wafer Bonded 6” substrates. Several beam tests on 3D pixel modules assembled with different read-out chips have been performed with encouraging results. In particular, the hit efficiency for particles impinging at 0º tilt (worst case) is 97% after irradiation to a fluence of 1×1016 neq cm−2. In order to investigate the device behavior at larger fluences, we have used 3D diodes. In this paper we report selected results from the characterization with position resolved IR laser of devices irradiated up to 3.5x1016 neq/cm2.

Keywords: Radiation-hard detectors, Radiation damage to detector materials (solid state), Si microstrip and pad detectors
Poster panel: 350

Poster Number:
N-19-350

Effect of low-energy proton doses on reach-through avalanche photodiode particle detectors (#2492)

K. Ogasawara1, F. Allegrini1, 2, M. Dayeh1, 2, M. Desai1, 2, S. Livi1, 2, B. Perez1, M. Starkey1, 2, J. Trevino1, S. Brown3

1 Southwest Research Institute, San Antonio, Texas, United States of America
2 University of Texas at San Antonio, San Antonio, Texas, United States of America
3 NASA, Goddard Space Flight Center, Greenbelt, Maryland, United States of America

Content

Reach-through avalanche photodiodes (APD) offer fascinating properties to improve or enhance measurements of suprathermal particles in space because of the low noise level and the fast response time in lieu of conventional solid-state detectors. Responding to the expanding demand of APDs as particle detectors, the low-energy (120 keV and 1.2 MeV) foreground proton radiation effect was investigated for the first time to estimate the operation lifetime using two reach-through APDs with different drift region thicknesses. In contrast to the previous proton damage studies with penetrating particles, the primary damage depth can be controlled by tuning the incident proton energy in the investigated range. When the incident energy was adjusted to stop right at the avalanche region, a significant reduction of the gain was observed at 1010-1011 protons/cm2 total dose level, and the detector gain was completely lost over 1012 protons/cm2 dose level. In other cases, in which proton damage was only in the drift region, only the increase of the leakage current was observed while the avalanche gain was stable over 1012 protons/cm2 dose level. The increase of the leakage current was steeper for higher-energy proton damages, reflecting the more energy deposited in the detector crystal.

Keywords: Avalanche Photodiode, space instrumentation, proton dose effect, Van de Graaff
Poster panel: 352

Poster Number:
N-19-352

Design of a Voltage Subtraction Bandgap Reference Circuit for Radiation Hardening (#2622)

M. Seung1, 2, W. Choi1, S. Hur2, I. Kwon2

1 Yonsei university, Electrical and Electronic Engineering, Seoul, Republic of Korea
2 Korea Atomic Energy Research Institute, Division of Nuclear I&C, Human Factors, and Automatic Remote Systems, Daejeon, Republic of Korea

Content

The bandgap reference circuit applicable to instruments requiring radiation hardness is presented in this paper. In nuclear power plants, radiation detector and temperature sensor are generally used to observe a reactor state. Therefore, the bandgap reference circuit utilized in sensors should be required a radiation hardening technology for the harsh environments. The proposed bandgap reference circuit is used with the subtraction of the voltages induced from two identical bandgap circuits which have the same temperature curvature and the different voltage magnitude while two reference voltages are only the difference on the design. With statistical simulations, the proposed design achieves about the radiation error rate of 0.93% and the temperature coefficient of 56.2 ppm/˚C in the range of -30 to 125˚ C, while the conventional bandgap circuit has 2.3% and 62 ppm/˚C, respectively.

Keywords: bandgap reference, radiation hardening, subtracting reference voltage
Poster panel: 354

Poster Number:
N-19-354

Fifty Million CPS OCR with 7-Element Silicon Drift Detector (#1084)

S. Barkan1, V. D. Saveliev1, E. Tikhomirov1, Y. - N. Wang1, M. Zhang1, E. V. Damron1, D. Redfern1

1 Hitachi High-Technologies, Chatsworth, California, United States of America

Content

This paper describes a new seven-element Silicon Drift Detector (SDD) that has been developed for synchrotron applications in which a very high count rate x-ray data collection is required.
When a 7-element SDD is used, special care must be taken for the “packing factor”, so that all elements are packed as close as possible to the center point and with minimal “dead space” between the elements. The purpose of optimizing the packing factor is to reduce the scattering background which is heightened as the element location is father away from the center. Optimized packing factor was achieved by using square-shaped SDD dies in a geometry that enabled packing the seven-element array into a tube with diameter of 38 mm.
Each of the seven die in this device has a 50 mm2 effective area for a total area of 350 mm2.  In addition, a significant improvement in the high count-rate capability has been achieved by using an ASIC preamplifier combined with an advanced digital pulse processor (DPP): the “FalconX” developed by XIA LLC (Hayward, CA USA), or the “Xspress3”, developed by Quantum Detectors (Harwell Oxford, UK).
The new 7-element SDD, together with its ASIC preamplifier and the new advanced digital processor, produces a dramatic increase in count rate capability to a level of more than 7 Mcps per channel and enhances the efficiency of the measuring methods whenever high count rate and good energy resolution play an important role.
One of the 7-element SDD spectrometers is in use at the National Synchrotron Light Source II (NSLS II) at the Brookhaven National Laboratories. Beamline application results will be presented at the IEEE NSS 2019 conference.

Keywords: SDD, OCR, ASIC, DPP, Packing factor
Poster panel: 356

Poster Number:
N-19-356

Percival P2M-FSI detector: first test at a Synchrotron Ring beamline with tender x-ray photons (#1314)

A. Marras1, 2, C. Wunderer1, 2, J. Correa1, 2, B. Boitrelle1, 10, S. Lange1, 2, N. Guerrini3, 4, M. Kuhn1, F. Krivan1, I. Shevyakov1, M. Zimmer1, M. Hoesch1, 11, F. Scholz1, 11, K. Bagschik1, 11, B. Marsh3, 4, I. Sedgwick3, 4, G. Cautero5, D. Giuressi5, R. Menk5, G. Pinaroli5, 9, L. Stebel5, T. Nicholls3, U. Pedersen6, N. Tartoni6, H. Graafsma1, 8, S. Rah7, H. Hyun7, K. - W. Kim7, A. Greer3

1 Deutsches Elektronen-Synchrotron, Hamburg, Germany
2 Center for Free Electron Laser Science, Hamburg, Germany
3 Science & Technology Faculties, Didcot, United Kingdom
4 Rutherford Appleton Laboratory, Didcot, United Kingdom
5 ELETTRA Synchrotron, Trieste, Italy
6 Diamond Light Source, Didcot, United Kingdom
7 Pohang Accelerator Lab, Pohang, Republic of Korea
8 Mid Sweden University, Sundsvall, Sweden
9 Udine University, Udine, Italy
10 SOLEIL Synchrotron, Saint Aubin, France
11 Petra III P04 beamline, Hamburg, Germany

Content

The adoption of high-brilliance X-ray sources (3rd generation Synchrotron Rings and Free-Electron Lasers) imposes demanding constraints on detectors: single-photon resolution, high dynamic range, fast readout (to allow single-shot experiments), low noise (for soft/tender x-ray detection).
Percival is an X-ray detector under development as a collaboration between DESY, STFC, ELETTRA, DLS and PAL to answer those needs. The P2M system is a 2M-pixel imager, featuring a large imaging area (~4x4cm2) without any dead or blind spaces.
In-pixel circuitry (lateral overflow) is included to extend the detector dynamic range, by modulating the sensor gain according to the impinging photon flux (independently pixel-by-pixel and image-by-image). Digital Correlated Double Sampling, analogue-to-digital conversion, and fast digital streamout are included as well. It is wire-bonded to a ceramic board, kept in vacuum (of the order of 1e-6 mbar) to avoid absorption of low-energy photons by atmosphere, and cooled to -20°C. A suitable vacuum vessel has been designed and built for sub-zero operation and low-energy-photon detection. The digitized sensor outputs are passed to a fast data-concentrator board, streamed out through parallel 10Gb ethernet links, and addressed to multiple receiving nodes through a buffer switch.
The P2M Front-Side-Illuminated version of the detector has been tested with tender (2keV) x-ray photons at P04 beamline in the Petra III Synchrotron Ring.
Direct synchrotron beam has been shone on the detector, and the lateral overflow circuitry (adaptively modulating the sensor gain, to extend the detector dynamic range) was verified in high-flux condition. In low-flux conditions, the detector was confirmed to be able to clearly distinguish single photons. A Back-Side-Illuminated version of the detector (suitable for softer x-rays) is being processed.

Keywords: CMOS imager, MAPS, Percival, tender x-rays
Poster panel: 358

Poster Number:
N-19-358

Characterization of an Enhanced Cooling Technology for Silicon Drift Detectors with Micro-Focus X-Ray Beam (#1743)

C. Cohen1, P. Busca1, M. Kocsis1, S. Benichou1, M. Morelle2

1 ESRF, GRENOBLE, France
2 Mirion Technologies, OLEN, Belgium

Content

The combination of new Digital Signal Processors (DSPs) and monolithic CMOS charge preamplifiers specifically designed to be used with Silicon Drift Detector (SDD) has dramatically increased the energy resolution and throughput of spectroscopy detector systems.  A well-known key parameter determining the detector throughput is the signal rise time at the output of the preamplifier. The development of compact, low-noise and efficient cooling systems can lead to a dramatic improvement in both electronic noise and count-rate capability. In this work, the influence of a novel compact cryogenic cooler developed historically for High-Purity Germanium detectors is studied and applied to the SDD case.  To analyse and compare performances, the signal rise time distribution at the preamplifier output has been mapped for various detector sizes and different temperatures down to -100 °C by using a micro-focused X-ray beam with a focal spot down to 100 µm. A simplified model has also been applied to verify the coherence of obtained results, the benefits of a DSP algorithm have been evaluated as well.

Keywords: SDD, cryocooler, rise time
Poster panel: 360

Poster Number:
N-19-360

Towards Efficiency and Count-Rate Enhancement of X-ray ARDESIA Spectrometer (#2185)

G. Utica1, 2, E. Fabbrica1, 2, M. Gugiatti1, 2, I. Hafizh1, 2, M. Carminati1, 2, A. Balerna3, G. Borghi4, F. Ficorella4, A. Picciotto4, N. Zorzi4, A. Capsoni2, S. Coelli2, C. E. Fiorini1, 2

1 Politecnico di Milano, DEIB, Milan, Italy
2 INFN, Sezione di Milano, Milan, Italy
3 INFN, Laboratori Nazionali di Frascati, Frascati, Italy
4 Fondazione Bruno Kessler, Trento, Italy

Content

ARDESIA is an SDD-based, multichannel X-ray spectrometer, optimized for synchrotron applications requiring a high-count rate (>1Mcps per channel) and a high-resolution (e.g. below 150eV FWHM at peaking times faster than 200ns) for X-ray fluorescence detection. This paper describes improvements made for the ARDESIA spectrometer on detection efficiency and overall counting rate capability to better match requirements from synchrotron experiments. These improvements have been obtained by increasing the number of channels, from 4 to 16, and the SDD thickness to 800μm, the first thicker SDDs for FBK. The new detection module and the new complete spectrometer are described in detail. Then, the results of the new prototype are reported and discussed.

Keywords: Silicon Drift Detector, Synchrotron, X-ray Spectroscopy, Thick detector, SDD
Poster panel: 362

Poster Number:
N-19-362

Spatial Resolution of Crystal-Based Front Imager (#2502)

C. Hu1, L. Zhang1, R. - Y. Zhu1, J. Chen2, D. Ding2

1 California Institute of Technology, Pasadena, California, United States of America
2 Shanghai Institute of Ceramics, Shanghai, China

Content

We report an investigation on spatial resolution for BaF2:Y and LYSO monolithic plate and pixelated crystal screen based front imager for GHz hard X-ray imaging. Their spatial resolution was evaluated by using line-pair pattern and knife edge methods. This work provides a proof of principle for ultrafast inorganic scintillator-based GHz hard X-ray front imager.

Keywords: Ultrafast crystal scintillators, GHz hard x-ray imaging, Spatial resolution
Poster panel: 364

Poster Number:
N-19-364

A low-energy x-ray Compton polarimeter prototype (#2640)

T. Krings1, U. Spillmann2, M. Vockert3, 4, G. Weber2, 3, T. Stöhlker2, 3

1 Forschungszentrum Jülich GmbH, Institut für Kernphysik (IKP), Jülich, Germany
2 GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
3 Helmholtz-Institut Jena, Jena, Germany
4 Friedrich-Schiller-Universität Jena, Institut für Optik und Quantenelektronik, Jena, Germany

Content

To learn about the dynamics of atomic transitions in the mid- and high-Z regime it is of great importance to perform a reliable measurement of the polarization of emitted x-rays from the reaction channel of interest. To cover the relevant energy range from a few keV to approximately 30 keV we have developed a Compton polarimeter prototype to determine the degree of linear polarization of this radiation. The basic concept is based on a passive low-Z scatterer (e.g. Be, SiC, PE) in which the x-rays will undergo Compton scattering and in a subsequent step they will be deposited on a pixelated HPGe detector. The asymmetry of the scattering distribution is a signature of the degree of linear polarization. The Ge detector we processed in-house from a ~3 mm thick high purity Germanium wafer. On the back side contact a structure of 19 hexagonal pixels was formed by photolithographic techniques. The detector may be used as a 19-pixel x-ray detector or in combination with a scatterer as Compton polarimeter. The readout stage is split into two parts. The first part is the cryogenically cooled FET input stage which is connected to the detector elements by spring-loaded pins. The second stage is built from discrete charge sensitive preamplifiers at room temperature. With the present setup we achieve a resolution of ~800-850 eV [FWHM] for 60 keV photons from a Am-241 source. In our presentation we will discuss the detector system as well as the conducted test measurements.

Keywords: polarimetry, compton scattering, x-rays, atomic physics
Poster panel: 366

Poster Number:
N-19-366

Thick Silicon Sensors for Hard X-ray Science at LCLS  (#2698)

J. Hasi1, J. D. Segal1, C. J. Kenney1, M. Kwiatkowski1, D. Doering1, A. Dragone1, G. Blaj1, C. - E. Chang1, L. Rozario1

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

Content

The Linac Coherent Light Source is being upgraded with a undulator line that will allow x-rays with energies up to 25 keV in the first harmonic. This present a challenge of recording these photons with high efficiency to support the science program. The existing detectors mostly have silicon sensors that are 500 microns thick. However, these sensors are largely transparent to hard x-rays, which results in less science and increased radiation damage to the downstream electronics. We have designed and fabricated 1000 micron thick silicon sensors, flip-chip bonded them to ePix10k integrated circuits, and tested them with hard x-rays in preparation for the start of LCLS II operations in 2020.

Keywords: Hard x-rays, LCLS, xray, sensor
Poster panel: 368

Poster Number:
N-19-368

Characterisation of the Segmented Inverted-coaxial Germanium Detector SIGMA (#1322)

F. Pearce1, A. Boston1, L. Harkness-Brennan1, D. Judson1, P. Nolan1, R. Page1, E. Rintoul1, J. Wright1, M. Labiche2, J. Simpson2, C. Unsworth1, D. Radford3

1 University of Liverpool, Oliver Lodge Building, Liverpool, United Kingdom
2 STFC, Daresbury Laboratory, Warrington, United Kingdom
3 Oak Ridge National Laboratory, Physics Division, Oak Ridge, Tennessee, United States of America

Content

The prototype Segmented Inverted-coaxial GerMAnium (SIGMA) detector has undergone a series of experimental measurements at the University of Liverpool. This is the first p-type detector of its kind to be manufactured. The p+ point contact offers superior energy resolution over other large volume High Purity Germanium (HPGe) detectors, while the outer n+ contact is segmented into 19 segments to provide timing information for the start time of pulses, allowing interaction position to be precisely determined. The prototype detector has achieved an energy resolution of 0.85 keV at 122 keV and 2.21 keV at 1332 keV in the point contact, which acts as the main readout channel, and an average response of 1.20 keV at 122 keV and 2.47 keV at 1332 keV in the outer segments. The dimensions of the crystal have been measured for comparison with the initial design using a collimated 1mm 241Am beam mounted on a x-y scanning table. The beam was scanned across the front face and side of the detector in a 1mm grid. The low penetration distance of the 60 keV peak of 241Am allowed for the investigation of surface features of the crystal, including holding structures and segment boundaries. The unique electrode configuration of SIGMA results in pulses characterised by a sharp increase in pulse height close to the point contact, creating distinct pulse shapes dependent on interaction position. Pulse Shape Analysis (PSA) algorithms use a database of simulated charge pulses to determine the location of an interaction of unknown location. To experimentally validate a simulated database, a number of locations within the detector have been investigated using coincidence scanning. A 137Cs collimated 1mm beam directed in the z direction is held at multiple x-y positions and the interaction depth is determined by 4 rings of collimated auxiliary BGO detectors, operated in coincidence with SIGMA. The average pulse shape for each location was calculated for comparison with the simulated response.

Keywords: Point contact, HPGe, Gamma ray tracking, Pulse shape analysis
Poster panel: 370

Poster Number:
N-19-370

4µm pore Microchannel Plate and its performance (#1579)

S. L. Liu1, 4, B. J. Yan1, 2, K. L. Wen1, 3, Y. J. Lin1, 2

1 Institute of High Energy Physics, CAS, Center of Experiment Physics, Beijing, China
2 State Key Laboratory of Particle Detection and Electronics, Beijing, China
3 Henan University, School of Physics &Electrics, Kaifeng, China
4 University of Chinese Academy Sciences, School of Physics Sciences, Beijing, China

Content

The microchannel plate (MCP)with ultra-small pore can not only improve the spatial and temporal resolution, but also improve the anti-magnetic field capability of the device which made of this MCP, but its gain not ideal. Therefore, on the basis of the 4µm pore MCP, we use ALD technology to make nano-sized high secondary emitting material (Al2O3) film on the inner channel and the input face, which not only improves the gain, but also increases the cumulative pick-up charge, and then effectively prolonging its lifetime, the adoption of this MCP component for use in MCP-PMT or other detection or imaging devices will effectively improve the spatial and temporal resolution of such products in the field of nuclear detection and imaging, There will be a good prospect of application.

Keywords: Microchannel Plate, spatial and temporal resolution, magnetic field, ALD
Poster panel: 372

Poster Number:
N-19-372

Development of a material model for hydrogenated amorphous silicon in Synopsys TCAD (#1596)

J. A. Davis1, 2, M. Boscardin4, 5, S. Dunand10, L. Fano3, 6, M. Menichelli3, A. Morozzi8, F. Moscatelli3, 7, M. Movileanu-Ionica3, D. Passeri3, 8, M. Petasecca1, M. Piccini3, A. Rossi3, 6, A. Scorzoni3, 8, B. Thompson1, G. Verzellesi4, 9, N. Wyrsch10

1 University of Wollongong, Centre for Medical Radiation Physics, Keiraville, Australia
2 University of Wollongong, Illawarra Health and Medical Research Institute, Keiraville, Australia
3 INFN, Perugia, Italy
4 INFN TIPFA, Trento, Italy
5 Fondazione Bruno Keller, Trento, Italy
6 Dip. Di Fisica dell'Università degli studi di Perugia, Perugia, Italy
7 CNR-IOM, Perugia, Italy
8 Dip. Di Ingegneria dell'Università degli studi di Perugia, Perugia, Italy
9 Università di Modena e Reggio Emilia, Moderna, Italy
10 Ecole Polytechnique Federale de Lausanne, Institute of Microengineering, Neuchatel, Switzerland

Content

There is a renewed interest in the use of hydrogenated amorphous silicon or a-Si:H, for use in particle detection applications due to its low cost and radiation tolerance. Given its long history in photo-voltaic applications, material models for a-Si:H have been developed in commercial multi-variate physics software packages like SILVACO. In this study we investigate the development of a new model of a-Si:H for use with SYNOPSYS TCAD. Validation of the model is achieved via comparison with experimental measurements within the literature. Experimental and simulated results of the static current density for a bias range of 0 to 400V agree within 0.2µA/cm2. Charge collection studies using the minimum ionising particle model were performed. The simulations data show the same time response in terms of drift (~3 ns) and diffusion (20-30ns) dominated collection as evident in the experimental measurements performed with laser light of varying intensities. The success of this model will be evaluated in their applicability to predict the performance of new devices soon to be developed. Full analysis of results and an evaluation of the a-Si:H model will be presented at NSS 2019.

Keywords: a-Si:H, Radiation detectors, TCAD
Poster panel: 374

Poster Number:
N-19-374

A proof-of-concept CdTe detector for in-situ measurement of strontium-90 in groundwater (#1767)

G. Turkington1, K. A. A. Gamage1, J. Graham2

1 University of Glasgow, Electronics & Engineering, Glasgow, United Kingdom
2 National Nuclear Laboratory, Contaminated Land and Remediation, Seascale, Germany

Content

This paper describes the design of a proof-of-concept cadmium telluride semiconductor detector for in-situ detection of strontium-90 at nuclear decommissioning sites. The activity of strontium-90 in groundwater must be routinely monitored but existing lab-based techniques are time-consuming and expensive. An alternative approach is taken by measuring the beta particles released during strontium-90 decay, where the detection system consisted of a cadmium telluride Ohmic detector (10 x 10 x 1 mm), compact charge sensitive preamplifier and pulse shaping unit. The complete unit has been characterised to determine its suitability for the direct measurement of strontium-90 decay. This paper presents findings on the design of the device, its stability of the device over time, its response to beta radiation, room temperature operation and performance at high dose rates.

Keywords: Radioactive waste, Semiconductor radiation detectors, semiconductor materials
Poster panel: 376

Poster Number:
N-19-376

Detecting Nuclear Radiation with an Uncovered CMOS Camera & a Long-Wavelength Pass Filter (#1921)

Z. Yan1, Y. Hu1, G. Huang1, T. Dai2, Z. Zhang1, Q. Wei1

1 University of Science and Technology Beijing, School of Automation and Electrical Engineering, Beijing, China
2 China-Japan Friendship Hospital, Department of Radiation Oncology, Beijing, China

Content

In this article, we propose a method to detect nuclear radiation based on a CMOS camera and a long-wavelength pass filter. Firstly, we capture videos and gain image dataset through the camera with and without the filter individually. Then the inter-frame difference algorithm and Gaussian smoothing method are used to reduce the interference of moving objects and visible light to the images. At last, a series of thresholds were selected to test the validity of our detecting method on validation set. The experimental results present that the promoted method can effectively detect nuclear radiation.

Keywords: nuclear radiation detection, CMOS camera, long-wavelength pass filter, inter-frame difference
Poster panel: 378

Poster Number:
N-19-378

VIDARR - Monitoring Reactor Antineutrino Emissions  (#2393)

J. Coleman1, Y. - J. Schnellbach1, C. Metelko1, R. Mills2, G. Holt1, 2, R. Collins1

1 Physics Dept, University of Liverpool, Department of Physics, Liverpool, United Kingdom
2 NNL, Nuclear and Reactor Physics, Seascale, United Kingdom

Content

Monitoring a nuclear reactor using antineutrinos, allows a measurement of the power output and the state of the core directly without outside interference or signal masking. VIDARR is capable of interrogating a reactor at a stand-off distance of up to 100 m, providing a tool for safeguards that can be operated with low overhead, providing continuous monitoring, while following recommendations from a safeguards perspective.
The detection of reactor antineutrinos is achieved by detecting inverse beta-decays inside a tonne scale instrumented volume of plastic scintillator, read out by an array of solid-state silicon photomultipliers. By using a highly segmented fiducial region, this approach allows particle classification and rejection of known background signatures including cosmic rays. Combined with the time-delayed double coincidence structure of inverse beta-decays, this allows for a strong background rejection and identification of antineutrino candidates.
This provides a direct measurement of the core burn-up rate, whereas existing industry approaches infer the core state using thermal hydraulic measurements and neutron rates, assisted by log books. These inferred measurements are often combined with manual inspections for verification. The  complementary information provided by this approach opens the door to future developments.
Previously, a smaller proof-of-concept device has been trialled at the Wylfa Magnox Power Plant. This initial deployment has informed the development of the VIDARR prototype. Here we present the prototype incorporating several unique advances in its sensor readout electronics and analysis techniques. The goal is now deploying the system at a Nuclear facility to demonstrate its capability for remote power monitoring and further core-related measurements.

Keywords: Reactors, safeguards, antineutrinos, SiPMs, Plastic scintillator
Poster panel: 380

Poster Number:
N-19-380

Mixed-Radiation Field Event Classification by Pixel Detectors Timepix and Timepix3 (#2660)

C. Granja1, J. Jakubek1, C. Oancea1, E. Benton2, S. Kodaira3, J. Stursa4, V. Zach4, P. Krist4, D. Chvatil4, A. Mackova4, V. Havranek4, M. Martisikova5, S. Polansky1

1 Advacam s.r.o., Prague, Czech Republic
2 Oklahoma State University, Stillwater, Oklahoma, United States of America
3 National Institute of Radiological Sciences, Chiba, Japan
4 Nuclear Physics Institute, Czech Academy of Sciences, Rez near Prague, Czech Republic
5 German Cancer Research Center, Heidelberg, Germany

Content

The resolving power of Timepix and Timepix3 detectors for wide-range particle detection is examined for discrimination into main radiation components. The methodology of classification of events has been developed based on measurements in defined radiation fields. The goal is to characterize mixed-radiation fields consisting namely of X-rays and charged particles in terms of particle-types (species), spectral response (energy loss) and direction in wide field-of-view (essentially 2π) with a single compact tracking detector. Tests and calibration measurements were performed at electron, proton and ion fields at defined energies and incident directions. High-resolution pattern recognition analysis of single particle tracks evaluates events according to three degrees of freedom – the particle type (X-rays, light (LCP) and heavy charged particles (HCP)), energy range (low or high energy – depending on their range being smaller or larger than the pixel size of the detector semiconductor sensor) and direction (incident angle to the sensor plane). Characteristic cluster analysis parameters are derived for spectral and tracking morphology. For energetic charged particles are derived their incident direction, stopping power and Linear Energy Transfer. Further, we make use of ratios and correlations between cluster parameters including 2D-scatter plots. A physics-based wide-range classification is proposed for a broad event groups – namely light charged particles (electrons, muons) of both low and high energy incident perpendicular including X-rays, high energy LCPs non-perpendicular, protons of low energy omnidirectional and high energy non-perpendicular, alpha particles and light ions of low energy omnidirectional and high energy non-perpendicular, heavy ions of low energy omnidirectional and high energy non-perpendicular. The technique and methodology developed for Timepix are enhanced by the use of the new ASIC chip Timepix3 (work and results will be presented).

Keywords: Particle tracking, Position sensitive particle detectors, Semiconductor radiation detectors, Space radiation

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