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NSS Poster

Session chair: Lipton , Ronald (Fermi National Accelerator Laboratory, Batavia, USA); Maehata , Keisuke (Teikyo Univ., Omuta, Japan)
Shortcut: N-09
Date: Wednesday, 20 October, 2021, 7:00 AM - 8:45 AM
Room: NSS - 1
Session type: NSS Session


Click on an contribution to preview the abstract content.


A Low Noise, High Linearity DC-couped APD Readout ASIC for Electromagnetic Calorimeter in Super Tau-charm Factory (#16)

Z. Li1, J. Wang1, X. Luo1, R. Zheng1, Y. Hu2

1 Northwestern Polytechnical University, School of Computer, Xi’an, China
2 IPHC, University of Strasbourg, Strasbourg, France


This paper presents a novel low-noise high-linearity front-end readout application-specified integrated circuit (ASIC) for electromagnetic calorimeter based on DC-coupled avalanche photodiode (APD) in super tau-charm factory (STCF). The ASIC includes four-channel analog front-ends. Bias circuits and band-gap circuit are integrated as well. Each readout chain consists of a charge sensitive amplifier (CSA), a slow shaper, a baseline holder (BLH), a peak detect and hold circuit (PDH), and an analogue buffer. APD with a large detector capacitance will increase equivalent noise charge and extend rise time of the preamplifier, resulting in attenuated energy and time resolution of the ASIC. A low noise CSA working in current mode and a CR-(RC)5 high-linearity semi-Gaussian shaper were proposed to decrease the noise induced by a 270 pF detector capacitance and enhance the counting rate. A prototype ASIC was implemented in TSMC 0.18 μm 1.8 V/3.3 V mixed-signal CMOS process, and the die size is 1.1mm×2.4mm . The preliminary test results have been obtained. The input charge range is from 5 to 400 fC. The measured signal to noise ratio is better than 6.6:1 with the leakage current of 100nA and the detector capacitance of 270 pF. The maximum nonlinearity of the high-order shaper is less than 1%. And the maximum count rate is up to 400 kcps. The proposed ASIC is a good solution of front-end electronics for the electromagnetic calorimeter in STCF.

Keywords: APD readout, ASIC, DC-coupled, Low Noise, High Linearity

Low Noise Front-end Electronics for a CZT-based Gamma-ray Spectrometer (#692)

M. Zhao1, 2, C. Feng1, 2, Z. Zhou1, 2, Y. Wang1, 2, Z. Cao1, 2, P. Cao1, 2, Q. An1, 2

1 University of Science and Technology of China, State Key Laboratory of Particle Detection and Electronics, Hefei, China
2 University of Science and Technology of China, Department of Modern Physics, Hefei, China


A low noise, low power consumption front-end electronics module, for the readout of cadmium zinc tellurium (CZT) detector, is presented in this paper. It is used for a high resolution gamma ray spectrometer aiming for in-situ environmental gamma ray measurements. The module consists of 8 independent channels of charge sensitive amplifiers (CSA), high voltage module, and calibration module. Test results show that the rise time is about 31 ns, and the RMS of equivalent noise energy is about 1.56 keV, which equals to 0.054 fC of equivalent noise charge (ENC), consistent with the simulation results. The power consumption is about 80 mW per channel. It is relatively fast response, low noise, and low power consumption for the front-end electronics module with discrete components. Then we used a quasi-hemispherical CZT detector with the sensitive volume of 10 mm * 10 mm * 10 mm and the electronics module to obtain the spectrum of 137Cs as the radioactive source. Energy resolution of 1.8% at 662 keV FWHM at the room temperature is obtained, without any special discrimination methods, which is satisfied for our application.

Keywords: Charge sensitive amplifier, CZT Detector, Gamma ray detection

Design of a Current-Mode Front-End Readout ASIC Featured 100 pC and 10 Mcps for High-Speed Photon Counting (#828)

J. Wang1, Q. Xu1, B. Wang1, J. Geng1, P. Huang2, W. Gao1

1 Northwestern Polytechnical University, School of Computer Science and Technology, Xi An, China
2 National Institute of Measurement and Testing Technology, Cheng Du, China


High-speed photon counting techniques play an important role in the field of nuclear medical imaging and high-energy physics experiments. A count rate of larger than 10 Mcps is required in some applications. This paper presents the design of a current-mode photon-counting readout ASIC for high-gain detectors to meet this target. A regulated common-gate amplifier and a current-mirror current mirror with negative feedback are proposed to implement the preamplifiers. The input resistance and the -3dB bandwidth of these preamplifiers are carefully taken into account. In addition, a current-mode comparator is adopted to reduce the propagation time. In order to mitigate the effects of preamplifier output noise, a current-mode comparator with hysteresis is designed. An eight-channel front-end readout ASIC is designed in CMOS 0.35 μm 3.3 V process. It consisted each channel of a current-mode preamplifier, a current discriminator, a 7-bit current-steering digital-to-analog converter (DAC) and a large bandwidth output buffer. Four versions of readout circuits are integrated according to design considerations: 1) The comparisons of different input resistance and bandwidth of preamplifiers; 2) The optimum combination of the topologies of current preamplifiers and current comparator. The post-simulation results are listed as followed. The maximum input charge is 100 pC. The minimum input impedance and the maximum -3dB bandwidth of the preamplifier are 20 Ω and 600 MHz, respectively. The maximum propagation time of the current comparator is less than 5 ns.  The counting rate exceeds 10 Mcps. The fabricated chip has been back. The die photograph is given. The performance of the proposed circuits will be evaluated in the next step.   

AcknowledgmentThe authors would like to thank the teachers with the Institute of Microelectronics, Northwestern Polytechnical University, Xi'an, Shanxi Prov. of China for their valuable advice.
Keywords: ASIC, Front-End Readout, Current Mode

Design of a Low-Power Front-End Readout ASIC Based on Energy-Efficient Amplifiers, Featured 126 e-(rms), 0.6 mW/Channel for Si-PIN Detectors (#874)

B. Wang1, Q. Mao1, P. Huang2, W. Gao1

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


Working life is an essential performance index for battery-powered portable radiation detectors. In these applications, an energy-efficient front-end electronic is of great importance. According to the comparison of mostly used amplifiers, an inverter amplifier, which can achieve the highest energy efficiency, is proven to be a good candidate for the analog front-ends. However, such amplifier suffers from low gain which should be improved in the real applications.  In addition, the optimum W/L ratios of both PMOS and NMOS transistors in this topology requires careful consideration in the step of noise optimization of the inverter amplifier. This paper presents design techniques and experimental results of an energy-efficient front-end readout application-specific integrated circuit (ASIC) based on gain-boost inverter amplifiers for Si-PIN detectors. A tradeoff between noise and power dissipation is performed in the first part. Next, an ASIC prototype including eight-channel analog front-ends is designed in CMOS 0.35 μm mixed-signal 3.3 V process. Each channel mainly includes a charge sensitive amplifier, a slow pulse shaper, an output buffer, a fast shaper and a discriminator. In these blocks excluding the output buffer, all core amplifiers are implemented by the inverter-based amplifier. The die size is 2.1 mm × 2.4 mm. The simulation results are obtained. The input charge range is 0.2 ~ 24 fC. The equivalent noise charge is 126 e- + 11 e- / pF. The power dissipation is about 0.6 mW/channel. The fabrication of the chip has been finished. For future work, the ASIC will be measured for performance evaluation. Moreover, the energy efficiency will be improved to satisfy the requirements of portable nuclear instrumentation such as electronic personal dosimeters and energy-spectrum analyzer.

AcknowledgmentThe authors would like to thank the teachers with the Institute of Microelectronics, Northwestern Polytechnical University, Xi'an, Shanxi Prov. of China.
Keywords: Inverter-based amplifier, Energy Efficiency, Front-End Readout, Low Noise, Radiation Detectors

The Design of a Fast Front-end Readout ASIC for Time Correction with Low Voltage (#939)

Z. Zhao1, R. Zheng1, J. Li1, X. Zheng1, J. Wang1, Y. Hu1

1 Northwestern Polytechnical University, Xi’an, China


To meet the requirement of high resolution in the timing Resistive-Plate Chambers (RPCs), a fast front-end readout ASIC for time correction is presented.   There are eight readout channels in the designed ASIC, each channel is composed of a Preamplifier with wide bandwidth, a discriminator with hysteresis function, a differential digital-to-analog converter (DAC), the bias circuit and SPI interface. The preamplifier is designed with wide bandwidth and large supply currents to increase slew rate and get the fast leading edge. The baseline of the preamplifier’s differential output can be changed with the threshold feedback. Besides, the input impedance of preamplifier is programmable with external resistor, which can be well matched with the detector. The ASIC is implemented in GSMC 0.13 μm CMOS mixed-signal 1.2 V process, and it is a challenge to realize fast signal readout in such low supply voltage. The equivalent noise charge is 1238 eRMS. The power dissipation is about 7.5 mW/channel, which is much lower than that of similar chips.

AcknowledgmentThe research is supported in part support in part by National Key National Natural Science Foundation of China under Grant, NO. 11835007, NO. 11835008, NO. 11705148 and NO. 11875221, Natural Science Foundation of Shaanxi province under Grant NO. 2019JQ-268, Research and Development Program of China under Grant NO. 2018YFA0404302, Innovation Guidance Support Project for Taicang Top Research Institutes, No. TC2019JC05.
Keywords: Resistive-Plate Chambers (RPCs), Fast front-end readout, ASIC, Low supply voltage.

Ultra-Low Power Discrete-Time Readout for CMOS Radiation Sensors (#1318)

S. Durando1, 2

2 INFN, ARCADIA, Turin, Italy


This paper presents the design of a discrete time front-end electronics for CMOS radiation sensors with a power consumption of 11 nW/pixel. The architecture is inspired by the DRAM sensing techniques and it is suitable for small pixel readout. The design is implemented in a 110 nm CMOS technology and consists of a discrete time binary front-end composed by a source follower input stage, an inverting discriminator with offset compensation and a digital buffer. The work is carried out in the framework of the ARCADIA collaboration, which aims to develop fully-depleted monolithic CMOS sensor with low noise, fast charge collection and low power readout, compatible with standard fabrication processes. The first prototype of the discrete-time front-end is implemented in a 2x2 mm^2 matrix composed by 4 sectors of 6 columns of 24 50 μm pitch pixels. It has been submitted in November 2020 and test results are expected by September 2021. Simulations show a power density below 1 mW/cm^2 for a frame rate of 10 Khz. The circuit performance have been simulated with systematic and random process variation Monte Carlo simulation.

Keywords: CMOS radiation sensors, Low power electronics, Space experiments, Silicon trackers, DRAMs.

Clock Distribution and Synchronization Based on DDS for SHINE (#1432)

J. Qin1, 2, J. Gu1, 2, L. Zhao1, 2, Y. Fan1, 2, J. Zhu1, 2, Z. Jiang1, 2, S. Liu1, 2, Q. An1, 2

1 University of Science and Technology of China, the State Key Laboratory of Particle Detection and Electronics, Hefei, China
2 University of Science and Technology of China, Department of Modern Physics, Hefei, China


Shanghai High repetition rate X-ray Free Electron Lasers and Extreme light facility (SHINE) is expected to be the first hard X-ray FEL facility in China, which has been under construction. Hundreds of devices will be integrated in such kind of accelerators typically, and the perimeter of the SHINE accelerator is about 3.1 km. In order to make sure all the devices work exactly in a uniform manner, a high-precision multi-node clock distribution and synchronization system is required. For the exact reference clock fed into the clock distribution system is about 9.028 MHz, standard White Rabbit (WR) protocol cannot directly deal with it. A promising method is that extracting the frequency and phase messages of the input clock by the DDS circuit on the master node, and then recovering it in all slave nodes according to the received frequency and phase messages. While the reference clocks of both master and slave nodes are synchronized using WR. A prototype electronics is designed, and efforts are devoted to both hardware and Field Programmable Gate Array (FPGA) logic design to achieve high precision clock synchronization, fine phase adjustment, and frequency tuning. Test results show that the prototype can achieve multi-node machine clock distribution and synchronization at several kilometers distance, and the synchronization accuracy is better than 0.7 ns with the skew jitter better than 18 ps RMS within a frequency range from about 1 Hz to 1 MHz. Moreover, the temperature drift is less than 2 ps/℃.

Keywords: Clock distribution, White Rabbit, DDS, SHINE

Design and Implementation of Readout Electronic Trigger for Dark Matter Prototype Detector Based on Liquid Argon (#107)

K. Zhao1, 2, Z. Shen1, 2, Q. Zhao3, H. Yu1, 2, X. Zhu1, 2, S. Liu1, 2

1 University of Science and Technology of China, State Key Laboratory of Particle Detection and Electronics, Hefei, China
2 University of Science and Technology of China, Department of Modern Physics, Hefei, China
3 Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China


A real-time, flexible and scalable readout electronic trigger is presented in this paper, for the liquid argon(LAr) dark matter prototype detector. This electronic trigger is designed based on the high-speed serial bus PXIe platform. The trigger and clock unit (TCU) communicates with the data acquisition unit (DAU) through the star bus PXIe_DSTAR on the PXIe backplane. The waveform information is collected by the DAU and is gathered to the TCU for advanced processing through the star bus. Then the TCU sends the processed result back to each DAU within 200 ns. With a successful trigger, the PC will obtain the waveform data from DAUs by PCIe bus. This trigger design can flexibly expand the number of channels as needed. Using the electronic trigger, a large number of invalid cases can be discarded to reduce the pressure of massive data storage. Jointed with the LAr detector, the tests which included single-photon energy spectrum and low-energy 83Krm source tests have been completed.


Project supported by the National Key Research and Development Program (2016YFA040000300);Project supported by the National Natural Science Foundation of China (11805201).

Keywords: Dark Matter, WIMPs, Trigger System, Liquid Argon

Design of Waveform Digitizing Front-end Electronics for a Prototype Multi-purpose TPC at CSNS Back-n (#125)

C. Zhen1, 2, F. Changqing1, 2, C. Haolei1, 2, F. Ruirui3, 4, Y. Han3, 4, W. Jiaqi1, 5, L. Shubin1, 2

1 University of Science and Technology of China, State Key Laboratory of Particle Detection and Electronics, Hefei, China
2 University of Science and Technology of China, Department of Modern Physics, Hefei, China
3 Chinese Academy of Sciences, Institute of High Energy Physics, Beijing, China
4 Chinese Academy of Sciences, Spallation Neutron Source Science Center, Dongguan, China
5 University of Science and Technology of China, Institution of Advanced Technology, Hefei, China


Multi-purpose Time Projection Chamber (MTPC) at the Back-n white neutron source of China Spallation Neutron Source (CSNS) is aimed at neutron resonance radiography and the measurements of neutron induced light charged particles or fission particles. The prototype MTPC is completed as a verification version with 1519 anode channels. A flexiable integrated waveform digitizing front-end electronics  based on off-the-shelf components was designed to read out anode signals. The front-end electronics is divided into pre-amplifier module (PAM) and analog to digital module (ADM). PAM integrates the anode charge signals and converts them into differential signals. ADM performs analog waveform digitization, digital filtering, online data processing and packaging. PAM is connected to ADM via a flexible printed circuit (FPC) and the PAM can be replaced according to different requirements of detectors. When digitizing up to 64 channels at 40 MHz, the power consumption is around 140 mW per channnel. The performance of the front-end electronics has been tested in the lab. The integral nonlinearity (INL) is less than 0.35\%, and the average equivalent noise charge without any input load is around 0.76 fC with 2.8 pC dynamic range. The readout electronics has been performed a jonit test with the prototype MTPC. By analyzing collected anode signals, the 3D-track of neutron induced light charged particles was successfully reconstructed. This results indicate that the front-end electronics works well and can satisfy the requirements of the prototype MTPC.

AcknowledgmentThe author thanks colleagues from State Key Laboratory of Particle Detection and Electronics and China Spallation Neutron Source Science Center for their help. This work was supported in part by the National Natural Science Foundation of China under Grant 11922510, in part by the Fundamental Research Funds for the Central Universities under Grant WK2360000011.
Keywords: time projection chamber, waveform digitizing, front-end electronics, Back-n neutron beam

Front-end electronics under high water pressure for Hyper-Kamiokande experiment (#214)

S. Izumiyama1, Y. Kataoka2, Y. Takemoto2, Y. Hayato2, T. Suzuki1, Y. Yamaguchi1, M. Kuze1

1 Tokyo Institute of Technology, Department of Physics, Tokyo, Japan
2 The University of Tokyo, ICRR, Hida-city, Japan

Hyper-Kamiokande collaboration


Hyper-Kamiokande (HK) is a next generation neutrino and nucleon decay experiment. The HK detector consists of a large cylindrical water tank, whose height is 71 m and diameter is 68 m, and 40,000 PMTs for a inner detector and 10,000 PMTs for a outer detector. They detect Cherenkov radiation emitted by charged particles which are generated in neutrino interactions or nucleon decays. The HK will take over Super-Kamiokande (SK) detector, which is a water Cherenkov detector operating currently, with eight times larger active volume than that of the SK. The construction of the HK detector was started in 2020, and the HK plans to start operation in 2027. In order to avoid attenuation and deterioration of the PMT signal in the large detector, we plan to install the front-end electronics in the water tank. In this paper, we report on the developed prototype of the electronics system for the HK, that consists of high speed digitizers, a timing synchronization system and underwater vessels. We integrated them and checked behavior in pressurized water. Their results show that the prototypes work well under the high pressure and are promising for the HK.

Keywords: data acquisition system, front-end electronics, water Cherenkov detector

An Algorithm Demonstrator for the L0 Muon Barrel Trigger of the ATLAS Experiment for HL-LHC (#281)

A. Albano1

1 INFN Napoli and Universita' di Napoli, Napoli, Italy

This is a submission on behalf of ATLAS TDAQ speakers committee. The presenter will be assigned later once we are notified this contribution is accepted.


The ATLAS Collaboration has planned significant upgrades to the muon system, in order to cope with the instantaneous luminosity that will be delivered by the Large Hadron Collider (LHC) machine. The upgrades will allow the Muon Spectrometer to keep and improve its current performance for the High Luminosity LHC program (HL-LHC) expected to start in ∼2027. Together with the detector, most of the trigger and readout electronics of the Muon Spectrometer will be replaced, so that all hit data will be optically transferred from the frontend to the backend boards, where the first-level muon trigger (L0Muon) will be executed with latency of 10 µs and maximum trigger rate of 1 MHz.
For the Barrel region, the L0 muon trigger algorithm is performed off-detector by 32 ATCA FPGA-based boards, called Sector Logic (SL), which receive detector data, perform the L0 algorithm, use the muon candidate track information from the MDT detectors and send the muon trigger candidate information to the Central Trigger Processor.
In this work, we present a proof of concept of the trigger candidate identification algorithm for the L0Muon trigger in the barrel region. It is executed in the SL FPGA and it is based on a massive use of Digital Signal Processors (DSP) Slices available in a Xilinx FPGA device. The algorithm is able to identify up to three muon candidates with a transverse momentum (pT) higher than a given threshold, and uses the DSP features of manipulating a large amount of bits and of providing results of its calculation in few clock cycles, with a low and deterministic latency.
We discuss a first implementation of our architecture in a Xilinx Evaluation board based on a Kintex-7 FPGA, although the design can be easily targeted to newer or larger devices, such as the Ultrascale+ that will be used in the experiment. We describe the logic resources occupation of the design, its performances in terms of maximum operation frequency and latency.

Keywords: Trigger algorithm, FPGA, DSP

Study on Readout Electronics of a Scintillator Imaging Electromagnetic Calorimeter Prototype for CEPC (#286)

Z. Shen1, 2, A. Zhou1, 2, S. Liu1, 2, Y. Niu1, 2, J. Liu1, 2, Y. Zhang1, 2

1 University of Science and Technology of China, State Key Laboratory of Particle Detection and Electronics, Hefei, China
2 University of Science and Technology of China, Department of Modern Physics, Hefei, China


Circular electron positron collider (CEPC) is proposed to research Higgs and particle flow algorithm (PFA) will be adopted to get a high energy resolution. As a PFA calorimeter, CEPC electromagnetic calorimeter (ECAL) has the feature of fine granularity, which raise demands of high integration, low noise and low power consumption to the readout electronics. In this paper, a readout system of CEPC ECAL prototype is designed and implemented. The system can not only readout the signals of high-density SiPMs, but also has functions such as electronic self-check, gain monitoring, and temperature compensation. And the cosmic ray test proves the system performs well.

AcknowledgmentThis work was supported in part by the National Natural Science Foundation of China (Grant No.: 11635007), in part by National Key Programme for S&T Research and Development (Grant No.: 2016YFA0400400).
Keywords: Readout electronics, CEPC, ECAL, SiPM

High-Performance Reconfigurable Digital Instrument for Multi–Channel Time Measurements (#310)

E. Ronconi1, F. Garzetti1, N. Corna1, N. Lusardi1, S. Salgaro1, A. Costa1, A. Geraci1

1 Politecnico di Milano, DEIB, MILANO, Italy


A very compact and fully programmable instrument for time measurements at high–performance is present. The instrument is a complete bundle of hardware, firmware, and software. It consists of a Time-to-Digital Converter (TDC) hosted on a Xilinx 28–nm 7–Series Kintex-7 FPGA. The hardware is composed by two modules, an analog front–end and a digital processing board. The on-board processing is the kernel of the design: it hosts the power section and the FPGA that performs the digitization and elaboration of the timestamps and manages the communication with a Personal Computer for the readout. The front–end is, instead, a plug–in board that converts the external time–events into Low-voltage differential signaling (LVDS) signals compatible with the FPGA. In this manner, different front–end modules with different number of channels, i.e. 8 or 16, and architectures, i.e. threshold comparators and constant fraction discriminators, can be interchanged to meet different the detector needs. An additional channel is present for synchronization purposes. The TDC is based on a Tapped Delay–Line (TDL) architecture, organized as a multi-channel (up to 17) IP–Core; it is capable of generating timestamps with resolution (LSB) of 36.6 fs and precision below 12 ps r.m.s., at an acquisition rate of 50 Msps and with a dead—time below 10 ns for each channel; differential and integral non–linearity errors (DNL and INL) are kept below 0.8 ps and 4 ps respectively. An extremely wide Full-Scale Range (FSR) is guaranteed by the use of Nutt-Interpolation technique.

The readout of the measurements is performed by a Personal Computer (PC) through an Universal Serial Bus 3.0 (USB) connection and a user–friendly software interface. This system is not only customizable from a hardware point of view, but also in terms of firmware and software. Indeed, the user can easily insert custom Hardware Description Language (HDL) modules onto the FPGA or a C++ plug–in for additional needs.

Keywords: Time-to-Digital Converter (TDC), IP-Core, Field-Programmable Gate Array (FPGA), Time Measurement.

High-Performance Synchronizations Algorithms for multiple Time-to-Digital Converters (#351)

F. Garzetti1, N. Lusardi1, N. Corna1, E. Ronconi1, A. Costa1, S. Salgaro1, M. Giulia1, A. Geraci1

1 Politecnico di Milano, DEIB, MILANO, Italy


Nowadays applications like Time-of-Flight Positron Emission Tomography (TOF-PET) and Light Detection and Ranging (LIDAR) require measurement systems which allow to reach very high performance in terms of precision and resolution. In addition to this they need an ever-increasing number of channels working in parallel, even up to hundreds. These requirements lead to a huge area occupation when considering a real-time elaboration in Field Programmable-Gate Array (FPGA), thus, the required system becomes not implementable on a single device, making the classical Time-to-Digital-Converter (TDC) structure no more satisfactory. The solution is given by the implementation of a network of connected TDCs based on FPGAs. In this contribution, FPGA structure has been chosen in order to guarantee fast prototyping and flexibility. The idea behind this work is to connect many devices in order to guarantee the desired number of channels, keeping high the performance in terms of resolution and precision. Since the idea is to consider more connected devices, errors are introduced by mismatches in the clock frequency values, which make timestamps coming from different devices not comparable. Aim of this contribution is the introduction of a synchronization algorithm applied to all the devices, which allows to make comparable timestamps coming from different devices without any loss in performance, in terms of precision in the measurement. The algorithm proposed in this work allows the synchronization among devices by means of a self-compensation mechanism on each device. This is possible by adding a channel to each TDC dedicated to the spread of a low-frequency signal called REF, useful for the application of the synchronization algorithm.

Keywords: Time-to-Digital Converter (TDC), Field Programmable Gate Array (FPGA), System-on-Chip (SoC), Network, Synchronization.

Design, Characterization, and Performance of a Modular Multi-Channel Waveform Readout for Neutron Imaging Applications (#400)

K. Keefe1, 2

1 University of Hawaii at Manoa, Physics and Astronomy, Honolulu, Hawaii, United States of America
2 Sandia National Labs, 08647, Livermore, California, United States of America

Single Volume Scatter Camera, (SVSC)


The Sandia National Laboratories Compact Electronics for Modular Acquisition (SCEMA) module is designed as scalable multi-channel (16+2) waveform readout module. In order to meet the demands of a truly scalable and modular design, a new concentrator printed circuit board (PCB) is designed to be able to interconnect multiple SCEMA modules. A modular system increases the number of readout channels from a single SCEMA to N*(16+2), where N=8 is the number of SCEMA modules available to be connected to a single concentrator. Additionally, in neutron imaging and low latency-trigger applications a concentrator allows for a single synchronous trigger for each module in the system, as well as improved timing resolution among SCEMAs by providing a synchronous distributed clock. The full concentrator system is implemented on two different design approaches to neutron imaging. Each design approach involves a specialized “interposer” board specifically designed for the specialized neutron imaging method. Here we present the results of the full concentrator system, an updated SCEMA-B characterization, and the characterization of two different interposer solutions adapted to neutron imaging based on the modular SCEMA+concentrator system


Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525. The US DOE National Nuclear Security Administration, Office of Defense Nuclear Nonproliferation Research and Development for co-funding this work. Approved for unlimited release: SAND2021- 5559 A

Keywords: Digital electronic circuits, Front-end electronics for detector readout, Data acquisition circuits, Modular electronics, Silicon Photomultipliers

FPGA-based SiPM Timestamp Detection Setup for High Timing Resolution TOF-PET Application (#413)

N. Lusardi1, F. Garzetti1, S. Salgaro1, N. Corna1, E. Ronconi1, A. Costa1, A. Geraci1, E. Ripiccini2, F. Gramuglia2, T. Milanese2, C. Bruschini2, E. Charbon2

1 Politecnico di Milano, DEIB, MILANO, Italy
2 École polytechnique Fédérale de Lausanne, AQUA, Lausanne, Switzerland


High timing resolution is an important parameter of sensors and detectors used in many fields like particle and medical physics. Commercial Positron Emission Tomography (PET) scanners use detectors made of inorganic scintillator instrumented with photodetectors like Photomultiplier Tubes (PMTs) and Silicon Photomultipliers (SiPMs). The use of high granularity gamma-ray cameras in PET scanners for high quality imaging comes with a significant rise of the number of read-out channels. For this reason, compact data acquisition systems able to keep a high timing resolution are required. With this aim, in this work we propose a digital and reconfigurable high-resolution timestamp detection setup and real-time processing system based on Field Programmable Gate Array (FPGA). In particular, we present the measurements of Coincidence Time Resolution (CTR) of prompt gamma-rays emitted by a 22 Na source and detected by two single LYSO crystals coupled to analog SiPMs. In order to reduce up to tens of picoseconds the otherwise nanoseconds time-walk error which is due to the distribution of the scintillator emission time, the signals from the SiPMs are converted into digital pulses by means of Constant Fraction Discriminators (CFDs) and sent to a read-out board where the timestamping and processing algorithms, i.e. histogramming and time-tagging, are implemented on a Xilinx 28-nm 7-Series Artix-7 100T FPGA. The board is a compact system, featuring three overall channels, among which one might be used for advanced synchronization purposes. The timestamp generation is computed by an high-performance fully-FPGA based Time-to-Digital Converter (TDC) with a resolution (LSB) of 36.6 ps and a single-shot channel precision up to 12 ps r.m.s. over an extended dynamic-range. In this manner, a CRT of hundreds of picoseconds, comparable with the state-of-the-art, is achieved.

Keywords: Time-to-Digital Converter (TDC), Silicon Photomultiplier (SiPM), Field Programmable Gate Array (FPGA), Scintillator, Constant Fraction Discriminator (CFD)

Design of Low Power Consumption Digital MCA Module for In-situ Environmental Gamma-ray Measurements (#735)

Z. Zhou1, 2, C. Feng1, 2, M. Zhao1, 2, Y. Wang1, 2, Z. Cao1, 2, P. Cao1, 2, Q. An1, 2

1 University of Science and Technology of China, State Key Laboratory of Particle Detection and Electronics, Hefei, China
2 University of Science and Technology of China, Department of Modern Physics, Hefei, China


A digital multichannel analyzer (MCA) module with 8 readout channels for in-situ gamma-ray detection is developed and described. To adapt to a variety of environments, the in-situ detection system needs to be portable. Therefore, the MCA module is designed with low power consumption (1.3 W in total, 0.16 W per channel) and small size, which is based on a power-efficient ADC with multi-channel integration and a flash-based FPGA. In order to improve the energy resolution of the gamma-ray detection system, signals are digitized and processed individually for each readout channel in the digital MCA. Besides, digital filters with proper parameters and accurate energy calculation methods are realized in the flash-based FPGA. Then, combining with CdZnTe (CZT) detectors and accompanying front-end circuits, the function of digital filtering has been verified, and the performance of the digital MCA has been tested. Results show that the energy resolution is 1.7% (FWHM) at 662keV, which is similar to the intrinsic resolution of CZT detector with the quasi-hemispherical electrode structure.

Keywords: Gamma-ray Detection, Digital Multichannel Analyzer, CdZnTe Detector, Flash-based FPGA, Digital Filter

Data AcQuisition System Development for a new 262k Photon Counting Pixel Detector at the SOLEIL Synchrotron (#853)

E. H. Ait Mansour1, F. Orsini1, A. Dawiec1

1 SOLEIL Synchrotron, Detectors, Experimental Division, Gif-sur-Yvette, France


Single photon counting hybrid pixel detector technology with short gate capability has been chosen to perform time-resolved pump-probe experiments in the energy range 5-15 keV at SOLEIL Synchrotron. The detector prototypes, based on the UFXC32k [1], were developed for this initial purpose mainly due to chip readout speed that can reach 28 kfps in current configuration. After completion of small-size prototypes, a new detector demonstrator of medium size with 8 chips, providing expected high performance and multiple acquisition modes, is now under development and it represents a challenge in our detector development program. This paper presents a new data acquisition system and image recovering architecture dedicated for this demonstrator. It is based on a Xilinx Virtex-7 FPGA and PandaBlocks firmware for 8 UFXC32k control and status. The DAQ system enables to stream data from the detector with four 10 Gb/s Ethernet links reaching up to 40 Gb/s bandwidth through four high-speed transceivers. The new architecture allows for reading 8 chips simultaneously, without reducing images frequency.


The authors gratefully acknowledge the support of SOELIL Synchrotron for post-doc funding. The authors would like to thank the reviewers for their criticisms, comments and suggestions.

Keywords: Data Acquisition System, UFXC32k, Photon Counting Detectors, Data Descrambler, PandaBlocks.

Qualification of a Silicon Photomultiplier scalable readout system (#912)

R. Santoro1, N. Ampilogov1, C. Tintori2, M. Caccia1

1 Universita degli studi dell'Insubria, Dipartimento di Scienza e alta Tecnologia, Como, Italy
2 Caen S.p.a., Viareggio, Italy


The Front-End Readout System (FERS) is a general purpose and scalable platform designed by CAEN S.p.A. to fulfill the typical requirements of a SiPM based instrumentation. The system can operate from 64 up to few thousand of channels and allows measuring the analog response correlated to the light intensity, time stamping the event occurrence, or counting the generated pulses. Moreover, the platform was designed to host different front-end ASIC with a first embodiment based on the CITIROC1A chip, designed by WEEROC.

This paper reports an initial characterisation of the FERS system, driven by two applications: high granular calorimetry for high energy physics and multi-channel dosimetry for brachytherapy.

Keywords: SiPM, Readout system for Calorimeters, Biomedical Imaging

Nanosecond machine learning with BDT for high energy physics (#1085)

T. M. Hong1, B. Carlson1, B. Eubanks1, S. T. Racz1, S. T. Roche1, J. Stelzer1, D. C. Stumpp1

1 University of Pittsburgh, Physics and Astronomy, Pittsburgh, Pennsylvania, United States of America


We present a novel implementation of classification using boosted decision trees (BDT) on FPGA. Our BDT approach offers an alternative to existing packages, including those that implement neural networks on FPGA, with less dependence of DSP utilization that is replaced by other resources. Our design philosophy is to remove clocked operations in favor of combinatoric logic through High Level Synthesis. The firmware implementation of binary classification requiring 100 training trees with a maximum depth of 4 using four input variables gives a latency value of about 10ns at various clock speeds.  We optimize the parameters using a software package, which interfaces to Xilinx Vivado through High Level Synthesis.  Such a tool may enable the FPGA-based trigger systems at the Large Hadron Collider to be more sensitive to new physics at high energy experiments. The work is described in


TMH and BTC were supported by the US Department of Energy [award no. DE-SC0007914]. BTC was supported by the PITTsburgh Particle physics Astrophysics and Cosmology Center(PITTPACC). JS was supported by the US Department of Energy [award no. DE-SC0012704]. BRE was supported by the US National Science Foundation [award nos. PHY-1948993 and PHY-1624739]. DCS was supported by the NASA Pennsylvania Space Grant Consortium.

Keywords: FPGA, trigger, machine learning, high energy physics

Architecture and First Characterization of the Microstrip Silicon Detector Data Acquisition of the FOOT experiment (#1098)

M. Barbanera1, 2, K. Kanxheri1, G. Ambrosi1, G. Silvestre1, S. Biondi3, R. Ridolfi3, M. Villa3, D. Aisa1, M. Caprai1, M. Ionica1, P. Placidi1, L. Servoli1

1 Istituto Nazionale Fisica Nucleare, Perugia, PG, Italy
2 Universitá di Pisa - Dipartimento di Ingegneria dell'Informazione, Pisa, PI, Italy
3 Istituto Nazionale Fisica Nucleare, Bologna, BO, Italy


Oncological hadrontherapy is a novel technique for cancer treatment that improves over conventional radiotherapy by having higher effectiveness and spatial selectivity. The FOOT (Fragmentation of Target) experiment studies the nuclear fragmentation caused by the interactions of charged particle beams with patient tissues in Charged Particle Therapy. Among the several FOOT detectors, the silicon Microstrip Detector is part of the charged-ions-tracking magnetic spectrometer. The detector consists of three layers of two silicon microstrip planes arranged orthogonally between each other to enable the tracking capability. Ten 64‑channel commercial devices read-out each plane and five external ADCs digitize their analog output. For each layer, a Field-Programmable Gate Array collects the output of the ten ADCs, possibly processes the data, and forms a packet to be sent to the experiment central data-acquisition. This data acquisition system shall withstand the high trigger rate and detector’s throughput at any time. In this work, we discuss the architecture of the data acquisition system—in particular of the silicon microstrip detector one—and the first results obtained from the layer’s prototype.

Keywords: Hadrontherapy, Oncology, Nuclear Fragmentation, Microstrip Detector, FOOT

Readout electronics development of a Double-Sided Strip Design LiInSe2 neutron imaging detector (#1233)

M. A. Benkechkache1, 2, L. Drouet1, 2, J. Gallagher1, 2, R. Golduber1, 2, E. D. Lukosi1, 2

1 University of Tennessee, Nuclear Engineering Department, Knoxville, Tennessee, United States of America
2 University of Tennessee, Joint Institute for Advanced Materials, Knoxville, Tennessee, United States of America


As a direct neutron conversion semiconducting material, Lithium Indium Diselenide “LiInSe2” has well proved its capability for neutron imaging. Its high spatial resolution and excellent detection efficiency makes it as a good candidate to be used in the development of a neutron imager for DOE facilities. The associated electronics for a novel detector design are also required to have a well performing neutron imager. Therefore, our project considers a Double-Sided Strip Design LiInSe2 configuration with the goal of building a neutron imager with a timing resolution as low as 1us and a spatial resolution of 5um. To this purpose, our work here reports on the development achieved so far on building the different blocks of the detection system with much focus on the readout electronics. The LiInSe2 sensing part is prepared and characterized by testing its electrical behavior and radiation response, then patterned with a doublesided cross strip. The signal from each strip is readout out with a custom-made double ASIC daughter board connected to a main acquisition board “LISeDAQ” to process the analogue data that comes from the daughter board and to control the whole system. The electronics design of each board is reported in this work.

Keywords: DSSD, LiInSe2, LISeDAQ, Neutron Imaging

A scalable switching network for ETROC readout in CMS experiment (#1327)

D. Gong1, Q. Sun2, X. Huang1, C. Liu1, T. Liu1, T. Liu2, H. Sun1, J. Wu2, J. Ye1, J. Olsen2, L. Zhang1, W. Zhang1

1 Southern Methodist University (US), Physics, Dallas, Texas, United States of America
2 Fermi National Accelerator Laboratory, Batavia, Illinois, United States of America


We present a scalable switching network in the Endcap Timing Read-Out Chip in CMS experiment. The readout composes of a readout network based on a repetitive building block distributed on each pixel and a global readout component. We propose some simple switching cells which naturally composes a network that conducts the propagation of data and control signals between the global component and each pixel correctly in a clock period. The control signal of the switching cells is the hit flag of the pixel and no complicated comparison logic is needed to sort the readout data in the order of the bunch-crossing identification. We also keep an express channel for fast signal or potential trigger data in the readout. User has the flexibility to allocate the bandwidth between the regular data and the trigger data. We impose the redundancy design and error verification and correction in the readout due to the harsh environment of the pixel detector. Because the repetitive building blocks of total 256 are identical for each pixel, this structure greatly simplify the verification and layout work of the readout. We are implementing the whole readout in the 65 nm CMOS process. We also developed a FPGA based readout system to verify the readout system. We expect the chip is being submitted in September this year.

AcknowledgmentWe are grateful to Dr. Paulo Moreira, Dr. Rui Francisco, and Dr. Szymon Kulis of CERN for sharing the ELT library in lpGBT.
Keywords: digital circuits, pixel readout, CMOS integration circuits, front end electronics

Statistical evaluation of field of view in airborne radiation survey by comparison with the ground-based survey. (#145)

M. Sasaki1, Y. Sanada1

1 Japan Atomic Energy Agency, Collaborative Laboratories for Advanced Decommissioning Science, Minamisoma, Japan


In this study, we evaluated the field of view of airborne radiation survey which is obtained around the Fukushima Daiichi Nuclear Power Plant using the unmanned helicopter by comparison with a ground-based survey in the ambient dose rate. The field of view was evaluated from the convergence tendency of the error between airborne radiation survey value and ground-based measurement value. The convergence tendency of the error between the value of airborne radiation and the value of ground-based measurement was calculated by changing the mesh size. As a result, the field of view of airborne radiation survey at 50 m and 130 m altitudes were 100 m and 150 m mesh size respectively. These evaluation results are helpful for understanding the contour map of airborne radiation surveys. In addition, it is useful for the decision of flight conditions.

Keywords: Fukushima, FDNPP, Field of view, Radiation monitoring, UAV.

Feasibility Analysis of X-ray Backscatter Imaging inside Pipeline and Intelligent Defect Recognition (#302)

H. Li1, H. Li1, D. Y. Li1, X. W. Yan1, M. Q. Niu1

1 China Institute for Radiation Protection, Nuclear and Radiation Frontier Technology Research Center, TaiYuan, China


In view of the current situation that the traditional inspection methods are not good for the inspection of weld defects of deep buried underground pipelines, a defect detection method using X-ray backscatter imaging technology is proposed. The purpose of this work is to demonstrate the feasibility of X-ray backscatter imaging in pipeline and to explore automatic defect identification algorithm. The Monte Carlo software (Geant4) has been used to establish the model of X-ray backscatter imaging system in the pipeline. The system is composed of X-ray tube, rotatable collimators, rotatable detectors and other parts. The flying point scanning mode is adopted. In this paper, there is a linear relationship between the spot diameter and image contrast. The system can be effectively used to locate and identify the internal defects of pipelines, and has the feasibility of industrial application. Furthermore, an intelligent defect recognition algorithm based on supervised learning method was designed. Transfer learning has been used to alleviate the conflict problem between the high accuracy and small data set.  The weld defect detection images in GDX-ray database were used to train the machine learning model. The recognition accuracy of the algorithm was 88.06% when transfer learning method had been used.

Keywords: Internal inspection of petroleum pipelines, intelligent defect detection, non-destructive testing, X-ray backscatter imaging, transfer learning

Geant4-DNA Based Monte Carlo Simulation to Study Tritium-Induced DNA Damage (#718)

T. Aso1, 5, Y. Hirao2, M. Hara3, S. Fujiwara4

1 National Institute of Technology, Toyama College, Electronics and Computer Engineering, Imizu, Japan
2 Nagoya University, Graduate School of Medicine, Nagoya, Japan
3 University of Toyama, Faculty of Science, Academic Assembly, Toyama, Japan
4 Kyoto Institute of Technology, Faculty of Material Science and Engineering, Kyoto, Japan
5 High Energy Accelerator Organization, Computing Research Center, Tsukuba, Japan


Radiation damage in living cells causes tissue death and malignant alteration of the cells. The damage is induced through a series of complex processes that consists of physics, physicochemical, chemical, biochemical, and biological processes. Because of complexity of these processes, the simulation with mechanistic approach incorporates many adjustable parameters. Our research project aims to develop a simulation tool for studying DNA damages due to direct and indirect processes and to verify it against the experiments of radiation damages in DNA. On contrast to the other research that simulates high linear energy transfer ion beams, we particularly focused on tritium-induced DNA damages which are taken place by a low energy beta-ray on the maximum energy of about 18.6 keV. In such energy range of electrons, the indirect effect is more critical than that for ions. The goal is to propose and deploy a stochastic model of strand breaks in DNA for low-energy beta-rays in the simulation based on the Geant4-DNA. In this paper, we report on our research activities about the mechanistic approach with atomistic DNA models, the regional approach with a clustering algorithm in a simple cylindrical model of DNA structure, and the gamma irradiation experiment to study isotope exchange reactions.

AcknowledgmentThis work was supported in part by the JSPS KAKENHI 18K11650 and 21K12116.
Keywords: DNA damage, Geant4-DNA, Tritium, Low energy beta-ray, Monte Carlo simulation

Modelization of Solid State Detectors using Advanced Multi-Thread Code and Comparison with Measurements (#783)

A. Loi1, D. Brundu1, A. Cardini1, A. Lai1, A. Contu1, G. M. Cossu1, B. G. Siddi2, S. Vecchi2, A. Lampis1, M. Garau1, M. M. Obertino3

1 INFN, sezione Cagliari, Physics, Monserrato, Italy
2 INFN, sezione Ferrara, Physics, Ferrara, Italy
3 INFN, sezione Torino, Dipartimento di Scienze Agrarie, Forestali ed Alimentari, Torino, Italy


Computational simulation occupies an important role in the development of solid state detectors. The idea to replicate virtually the entire detector chain, from energy deposition within the sensor to the final digitization of the collected data, allows a deep understanding of the detector physics and front-end electronics performance, with the possibility to perform changes before fabrication submission.

An important aspect of detector simulation is the compromise between the detail level of the simulation and the computing time required. Advanced simulation packages, such as TCAD, provide very detailed sensor physics but lack in sufficient short simulation time and a proper description of energy release within the material. At the same time, developing a dedicated simulation by repeating the same steps already implemented in existing tools makes the calculus redundant and time inefficient.

The TimeSPOT Code for Detector Simulation (TCoDe) and TimeSPOT Front-end Booster (TFBoost) are specifically developed to support already existing simulation software such as TCAD and GEANT4 by only computing the transient simulations, which are the most time consuming and statistically relevant steps. Computation is performed by using advanced CPU and GPU multi-thread architecture.

This work describes an overview of the latest updates and functionalities of TCoDe and TFBoost, with a focus on the computational performances at very high statistics above 100.000 events. Latest applications and comparisons with test beam data are also discussed.

AcknowledgmentThis work was supported by the Fifth Scientific Commission (CSN5) of the Italian National Institute for Nuclear Physics (INFN), Project TimeSPOT (CSN5 open-call contest, 2017).
Keywords: detector simulation, TCAD, 3D silicon sensors, fast timing, TCODE and TFBOOST

Optimization Simulations for a Gamma-Ray Calibration Standard for a Novel Cyclic Neutron Activation Analysis Pneumatic System at the Penn State Breazeale Reactor (#974)

C. A. Lani1, B. D. Pierson2, S. M. Lyons3, M. Flaska1

1 Penn State, Ken and Mary Alice Lindquist Department of Nuclear Engineering, State College, Pennsylvania, United States of America
2 Pacific Northwest National Laboratory, Energy and Environment, Richland, Washington, United States of America
3 Pacific Northwest National Laboratory, National Security, Richland, Washington, United States of America

This work has been funded by the Department of Defense, Defense Threat Reduction Agency, Grant #12393672.


For new experimental setups, the initial testing and calibrations can become expensive and time consuming without prior optimization. However, these possible issues can be mitigated using realistic modeling and simulations. Specifically, an experiment can be performed virtually using realistic simulations and the expected experimental results can be predicted a priori. At the Penn State’s Breazeale Reactor, a new pneumatic transfer system has been developed for the detection and characterization of short-lived fission fragments to enhance existing nuclear data. The system accomplishes this task by transporting samples cyclically between an assortment of gamma-ray/neutron detectors and the reactor core with sub-second transit times. To ensure a fully optimized gamma-ray calibration standard is used for this system, a simulation model is being developed using Geant4 and its module that can calculate relevant cascade summing corrections (G4CSC). The predictions made with these simulations will allow us to optimize the irradiation sample characteristics and our gamma-ray/neutron detection system. In the full paper, the experimental data will be compared to the simulations to determine all important discrepancies, and to validate the developed simulation tools.

Keywords: Pneumatic system, Cyclic Neutron Activation Analysis, Short-Lived Fission Fragments, Geant4 Simulations

Characterisation of GS20 using epithermal neutrons and high-energy gamma-rays in borehole logging: A simulation approach (#989)

A. Bala1, 2, D. Jenkins1, J. Bordes1

1 University of York, Department of Physics, York, United Kingdom
2 Usmanu Danfodiyo University Sokoto, Department of Physics, Sokoto, Nigeria


The oil and gas industries uses neutron porosity tool to estimate the hydrogen index during logging activities. This tool consist of two thermal neutron detectors, usually 3He tubes and a fast neutron source. As the fast neutrons propagate into the rock formation, they are slowed down to thermal energies. However, not all the fast neutrons get fully thermalised, some epithermal neutrons still makes it to the detectors. Contribution due to these epithermal neutrons are not utilised when 3He tubes are used. Furthermore, the high-energy gamma-rays emitted by the neutron source interact with the rock formation through pair production. In this work, we present the potential of a lithium-loaded glass detector (GS20) to provide useful information from both the epithermal neutrons and the high-energy γ-rays in a single logging tool. The results presented shows that lithium-loaded glass scintillator can provide information about the hydrogen index and the density of the material in the rock formation.

AcknowledgmentMy acknowledgements goes to Nigeria government through petroleum technology development fund (PTDF) who fully funded my research and the the co-authors for their great contributions.
Keywords: Borehole logging, 3He tube, NaI(Tl), rock formation

Image up-sampling algorithm for superposing images with different spatial resolutions (#1211)

H. Jo1, D. Lee1, S. Cho1

1 Korea Advanced Institute of Science and Technology, Department of Nuclear and Quantum Engineering, Daejeon, Republic of Korea


In this paper, an image up-sampling algorithm for fast-neutron plus high-energy X-ray hybrid cargo inspection system is proposed. The proposed method adopts X-ray image’s cluster information to up-sample the neutron image. The proposed method is shown to be able to up-sample the neutron image with a low spatial resolution effectively utilizing the X-ray image’s high spatial resolution with a low level of image noise. Consequently, it shows a much improved material decomposition performance compared to the analytic image up-sampling algorithms such as linear interpolation.

AcknowledgmentThis work was supported in part by Korean National Research Foundation [2019M2A2A4A0503148723] and the institute of Civil Military Technology Cooperation under grant [18CM5005].
Keywords: Neutron, X-ray, Cargo inspection, image up-sampling, material decomposition

Isotope Recognition in Gamma Spectra by using an Image Driven Hopfield Neural Network (#1269)

L. A. Valdez1

1 University of Texas at San Antonio, Electrical Engineering, San Antonio, Texas, United States of America


Recognition of radioactive isotopes, which constitute a homeland security threat, has been the center of attention of many research fields. Among them the field of machine learning and Artificial intelligence has attracted high attention due to the recent advances in computing. Many other methods have been trying to approximate the identification of signature spectra by handling uncertainty of measured gamma ray signals. This work proposes a method that combines image processing with the established tool of Artificial Hopfield Neural Network (HNN). HNN memorizes a set of predetermined simulated gamma-ray signatures and eliminates uncertainty gamma spectra redundancies by matching the measured spectra to the closest one in its memory. The type of HNN in our work utilizes the Hebbian learning algorithm to memorize the signatures. The purpose of Hopfield Neural network is to self-learn the spectrum image pattern and identify any uncertainties or noise incurred by the radiation and subsequently to obtain a more fast and precise reading of the source in question. The proposed method is tested on a set of gamma-ray spectra of various spectral variation, with results showing an accuracy of 90%.

Keywords: Hopfield Neural Networks, Image processing data

Compton Imaging Capability of Spherical Detector System Design based on GAGG Scintillators (#256)

X. Liang1, L. Shuai1, Z. Zhang1, C. Wei1, L. Wei1, X. Hu1

1 Institute of High Energy Physics, Chinese Academy of Sciences, Beijing Engineering Research Center of Radiographic Techniques and Equipment, Beijing, China


In the research of this paper, based on the symmetry of the icosahedron, a spherical detector system for gamma imaging was devised based on 80 GAGG (Ce:GAGG,  Gd3Al2Ga3O12) scintillator pixels. The spherical hollow design of detector system combines both coded aperture imaging and Compton imaging capabilities. For the Compton imaging, simulation results showed that the proposed design of detector system could successfully reconstruct the 22Na and 137Cs sources by simple back-projection algorithm. Considering the practical pitch size and energy resolution of GAGG scintillator coupled to SiPMs (silicon photomultipliers), individual and multiple sources of 22Na and 137Cs sources were evaluated. The angular resolution and imaging efficiency of the 137Cs simulations were approximately 30° and 4% respectively. The high intrinsic imaging efficiency and reasonable imaging quality make this detector system design attractive for radiation imaging.

Keywords: Compton imaging, coded aperture and Compton, Radiation imaging

Evaluation on Single Scatter Correction in Compton Camera Imaging (#713)

D. Kim1, M. Uenomachi2, K. Shimazoe3, H. Takahashi1, 3

1 The University of Tokyo, Department of Nuclear Engineering and Management, Bunkyo, Japan
2 RIKEN, Nishina Center for Accelerator-Based Science, Wako, Japan
3 The University of Tokyo, Department of Bioengineering, Bunkyo, Japan


Compton imaging is a powerful imaging method used to acquire the distribution of gamma-ray emitting radioactive sources. It can be used for various applications, including homeland security and medical imaging. For these applications, correction of the scatter effect is important for more quantitatively accurate imaging because they might result in noise in the reconstructed image. In this study, a single scattering correction was conducted by setting arbitrary scattering points on the attenuating material. The results showed that the method effectively removed the noise on the reconstructed image while not impairing the image quality.


This work was supported by JSPS KAKENHI, Japan Grant Numbers 17H06159 and 19H00881. The authors wish to thank the organization for their financial support.

Keywords: Compton Camera, Scatter Correction

u-Rania: a neutron detector based on u-RWELL technology (#827)

R. Farinelli1

1 INFN, Ferrara, Ferrara, Italy

on behalf of Urania working group


An innovative detection technique is needed in particle physics for neutron particles due to the He-3 crisis. This new challenge will impact with application in new fields outside the high energy physics, e.g. radioactive waste monitor, homeland security application, scanner with neutron scattering. Gaseous detector together with a proper converter can be used for these purposes: a boron coated cathode converts the neutron and the products are detected with μRWELL technology, a single amplification stage gas detector with a resistive spark protection layer. This contribution will provide an overview of the project, the detector design and the simulation studies. Several configurations have been tested with a Am241-B neutron source. Results of the detection efficiency will be provided together with a new electronics used to measure the single neutron interaction. The design of the detector has a low production and assembly cost and it has been shared with the industry where the technological transfer has started. The future R&D is focused on optimizing the detection efficiency, improving the electronics sensitivy and producing large area detectors.

AcknowledgmentATTRACT-uRANIA project,funded by the European Community and the INFN-CNS5
Keywords: Gas Detectors, Neutron detector, Radioactive waste monitor, Neutron imaging

Double Photon Coincidence Imaging for Radioisotope Microscopy (#895)

H. Takahashi1, A. Choghadi1, K. Shimazoe1

1 The University of Tokyo, Department of Bioengineering, Tokyo, Japan


We propose a new concept of time/position correlation type tomography method using a focusing gamma-ray collimator and a double photon emission nuclide. This three-dimensional imaging method utilizes the correlation between two gamma-ray photons and provides the radioactivity concentration in the body with high resolution, high sensitivity, and high signal to noise ratio. In-111 is known as a cascade gamma-ray emission nuclide. K-43 are also fast double photon emission nuclides. A demonstration experiment has been performed with a focusing collimator and an In-111 source. The use of a focusing collimator provided a three-dimensional radioactivity distribution without a reconstruction method. The double photon coincidence method provides a low background measurement as well. Scanning a target sample may lead a very accurate RI microscopy.

Keywords: Double Photon Emission, Coincidence, DPECT, gamma rays, Multi-nuclide Imaging

iSANDD: intelligent Segmented Autonomous Neutron Directional Detector (#1172)

V. Li1, S. Dazeley1, I. Jovanovic2, F. Sutanto1, T. Wu2, N. Bowden1, T. Classen1, M. Ford1, N. Zaitseva1

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


We present the application of several technologies and approaches that could lead to smaller, less expensive high-performance directional neutron imaging systems. Pulse-shape-sensitive plastic scintillators, multi-pixel photosensors, artificial-intelligence-driven object-identification and analysis algorithms, and compact low-power multi-channel electronics are at the technology readiness level where they could be implemented in a compact neutron-gamma passive imaging device. This opens a wide range of potential use cases of these systems --- from nuclear non-proliferation to basic science.
In the recent past, we have demonstrated a reliable PSD in segmented plastic scintillators developed at LLNL instrumented with SiPM arrays and waveform digitizers. The plastics can either be doped with 6Li or left undoped. We are now investigating the utility of Positron-Emission-Tomography (PET)-scanner based electronics as a readout for the new prototype detector. The challenge arises in achieving PSD in such a system, as the electronics are not designed to store full waveforms --- only charge and timestamp for a given integration window are recorded. We report on progress towards a potential way around this problem and present a characterization how the system performs with respect to PSD and the time of flight.

AcknowledgmentThis work was supported by the U.S. Department of Energy National Nuclear Security Administration and Lawrence Livermore National Laboratory [Contract No. DE-AC52-07NA27344; LDRD tracking number 21-FS-025; release number LLNL-ABS-822319].
Keywords: autonomous radiation detectors, low-power electronics, compact double-scatter neutron imager, segmented PSD plastic scintillator, gamma/fast-neutron/thermal-neutron detection

Development of an ultra-high-resolution WDS-PIXE system by using image processing (#325)

K. Ushijima1, J. Kawarabayashi2, N. Hagura2, 3

1 Tokyo City University, Cooperative Major In Nuclear Energy, Tokyo, Japan
2 Tokyo City University, Department of Nuclear Safety Engineering, Tokyo, Japan
3 Tokyo City University, Atomic Energy Research Laboratory, Kanagawa, Japan


To apply an ion beam analysis technique to the research and development of functional composite materials, and we are planning to design and demonstrate an analysis system with high energy resolution. The target energy resolution is high enough to detect the difference in chemical bonding states. Although the Wavelength-dispersive spectroscopic PIXE (WDS-PIXE) method has already been known, we will apply image processing techniques that we have studied in the field of neutron radiography to develop a system that maintains high energy resolution while keeping the distance between the X-ray source and the detector as close as possible to increase the efficiency of X-ray focusing. The design concept of a compact analysis chamber is described, and the results of an experiment on the acquisition of X-ray bright spots by a CCD image sensor are presented. From the results of this experiment, it was confirmed that the X-ray bright spot was detected across multiple pixels, and there was a prospect that the energy resolution can be improved by applying image processing techniques.

AcknowledgmentThis work was supported by JSPS KAKENHI Grant Number 20K05385.
Keywords: Wavelength dispersive spectrometry, PIXE, image processing, energy resolution

Scintillation properties of phenanthrene crystals for neutron detection (#33)

A. Yamaji1, S. Kurosawa1, A. Yoshikawa2, 1

1 Tohoku University, New Industry Creation Hatchery Center, Sendai, Japan
2 Tohoku University, Institute for Materials Research, Sendai, Japan


3He gas proportional counters have been widely used in neutron detection applications such as homeland security and medical imaging. In recent years, the problem of 3He production shortage occurred and the alternatives have been studied. One of the alternatives is an organic crystal scintillator, which has low sensitivity for gamma-ray and high reaction cross-section in a wide energy neutron range. In this work, we focused on phenanthrene, which is isometric with anthracene. We grew phenanthrene crystals by using the self-seeding vertical Bridgman technique and evaluated their scintillation properties for neutron detection. Transparent phenanthrene crystal with a diameter of 12 mm was grown and had several cracks on the surface. Fourier Transform Infrared Spectroscopy spectrum of grown phenanthrene crystal in the range of 400 cm-1 – 3500 cm-1 was measured. These peaks were identified by the presence of the functional group of phenanthrene and there are no indistinct peaks. Radioluminescence measurements under 5.5 MeV alpha-ray excitation were carried out. There were several emission peaks at 408, 430, 455 and 490 nm due to the S1 → S0 transitions. The light yield under 5.5 MeV alpha-ray irradiation was estimated to be 1.15 times higher than that of lithium glass GS-20.

Keywords: Crystals, Neutrons, Organic materials, Scintillators

Large Size Fast Decay LYSO Single with Low Afterglow (#204)

L. Dai1, R. Mao2

1 SHANGHAI UNIVERSITY, School of Materials Science and Engineering, Shanghai, China
2 Icebrook Instrumentation Co., Ltd, Shanghai, China


We present in this work large size LYSO crystal with fast decay and low afterglow. The LYSO crystal with diameter of 90 mm and 200 mm in length was grown by CZ method. Samples with dimension of 10X10X150 mm for high energy physics experiment (HEP) and 4X4X20 mm for PET machine were made. Optical and scintillation properties including transmittance, scintillation spectrum, light output (L.O.), decay kinetics and scintillation afterglow (AF) were investigated. No obvious absorption band was found within wavelength interested. The L.O. was determined to be 39000 photons/MeV for the 4X4X20 mm sample. The decay time was found to be 33 ns measured by time correlated single photon counting method. The AF is found to be 0.018% at 100 ms for the 4X4X20 mm sample, which is about 20 times lower than for the traditional LYSO crystal. The light response uniformity (LRU) for the 150 mm long sample with both end coupling to PMT was also performed. This newly developed LYSO crystal features fast, high light output and low afterglow and is promising for both HEP and medical imaging.

Keywords: Scintillation Aftergow, LYSO, Light Output, Decay Kinetic, Light Response Uniformity

The 3DIT project: development of new plastic scintillator 3D printed. (#346)

M. Marafini1, 2, P. De Maria3, M. De Simoni6, 2, M. Fischetti5, 2, G. Franciosini6, 2, S. Milena2, S. Morganti2, D. Rocco5, A. Sarti5, 2, A. Trigilio6, A. Schiavi5, A. Sciubba5, 4, M. Toppi5, 4, G. Traini2, V. Patera5, V. Pettinacci2, L. Mattiello5

1 CREF - 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 Dipartimento di Scienze e Biotechnologie Medico-Chirurgiche, Sapienza Università di Roma, Rome, Italy
4 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di LNF, Frascati, Italy
5 SBAI - Dipartimento di Scienze di Base e Applicate per l'Ingegneria, Sapienza Università di Roma, Rome, Italy
6 Dipartimento di Fisica, Sapienza Università di Roma, Rome, Italy


Organic scintillators consist of organic molecules and eventually a wavelength shifter (primary and secondary dopants respectively), homogeneously dispersed in a transparent polymeric matrix, generally consisting of polyvinyltoluene (PVT) or polystyrene (PS). The main advantages of organic materials are: fast time response, flexibility in manufacturing and low cost.  Nevertheless, commercial plastic scintillators are not suited for very customised thin structures while, up to know, the 3D printer technique (metallic, ceramic and polymeric) exploited for the mechanical structures of the detectors, allows for high precision manufacturing (tolerances of few tens of $\mu m$).
The 3DIT project is a feasibility study dedicated to the research and development of fast plastic scintillators in polymeric matrices obtained by means of additive manufacturing.\\
 The possibility of developing plastic scintillators with new molecules has been demonstrated using a system of a PVT polymer matrix loaded with various concentrations of scintillating compounds. Both liquid and solid compounds have been characterised in terms of transmittance and absorption with photoluminescence spectroscopy measurements. The samples of plastic scintillators showed excellent optical transparency, even at high concentrations.
Both liquid and solid samples have been tested with several sourced of radiations (cosmic rays, gamma sources and  ion beams) in order to characterise the light output of the scintillators coupled with commercial photomultiplier tubes. The samples show promising light output and excellent timing properties.
The 3DIT project will integrate the newly synthesised organic scintillators in the compound of a commercial 3D printer material, thus to obtain good quality and stable dispersions of the compounds in the transparent resins used for 3D printing. The preliminary and promising results will be shown.

Keywords: fast scintillators, time detector, organic scintillator

Optimising the Emission Wavelength of Mixed-Halide Perovskite Scintillators (#473)

I. H. B. Braddock1, S. S. Alghamdi1, S. H. Bennett1, C. Crean2, C. L. Grove1, J. G. O'Neill1, C. Shenton-Taylor1, S. J. Sweeney3, 1, M. P. Taggart1, P. J. Sellin1

1 University of Surrey, Department of Physics, Guildford, United Kingdom
2 University of Surrey, Department of Chemistry, Guildford, United Kingdom
3 University of Surrey, Advanced Technology Institute, Guildford, United Kingdom


Lead halide perovskite nanocrystals show promise as scintillators due to their strong X-ray stopping power, bright luminescence, fast response time and low-cost manufacture. In addition to this, it is possible to adjust the luminescence wavelength of the perovskite across the entire visible spectrum. Here, we present nanocrystals with emission wavelengths between 403 and 531 nm, and compare their luminescence and time-response. We also present a nanocomposite scintillator, consisting of perovskite nanocrystals loaded into a 1 cm cube of plastic scintillator. Considering various wavelength-dependent factors such as the quantum efficiency of a PMT, it is then possible to select the optimum nanocrystal for the nanocomposite scintillator detector system. By improving transmission through the composite, the proportion of high-Z perovskite nanocrystals can then be increased, with the aim of producing a plastic scintillator from which photoelectric absorption peaks may be observed.

AcknowledgmentThe project or effort depicted was or is sponsored by the Department of the Defense, Defense Threat Reduction Agency. The content of the information does not necessarily reflect the position or the policy of the federal government, and no official endorsement should be inferred.
Keywords: Scintillator, Plastic Scintillator, Perovskite, Nanocrystal

TlCl:Be,I – A fast and dense scintillator (#592)

J. Glodo1, E. van Loef1, Y. Ogorodnik1, L. Soundara Pandian1, C. Sosa1, G. Ariño-Estrada2, S. R. Cherry2, K. Shah1

1 Radiation Monitoring Devices, Inc (RMD), Research, Watertown, Massachusetts, United States of America
2 University of California, Davis, Department of Biomedical Engineering, Davis, Massachusetts, United States of America


Due to the high atomic number (81) of Tl, compositions containing Tl are attractive hosts for radiation detection.  Several Tl based scintillators, such as Tl2LiYCl6 and Tl2ZrCl6, have recently shown good scintillation properties.  In parallel, TlBr has proven to be a very promising semiconductor host.  In the search for dense and fast scintillators we have recently evaluated TlCl as a scintillator host.  With the density of 7 g/cm3 and effective atomic number of 77 it is a very appealing host. Continuing from Hofstadter early investigation of this material, we have grown TlCl compositions with selected dopants such as Be,I and evaluated their scintillation properties.  The emission under x-ray excitation is relatively broad and peaks at 450 nm.  We expect that the scintillation results from either a trapped exciton or donor-acceptor pair (double doping).  The scintillation decay curves showed multiple components with the main time constant of 10 ns (~76%), making it suitable for fast counting applications.  The light yield was estimated in the range of 2,000 photons/MeV, which is high enough for gamma ray spectroscopy at high count-rates with moderate energy resolution.  Since the material has high refractive index (>2), it also produces Cherenkov photons that can be used for fast timing, making it attractive for Positron-Emission-Tomography (PET).  In this presentation we will discuss the properties of TlCl compositions grown with Be,I and other dopants and potential applications for these materials.

AcknowledgmentThis work has been supported by the US Defense Threat Reduction Agency, under competitively awarded contract HDTRA1-21-P-0007.  This support does not constitute an express or implied endorsement on the part of the Government.  DISTRIBUTION A: Approved for public release.
Keywords: TlCl, scintillator, medical imaging

Temperature Dependent Polysiloxane Scintillators for Improved Discrimination of Neutrons and Photons (#612)

J. Arrue1, C. Chandler2, A. Erickson1, A. Sellinger2

1 Georgia Institute of Technology, Nuclear and Radiological Engineering, Atlanta, Georgia, United States of America
2 Colorado School of Mines, Department of Chemistry, Golden, Colorado, United States of America


Polysiloxane hybrid/organic scintillators have been shown to have equal or better figure of merit (FoM) as a Thermoplastics. [2] This specific study [3] used a polysiloxane with 2,5-diphenyl-oxazole (PPO) as the primary dopant, and EJ-299 as the control. In the publication showing how polysiloxanes are comparable to heavily doped thermoplastics, it was also shown 9,9-dimethyl-2-phenyl-9H-fluorene (PhF) is equal or better of a primary scintillator than PPO. For this study, the temperature is altered from 20-50c to observe if there is a change in performance. Temperature is adjusted between 20c-50c for 1-5wt% PhF. For 4% PhF, there was a change in FoM of 1.32 to1.56 between channel 3000 by changing the temperature from 20c to 50c. For the light yield, there was a 1% increase from 20c to 50c. These results could help further the understating of how pulse shape discrimination works with regards to how the single and triplet states as a function of temperature.

AcknowledgmentThis material is based upon work supported by the Department of Energy / National Nuclear Security Administration under Award Number(s) DE-NA0003921. This report was prepared as an account of work sponsored by an agency of the United States Government.  Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.  Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.  The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Keywords: Neutron Detection, Organic Scintillator, Polysiloxane, Pulse Shape Discrimination

High Density and Fast Scintillator Materials for Gamma-ray Detection (#669)

R. Hawrami1, E. Ariesanti2, A. Burger2

1 Xtallized Intelligence, Inc., Nashville, Tennessee, United States of America
2 Fisk University, Life and Physical Sciences/Physics, Nashville, Tennessee, United States of America


In this paper we present crystal growth and results from 16-mm diameter cerium (Ce)-doped Tl2LaCl5 (TLC) and europium (Eu)-doped TlCa2Br5 (TCB) as well as one-inch diameter cerium-doped Tl2GdBr5 (TGB) and europium-dopedTlSr2I5 (TSI), each grown in a two-zone vertical furnace by the modified Bridgman method. Samples extracted and processed from the grown boule are characterized for their scintillation properties like energy resolution, light yield, decay time and non-proportionality. Energy resolution (FWHM) at 662 keV of 5.1%, 3.4%, 4.0%, and 3.3% are obtained for samples of TGB, TLC, TCB, and TSI, respectively. Ce doped TGB and TLC have single decay time components of 26 ns and 48 ns, respectively, while Eu doped TCB and TSI have long decay times with primary decay constants of 571 ns and 630 ns. These compounds exhibit good proportionality behavior when compared to NaI:Tl and BGO.

Keywords: Crystal growth, Gamma-ray detector, Scintillation detector, Thallium-based metal halide crystals

Characterization of scintillating materials in use for brachytherapy fiber based dosimeters (#799)

S. Cometti1, A. Gierej3, T. Baghdasaryan3, J. Van Erps3, F. Berghmans3, A. Giaz1, S. Lomazzi1, R. Santoro1, M. Caccia1, S. O'Keeffe2

1 Università dell'Insubria, DISAT, Como, Italy
2 University of Limerick, Optical Fibre Sensors Research Centre, Limerick, Ireland
3 Brussels Photonics (B-PHOT), Vrije Universiteit Brussel and Flanders Make, Department of Applied Physics and Photonics, Brussels, Belgium

This contribution is submitted on behalf of ORIGIN project.


This paper describes a method to evaluate the light yield and the characteristic decay time of inorganic scintillators used in probes for in vivo brachytherapy dosimeters. The expected scintillating decay time is about hundreds of microseconds and the light emission is diluted in a trail of single photons. As a consequence, the identification of the scintillation occurrence, the estimation of the light yield, and the extraction of the time characteristic are challenging. The results show that the two scintillators have a similar decay time which is of the order of 500 μs while the light yield of the material selected for the low dose rate treatment is almost 4 times higher than the one for the high dose rate therapy.

Keywords: Brachytherapy, Inorganic scintillators, single photoelectron, SiPM

An entropic approach to new scintillator design: precursor synthesis (#1087)

M. Zhuravleva3, 1, C. Melcher1, 3, K. Sickafus3, J. Smith2, J. Glodo4, Y. Wang4, K. Shah4

1 University of Tennessee, Scintillation Materials Research Center, Knoxville, Tennessee, United States of America
2 University of Tennessee, Nuclear Engineering Department, Knoxville, Tennessee, United States of America
3 University of Tennessee, Materials Science and Engineering Department, Knoxville, Tennessee, United States of America
4 Radiation Monitoring Devices, Watertown, Massachusetts, United States of America


For the first time we are adopting an entropic design concept for the discovery and development of novel scintillator compositions. We aim to develop new polycrystalline ceramic scintillation materials that will provide both improved performance and lower cost compared to the currently used technology for high-energy X-ray radiography and other applications. Previous research demonstrated the potential of mixed garnet scintillators such as GLuGAG:Ce and GYGAG:Ce for high scintillation performance. We now propose a new design concept that uses equimolar proportions of 4-7 rare earth elements to produce a stable cubic phase with uniform elemental distribution and with unique scintillation capability. This approach maximizes the configurational entropy and minimizes the Gibbs free energy thereby leading to a new family of high-entropy compounds. Our current work focuses on multi-component rare earth aluminum garnets with a general formula RE3Al5O12 where RE is several rare earth elements taken in equimolar ratios. The first step is to develop nano-size, phase-pure powder precursors that will be hot-pressed into transparent optical ceramics. We have explored low-temperature aqueous solution methods as alternatives to costly flame spray pyrolysis for producing powder precursors. We have successfully synthesized single cubic garnet phase precursor powders as confirmed by powder X-ray diffraction. We are investigating the effect of synthesis parameters on particle size and morphology. We have successfully incorporated Ce3+ as a luminescent activator and observed the expected 5d-4f emission.


This material is based upon work supported by the U.S. Department of Homeland Security under Grant Award Number 20CWDARI00037-01-00. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Department of Homeland Security”.

Keywords: ceramic, polycrystalline, scintillator

Growth of ternary eutectic scintillator for high resolution radiation imaging. (#1222)

Y. Takizawa1, K. Kamada1, 2, N. Kutsuzawa2, M. Yoshino1, S. Yamamoto3, K. J. Kim1, R. Murakami2, 1, V. V. Kochurikhin2, A. Yoshikawa1, 2

1 Tohoku University, Sendai, Japan
2 C&A corporation, Sendai, Japan
3 Nagoya University, Nagoya, Japan


In this study, ternary eutectic scintillators such Tl:CsI/CsCl/NaCl,  were grown by the Czochralski and bertical Bridgeman method at various pulling rates. Crystal growth conditions such as rotation, pulling rates, and crystal growth setup were analyzed. By examining the structure of the obtained eutectic, the growth orientation of the CsI phase as well as the optimum pulling speed and rotation speed were found. A transparent eutectic plate of about 3x5 mm was prepared from the grown sample, and scintillation properties such as light output and decay time after excitation by 662 keV gamma-rays were evaluated. The performance was compared with the Tl: CsI single crystal standard. Furthermore, a β-ray imaging test was carried out by combining the eutectic plate and an electron-multiplied charge coupling device camera, and the position resolution as an imaging device was evaluated.

Keywords: scintillator, eutectic, crystal growth

Growth and characteristics of p-terphenyl crystals for neutron scintillator (#1294)

A. Yamaji1, S. Kurosawa1, A. Yoshikawa2, 1

1 Tohoku University, New Industry Creation Hatchery Center, Sendai, Japan
2 Tohoku University, Institute for Materials Research, Sendai, Japan


For neutron detection, p-terphenyl crystals were grown and their scintillation properties were evaluated. We have developed organic crystals for neutron scintillators with high melting temperatures higher than 200°C and fast decay times in the nanosecond range. In the previous work, p-terphenyl crystal showed a promising light yield (1.80 times that of lithium glass scintillator GS-20) and decay time of 5.8 ns. In this study, 2-inch size p-terphenyl crystals were grown by the Self-Seeding vertical Bridgeman technique. As-grown p-terphenyl crystal appeared transparent and had no cracks. Grown crystals were cut and polished for pulse shape discrimination (PSD) and neutron imaging tests. PSD test was performed by using the two integrated charge integration methods and its figure of merit was estimated to be 0.96. A p-terphenyl array consisting of 8 x 8 pixels  with sizes of 6 x 6 x 6 mm3 for a neutron imaging test. The 2-dimensional neutron imaging was succeeded to be reconstructed under neutron irradiation from a 252Cf isotope.

Keywords: Crystals, Neutrons, Organic materials, Scintillators

Core Valence Luminescence in Fast Scintillators Cs2ZnCl4 and Cs3ZnCl5 and Scale Up to Growth of Large Diameter Crystals (#1400)

D. Rutstrom1, 2, L. Stand1, 2, C. Delzer1, 3, M. Koschan1, M. H. Du4, J. Glodo5, E. van Loef5, K. Shah5, C. L. Melcher1, 3, M. Zhuravleva1, 2

1 Scintillation Materials Research Center, Knoxville, Tennessee, United States of America
2 University of Tennessee, Materials Science and Engineering Department, Knoxville, Tennessee, United States of America
3 University of Tennessee, Nuclear Engineering Department, Knoxville, Tennessee, United States of America
4 Oak Ridge National Lab, Oak Ridge, Tennessee, United States of America
5 Radiation Monitoring Devices, Watertown, Massachusetts, United States of America


Undoped Cs2ZnCl4 and Cs3ZnCl5 single crystals were studied for use in timing applications. High quality transparent crystals were grown ranging from 7 mm in diameter up to ~1 inch in diameter (larger sizes than those fabricated in previous works). Cs2ZnCl4 and Cs3ZnCl5 were measured to have single component scintillation decay times of 1.2 ns and 1.8 ns, respectively. These extremely fast decay times are a result of the core valence luminescence mechanism observed in a variety of CsCl-containing materials. The crystals measured in this work had light yields of ~1100 ph/MeV (Cs2ZnCl4) and 740 ph/MeV (Cs3ZnCl5), which are consistent with those reported in previous publications. Radioluminescence spectra had maximum emission wavelengths of 290 nm and ranged from ~200 nm to 550 nm. The timing resolution of Cs2ZnCl4 obtained with the optimal CFD fraction was 137 ps. Cs2ZnCl4 and Cs3ZnCl5 may be advantageous over BaF2 (a well-known commercially available "fast" inorganic scintillator) due to having emission wavelengths more suitable to the sensitivity range of a photomultiplier tube, as well as their comparable decay times that account for a larger portion of the total light than that of BaF2 (t1 = 0.8 ns (15%) ; t2 = 630 ns (85%)).


This material is based on work supported in part by the Department of Energy National Nuclear Security Administration through the Nuclear Science and Security Consortium under Award Number DE-NA-0003180. This material is based upon work supported under a Department of Energy, Office of Nuclear Energy, Integrated University Program Graduate Fellowship. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the Department of Energy Office of Nuclear Energy.

Keywords: scintillator, crystal growth, single crystal, inorganic, timing

Development of a compact and portable high-sensitivity omnidirectional Compton camera with detector rotation function (#58)

S. Ishikawa1, H. Muraishi1, R. Enomoto2, H. Katagiri3, M. Kagaya4, T. Watanabe5, D. Kano5, S. Nakamura6, Y. Watanabe1, H. Ishiyama1

1 Kitasato University, Sagamihara city, Japan
2 University of Tokyo, Kashiwa city, Japan
3 Ibaraki University, Mito city, Japan
4 National Institute of Technology, Sendai College, Sendai city, Japan
5 National Cancer Center Hospital East, Kashiwa city, Japan
6 National Cancer Center Hospital, Chuo city, Japan


We report the development of a compact and portable high-sensitivity omnidirectional Compton camera in this study. This system can visualise radioactive Cesium with surface or air dose rates of less than 1 μSv/h released by the Fukushima Daiichi Nuclear Power Plant accident, and low-level gamma radiation sources like radioactive contamination and materials in medical facilities. We adopted the Compton camera technology reported in a previous study (Muraishi et al., Jap. J. Appl. Phys. 2020). This technology enables shift-invariant gamma-ray imaging. The detector can be operated from a PC via Wi-Fi at 12 V DC, and 15 W power. Furthermore, by adopting metal package photomultiplier tubes (PMTs) and optimising the crystal arrangement, we miniaturized the detector and improved image quality. The results of outdoor measurements in Fukushima prefecture, Japan, and radioactive material measurements at a boron neutron capture therapy (BNCT) facility using this detector will also be reported.

AcknowledgmentThis study was supported by the Open Source Consortium of Instrumentation (Open-It), Japan, JSPS KAKENHI Grant (No. 15H04769 and 19H04492).
Keywords: Gamma-ray imaging, Compton camera, CsI (Tl), Radioactive cesium, Fukushima Daiichi nuclear powerplant accident

The performance of the new KETEK low-noise SiPM array series: Characterization in a Compton camera component study (#283)

T. M. Binder1, 2, Y. J. Zhou1, K. Kamada3, K. Parodi1, F. Schneider2, F. Wiest2, P. G. Thirolf1

1 Ludwig-Maximilians_Universität München, Chair for experimental and medical physics, Garching, Germany
2 KETEK GmbH, Munich, Germany
3 C&A Corporation, Sendai, Japan


Compton cameras (CC) allow for spatially resolved γ detection. The γ-ray origins are reconstructed by measuring the interaction positions and energy deposits in the scatter and absorber components, allowing to determine the scattering angle. Consequently, the energy resolution of the CC components plays a major role in the component selection and detector design. For scintillators the energy resolution strongly depends on the scintillation material, but also on the photosensor and signal processing electronics. For our CC prototype, built from a 16 × 16 GAGG scintillation array (scatterer) with 1.6 mm crystal pitch and a monolithic LaBr3:Ce block (50 × 50 × 30 mm3), we investigated the energy resolution of the components in a readout configuration involving the new KETEK low-noise SiPM array series (PA33XX-WL-0808) for the individual camera components and compared the performance to that of the previous generation (PA33XX-WB-0808). Furthermore, we commissioned a CC prototype equipped with the new SiPM series and evaluated its energy resolution. For the GAGG scatterer an energy resolution of 9.4% was measured. An improvement between 0.9% and 1.8% (inclusive method) was achieved due to the superior balance of SiPM saturation, PDE and noise compared to KETEK’s previous SiPM array generation. For the absorber detector a comparable energy resolution was obtained for SiPM arrays of the two generations with comparable microcell sizes (47 μm vs. 50 μm). However, the reduced noise of the WL-SiPM arrays allowed to obtain an excellent energy resolution of 4.1% over a wider range of applied bias voltages (5.0 V – 6.0 V).

AcknowledgmentThis work was supported by the Bayerische Forschungsstiftung
Keywords: SiPM, Compton camera, low-noise

A Scattering and Attenuation Measurement Instrument for Neutrino Detector Fill Material (#431)

J. Hecla1, O. Akindele2, S. Dazeley2, A. Bernstein2

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


Detailed understanding of the attenuation and scattering properties of fill media used in neutrino detectors is critical to the ability to accurately simulate detector performance. To better understand the optical parameters of fill media, a system has been developed which provides simultaneous attenuation and scattering measurements for highly transparent liquids.  This horizontal, adjustable path-length “long-arm” system allows for complete isolation from the atmosphere, simple calibration and a high degree of vibration insensitivity. In addition to scattering measurements, the system is equipped with adjustable polarizers to separate Rayleigh and Mie scattering components in complex media. Attenuation, scattering and depolarization ratio measurements have been performed with DI water, which agree well with past experimental results in the 405-532nm range. Measurement of attenuation lengths above 100m has been consistently demonstrated. Application of this system to materials such as water-based liquid scintillators is ongoing.


 This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

J. J. Hecla is a graduate student in the Department of Nuclear Engineering at the University of California Berkeley, Berkeley CA 94709. (e-mail: A. Bernstein, O. Akindele and S. Dazeley are employees of Lawrence Livermore National Laboratory, Livemore CA.

Keywords: Neutrino detection, water-based liquid scintillator, Rayleigh scattering, Mie scattering, optical attenuation

X-ray detector using HfO2 or Bi2O3 nanoparticle-loaded plastic scintillator up to 40 wt% loading with Si-PM for high energy X-rays (#632)

S. Kishimoto1, A. Toda2

1 High energy accelerator research organization, Inst. of materials structure science, Tsukuba, Japan
2 Tokyo Printing Ink Mfg. Co., Ltd., Saitama, Japan


We have been developing an X-ray scintillation detector using heavy metal nanoparticle-loaded plastic scintillator with Si-PM as photodetector for application to synchrotron radiation nuclear resonant scattering (SR-NRS). We already produced HfO2 nanoparticle-loaded plastic scintillators (Hf-PLSs) by mixing with polyvinyl toluene (PVT) and 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (b-PBD) as fluorophore. A 40 wt% Hf-PLS of ⁓3×3×3 mm3 in size was mounted on a Si-PM, Hamamatsu Photonics S13360-3025CS (MPPC). The MPPC was cooled with the Hf-PLS down to −20 °C to suppress the thermal noise and to increase the gain. The property for high energy X-rays was investigated using synchrotron X-ray beam at beamline BL-14A of the Photon Factory. The detection efficiency for 2.8 mm thickness of the Hf-PLS was 30.4 ± 0.2 % at 57.6 keV (the first excitation level on 127I). The time resolution (full width at half maximum, FWHM) of 0.29 ± 0.06 ns was obtained at 57.6 keV. We are now preparing Bi2O3 nanoparticle-loaded plastic scintillators (Bi-PLSs) up to 40 wt% loading. Bismuth has the atomic number (Z) of 83 and the K absorption edge at 90.5 keV, higher than 65.3 keV of hafnium (Z=72). This brings a higher detection efficiency up to the Hf-K absorption edge and a better timing performance in a wider range before the Bi-K absorption edge. We will test the scintillation detector mounting a 40 wt% Bi-PLS on MPPC using synchrotron X-ray beam of 73.0 keV for application of the SR-NRS on 193Ir. The pulse height and time spectra were already observed with a detector using 40 wt% Bi-PLS (8 mm in diameter and 3 mm in thickness) and photomultiplier tube (Hamamatsu R7400P), at 67.4 keV (the first excitation level on 61Ni). A high detection efficiency of 27.0 ± 0.1% for 3 mm in thickness and a good time resolution (FWHM) of 0.26 ± 0.06 ns were obtained. We will present the results for the detector using 40 wt% Bi-PLS and MPPC at 73.0 keV at the conference.

Keywords: scintillation detector, Si-PM, plastic scintillator, time resolution, high energy X-ray

Regional variation in neutron/gamma pulse-shape discrimination in an organic scintillator (#644)

P. M. Collins-Price1, M. Joyce1

1 Lancaster University, Engineering, Lancaster, United Kingdom


This paper describes the use of a Hamamatsu H13700 16 x 16 multi-anode photomultiplier tube (MAPMT) to quantify regional variations in the confidence of neutron/gamma discrimination across the volume of a continuous EJ-276 organic scintillator. Individual MAPMT outputs are manually selected and input to a mixed-field analyser (MFA) performing pulse-shape discrimination (PSD) by pulse-gradient analysis (PGA). Accuracy of the PSD response is compared for events occurring within different regions of the scintillator volume by varying the centre of interaction using an aperture collimator. Positional variation in scintillator light response is measured by selecting individual readout anodes. Light pulse dispersion behavior is investigated by comparing the change in analogue output to supplied crosstalk data for adjacent anodes. This study is ongoing, and its findings could inform future PSD developments to increase the efficacy of particle identification and position-sensitive neutron counting methods for nuclear safeguarding and materials assay.

AcknowledgmentThis research is supported by Lancaster University.
Keywords: gamma rays, neutrons, position-sensitive, pulse-shape discrimination, scintillation counters

Tri-modal 3D Gamma-Ray and Neutron Mapping with Neutron Gamma Localization and Mapping Platform (#727)

I. Cho1, J. Cates2, R. Pavlovsky2, K. Vetter1, 2

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


The combination of recent developments in the manufacturing of high energy resolution and thermal neutron sensitive elpasolite scintillators and pulse-shape discrimination (PSD) capable and fast-neutron sensitive plastic scintillators provide new means in the detection and mapping of radiological and nuclear materials. In particular when integrated into the Scene-Data Fusion (SDF) enabled Localization and Mapping Platform (LAMP), such a tri-modal detection and mapping instrument can be deployed in man-portable modes or on small unmanned aerial systems promising accurate, quick, and safe 3D mapping operations in complex radiological environments. We present results that demonstrate the feasibility of such a tri-modal-based 3D mapping instrument consisting of four CLLBC detectors arranged around a PSD-capable plastic scintillator. The instrument provides rich radiological and contextual data sets that can be utilized for applications ranging from proliferation detection to emergency response and nuclear forensics. Of particular interest is the evaluation of the value of each detection mode and their correlations for these applications. We will present results of measurements with a tri-modal LAMP system in a hand-portable configuration and deployed on a small unmanned aerial system demonstrating the feasibility to detect, localize, and discriminate gamma-ray only sources and fission sources such as Cf-252.

AcknowledgmentWe thank the Applied Nuclear Physics Program at Lawrence Berkeley National Laboratory for space, detector parts, and tools to conduct our demonstrations. We thank the BEARing Group at UC Berkeley for reviewing and useful discussion on the project. 
Keywords: Scintillation, CLLBC, NGLAMP, PSDPS, Trimodal Detection

Neutron detector using a semi-transparent composite of powder Li glass scintillator (#861)

K. Watanabe1, A. Ishikawa2, A. Uritani2

1 Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka, Japan
2 Nagoya University, Department of Applied Energy Engineering, Nagoya, Japan


We are developing an optical fiber type neutron detector using a small scintillator.  This type of neutron detector is a promising candidate for the online neutron monitor in the Boron Neutron Capture Therapy (BNCT).  The optical fiber type neutron detector using a small Li glass scintillator, which has short decay time, can show a clear neutron peak in the signal pulse height and excellent counting rate capabilities.  However, the only disadvantage of this detector is the use of a random-shape small scintillator.  Since it is difficult to shape a small and fragile scintillator, the use of a random-shape scintillator is inevitable.  One of the ways to fabricate a well-shaped small scintillator with transparency is to use a composite of scintillator powder and a UV curable resin with the stamping process.  As a feasibility study, we attempted to fabricate a semi-transparent composite of powder Li glass neutron scintillator.  We also measured the neutron response of the fabricated scintillator.  We successfully demonstrated that the fabricated detector can show a clear neutron peak in the signal pulse height spectrum.  This result suggested that the optical fiber type detector with a well-shaped small neutron scintillator can be realized by the stamping process of the proposed semi-transparent composite scintillator.


This work was partially supported by the Japan Society for the Promotion of Science under KAKENHI 18H03468.

Keywords: Li glass scintillator, neutron scintillator, optical fiber type neutron detector, semi-transparent composite

Performance study of plastic scintillators coupled to SiPM for fast-timing measurements (#1022)

J. Benito García1, M. García Díez1, V. Sánchez-Tembleque1, L. M. Fraile Prieto1, J. M. Udias Moinelo1

1 Universidad Complutense de Madrid, Grupo de Física Nuclear, Madrid, Spain


Plastic scintillators are widely used as  beta-particle detectors in nuclear physics. Thin plastics, with thicknesses of few mm, coupled to fast photomultiplier tubes (PMT) are employed for timing measurements. This configuration provides excellent time resolution and homogeneous energy response for a wide range of incident beta particle energies.

On the other hand, silicon photomultipliers (SiPMs) keep gaining relevance due to their compact size, insensitivity to magnetic fields and no need for high voltage supply. Their small size is very attractive for nuclear physics experiments. In the case of plastic fast-timing beta detectors in particular, where most of the space is occupied by the PMT, SiPMs would make it possible to build very compact detectors, provided that they exhibit similar time resolutions. In addition, this would allow to increase the number of detectors, and thus the overall efficiency, while releasing space iin complex setups.

The increased efficiency and flexibility for extended configurations are important points for future measurements at the ISOLDE Decay Station (IDS), where coincidence-delayed βγγ(t) fast-timing experiments are performed. For this purpose, we have tested a new detector based on an EJ-232 scintillator plastic coupled to MICROFJ-SMA-30035-GEVB SiPM from SensL.  Processing the fast signal output of this SiPM we have obtained a time resolution of (155 ps CRT FWHM) against a reference detector. This value is comparable with the one obtained with the same plastic coupled to a fast PMT, which makes this configuration very promising for future experiments.

AcknowledgmentThis work have been supported by EU regional funds (RTC-2015-3772-1, RTC2019-007112-1) Spanish MINECO through projects (FPA2015-65035-P), CAM (S2013/MIT-3024 TOPUS-CM, B2017/BMD-3888 PRONTO-CM) and by EU's H2020 under MediNet a Networking Activity of ENSAR-2 (grant agreement 654002). J.B. acknowledges support from the UCM under Grant No. CT27/16-CT28/16
Keywords: Plastic scintillator, SiPM, PMT, beta detector, fast-timing

Simulating Properties of Integrated Fibers as Conformal Radiation Detectors (#1238)

J. B. Sesler1, F. Naqvi1, A. Danagoulian1

1 Massachusetts Institute of Technology, Nuclear Science and Engineering, Cambridge, Massachusetts, United States of America


New manufacturing capabilities at Advanced Functional Fibers of America at MIT allow scintillating material to be drawn into fibers with embedded photodetectors, which could be assembled into the first fully integrated conformal radiation detection fabrics. This work investigates the properties of such a fabric using Monte Carlo simulations, with the goal of comparing results to a parallel effort to make and test fibers using gamma sources. Simulations run with the Grasshopper front-end to Geant4 allow tracking particle interactions in the fabric, which can determine the detection efficiency that can be expected from a fabric. Also of interest is determining whether fiber detectors can distinguish gamma and neutron, since the recoil electrons of gamma interactions have a longer range than recoil protons from neutron interactions, and should therefore trigger multiple fibers. Simulations should also help determine how much of the radiation energy will be deposited in the fiber as light, and how much of the light can be expected to propagate to the photodetector. Preliminary results show that it is possible to track which fibers are activated by interactions of a simulated particle, and suggest that both gamma and neutron radiation can trigger multiple fibers. The conclusions of this study will give insight into designing integrated fibers for optimal performance and their potential for use in affordable large-area and wearable detectors. Wearable detectors are of particular interest for integration into warfighter uniforms to provide distributed, wide-area detection capability and the ability to triangulate sources through networked sensors. Future work will consider the application of Compton backprojection in order to extract directional information from fiber responses.


Work supported in part by the U.S. Defense Threat Reduction Agency

Keywords: Integrated Fibers, Monte Carlo Simulation, Radiation Detectors, Scintillators

Study of macrobending losses in plastic scintillating fibres exposed to beta sources (#1311)

N. Dufour1, G. Bertrand1, A. Sari1, F. Carrel1

1 Commissariat à l'Energie Atomique et aux Energies Alternatives, Université Paris-Saclay, CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, Gif-sur-Yvette, France


Scintillating fibres are organic scintillators with optical fibre properties. They can be manufactured in lengths of a few kilometres at a low cost, allowing the development of detectors with lengths reaching a dozen meters and more. Moreover, they are flexible and can adapt to the shape of measured surfaces and follow curved lines. However, optical fibres are prone to losses when bent, and studies have thoroughly examined this phenomenon called macrobending losses. Nevertheless, such studies have never been reported for scintillating fibres as detection device in the field of nuclear measurement. The aim of this paper is to investigate the evolution of the response of a scintillating fibre subjected to bending stresses during measurements involving radioactive sources, in order to either calculate correction factors or define a critical bending angle. Using one hundred BCF-10 scintillating fibres assembled in a single bundle, and using plastic cylinders of various diameters to roll the bundle around, we measure the evolution of both the counting rates and acquisition spectra. Various radioactive sources have been used, among which a 90Sr-90Y pure beta source. First results show that bending the detector around a 10 cm diameter cylinder with angles between 0° and 90° do not affect counting rates or acquisition spectra. However, at an angle of 180°, counting rate decreases by half compared to 90°, yet the shape of the spectrum is kept unchanged. Further, this study will help to assess and take into account the influence of macrobending losses in scintillating fibre-based detectors, such as the ones used in Japan at Fukushima Daiichi and its surroundings to characterize radiologically large contaminated areas and respecting potential demarcation lines.

Keywords: Scintillating fibre, Macrobending loss

Potential and applications of large-area Si(Li) detectors developed for the GAPS project (#161)

H. Fuke1, Y. Shimizu2, M. Kozai1, F. Rogers3, K. Perez3, C. Hailey4

1 Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Sagamihara, Japan
2 Kanagawa University, Department of Physics, Yokohama, Japan
3 Massachusetts Institute of Technology, Department of Physics, Cambridge, Massachusetts, United States of America
4 Columbia University, Columbia Astrophysics Laboratory, New York, New York, United States of America


Novel lithium-drifted silicon [Si(Li)] detectors have been developed for the balloon-borne General AntiParticle Spectrometer (GAPS) experiment. These Si(Li) detectors feature a large sensitive area (~9cm-diameter active area segmented into 8 readout strips), a thick active layer (~2.2mm), and a high energy resolution (~4 keV full-width at half-maximum, FWHM) for 20 – 100 keV X-rays. The operating temperature is set at ~–40oC, far above the liquid nitrogen temperatures required for conventional Si(Li) X-ray detectors. These Si(Li) detectors were developed for compatibility with mass production, as the GAPS tracker will be filled by >1000 detectors arranged three-dimensionally. In this presentation, we will discuss potential improvements of this Si(Li) detector model for possible applications beyond the ongoing GAPS program. The leakage current (LC) is the primary detector property that limits energy resolution of the present Si(Li) model. We found that the LC decreases exponentially as the detector is cooled; at –100oC, the LC was <1 pA, or less than 10–3 of the nA-scale LC at –40oC. The energy resolution is halved at –60oC, as expected, and will be further improved at lower temperatures. This substantiates that the potential of the Si(Li) wafer can be more highly exerted at ~–100oC, which is still substantially higher than the liquid nitrogen temperatures. By dividing the sensitive area into finer structure, the capacity of each segment will be decreased, and the energy resolution will be further improved to sub-keV scale. These improvements will guide us in designing a next-generation experiment beyond the present GAPS program. Improved Si(Li) detectors will be also useful for imaging apparatus in other fields such as medical and biological applications as well as security inspections. As an example, by arraying the improved Si(Li) detectors, a Compton-camera-type three-dimensional single-photon emission computed tomography (SPECT) can be constructed.

Keywords: Lithium-drifted silicon radiation detectors, X-ray detectors, three-dimensional detector arrays, leakage currents, biomedical applications

Contribution of Interface State and Bulk Damages to the Dark Current Increase in SOI Pixel Sensor with Pinned Depleted Diode Structure (#230)

H. Suzuki1

1 University of Tsukuba, Tsukuba, Japan


We have been developing pixel detectors based on Silicon-On-Insulator (SOI) technology, where the PN diodes formed in the support silicon substrate are connected to the SOI-CMOS circuits through the buried oxide (BOX) layer. They are promising for precision particle detectors as intelligent circuits can be integrated monolithically. In the SOI detectors, the interface between the sensor silicon and the BOX layer contributes to dark current increase. A Pinned Depleted Diode (PDD) structure that fixes the potentials on the sensor surface and suppresses the formation of a depletion layer at the interface has been proposed. Significant reduction in the dark current has been demonstrated, while the radiation induced dark current increase still remains as an issue. The main cause of the increase in dark current is considered to be the expansion of the depletion layer due to trapped charges in the BOX layer and carrier excitations via radiation-induced interface states or bulk defects. Evaluation of these contributions is essential for improvement of the radiation hardness. Therefore, TEG chips with a PDD SOI pixel array (pixel size is 36 μm×36 μm ) and MOSFETs, whose gate insulator is the BOX layer, were exposed to protons to the fluence (dose) of 9.63×1013 neq/cm2  (70 kGy) and 5.02×1014 neq/cm2  (390 kGy). The leakage current increases due to interface state, trap charges, and bulk damage were quantitatively evaluated using the current recovery effect of isochronal annealing conducted from 60℃  to 300℃  for 30 min each. It was found that the main dark current increase (measured at room temperature) of the order of 0.71 nA/pixel  and 4.7 nA/pixel  is due to the interface states, and that the influence of in-bulk defects is of 0.040 nA/pixel  and 0.10 nA/pixel , at the two fluences, respectively. This suggests that the radiation hardness of devices with PDD may be significantly improved by suppressing the contribution of the radiation-induced interface states.

AcknowledgmentThe authors would like to acknowledge the valuable advice and great work by the personnel of LAPIS Semiconductor Co., Ltd. The present work was supported by KEK Detector Technology Project and by Tomonaga Center for the History of the Universe, University of Tsukuba. This work was also supported by VLSI Design and Education Center (VDEC), the University of Tokyo in collaboration with Synopsys, Inc., Cadence Design Systems, Inc., and Mentor Graphics, Inc. The proton and gamma irradiations were respectively conducted at Cyclotron and Radioisotope Center (CYRIC), Tohoku University and at Takasaki Laboratory, National Institute for Quantum and Radiological Science and Technology. We acknowledge their personnel and ATLAS-Japan members for their help in the CYRIC irradiation.
Keywords: silicon-on-insulator (SOI), Pinned Depleted Diode (PDD), dark current, Total ionizing dose (TID), non-ionizing energy loss (NIEL)

Study of the response of a double SiC-based diode detector to 14.1 MeV neutrons for an irradiation campaign preparation (#477)

V. Valero1, L. Ottaviani1, A. Lyoussi2, C. Destouches2, B. Cheymol3, M. Carette1, A. Volte1, C. Reynard-Carette1

1 Aix Marseille Univ, Université de Toulon, CNRS, IM2NP, Marseille, France
2 CEA/DES/IRESNE/DER, Section of Experimental Physics, Safety Tests and Instrumentation, Cadarache, F-13108, Saint Paul-lez-Durance, France
3 Laboratoire de Physique Subatomique et de Cosmologie, Université Grenoble-Alpes, CNRS/IN2P3, Grenoble, France


In the field of nuclear instrumentation, neutron detection is at the heart of the concerns. In fact, these detectors can be used for fission energy applications such as ex-core and in-core monitoring, safety requirements or for fusion energy applications such as neutron diagnostic on Test Blanket Modules (TBM). Since many years, wide bandgap semiconductors such as Silicon Carbide (SiC) are studied because of their interested properties which are their wide bandgap, high breakdown field, high temperature and high radiation resistance. They are suitable in particular for a use in harsh environments even with a mixed neutron and g background as encountered in a research reactor core. The detection on a wide energy from thermal to fast neutron is an additional reason of interest for this kind of detectors. In this work, SiC-based neutron detectors and their acquisition chain are tested at the Laboratoire de Physique Subatomique et Cosmologie of Grenoble (France) by using a Deuterium-Tritium neutron generator. The latter produced a 14.1 MeV neutron flux around 5×107 n·cm‑2·s-1 at 3 cm of the Tritium target. Various parameters, equipment and detectors are tested to define the best acquisition chain for the preparation of a future irradiation campaign in a research reactor. Moreover, due to the elaboration of a new detector composed of two diodes in a single housing, comparisons and characterization of the diodes with and without thermal Neutron Converter Layer respectively are achieved simultaneously. The influence of the bias voltage on the obtained Pulse Height Spectrum is also studied.

Keywords: Fast neutron, deuterium-tritium generator, nuclear instrumentation, semiconductor detectors, silicon carbide.

Neutron Detection with Diamond Detectors in a High Background of γ-rays Using Digital Signal Processin (#776)

X. Xu1, M. Hagiwara2, 1, S. Kamada3, H. Iwase2, M. Nakhostin4

1 The Graduate University for Advanced Studies (Sokendai), High Energy Accelerator Organization(KEK), つくば市, Japan
2 High Energy Accelerator Organization(KEK), Radiation Science Center, つくば市, Japan
3 National Maritime Research Institute, Marine Risk Management, Tokyo, Japan
4 Imperial College London, Department of Physics, London, United Kingdom


We report on the thermal neutron detection performance of two CVD diamond detectors in a strong background of γ-rays using digital signal processing techniques.
The detectors were coupled to a fast current-sensitive preamplifier whose outputs were recorded with a fast waveform digitizer. A digital technique was used to discriminate between neutron and γ-ray pulses. The excellent performance of the detectors was experimentally demonstrated with a neutron source based on a 30 MeV electron beam with the peak current of around 180 mA. The detectors exhibit energy resolutions of ~8.6% for thermal neutron peak with an excellent rejection of background γ-rays.

Keywords: CVD, neutron detector, digital signal processing, n/γ discrimination

Test Results of Low Gain Avalanche Detectors (DC and AC) for Picosecond Time Measurement using a 120 GeV Proton Beam for TOPSiDE at the EIC (#997)

M. Jadhav1

1 Argonne National Laboratory, Physics Division, Lemont, Illinois, United States of America


The Timing Optimized PID Silicon Detector for the EIC (TOPSiDE) is Argonne's proposed central detector concept for the Electron-Ion Collider, with its physics goals of perturbative and non-perturbative Quantum ChromoDynamics (QCD) studies of the structure of nucleons and nuclei. It requires high precision tracking, good vertex resolution, and excellent particle identification with a timing resolution of around 10 ps or better. TOPSiDE uses Ultra-Fast Silicon Detectors (UFSD) based on the Low-Gain Avalanche Detector (LGAD) technology. The LGADs are proven to provide timing resolutions of a few 10s of picoseconds. I will present the results of 35 μm and 50 μm thick DC-LGAD tests at Fermilab Test Beam Facility with 120 GeV proton beam. The best timing resolution of DC-LGADs in a test beam to date is achieved using three combined planes of 35 μm thick LGADs at -30 ºC with a precision of 14.3 ± 1.5 ps. The latest test measurements of AC-LGADs using single-channel and multichannel read-outs will also be presented.


This work is supported by Laboratory Directed Research and Development (LDRD) funding from Argonne National Laboratory, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-06CH11357. The LDRD project name is "Tomography at an Electron-Ion Collider: Unraveling the Origin of Mass and Spin". This work is also supported by the United States Department of Energy, grant DE-FG02-04ER41286. This document is prepared using the resources of the Fermi National Accelerator Laboratory (Fermilab), a U.S. Department of Energy, Office of Science, Fermi Lab Test Beam Facility. The test results reported are performed within the EIC LGAD consortium. 

Keywords: Silicon radiation detectors

Study of Low Gain Avalanche DetectorsLGAD with high timing resolution for Timing Measurements in detector of ILC Detectors (#1322)

M. Kuhara1, T. Suehara2, K. Kawagoe2, T. Yoshioka3, Y. Kato4

1 Kyushu University, Graduate School of Science, Fukuoka, Japan
2 Kyushu University, Faculty of Science, Fukuoka, Japan
3 Kyushu University, Research Center for Advanced Particle Physics, Fukuoka, Japan
4 The University of Tokyo, Graduate School of Science, Tokyo, Japan


Low Gain Avalanche Detectors (LGADs) are silicon sensors with avalanche multiplication, giving precise information of the timing of the signal to a few tens of picoseconds. Application of LGADs to as higher timing resolution sensor for  an application to  Silicon-Tungsten electromagnetic calorimeter (SiW-ECAL)  offor detector of  the International Large Detector (ILD) is being investigated of the International Linear Collider (ILC). Time-of-Flight (ToF) information by the LGADs It is expected to improve identification of hadrons by combining with the energy deposit at the tracker.  that measurement of Time-of-flight (ToF) with higher timing resolution improves particle separation power. As a step in research of LGAD, we tested Avalanche Photo-Diodes (APDs) are sensors for optical photons, having identical structure of LGADs. We measured response of APDs with a positron beam to investigate the possibility of LGADs for the calorimeter. With penetrating beam over three identical APDs, timing correlation corresponding to about 90 psec of the timing resolution of a single sensor is obtained. The resolution can be further improved by full correction of timewalk and electronic jitters, which are currently ongoing.


The test beam experiment was conducted with the support of ELPH, Tohoku University. We appreciate Omega group for the support on the operation of the Skiroc2-CMS chip. This work is partially supported by JSPS KAKENHI Grant Number JP17H05407.

Keywords: ILC, LGAD, APD

Construction and operation of Gas Electron Multiplier Tracker for the J-PARC E16 Experiment in Run0 (#95)

T. Murakami1, 2

1 The University of Tokyo, Department of Physics, Graduate School of Science, Bunkyo, Japan
2 RIKEN, Nishina Center for Accelerator-based Science, Wako, Japan

for the J-PARC E16 Collaboration


The mass of vector mesons at finite density is expected to change due to the restoration of broken chiral symmetry. In the J-PARC E16 experiment,  and   decayed from the vector mesons in nuclei are measured. To obtain significant statistics, we use a high-intensity beam up to 1×/spill. To cope with the expected counting rate of 5 kHz/, we have developed and constructed a detector using Gas Electron Multiplier (GEM). The GEM foils are manufactured by a Japanese company, and the number of used foils, 72, is the largest in Japan. The GEM chambers have been mass-produced and installed in the J-PARC high-momentum beamline. In the commissioning run (Run0), the chambers are operated under the same environment as coming physics run and calibration data are collected.


We would like to express our gratitude to the staff members of J-PARC Hadron Experimental Facility for their effort to construct and operate the J-PARC high-momentum beamline. We also thank to KEK electronics system group and open source consortium of instrumentation (OpenIt) for their help in the development and test of the ASICs. This work was supported by RIKEN Junior Research Associate Program, RIKEN SPDR program, MEXT/JSPS KAKENHI Grant numbers 19654036, 19340075, 21105004, 26247048, 15H05449, 15K17669, 18H05235, 20H05647, and the Ministry of Science and Technology of Taiwan Grant number MOST108-2112-M-001-020.

Keywords: Gaseous micropattern detector, GEM, Tracker.

Gas and irradiation studies for the Micromegas detectors of the ATLAS New Small Wheel (#362)

I. Gnesi1

1 INFN, Cosenza, Italy

On behalf of ATLAS Muon Collaboration


The ATLAS collaboration has chosen the resistive Micromegas technology for the high luminosity upgrade of the first forward muon station, the New Small Wheel (NSW). One of the main features being studied is the HV stability of the detectors, mainly related to the resistivity pattern of the strips. Among the several approaches to enhance the stability of the detectors, the use of different gas mixtures are being studied. A ternary argon-CO2-isobutane mixture has shown to be effective in dumping discharges and dark currents. The presence of isobutane in the mixture required a set of ageing studies, ongoing at the GIF++ radiation facility at CERN. A summary of the results obtained up to now will be shown, as well as the upcoming test plans, mainly focused on O(1 year equivalent) time scale ageing effects.

Keywords: MICROMEGAS, MPGD, ageing

Trench-MWPC 3He detector for the XtremeD neutron diffraction instrument (#538)

D. Barkats1, J. - C. Buffet1, S. Cuccaro1, B. Guerard1, F. Lafont1, J. Marchal1, J. Pentenero1, N. Sartor1

1 Institut Laue Langevin, Grenoble, France


A large curved MWPC detector was fabricated for the new XtremeD instrument dedicated to neutron diffraction studies of powder and crystal samples under extreme conditions of pressure, temperature, and magnetic field. This instrument will be installed at ILL on an upgraded neutron guide with increased intensity.  The Trench-MWPC design has been adopted to cope with the high counting rate requirement of the instrument. The detector consists of nine modules mounted inside an Aluminum pressure vessel to fulfil the stringent requirements in terms of angular coverage (130° x 24°), and angular resolution (0.15° x 0.19°). The technical challenges and solutions regarding the mechanical design, fabrication of the pressure vessel and the detection modules are discussed and the first results obtained during the experimental characterization of the detector with neutrons are presented.

Keywords: Multi Wire Proportional Chamber, 3He detector, Trench-MWPC, neutron detector

Cathode Material Study of Gas Scintillation Dose Imager for Hardon-therapy (#795)

T. Fujiwara1, Y. Koba3, Y. Mitsuya2, Y. Nakayam4, K. Maehata5

1 National Institute of Advanced Industrial Science and Technology (AIST), Tskuba, Japan
2 University of Tokyo, Tokyo, Japan
3 National Institute of Radiation Science, Chiba, Japan
4 Kyushu University, Fukuoka, Japan
5 Teikyo University, Fukuoka, Japan


Hadron therapy is known as one of the most efficient radiation therapies for cancers. For daily quality assurance (QA) measurements in hadron (mostly proton and carbon) radiotherapy, a dosimetry system that has a two-dimensional effective area, high spatial resolution, and linear response-to-dose is required. We demonstrate the dose imaging performance of a novel digital dose imager using carbon ion beams for hadron therapy. The dose imager is based on a newly-developed gaseous detector, a well-type glass gas electron multiplier. The imager is successfully operated in a hadron therapy facility with clinical intensity beams for radiotherapy. It features a high spatial resolution of less than 1 mm and an almost linear dose–response relationship with no saturation and very low linear-energy-transfer (LET)  dependence.

However, experimental results show small disagreement in fragment region, and spread out Bragg peak (SOBP) beam measurement. We assumed that this is due to the effect of secondary particles produced by the cathode material. Therefore, we have experimentally investigated the effect of the cathode material on various cathode materials. In this talk, we will discuss the evaluation results of using aluminum, copper, film, and graphite materials as cathode materials respectively.

Keywords: Glass GEM, hadron therapy, dose imaging, gas scintillation

A different concept for Gas Proportional Scintillation Counter: the annular anode. (#838)

P. A. Silva1, L. M. Fernandes1, C. M. Monteiro1

1 University of Coimbra, LIBPhys, Department of Physics, Coimbra, Portugal


Gas Proportional Scintillation Counters (GPSC) exploit the photon emission from the de-excitation of noble gas atoms as a detection mechanism. The size of the detector radiation window relative to the photosensor active area has always been a limitation in this type of detectors, since the amount of light collected by the photosensor may vary according to the axial distance of the incident x-ray interaction due to solid angle effects. An annular geometry for the detector anode defines a scintillation region for which the solid angle subtended by the photosensor remains constant, independent from the radiation interaction position, thus enabling to obtain a GPSC design with a large radiation window. Along with this advantage , the simplicity and robustness of this novel geometry could provide a step forward into the design of a portable GPSC, coupled to low power electronics, e.g. using SiPM or Large Area APDs instead of PMTs. We report on the simulation studies of the electric field in the detector volume for several parameters, like anode diameter, shape and applied voltage in order to maximize the annular anode GPSC detection efficiency. Simulation results also show the expected scintillation yield and energy resolution for 5.9 keV x-rays. Preliminary experimental studies for 5.9 keV x-rays are presented for an annular anode GPSC with a radiation window area of 50 cm2 and a photosensor sensitive area of 18 cm2. This type of portable, room-temperature detector, with large-detection-area and/ large-detection-volume can be an interesting choice for x-ray astronomy, competing with solid-state detectors.

Keywords: GPSC, Gas detectors, xenon, Scintillation, X-ray detectors

Improving spatial resolution in neutron detectors through signal coincidence ofthe nuclear capture (#884)

N. V. Duarte1, J. S. Marcos1, F. D. Amaro1

1 University of Coimbra, LIBPhys, Coimbra, Portugal


This work presents the simulation results of a novel detection technique that aims to improve the intrinsic spatial resolution of gaseous neutron detectors with solid boron converters, by simultaneously detecting both reaction products emitted in opposite directions in the B-10 neutron capture reaction. This is achieved by using a thin boron coating on a thin substrate, allowing for both particles to escape the solid detection layer and deposit their energy in opposite sides of the surrounding gas, where independent readout systems track their trajectory. The simulation results here presented show that by crossing the information of both detected signals there is potential to improve intrinsic spatial resolution (FWHM) by a factor of approximately 8 when comparing to conventional boron gaseous detectors.

Keywords: neutron detectors, B-10 detectors, 3He replacement

Studies on Primary Scintillation Emission in Xenon (#1228)

C. M. B. Monteiro1, J. M. R. Teixeira1, P. A. O. C. Silva1, R. D. P. Mano1, D. González-Díaz2, C. A. O. Henriques1

1 University of Coimbra, Department of Physics/LIBPhys-UC, Coimbra, Portugal
2 Univ. de Santiago de Compostela, Instituto Gallego de Física de Altas Energías, Santiago de Compostela, Spain


Xenon scintillation has been extensively used in recent particle physics experiments. However, information on primary scintillation yield is still scarce and dispersed. The mean energy required to produce a VUV scintillation photon (Wsc) in gaseous xenon has been measured in the range of 30-120 eV. Lower Wsc-values are often reported for alpha particles compared to electrons produced by gamma or x-rays, being this difference still not fully understood.

We carried out a systematic study on the absolute primary scintillation yield in xenon at 1.2 bar, using a Gas Proportional Scintillation Counter. A simulation model of the detector's geometric efficiency was benchmarked through the primary and secondary scintillation produced at different distances from the photosensor. Wsc-values were obtained for gamma- and x-rays with energies in the range from 5.9-60 keV and for 2-MeV alpha particles. No significant differences were found between alpha particles and electrons.
AcknowledgmentThis work is funded by FEDER, through the Programa Operacional Factores de Competitividade — COMPETE and by National funds through FCT - Fundação para a Ciência e Tecnologia, Lisbon, Portugal, in the frame of project UID/FIS/04559/2020 (LIBPhys).
Keywords: Gaseous detectors, X-ray detectors, Primary scintillation, Xenon

Development and Commissioning of the BμNID: an Event-Type Micropattern Gas Detector with 10B Converter for Energy-Resolved Neutron Imaging at J-PARC (#1381)

J. D. Parker1, H. Hayashida1, Y. Matsumoto1, T. Shinohara2, T. Kai2, T. Tanimori3

1 Comprehensive Research Organization for Science and Society (CROSS), Research and Development Division, Tokai, Japan
2 Japan Atomic Energy Agency, J-PARC Center, Tokai, Japan
3 Kyoto University, Department of Physics, Kyoto, Japan


Energy-resolved neutron imaging at a high-intensity, pulsed spallation neutron source requires a detector with good spatial and time resolutions and high count-rate capability. To better meet these needs, the BμNID (a micropixel-chamber-based neutron imaging detector with 10B converter) has been developed at the RADEN instrument at J-PARC. The BμNID, built on our standard μNID, consists of a gaseous time-projection-chamber employing a μPIC (MicroPIxel Chamber) two-dimensional, 400-μm pitch micropattern strip readout with 10 cm×10 cm area and all-digital, FPGA-based readout electronics. The main physical difference between the μNID and BμNID is the neutron converter, which for the former is 3He gas and a 10B thin-film for the latter. The advantages of the 10B converter are an increased rate performance, along with elimination of 3He, which is of limited supply. Heavier charged secondaries from the 10B converter result in a reduced event size as compared to 3He, with a corresponding increase in the maximum event throughput of the data acquisition system, and the reduced event footprint leads to a smaller chance of overlap at high rates. These two factors provide an improvement in the effective rate performance of up to a factor of 10. Commissioning of the new detector began in June 2020, and it was deployed for user experiments in February 2021. Currently, the BμNID features a spatial resolution of 300μm, 10-ns time resolution, a maximum effective global count-rate of 10 Mcps, and 3∼5% detection efficiency for thermal neutrons. In the present paper, we describe the optimization of the spatial resolution and count-rate performance of the detector carried out during commissioning and plans for improving the detector going forward.

Keywords: micropattern gas detector, boron converter, neutron imaging

TPC Development by the LCTPC Collaboration for the ILD Detector at ILC (#1390)

M. Titov1, H. Qi2

1 CEA Saclay, Irfu, Gif sur Yvette, France
2 IHEP, Beijing, China

on behalf of the LCTPC Collaboration


A large, worldwide community of physicists is working to realise an exceptional physics program of energy-frontier, electron-positron collisions with the International Linear Collider (ILC). The International Large Detector (ILD) is one of the proposed detector concepts at the ILC. The ILD tracking system consists of a Si vertex detector, forward tracking disks and a large volume Time Projection Chamber (TPC) embedded in a 3.5 T solenoidal field. The TPC is designed to provide 220 three dimensional points for continuous tracking with a single-hit resolution better than 100 μm in rφ, and about 1 mm in z. An extensive research and development program for a TPC has been carried out within the framework of the LCTPC collaboration. A Large Prototype TPC in a 1 T magnetic field, which allows to accommodate up to seven identical Micropattern Gaseous Detector (MPGD) readout modules of the near-final proposed design for ILD, has been built as a demonstrator at the 5 GeV electron test-beam at DESY. Three MPGD concepts are being developed for the TPC: Gas Electron Multiplier, Micromegas and GridPix. Successful test beam campaigns with different technologies have been carried out. Fundamental parameters such as transverse and longitudinal spatial resolution and drift velocity have been measured. In parallel, a new gating device based on large-aperture GEMs have been produced and studied in the laboratory. In this talk, we will review the track reconstruction performance results and summarize the next steps towards the TPC construction for the ILD detector.

Keywords: LCTPC

Development of Novel Designs of Resistive Plate Chambers (#1440)

B. Bilki1, 2, Y. Onel2, J. Repond2, K. K. Sahbaz1, 3, M. Tosun1, 3, L. Xia4

1 Beykent University, Istanbul, Turkey
2 University of Iowa, Iowa City, Iowa, United States of America
3 Ankara University, Ankara, Turkey
4 Argonne National Laboratory, Argonne, Illinois, United States of America

On behalf of the CALICE Collaboration


Resistive Plate Chambers (RPCs) exhibit a significant loss of efficiency for the detection of particles, when subjected to high particle fluxes. This rate limitation is related to the usually high resistivity of the resistive plates used in their construction. A novel design of RPCs, using only a single resistive plate, was developed and tested with prototype chambers of size ranging from 10 cm x 10 cm to 32 cm x 48 cm. The cosmic and beam tests confirmed the viability of this new approach for calorimetric applications where the particle rates do not exceed 1 kHz/cm2, such as CALICE digital calorimeters. The single-particle response of the chambers is also improved yielding pad multiplicities close to unity. In parallel to the development of the one-glass chambers, the effort on the development of semi-conductive glass and search for alternative lower-resistivity plates is ongoing. In addition to the development of high-rate capability solutions, we probed a new technique to mitigate the performance limitations of the projected alternative RPC gas mixtures.

Here we report on the construction of various different RPC designs, and their performance measurements in laboratory tests and with particle beams.

Keywords: resistive plate chambers, semi-conductive glass, secondary electron multiplication

Magnetic field imaging by cosmic-ray muons (Magic-µ) (#249)

T. Kin1, H. Basiri1, E. C. Gil2, A. Giammanco2

1 Kyushu University, Interdisciplinary Graduate School of Engineering Science, Kasuga, Japan
2 Université catholique de Louvain, Particle Physics and Phenomenology, Louvain-la-Neuve, Belgium


Cosmic-ray muon radiography, also called muography, consists of two techniques: absorption and scattering methods. Alvarez proposed the absorption method in 1970 to survey hidden chambers in pyramids. The method has been applied to various targets to inspect their density distribution or inner structure. Since Borozdin invented the scattering method in 2003, the muography approach can also identify nuclides, especially heavy ones such as uranium or plutonium. This study proposes a new approach, which aims at measuring magnetic fields. We call the project, Magic-µ, which is short for MAGnetic field Imaging by Cosmic-ray MUons. When passing through a magnetic field, charged particles are deflected and change their trajectories without losing kinetic energies. The charge of the muons, positive or negative, determines in which direction the trajectory is shifted. Given a magnetic flux density and a trajectory length in the magnetic field, i.e., we can uniquely determine the magnetic flux density along the trajectory for a specific trajectory shift. We have proposed a muography system with sensitivity to magnetic fields and developed data analysis methods to estimate a 3-dimensional magnetic flux density. In the present paper, we will treat the outline of the Magic-µ project and prospect.

Keywords: cosmic-ray muon, muon radiography, muography, magnetic field imaging

A new high voltage feedthrough concept for future liquid noble gas detectors (#1100)

E. Pantic1, L. Pagani1, H. Wang2, Y. Wang2, X. Xiao2

1 University of California Davis, Physics and Astronomy, Davis, California, United States of America
2 University of California Los Angeles, Physics, Los Angeles, California, United States of America


Physics experiments featuring liquid noble gas time projection chambers are becoming larger in scale, and consequently so have their high voltage requirements, making conventional design of high voltage feedthrough impracticable. A new concept for a high voltage feedthrough usable in cryogenic environment is proposed, which relies on the ability to fabricate a plastic material with tunable thickness and resistivity. The status of the R&D will be presented.

AcknowledgmentThis work is supported by NSF Grants  PHY-1622345, PHY-1622337, PHY-1812492 and PHY-1812547.
Keywords: Dielectrics, Cable Insulation, noble gas

Dynamic Electro-Thermal Feedback for Superconducting Transition Edge Sensor (#1305)

Y. Mitsuya1, H. Takahashi1

1 The University of Tokyo, Institute of Engineering Innovation, School of Engineering, Tokyo, Japan


In this study, we propose a new biasing scheme for superconducting transition edge sensor (TES). Conventionally, TESs have been operated under constant voltage bias, and this operating condition is called electro-thermal feedback (ETF). We propose a new ETF scheme, which dynamically changes the bias voltage accordingly with the pulse signal from the TES. This dynamic ETF scheme achieves faster pulse decay time and amplification of pulse height. We conducted numerical simulations and compared the dynamic ETF scheme with conventional static ETF.

Keywords: Superconducting detector, Transition Edge Sensor

Verification of the applicability of water Cherenkov detector to active neutron method and development of a prototype detector (#127)

K. Tanabe1, 2, M. Komeda3, Y. Toh3, Y. Kitamura4, T. Misawa4, H. Sagara2

1 National Research Institute of Police Science, Kashiwa, Japan
2 Tokyo Institute of Technology, Meguro, Japan
3 Japan Atomic Energy Agency, Tokai, Japan
4 Kyoto University, Kyoto, Japan


In the fields of nuclear security, a compact and low-cost non-destructive assay system to detect hidden nuclear material is required. Because the conventional active neutron method adopts an accelerator neutron source and 3He detectors, existing instruments are expensive and poorly portable. To solve this problem, we have developed an innovative nuclear material detection method using a 252Cf source, which is called the rotation method. In this study, we developed a water Cherenkov detector as a novel low-cost neutron detector to replace 3He detectors. The applicability of the water Cherenkov detector to the rotation method was validated using simulation. Subsequently, a prototype detector was subjected to a demonstration experiment, combined with the rotation device. As a result, the fission neutrons from nuclear material were measured by using pulse height discrimination. Our study shows a potential of the water Cherenkov detector as a neutron detector for the rotation method.


This work was supported by JSPS KAKENHI Grant Numbers JP20K15213. The experiments were carried out at the Institute for Integrated Radiation and Nuclear Science, Kyoto University (KURNS).

Keywords: Cherenkov, NDA, Neutron detector, Nuclear non-proliferation, Nuclear security

Polystyrene based neutron-gamma detector for radiation portal monitors (#511)

A. Kolesnikov1, A. Boyaryntsev1, P. Zhmurin1

1 Institute for Scintillation Materials, Kharkov, Ukraine


Radiation portal monitors are used for separate registration of gamma quanta and neutron radiation. Traditionally, two registration channels are used. Scintillation detector for detecting gamma quanta and helium-3 detector in the neutron channel. At the same time, the search for alternative detectors continues. Plastic scintillators are promising materials for solving such problems. Certain difficulties are due to the fact that plastic scintillators are sensitive to both neutrons and gamma. The paper presents some technical solutions aimed at achieving a reliable separation of neutron and gamma events. Proposed registration system approaching the requirements of the standards for radiation portal monitors. Registration efficiency up to 40% with an error rate of less than 1/10000 is achieved.

Keywords: Radiation Portal Monitors, mixed neutron gamma field, Security

Developing Delayed Gamma-ray Spectroscopy for Reprocessing Plant Nuclear Safeguards: Neutron Detection System Development (#663)

H. - J. Lee1, D. C. Rodriguez1, F. Rossi1, M. Koizumi1, T. Takahashi1

1 Japan Atomic Energy Agency, Integrated Support Center for Nuclear Nonproliferation and Nuclear Security, Tokai-mura, Japan


The Integrated Support Center for Nuclear Nonproliferation and Nuclear Security of the Japan Atomic Energy Agency is developing Delayed Gamma-ray Spectroscopy (DGS). The DGS instrument irradiates a sample with neutrons to induce fission and then observes gamma rays emitted during the radioactive decay of the fission products. Since DGS uses neutron sources, it is important to monitor these to both confirm the source consistency and normalize delayed gamma-ray spectra. In addition, prompt-fission and delayed neutron signatures can be used to verify the DGS analysis. To do this, 3He and 4He neutron detectors have been investigated. Since the DGS instrument must be compact, the neutron detectors will be close to the neutron sources and fissionable samples within the instrument. Consequently, several characterization studies were performed for short source-detector distances. This paper will describe experimental results with associated simulations, in light of how the neutron detection systems will be integrated into the DGS instrument.

AcknowledgmentThis work is supported by the Japan Ministry of Education, Culture, Sports, Science, and Technology subsidy for promoting nuclear security related activities.
Keywords: Delayed gamma rays, Neutron detection systems, 3He neutron detector, 4He neutron detector

Development of Radiation Source Identification Device based on 4π Gamma Imaging with LiDAR-SLAM (#747)

A. Mukai1, K. Yamagishi1, S. Hara1, R. Terabayashi2, K. Shimazoe3, Y. Tamura4, H. Woo5, T. Kishimoto5, H. Kogami5, Z. Zhihong3, M. Uenomachi6, A. Nurrachman3, H. Takahashi3, H. Asama5, F. Ishida7, H. Ebi1, E. Takada7, J. Kawarabayashi8, K. Tanabe9, K. Kamada10, H. Tomita1

1 Nagoya University, Department of Energy Engineering, Nagoya-shi, Japan
2 The University of Tokyo, Nuclear Professional School, Tokai-mura, Japan
3 The University of Tokyo, Department of Nuclear Engineering and Management, Bunkyo-ku, Japan
4 Tohoku University, Department of Robotics, Sendai-shi, Japan
5 The University of Tokyo, Department of Precision Engineering, Bunkyo-ku, Japan
6 RIKEN, Nishina Center for Accelerator-Based Science, Wako-shi, Japan
7 National Institute of Technology, Toyama College., Hongo-cho, Japan
8 Tokyo City University, Department of Nuclear Safety Engineering, Setagaya-ku, Japan
9 National Research Institute of Police Science, Kashiwa-shi, Japan
10 Tohoku University, Institute of Engineering Innovation, Aoba-ku, Japan


We are developing a device for radiation source identification based on 4p gamma imaging and Simultaneous Localization and Mapping (SLAM). The proto-type device equipped with a 3D LiDAR, a 4p gamma camera, and a 4p optical camera was mounted in an unmanned vehicle. 4p gamma-ray and optical images were measured during the movement of the device around 137Cs sources in thin barrier boxes. Combined with 4π gamma images and SLAM obtained by LiDAR data, both location and activity of each source were estimated.

AcknowledgmentThis work was supported in part by JSPS KAKENHI: Grant-in-Aid for Scientific Research (A), Grant Number 19H00881.
Keywords: Gamma-ray imaging, Source identification, CdTe detector, SLAM

Full calibration of an optically segmented single-volume scatter camera for neutron imaging (#762)

A. Galindo Tellez1

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

On behalf of the SVSC collaboration


The optically-segmented single-volume scatter camera aims to image neutron sources at a MeV scale. The detector, which corresponds to the first version of prototyping, consists of 64 bars of organic plastic scintillator bars EJ-204 placed in an array of 8 × 8, read out by two SensL J-series SiPM arrays with 6 mm 2 pixels size. Rubber silicon optical material EJ-560 of individual 5 mm × 5 mm × 0.5 mm is utilized as coupling material. The electronics were fully developed at the University of Hawaii, based on the 8-channel IRS3D application-specific integrated circuit, with the full system featuring 128 samples read out at 2.8 GSa/s. Calibrations on time, position and energy resolutions for the full detector are reported, as well as the systematics among outer and inner columns by implementing the muon telescope technique. Work toward full neutron imaging measurements will be reported.

Keywords: Fast neutron imaging, neutron scatter camera, nuclear security applications

X-ray Backscatter Security Inspection with Enhanced Depth of Effective Detection and Material Discrimination (#898)

A. Arodzero1, 2, V. Alreja3, S. Boucher1, P. Burstein4, P. Kulinich1, R. C. Lanza2, V. Palermo5, M. Tran3

1 RadiaBeam Technologies, LLC, Santa Monica, California, United States of America
2 Massachusetts Institute of Technology, Nuclear Science and Engineering, Cambridge, Massachusetts, United States of America
3 VJ Technologies, Inc., Bohemia, New York, United States of America
4 Skiametrics, LLC, Winchester, Massachusetts, United States of America
5 Vertilon Corp., Westford, Massachusetts, United States of America


X-ray imaging techniques based on Compton backscatter allow inspection and screening of a variety of vehicles, cargo containers, luggage, suspicious packages, aircraft and spacecraft components, as well as building walls and floors. Backscatter imaging systems are in wide use by government agencies, border authorities, law enforcement personnel, military organizations, and security services in many countries.
In contrast to commonly used transmission inspection systems, backscatter imaging involves positioning both radiation source and detectors on the same side of a target object. Such systems are exceptionally useful in situations where access to the inspected object is limited to a single side, making X-ray transmission system impractical.

Conventional backscatter inspection systems have a significant limitation in their ability to penetrate even moderately dense objects. Moreover, the signal is dominated by the first interrogated layer, e.g., the metal wall of a container or vehicle, or the front layer of wall. To overcome this fundamental limitation, we develop an advanced inspection technique, DeepBx, which uses energy- and current- modulated X-ray pulses, fast, time-resolving X-ray detectors, and an algorithm of image “peeling” processing.

We will present the results of testing a lab prototype of the DeepBx Imager: detection of prohibited substances hidden in phantoms of various objects and structures. These results will be presented in comparison with conventional backscatter imaging approaches.

Keywords: Homeland Security, X-ray backscatter imaging, Contraband detection, Explosive detection, Non-destractive inspection

Spectral correlations of radiological data with city-scale detector networks (#1076)

M. Salathe1, R. J. Cooper1, D. Hellfeld1, N. Abgrall1, M. S. Bandstra1, T. H. Y. Joshi1, B. J. Quiter1

1 Lawrence Berkeley National Laboratory, Applied Nuclear Physics Program, Berkeley, California, United States of America


City-scale networked detection systems offer the ability to leverage measurements across space and time to achieve a gain in overall radiological source detection performance. Due to the separation of detector nodes on the kilometer scale, it is generally not expected to observe a source in two detectors simultaneously. However, the knowledge of the network layout and supplementary information, such as transition times, can be leveraged to correlated measurements. We discuss and compare methods for data fusion of radiological measurement that are collected in the form of energy spectra on the node level. The expanse of city-scale detector systems requires that correlation are searched across many nodes and long time scales. We show, these factors need to be deliberated when choosing appropriate false positive and false negative probabilities and require careful calibration of thresholds in the individual systems. In line with earlier results based on gross-count analyses, we derive that the result of such a data fusion approach is a gain in sensitivity that scales with the square-root of the numbers of detectors. This limit could be overcome by leveraging detections from one system as a prior or support alternative hypotheses testing in other systems.

AcknowledgmentThis work was performed under the auspices of the U.S. Department of Energy by Lawrence Berkeley National Laboratory (LBNL) under Contract DE-AC02-05CH11231. The project was funded by the U.S. Department of Energy, National Nuclear Security Administration, Office of Defense Nuclear Nonproliferation Research and Development.
Keywords: Networked detection system, Radiation detectors, Statistics

Development of Oxygen Transmutation-based Calibration Sources for a Large Gd-Doped Water Cherenkov Detector (#1104)

K. Ogren1, R. Foster2, S. Fargher2, M. Malek2, S. Dazeley3, I. Jovanovic1

1 University of Michigan, Nuclear Engineering and Radiological Sciences, Ann Arbor, Michigan, United States of America
2 University of Sheffield, Department of Physics and Astronomy, Sheffield, United Kingdom
3 Lawrence Livermore National Laboratory, Livermore, California, United States of America


Large antineutrino detectors are a promising technology for remote nuclear reactor monitoring and discovery, which is of great interest for nonproliferation and treaty verification applications. One prominent detector design, now under consideration by the WATCHMAN scientific collaboration, relies on a multi-kiloton tank of gadolinium-doped water to detect inverse beta-decay (IBD) events caused by antineutrino interactions. Time-taggable calibration sources are especially useful for large-volume IBD detectors, as the coincidence timing information improves the fidelity of event reconstruction from the detector response and increases the efficiency of  background suppression. One such calibration source is 16N, which emits a beta-correlated gamma-ray with energy of 6.1 MeV, conveniently located near the high-energy range of the gamma-ray cascade produced by neutron captures on gadolinium. 17N is another potentially interesting calibration source, as it emits beta-correlated delayed neutrons. Because both 16N and 17N have half-lives of just a few seconds, their populations must be constantly replenished. Current designs for source delivery involve production of 16N by irradiating CO2 gas with 14.1 MeV neutrons from a DT generator; the gas then flows to a small decay chamber inside the detector volume. 17N can be produced using the same mechanism by simply substituting CO2 gas enriched in 17O, which allows the same mechanical transfer system to be leveraged for two distinct calibration sources. We present an initial demonstration of the production of 16N and 17N using a DT generator neutron source, as well as the design, construction, and initial tests of a specialized beta-tagging detector for conducting time-correlated measurements of 16N and 17N. We also report on exploration of 241Am13C as a potential alternative source of neutrons and 6.1 MeV gamma-rays.

Keywords: delayed neutrons, antineutrino detectors

Measurement Protocol Optimization using Machine Learning for Radiation Source Identification based on 4π Gamma Imaging (#1159)

S. Hara1, H. Tomita1, A. Mukai1, K. Yamagishi1, H. Ebi1, R. Terabayashi2, K. Shimazoe3, A. Nurrachman3, Z. Zhihong3, H. Takahashi3, M. Uenomachi4, H. Woo5, T. Kishimoto5, H. Kogami5, H. Asama5, Y. Tamura6, F. Ishida7, E. Takada7, J. Kawarabayashi8, K. Tanabe9, K. Kamada10

1 Nagoya University, The department of Energy Engineering, Chikusa-Ku, Japan
2 The University of Tokyo, The Nuclear Professional School, Tokai-Mura, Japan
3 The University of Tokyo, The Department of Nuclear Engineering and Management, Bunkyo-Ku, Japan
4 RIKEN, Nishina Center for Accelerator-Based Science, Wako,, Japan
5 The University of Tokyo, The Department of Precision Engineering, Bunkyo-Ku, Japan
6 Tohoku University, The Department of Robotics, Aoba-Ku, Japan
7 Toyama College, The National Institute of Technology, Toyama-Shi, Japan
8 Tokyo City University, The Department of Nuclear Safety Engineering, Setagaya-Ku, Japan
9 Police Science, The National Research Institute, Kashiwa-Shi, Japan
10 Tohoku University, The Institute of Engineering Innovation, Aoba-Ku, Japan


We are developing a method to identify radiation sources based on 4π gamma imaging. For more accurate identification, optimization of measurement protocol, i.e. selection of measurement points around target sources, should be optimized. We investigated the optimum measurement protocol using a simple computational model of a 4π gamma imager. Based on evaluation of several procedures of detector movement by a decision tree analysis, we decided on an algorithm of the detector movement. According to the proposed algorithm, two 137Cs point sources were identified using a multi-pixel CdTe detector mounted on an unmanned vehicle as a prototype 4π gamma imager.


This work was supported in part by JSPS KAKENHI: Grant-in-Aid for Scientific Research (A), Grant Number 19H00881.

Keywords: Gamma-ray imaging, Source identification, Machine learning

Reconstructing the Atomic Number and Area Density of Dual Energy X-ray Images (#1192)

P. Lalor1

1 Massachusetts Institute of Technology, Nuclear Science and Engineering, Cambridge, Massachusetts, United States of America


Since the 9/11 Commission Act of 2007, the United States has been pursuing significant efforts to screen 100 percent of cargo entering the U.S. borders. One avenue through which this is addressed is the use of radiography systems, which scan cargo for large, dense objects, such as nuclear material that has been heavily shielded to avoid detection through passive radiation portal monitors. A unique aspect of certain radiography systems is their dual energy capabilities, which could allow for a rough elemental analysis of the cargo contents since the attenuation of X-rays is sensitive to the atomic number of the material. This work investigates the capabilities and limitations of current dual energy X-ray scanners to discriminate between high-Z materials and ordinary cargo. Furthermore, this work proposes a method for approximating both the atomic number and area density of the contents of dual energy X-ray images. This is done using an exponential attenuation to determine the material type and thickness that best reproduces the measured transmission values. Regularization is also explored as a means to reduce the statistical fluctuations of the reconstructed result by improving the conditioning of the inversion. The conclusions of this study will offer insight into the ability for dual energy radiography systems to detect smuggled high-Z nuclear materials and shielding. These results can have a major impact on the current transportation security policies as well as provide a quantifiable basis for recommendations of future research and development in cargo security.

Keywords: Dual Energy Radiography, Nuclear Security

A low-power CLYC-based spectrometer for in-situ radioactivity measurements of mixed neutron-gamma field (#62)

K. Zhao1, 2, C. Feng1, 2, P. Lin3, Z. Wang1, 2, Y. Huang1, 2, K. Chang3, W. Xie3, C. Shan3, S. Liu1, 2

1 University of Science and Technology of China, State Key Laboratory of Particle Detection and Electronics, Hefei, China
2 University of Science and Technology of China, Department of Modern Physics, Hefei, China
3 China Nuclear Power Technology Research Institute Co.Ltd., Shenzhen, China


This paper proposes a low-power spectrometer based on Cs2LiYCl6: Ce(CLYC) scintillator, which aims to measure the mixed neutron and gamma field for outdoor applications. The instrument is 280 mm high and 120 mm in diameter, containing a ø 25.4 mm × 25.4 mm CLYC coupled to a PMT. In addition, the device integrates a signal conditioning module, a tailor-made readout module with real-time pulse shape recognition (PSD) function in the Flash-based FPGA, and a high-voltage supply unit. Through a multi-core cable, an external PC can obtain data from the FPGA. In this paper, we recapitulate the characterization results from this spectrometer. At 662keV of  137Cs, the energy resolution is about 4.8% with good linearity. The obtained gamma rejection ratio (GRR) is about 2.6×10-5 and the PSD figure of merit (FOM) value is 2.42 (with Am-Be neutron source). The total power of this device is 3.6W. With a coated aluminum alloy and sealed connector, a rainproof shell is designed to achieve an IP66 protection grade. A reliable RS485 Modbus protocol is used for data transmission, which can ensure the stable operation of the spectrometer in harsh environments.

AcknowledgmentThe authors would like to thank Lijun Diao and Yina Liu for their  help of testing with radioactive sources in the China Institute of Atomic Energy.
Keywords: spectrometer, CLYC, PSD, nuclear safety, low-power

The DIRC Detector for the Future Electron Ion Collider Experimen (#648)

G. Kalicy1

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


The next frontier project of nuclear physics in the United States will be the Electron-Ion Collider (EIC), planned to be built in the Brookhaven National Laboratory (BNL). Excellent particle identification (PID) is one of the key requirements for the EIC central detector. Identification of the hadrons in the final state is critical to study how different quark flavours contribute to nucleon properties. A detector using the Detection of Internally Reflected Cherenkov light (DIRC) principle, with a radial size of only 7-8 cm, is a very attractive solution for those requirements. The R&D program performed by the EIC PID collaboration (eRD14) is focused on developing a high-performance DIRC (hpDIRC) detector that would extend the momentum coverage well beyond the state-of-the-art 3 standard deviations or more separation of π/K up to 6 GeV/c, and contribute to low momentum e/π separation. Key components of the hpDIRC detector are a 3-layer compound lens and small pixel-size photo-sensors. This contribution will present major developments in the DIRC R&D program, with a focus on developing and validating the radiation-hard 3-layer lens, and an early stage of the hpDIRC prototype program in the Cosmic Ray Telescope at the Stony Brook University.

Keywords: PID, Cherenkov, Detector, DIRC, RICH

The End-of-Substructure card for the ATLAS ITk Strip Detector: Status of the electronics design and results from recent quality tests (#806)

R. Stroem1, A. Boebel1, H. Ceslik1, H. Colbow1, M. Dam2, S. Diez1, I. M. Gregor1, P. Goettlicher1, J. M. Keaveney3, J. N. Naidoo3, J. Oechsle2, S. Schmitt1, M. N. van der Merwe3, M. Stanitzki1, C. Wanotayaroj1, J. Wyngaard3

1 DESY, Hamburg, Hamburg, Germany
2 Niels Bohr Institute, Copenhagen, Denmark
3 University of Cape Town, Cape Town, South Africa


The silicon tracker of the ATLAS experiment will be upgraded for the upcoming High-Luminosity Upgrade of the LHC (HL-LHC). The main building blocks of the new strip tracker are modules that consist of silicon sensors and read-out ASICs, the latter hosted on hybrid PCBs. Up to 14 modules are assembled on carbon-fibre substructures, commonly named staves in the central barrel region and petals in the two end-cap regions, for mechanical support. An End-of-Substructure (EoS) card is located at the end of each substructure and facilitates the transfer of data, power, and control signals between the modules and the off-detector systems. The module front-end ASICs transfer data (up to 28 differential lines at 640 Mbit/s) to low-powered GigaBit Transceivers (lpGBT) ASICs on the EoS card. The lpGBT(s) provide data serialisation and uses 10 GBit/s versatile optical link (VL+) to transmit signals to the off-detector systems. To meet the tight integration requirements in the detector, several EoS card designs have been realised. The produced prototypes have been populated with the currently available versions of the lpGBT and VL+ ASICs. Here, we present the current status of the EoS card’s electronic design, results from extreme temperature and magnetic field tests, preliminary results from error rate tests in the presence of neutron radiation to test for susceptibility to single-event-upsets and detailed studies of the optical signal quality. We will also present the first results from full integration tests and briefly discuss the EoS card Quality Control (QC) procedure which aims to ensure that the EoS cards are up to specification and will stay fully-functional throughout the entire HL-LHC operation.

Keywords: ATLAS experiment, High-Luminosity Upgrade, LHC, Readout electronics, Strip tracker

A New Instrument for Measuring Nuclear Fission Induced Correlated Signatures (#1141)

S. Dazeley1, N. Bowden1, V. Mozin1, T. Stiegler1

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


Correlations between neutron multiplicity, neutron and gamma-ray energies and angular distributions are not fully understood. To address this, neutron and gamma-ray signatures need to be measured with high efficiency and angular and energy fidelity to constrain the models further. With the recent development of liter-scale volumes of 6Li-doped pulse shape discriminating (PSD) plastic scintillator, consideration should be given to new more flexible neutron multiplicity detector designs. Our group is testing one such scalable design. The full-scale detector consists of an array of 5x5cm cross-section bars of 6Li-doped PSD plastic scintillator 0.5-1.0m long with reflective wrapping and photodetectors placed at either end. The first iteration of this design consists of a set of two such modules. Each bar/module will be sensitive to both fast and thermal neutrons, and capable of position resolution at the 5-10cm level. The modules, containing no liquid scintillator, will be rugged and easily movable and reconfigurable in any arrangement around a hypothetical fission test source. For example, the modules may be placed adjacent to a source to optimize detection efficiency, or further away to optimize for time-of-flight and angular fidelity. The modules may be mixed and matched with gamma-ray detectors or other types of neutron detector if desired. The measurement capabilities and flexibility of this approach will be complementary with existing systems. Since the modules will be ruggedized, the whole system or parts thereof may be shipped to and incorporated into other already established systems if simulations show that it the modules will enhance the capabilities of the fully integrated system. The speaker will summarize the status of the system and our plans for scaling in the future.


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-822112

Keywords: fission data, neutron multiplicity detector, correlations

WERPAD: a CdTe pixel detector for wide energy range X-ray diffractions (#141)

H. Toyokawa1, C. Saji1, A. Shiro2, T. Shobu3, K. Suzuki4

1 Japan Synchrotron Radiation Research Institute, Hyogo, Japan
2 National Institutes for Quantum and Radiological Science and Technology, Hyogo, Japan
3 Japan Atomic Energy Agency, Hyogo, Japan
4 Niigata University, Niigata, Japan


The synchrotron radiation facility provides monochromatic X-rays but the beams have higher harmonics contamination. We proposed multi-energy X-ray diffractions using the primary and higher harmonics beams. This method could acquire larger Q information with the same exposure time of monochromatic beam measurement. Furthermore, the white X-ray Laue diffraction could determine the lattice spacing by measuring the angle and energy of diffraction patterns. According to this concept, we developed a Wide Energy Range Pixel Array Detector (WERPAD) combined with a CdTe sensor and photon-counting ASICs.

Keywords: Synchrotron radiation, Pixel detector, cadmium telluride

A Fast Diagnosis Tool for Tracking and Estimating sub-keV energy Electron Clouds (#1342)

B. Rotter1, I. Mostafanezhad1, E. Muller2, J. Bohon3, J. Smedley3

1 Nalu Scientific, LLC, Honolulu, Hawaii, United States of America
2 Brookhaven National Lab, Upton, New York, United States of America
3 Los Alamos National Lab, Los Alamos, New Mexico, United States of America


In this report we describe measurements taken of the current amplification effect of a diamond strip detector in a scanning electron microscope (SEM) in support of a proposed detector for the measurement and characterization of the electron cloud that accompanies accelerated particle bunches both spatially and temporally by utilizing diamond strip detectors read out by system-on-chip (SoC) high speed waveform digitizers developed by Nalu Scientific LLC (NSL).  The theory, detection methodology, and planned instrumentation will be discussed, as well as initial measurements.


This work is partially funded under U.S. DOE DE-SC0020458 grant.

Keywords: Electron Cloud Monitor, High speed digitizer, Diamond Strip Detector, beam diagnostics

Single Event Tolerance of X-ray SOI Pixel Sensors (#171)

K. Hagino1, M. Hayashida1, T. Kohmura1, T. Doi1, S. Tsunomachi1, A. Fujimori1, K. Maekawa1, M. Kitajima1, T. G. Tsuru2, H. Uchida2, K. Kayama2, R. Kodama2, K. Mori3, A. Takeda3, Y. Nishioka3, M. Yukumoto3, K. Mieda3, S. Yonemura3, T. Ishida3, T. Tanaka4, Y. Arai5, I. Kurachi6, H. Kitamura7, S. Kawahito8, K. Yasutomi8, M. Ueno9, M. Ozaki9, H. Nakajima10

1 Tokyo University of Science, Noda, Japan
2 Kyoto University, Kyoto, Japan
3 University of Miyazaki, Miyazaki, Japan
4 Konan University, Kobe, Japan
5 KEK, Tsukuba, Japan
6 D & S Inc., Tokyo, Japan
7 QST, Chiba, Japan
8 Shizuoka University, Hamamatsu, Japan
9 JAXA, Sagamihara, Japan
10 Kanto Gakuin University, Yokohama, Japan


We have been developing the X-ray SOI pixel sensor named “XRPIX” for the future X-ray astronomical satellite, FORCE. XRPIX is a monolithic active pixel sensor composed of a high-resistivity Si sensor, thin SiO2 insulator, and CMOS pixel circuits by utilizing the silicon-on-insulator (SOI) technology. Since XRPIX is capable of event-driven readout, it can achieve a high timing resolution better than ∼10 μs, which enables an extremely low background observation by adopting the anti-coincidence technique. The tolerance to single event upset (SEU) should be considered in the development of the CMOS integrated circuits for space use. Although the SOI-CMOS used in XRPIX is expected to be less sensitive to the SEU, it is necessary to measure the SEU cross-section, and quantitatively evaluate the SEU tolerance of XRPIX. In this work, we measure the cross-section of SEU of the shift register on XRPIX by irradiating heavy ion beams with linear energy transfer (LET) ranging from 0.0220 MeV/(mg/cm2) to 66.5 MeV/(mg/cm2). From the SEU cross-section curve, the saturation cross-section and threshold LET are successfully obtained to be 7.9−3.9+1.6 MeV/(mg/cm2 ) and 3.4−0.8+2.5 × 10−10 cm2/bit, respectively. Using these values, the SEU rate in orbit is estimated to be ∼0.03 event/year primarily due to the secondary particles induced by cosmic-ray protons. This SEU rate of the shift register on XRPIX is negligible in the FORCE orbit.

Keywords: single event effect, silicon-on-insulator technology, SOI pixel sensor, X-ray astronomy

STRATOSPOLCA: STRATOSpheric POLarimetry with Cadmium telluride Array (#395)

H. Neves1, 2, R. M. Curado da Silva1, 2, P. Afonso3, N. Auricchio4, E. Caroli4, I. Carmo5, M. I. Ferreira2, R. Gameiro6, J. Gonçalves7, A. Lemos7, J. M. Maia8, 1, D. Marques7, B. Matos2, A. Mendonça2, M. Moita9, D. Monteiro5, 1, A. Neves2, M. Neves2, A. Oliveira10, I. Oliveira2, J. Pereira2, P. Póvoa7, S. Rodrigues11, R. Roque2, J. Silva7, J. Silveirinha1, M. Simões2, G. Smith3, J. Sousa2, D. Torres7

1 LIP - Laboratório de Instrumentação e Física Experimental de Partículas, Coimbra, Portugal
2 University of Coimbra, Department of Physics, Coimbra, Portugal
3 American River College, Physics and Astronomy Dept, Sacramento, California, United States of America
4 INAF/OAS, Sezione di Bologna, Bologna, Italy
5 University of Coimbra, Department of Mechanical Engineering, Coimbra, Portugal
6 University of Coimbra, Department of Chemical Engineering, Coimbra, Portugal
7 University of Coimbra, Department of Electrical and Computer Engineering, Coimbra, Portugal
8 Universidade da Beira Interior, Department of Physics, Covilhã, Portugal
9 University of Ferrara, Dept. of Physics and Earth Science, Ferrara, Italy
10 Universidade de Aveiro, Departamento de Eletrónica, Telecomunicações e Informática, Aveiro, Portugal
11 University of Coimbra, Faculty of Medicine, Coimbra, Portugal


In the multi-messenger era, gamma-ray polarimetry may contribute to a wider understanding of gamma-ray transients associated to gravitational waves detection. Furthermore, high-energy polametry allows a deep understanding of the physical processes, geometry and magnetic fields of sources such as pulsars, solar flares, active galactic nuclei or galactic black holes.  However, the noise rate in the Compton regime polarimetry domain (~100 keV up to ~1 MeV) is higher than the source signal by one or two orders of magnitude, at balloon and orbital altitude. Herein, we will present the STRATOSPOLCA (STRATOSpheric POLarimetry with Cadmium telluride Array) experiment to be launched in the 31 ESA Bexus flight by October 2020 to address and analyse the mentioned signal-to-noise issue in the perspective of Compton polarimetry. The STRATOSPOLCA instrument is based on a small CdTe 5×5 pixels (each 2×2×10 mm3) prototype accommodated in the balloon gondola that will record the stratospheric gamma-ray background discriminating between single, double and multiple events during (~3 hours) the flight up to a maximal altitude of ~28 km. Results will be presented and discussed.

Keywords: gamma-rays, polarimetry, radiation detectors, high-altitude ballons, CdTe

Readout and Track Reconstruction for the NASA-UNH SONTRAC Instrument (#872)

G. Suarez1, G. A. De Nolfo1, A. Bruno1, M. C. Daehn1, J. J. Du Monthier1, I. Liceaga-Indart1, J. T. Link1, J. Legere2, R. Messner2, J. G. Mitchell1, J. Ryan2, T. Tatoli1

1 NASA Goddard Space Flight Center, Greenbelt, Maryland, United States of America
2 University of New Hampshire, Durham, New Hampshire, United States of America


The second-generation SONTRAC instrument is being developed by UNH and NASA to detect solar neutrons for understanding particle acceleration at the Sun. The SONTRAC scintillator consists of orthogonally stacked scintillating fibers read out by silicon photomultipliers to detect and track the recoil protons from double scatter neutron events in the 20-200 MeV range. The new instrument targets small satellites with highly constrained size, mass, and  power; bringing a new set of challenges to the design of the instrument electronics. We present an update to the readout system, algorithms for track  reconstruction, and tracking performance in a laboratory environment.

Keywords: Neutron imaging, Neutron tracking, Neutron spectrometer, Track reconstruction

Performance Characteristics of the NRL2 Front-end ASIC with High-Purity Germanium Strip Detectors (#1103)

J. M. Roberts1, 2, S. Boggs1, 2, G. De Geronimo4, A. Lowell2, B. Mochizuki2, J. Tomsick2, C. Sleator3, E. A. Wulf3

1 Center for Astrophysics and Space Sciences, University of California, San Diego, California, United States of America
2 Space Sciences Laboratory, University of California, Berkeley, California, United States of America
3 Naval Research Laboratory, Washington, D.C., United States of America
4 Stony Brook University, Stony Brook, New York, United States of America


Gamma-ray physics and astrophysics is now a mature science that is driving significant development in detector technologies and mixed-signal processing. As the science requirements push for higher channel density while maintaining low-power, low-noise, front-end electronics, the use of application-specific integrated circuits (ASICs) is becoming increasingly necessary in order to meet the performance demands of next-generation instruments. The NRL2 (Naval Research Laboratory 2) is a recently developed 32-channel front-end ASIC that features low-power, low-noise charge preamplification with 4 configurable gain settings, dual fixed fast and configurable slow shapers per channel for optimized timing and energy resolution, trimmable per-channel discrimination, time-to-analog conversion, and peak detect output. The NRL2 has been instrumented with a high-purity germanium (HPGe) dual-sided strip detector with 0.5 mm strip pitch. We report energy resolution capabilities of 2.4 keV FWHM at 59.54 keV with a gain setting of 18.4 mV/fC and a peaking time of 2 us and discuss preliminary results of our currently ongoing research.

AcknowledgmentThis work was sponsored by NASA (United States)NNH18ZDA001N APRA and NASA Explorer’s contract80GSFC21C0059.
Keywords: Application-Specific Integrated Circuit (ASIC), Gamma-Ray, High-Purity Germanium Detector (HPGe), Mixed-Signal, Compton

Ageing of Ge/Si and CZT samples for sensors and Laue lenses of future gamma-ray astrophysics telescopes (#1398)

R. M. Curado da Silva1, 2, M. Bettelli3, E. Caroli4, C. Ferrari3, L. Ferro5, J. M. Maia6, 1, M. Moita5, E. Virgilli4, A. Zappettini3

1 LIP - Laboratório de Instrumentação e Física Experimental de Partículas, Coimbra, Portugal
2 University of Coimbra, Department of Physics, Coimbra, Portugal
3 CNR, IMEM- Institute of Materials for Electronics and Magnetism Parma, Parma, Italy
4 INAF/OAS, Sezione Bologna, Bologna, Italy
5 University of Ferrara, Dept. of Physics and Earth Science, Ferrara, Italy
6 University of Beira-Interior, Department of Physics, Covilhã, Portugal


The analysis of LEO environment effects on the detection medium materials and/or focusing lens of future gamma-ray telescopes is crucial to design a high-energy astrophysics’ space mission. Herein, we intend to investigate radiation damage and ageing, and their effects on the operational performances in real in-orbit conditions, allowing to forecast the effective lifetime of the scientific instruments in space. The proposed materials to study are CZT, Ge and Si crystals as relevant components of All-sky Medium Energy Gamma-ray Observatory (AMEGO) and of Advanced Surveyor of Transient Events and Nuclear Astrophysics (ASTENA) missions, respectively, a Probe-class NASA mission proposal and a Voyage 2050 ESA Programme mission concept. CZT based sensors will be used in the calorimeter module of AMEGO as well as focal plane spectroscopic imager of the Narrow Field Telescope (NFT) on board ASTENA which is based on a Laue lens system. With support from ASI and INAF, Laue optics based in Ge and Si bent crystals are currently under development. We propose to test the impact of LEO environment on these materials to verify the stability of their curvature radius, efficiency and to monitor the strength of the crystals’ bonding to the quartz lens substrate which is made with a UV-curable adhesive with very low shrinkage and CTE. The crystals can be cut in different cross-section shapes (10x10 mm2 or 20x20 mm2) to fit the Euro Material Ageing requirements. In the NFT optics the material thicknesses vary from 1 to 5 mm according to the working energy passband. Concerning the samples of CZT sensors, small crystals (10x10 mm2 in area; 2-5 mm thickness) with metallized (Pt/Au) and passivated surfaces will be used. The experiment will allow verifying if and how fundamental electrical properties (e.g. bulk and surface currents, and charge transport properties) change due to space environment exposure, affecting the final detectors’ spectroscopic and imaging performances.

Keywords: CZT, Ge, Si, orbital environment, radiation damage

A TCAD Numerical Approach to Negative Capacitance Ferroelectric Devices Modeling for Radiation Detection Applications (#277)

A. Morozzi1, M. Hoffmann2, S. Slesazeck2, R. Mulargia3

1 Istituto Nazionale di Fisica Nucleare (INFN), Perugia Section, Perugia, Italy
2 NaMLab gGmbH/TU Dresden, Dresden, Germany
3 Istituto Nazionale di Fisica Nucleare (INFN), Genova Section, Genova, Italy


In this work advanced TCAD (Technology Computer Aided Design) modelling will be used aiming at investigating the potentiality of Negative Capacitance (NC) devices in non-conventional application domains (e.g. radiation detection). Numerical device-level approach to simulate the electrical characteristics of ferroelectric Hf0.5Zr0.5O2 (HZO) has been developed. The validation of the models and of the adopted numerical methods relies on the comparison between simulations and measurements of Metal-Ferroelectric Material-Metal and Metal-Ferroelectric-Insulator-Metal capacitors. The goal is to investigate the suitability of innovative NC devices to be used in High Energy Physics experiments detection systems, featuring self-amplificated segmented, high granularity detectors.


This work was financed by the INFN-CSN5, under INFN Young Researcher Grant “NegHEP” and was financially supported out of the State budget approved by the delegates of the Saxon State Parliament.

Keywords: Ferroelectric devices, TCAD simulation, Numerical models, Radiation damage effects

Neutron and Gamma-ray Irradiation Effects on Atom Switch-based FPGA (#671)

K. Ueno1, T. Sakamoto2, M. Miyamura2

1 High Energy Accelerator Research Organization (KEK), Institute of Particle and Nuclear Studies, Tsukuba, Japan
2 NanoBridge Semiconductor Inc., Tsukuba, Japan


For future particle physics experiments using the accelerator and space applications, a higher radiation tolerance on FPGA is desired. Atom Switch-based FPGA (AS-FPFA) is expected to be used under a high radiation level environment. We investigated the influence of single event upset (SEU), total ionizing dose effect (TID), and displacement damage dose (DDD) on AS-FPGA with neutron and gamma-ray irradiation. It was confirmed that there were no SEUs and DDDs up to the neutron fluence of 1012 n/cm2 and there were no TIDs up to the gamma-ray dose of 5 kGy. As a result, it was found that the AS-FPGA had the potential to be used in the high radiation environment. More investigations with higher radiation levels are ongoing. In this paper, we describe the details of the neutron and gamma-ray irradiation campaign and the results.

AcknowledgmentThe authors are grateful to Prof. Y. Furuyama, Dr. A. Taniike for the operation of the tandem electrostatic accelerator at Kobe University; Dr. H. Yashima for neutron exposure in the Kyoto University research reactor (KUR); Mr. I. Yoda for gamma-ray exposure in the Tokyo Institute of Technology Radioisotope Research Center; and the members of gamma-ray exposure operation in the Cobalt-60 Gamma-ray Irradiation Facility at the National Institute for Quantum and Radiological Science and Technology (QST).  They would like to thank Dr. Y. Kaneko, Dr. M. Washiya, and Dr. H. Kagawa of the Japan Aerospace Exploration Agency (JAXA) for the technical support. This work was supported by TIA collaborative research program "Kakehashi".
Keywords: Atom switch, FPGA, gamma-ray, neutron

In-orbit radiation damage characterization of SiPMs in GRID-02 CubeSat detector (#1289)

X. Zheng1, J. Wen1, H. Gao1, M. Zeng1

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

On behalf of the GRID collaboration.


Silicon photomultiplier (SiPM) has recently been used in several space-borne missions for scintillator readout, thanks to its solid state, compact size, low operating voltage and insensitivity to magnetic fields. However, a known issue of operating SiPM in space environment is the radiation damage and thus the performance degradation. In-orbit quantitative study of these effects is still very limited. In this work we present in-orbit SiPM characterization results obtained by the second detector of Gamma-Ray Integrated Detectors (GRID-02), which was launched on Nov. 6, 2020. An increase in dark current of ~100 μA/year per SiPM chip (model SensL MicroFJ-60035-TSV) at 28.5 V and 5°C is observed, and consequently the overall noise level (sigma) of GRID-02 detector increases ~7.5 keV/year. This increase is estimated to be ~50 μA/year per SiPM chip at -20°C, which indicates good effect of using a cooling system.
AcknowledgmentM. Zeng acknowledges funding support from the Tsinghua University Initiative Scientific Research Program.
Keywords: CubeSat, Dark current, Radiation damage, SiPM

Investigation of LED Stimulated Recovery of Radiation Damage in Optical Materials (#1442)

B. Bilki1, 2, H. Dapo3, I. G. Karslioglu1, 3, C. Kaya3, M. Kaya3, K. K. Sahbaz1, 3, M. Tosun1, 3

1 Beykent University, Istanbul, Turkey
2 University of Iowa, Iowa City, Iowa, United States of America
3 Ankara University, Ankara, Turkey


The radiation damage in the optical active media of collider detectors and beamline instrumentation is an outstanding problem. The exposed doses reach unprecedented levels in some current and projected implementations. In order to mitigate this, the development of optical materials with higher radiation resistance is underway. On the other hand, there is a significant lack of in-situ radiation damage recovery systems, whereas such systems have the potential to increase the useful lifetime of the optical materials considerably. Although it is well-known that stimulating the recovery of radiation damage with LED illumination significantly improves the recovery rate and the ultimate damage, a systematic study of the recovery e.g. as a function of the incident LED light spectra, intensity and exposure duration has not been performed. Here we attempt to do this study and present our first results of recovery from radiation damage under seven different recovery conditions.

Keywords: optical detectors, scintillator, glass, radiation damage and recovery, LED spectrum

Study on 3D dose real-time measurement technology based on new scintillating gels (#528)

X. Yan1, H. Li1, L. He1, 2, H. Zhang1, H. Jin1, X. Dai1, X. Zhang1, 3

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


In recent years, 3D dose measurement technology based on scintillation imaging has developed rapidly in the field of dynamic radiotherapy. Based on the previous research results, the tissue equivalent and luminescent properties of the newly developed scintillating gel are further optimized. The experimental results show that 1) the relative differences of mass attenuation coefficients of the gel compared with the ICRU recommended values for γ are within 5% in the range of 30keV to 20MeV; 2) the light yield has been increased from 50% to 80% of the one of standard liquid scintillator. Moreover, the dose characteristics of novel gel materials have been measured experimentally. The results show that there is a linear relationship between the gel light yield and the total dose, and no dependence on dose rate in the tested dose range of 20mGy to 200mGy. The energy response experiment of the gel shows that the luminosity is almost unchanged, and the integral charge differences are less than ±7% in the range of 65keV-250keV. In addition, the physical models have been improved and made of various parameter. At the same time, a system prototype has been developed, and dose verification experiment for 2D has been carried out on a radiotherapy platform in hospital. The results show that the maximum difference between the measured doses and the calculated values given by TPS system is 3.97%, and the average absolute deviation is 2.04%. This experiment verifies the accuracy of the system prototype for radiation dose measurement. An improved 3D dose reconstruction algorithm is still under development and going to report on this conference.

Keywords: 3D dose verification, New scintillating gel, Radiotherapy

Employing Total Ionizing Dose Effect in PN-Junction Photodetectors Implemented in Standard CMOS Technology for Dosimetry Application (#1427)

R. Khalili1, A. Pil-Ali2, S. Adnani2, M. A. Karami3

1 University of Guilan, Faculty of Sciences, Rasht, Iran (Islamic Republic of)
2 University of Waterloo, Department of Electrical and Computer Engineering, and Centre for Bioengineering and Biotechnology, Waterloo, Ontario, Canada
3 Iran University of Science and Technology, School of Electrical Engineering, Tehran, Iran (Islamic Republic of)


Radiation effects on electronic devices are usually considered as a significant source of degradation to the point where they can cause the device hard failure. The effect of total ionizing dose, which is a permanent effect, affects the performance of electronic devices by changing their current or voltage characteristics. In photodetectors specifically, increasing the effect of total ionizing dose leads to higher dark currents. Although this negative radiation effect is avoided in designing, there are applications that potentially benefit from it. Radiation dosimetry is among applications in which the effect of radiation on devices is used for monitoring purposes. In this work, we present the feasibility study of utilizing the total ionizing dose effect for radiation dosimetry. A PN-junction based photodetector implemented in 180 nm standard complementary-metal-oxide-semiconductor technology is simulated in Silvaco TCAD and its dark current under different gamma-ray radiation up to 1 Mrad is studied. Oxide-trapped charges and interface states formed by total ionizing dose effect induce more dark current, which is tabulated for different gamma-ray radiation doses up to 1 Mrad. A transimpedance amplifier is integrated with the photodetector to monitor and measure different levels of radiation, to demonstrate the conceptual design of the proposed dosimeter.


This work was supported in part by Iran University of Science and Technology, and University of Waterloo.

Keywords: Total Ionizing Dose, TID, Dosimetry, PN-iunction Photodetector, Radiation

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