IEEE 2017 NSS/MIC/RTSD ControlCenter

Online Program Overview Session: N-03

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NSS Poster Session I

Session chair: Angela Di Fulvio University of Michigan; Ralf Engels
 
Shortcut: N-03
Date: Monday, October 23, 2017, 13:40
Room: Grand Hall West
Session type: NSS Session

Contents

Click on a content entry to get a more detailed information.

Poster panel
(face) ID: 1


Poster Number:
N-03-001

Development and performance evaluation of low-cost, solely FPGA-based multi-channel TOT readout electronics for silicon photomultiplier array based scintillator detector applications (#1297)

X. Cheng1, Y. Zhong1, Y. Shao1

1 UT Southwestern Medical Center, Radiation Oncology, Dallas, Texas, United States of America

Content

We investigated a new readout electronics of photon sensors that is based on conventional time-over-threshold (TOT) method but it doesn’t use any active component (except FPGA) that is usually bulky and power consuming, and makes the circuit complex. Instead, our new design uses only a resistor, capacitor, one diode, and a FPGA to pick the required time stamps and achieve TOT signal measurement of energy. The advantages of the new design include simplifying the overall TOT design that can be easily implemented for large number of channels, using all off-the-shelve components with low cost, enhancing the performance by introducing almost entirely FPGA-based signal threshold level pickoff and subsequent signal processing of calibration, filtering, and measuring. In addition, the circuit is capable to continuously monitor the background noise to provide usual information about device performance status and environment changes during the operation that can be used for adaptive circuit variation-compensation or performance-optimization. Simulations show a reasonably good linearity. A prototype 1-ch circuit was developed with one resistor, one capacitor, one diode, and a FPGA. The measured results match with the simulation well in terms of linearity. In addition, a 16-ch readout prototype electronics was developed to read out an 8x8 array of 1.5x1.5x20 mm3 LYSO scintillators coupled to a 4x4 array of MPPCs. Most scintillators can be well identified, with average energy resolution around 31%. In summary, we have investigated a simple, low-cost FPGA based TOT readout electronics without active components, and demonstrated its feasibility with promising performance for radiation detector readout, although further improvement is necessary by optimizing the component parameters.

Keywords: time-over-threshold, FPGA, MPPC, low cost
Poster panel
(face) ID: 3


Poster Number:
N-03-002

FPGA based tdc for the Drift Chamber detector of the KLOE2 experiment (#1392)

P. Albicocco1, A. Balla1, P. Ciambrone1, E. Perez1, P. Branchini2

1 Laboratori Nazionali di Frascati, INFN, Frascati, Italy
2 Sezione INFN Roma Tre, INFN, Roma, Italy

Content

The KLOE2 experiment is operating at the Dafne e+e- collider, designed to reach an instantaneous luminosity of 2*1032 cm-2 s-1 at the Phi  resonance. Secondary vertex displacement are of paramount importance for the measurement of the CP violation in the kaon system. The most relevant detector to identify and reconstrut particles in the final state is the Drift Chamber. After 20 years of operation the front-end electronics of the detector was obsolete. Moreover the drift chamber electronics was based on an ASIC production line whch was discontinued. New tdcs had to be built whose architecture was based on the newest FPGAs present on the market. In this paper we describe the architecture, the performance of the new tdcs and their front-end data acquistition FPGA based. The new electronics has  already been installed in the experiment.

Keywords: Analog and digital circuits
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(face) ID: 5


Poster Number:
N-03-003

Serial Powering for Inner Tracker Detectors at the HL-LHC (#1690)

D. A. Strom1, M. Meschini1, S. Paoletti1, G. Sguazzoni1, K. Chatterjee1, R. D'Alessandro1, M. Brianzi1

1 INFN Sezione di Firenze, Physics, Florence, Italy

On behalf of the CMS and ATLAS Collaborations

Content

The Large Hadron Collider will be upgraded to deliver peak instantaneous luminosities up to 7.5x10^34 cm-2s-1 and up to 3000 fb-1 during the 10-year High Luminosity phase (HL-LHC). New silicon tracking detector systems will be installed to fully exploit the physics potential of the upgraded machine. Inner tracker systems will be composed entirely of silicon pixel modules and capable of withstanding intense radiation environments while minimizing material in the detector region. Serial power distribution systems offer an attractive approach to fulfill the required granularity, radiation tolerance, and material constraints for these next-generation pixel detectors. Design choices for powering the inner tracker front-end electronics are discussed along with recent R&D activities in novel serial powering schemes. First results from system tests of a serial power supply prototype are presented.

Keywords: Current supplies, low-power electronics, power distribution, power semiconductor devices, power supplies, semiconductor detectors.
Poster panel
(face) ID: 7


Poster Number:
N-03-004

Development of a Multi-channel ASIC with Individual Energy and Time Digitization for SiPM Readout (#1966)

Y. Chen1, 2, Z. Deng1, 2, Y. Liu1, 2

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

Content

Silicon photo-multipliers (SiPM) has gain an increasingly wide use in Positron Emission Tomography (PET) detector systems, especially in those with "Time-of-Flight" (TOF) ability or monolithic scintillators, for it provides advantages such as compactness, liability for array fabrications, and intrinsic fast response. We developed a 64-channel ASIC chip with the individual digitization of the energy and time stamp in each channel, thus omitting the channel multiplexing which would degrade the timing resolution. A multi-channel time digitization based on the  "Time-to-Amplitude" method is adopted to achieve low power consumptions (<5 mW/CH) and small differential nonlinearity (<0.1 LSB). 24ps (rms) timing resolution is obtained together with 10-bit dynamic range. A switched capacitor is used to sample the input charge with dynamic range up to 49.5 pC and integral nonlinearity smaller than 0.4%. Both digitized energy and time information is transmitted via a 200-MHz SPI interface. The ASIC is fabricated in 0.18 μm CMOS process and can be used for the readout of both pixelated and monolithic scintillator modules in PET systems with high timing resolutions

Keywords: ASIC, SiPM, Multi-channel Readout, DIgitization, Timing resolution, Monolithic Scintillator
Poster panel
(face) ID: 9


Poster Number:
N-03-005

Front-End ASIC Including SAR ADC for Coplanar-Grid CZT Radiation Detector (#2319)

I. Kwon2, Y. Lee1, G. Kim3, C. Kim1, C. H. Kim2, J. - Y. Yeom1, 4

1 Korea University, Department of Bio-convergence Engineering, Seoul, Republic of Korea
2 Korea Atomic Energy Research Institute, Nuclear ICT Research Division, Daejeon, Republic of Korea
3 Sejong University, Department of Nuclear Engineering, Seoul, Republic of Korea
4 Korea University, School of Biomedical Engineering, Seoul, Republic of Korea

Content

This paper describes an application specific integrated circuit (ASIC) design for Cadmium Zinc Telluride (CZT) Coplanar Grid (CPG) radiation detectors. The specialized ASIC would provide low-noise and fast-digitizing performance to distinguish grid signals and cathode signal induced by the promising radiation detector. In order to process the fast signals in range of sub-micro seconds, a 500 MHz clock frequency is generated by an on-chip ring oscillator. In addition, three charge-sensitive amplifiers (CSAs) are implemented to convert voltage signals as a front-end readout circuits with low noise from CPG detectors to the digitizing circuit. The entire architecture (analog/digital mixed design) consists of analog front-end circuits and a moderate successive approximation (SAR) analog-to-digital converter (ADC) with supporting digital components. This new configuration for the specialized radiation detector is currently being fabricated in a standard 180 nm CMOS process with a 1.8 V supply voltage.

Keywords: ASIC, CZT, CPG, CSA, SAR-ADC
Poster panel
(face) ID: 11


Poster Number:
N-03-006

Front-End ASIC Including RHBD ADC for Semiconductor Detector (#2621)

Y. Lee1, I. Kwon2, C. Park1, Y. Kim1, C. H. Kim2, K. Lee1, 3, J. - Y. Yeom1, 3

1 Korea University, Department of Bio-convergence Engineering, Seoul, Republic of Korea
2 Korea Atomic Energy Research Institute, Daejeon, Republic of Korea
3 Korea University, School of Biomedical Engineering, Seoul, Republic of Korea

Content

For decades, radiation-hardened-by-design (RHBD) techniques have been developed to guarantee reliable operation of electronics in harsh radiation environments such as space, nuclear, and scientific applications. However, all techniques that utilize redundancy lead to performance penalties in speed, area and resolution by duplicated blocks, voting circuits or extra bits. In order to preserve performances of electronics, we propose a small-area, low resource-overhead data-converter architecture that is immune to radiation impact events. Specifically, it is an architecture that includes three kinds of novel radiation-hardened designs for both the analog and digital components in an analog-to-digital converter (ADC) structure: a) error detectable tri-state buffer for flip flop against digital single-event transient (DSET), b) error detection storage in flip flop against single-event upset (SEU), and c) algorithm for the analog part of a successive-approximation (SAR) ADC. A mixed-signal architecture chain, consisting of a charge sensitive preamplifier (CSP) and the novel RHBD SAR ADC for semiconductor detectors such as CZT, was implemented in standard 0.18 um CMOS technology with a 1.8 V supply voltage. Simulation results show that the techniques can successfully recognize errors induced by radiation impact events with 36 MS/s and 8 bit resolution.

Keywords: RHBD, harsh radiation environment, SET, SEU, SAR ADC, semiconductor detector, charge sensitive preamplifier
Poster panel
(face) ID: 13


Poster Number:
N-03-007

Test Results of the Tracking Detector Readout ASIC, SMX2, for the Compressed Baryonic Matter Experiment (#2758)

K. Kasinski2, J. Lehnert1, A. Rodriguez-Rodriguez1, W. Zubrzycka2, R. Szczygiel2, C. J. Schmidt1

1 2GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Hesse, Germany
2 AGH University of Science and Technology, Department of Measurement and Electronics, Krakow, Malopolskie, Poland

Content

STS/MUCH-XYTER2 (SMX2) is a prototype readout ASIC designed for the double-sided silicon microstrip sensor stations of the Silicon Tracking System (STS) and gas electron multipliers of Muon Chamber (MUCH) in the Compressed Baryonic Matter (CBM) experiment at FAIR. This self-triggered, 128-channel chip enables digitization of amplitude and time of generated charge with 250 kHit/s/channel rates while keeping 10 mW/channel power budget. Each channel contains a charge sensitive amplifier with switchable gain and pulsed reset circuit for baseline restoration, and two-path signal processing for time measurement (<5 ns resolution) and for amplitude measurement using continuous-time, 5-bit flash ADC. The back-end implements pre-sorting of the incoming hits, multiple throttling and diagnostic features. The read-out is provided via GBT-based DAQ infrastructure designed for the CBM experiment enabling transfer rates up to 47 MHit/s/chip using dedicated protocol. The 10 mm x 6.7 mm ASICs were fabricated in Q3 2016 using UMC 180 nm CMOS MM/RF process. Details of architecture together with characterization and irradiation results will be presented.

Keywords: detector readout, tracking detectors
Poster panel
(face) ID: 15


Poster Number:
N-03-008

An 8-channel ASD in 130 nm CMOS with superior performance of risetime, noise and threshold uniformity for ATLAS drift tube readout at the HL-LHC (#3004)

R. Richter1, A. Baschirotto2, H. Kroha1, M. Dematteis2, V. Danielyan1, F. Resta2, M. Fras1, S. Abovyan1, Y. Zhao1

1 Max-Planck-Institute for Physics, HE Physics, Munich, Germany
2 Univ. Milano-Bicocca, Physics Department, Milano, Italy

Content

The increase of the LHC luminosity for operation in Phase-II by nearly an order of magnitude requires a complete renewal of the readout electronics of the ATLAS Muon Detector, which is composed of about half a million Monitored Drift Tubes (MDT). While most of the readout chain is based on digital technology, the first stage, an Amplifier-Shaper-Discriminator module (ASD), determines the performance of the readout for crucial parameters like time resolution, gain uniformity, efficiency and noise rejection. Given an average electron drift velocity of in the MDT of 20 mm/ns the signal rise time at the discriminator  must be below 10 ns to keep pulse height dependent slewing effects at a tolerable level. This is a precondition for reaching the target spatial resolution of 80 mm RMS per drift tube, resulting in a transverse momentum resolution of 10% for muon tracks of 1 TeV.

To optimize rise time and other parameters, an eight-channel ASD chip, using the IBM 130 nm CMOS 8RF-DM technology, has been designed, produced and characterized for the respective performance.  Main challenges of the design were fast peaking time, which required careful control of stray capacitances, and low exposure to noise sources from supply lines as well as internal substrate coupling between discriminator and preamplifier.

In this paper we present the design strategy, comparison of simulation with lab measurements and resolution studies in a high-energy test beam at CERN. In addition, we compare the performance of this ASIC to the one, made in an older, now obsolete, technology, with respect to the most relevant parameters.

Keywords: ATLAS; Amplifier-Shaper-DiscriminatorMuon-Drift-Tubes; Detector; CMOS Front-End
Poster panel
(face) ID: 17


Poster Number:
N-03-009

MuTRiG: a Mixed Signal Silicon Photomultiplier Readout ASIC for the Mu3e Experiment (#3254)

W. Shen1, H. Chen1, V. Stankova1, K. Briggl1, Y. Munwes1, H. - C. Schultz-Coulon1

1 University of Heidelberg, Kirchhoff Institute for Physics, Heidelberg, Baden-Württemberg, Germany

Content

MuTRiG is a 32-channel mixed-signal Silicon Photomultiplier (SiPM) readout ASIC designed for the Mu3e experiment.  It is dedicated to the readout of the Mu3e Tile Detector and the Mu3e Fibre Detector of the Mu3e Experiment with high timing precision and high data rate capability.  The Mu3e experiment is designed to probe new physics by searching for the lepton flavour violating decay of μ + → e + e + e − at a sensitivity level of 10 −16 . A Mu3e Tile Detector with a high timing resolution of 100 ps (σ) as well as a Mu3e Fibre Detector with 500 ps (σ) timing resolution is required respectively to suppress the combinatorial background below the signal level and to facilitate the event reconstruction.  As challenges to the detector system and the readout electronics, the event rate of the Fibre Detector is expected to be between 700 kHz/channel and 1.3 Mhz/channel.  Each of the channel in the MuTRiG chip consists of an analog front-end and a Time-to-Digital Converter (TDC), as well as integrated digital logic circuitry for event processing and data transmission to an external Data Acquisition system (DAQ).  Additional functionalities such as external trigger function, channel event counters and CRC for data transmission error detection. A gigabit serial data link consisting of a Double Date Rate (DDR) serializer and a customized LVDS transmitter has been implemented in the MuTRiG chip to tackle the high event rate challenge from the Mu3e Fibre Detector.  Characterization measurements have shown an analog front-end jitter of less then 20 ps for injecting charge measurements and reliable 8b/10b encoded data transmission at a data rate of 1.28 Gbps. In this paper we will present the detailed characterization measurements of the MuTRiG chip in a high hit rate condition.  Details concerning the BGA packaging issues of the chip as well as the design and characterization of the tile detector submodule will also be presented.

Keywords: Mu3e, SiPM, ASIC, Scintillator, Gigabit link, Time of Flight, High Resolution Timing
Poster panel
(face) ID: 19


Poster Number:
N-03-010

Using the SIPHRA ASIC with an SiPM array and scintillators for gamma spectroscopy (#3513)

A. Ulyanov1, D. Murphy1, A. Fredriksen2, J. Ackermann2, D. Meier2, S. McBreen1, L. Hanlon1

1 University College Dublin, School of Physics, Dublin, Ireland
2 Integrated Detector Electronics AS (IDEAS), Oslo, Norway

Content

SIPHRA is a low-power (30 mW) application specific integrated circuit (ASIC) recently developed by IDEAS, Norway for readout of photomultiplier tubes and silicon photomultipliers (SiPMs). The ASIC has 16 input channels and one summing channel. Each channel can be used for timing and pulse height spectroscopy with a programmable shaping time of 200 ns, 400 ns, 800 ns, or 1600 ns. The current mode input stage (CMIS) is designed for large negative charge (-16 nC, -8 nC, -4 nC, and 0.4 nC), depending on the programmable attenuation. The ASIC contains a 12-bit ADC for pulse-height digitization. SIPHRA’s performance has been tested using a 4x4 array of 6 mm B-series SiPMs from SensL and a number of scintillator crystals (BGO, LYSO, LaBr3:Ce and CeBr3). In measurements with common gamma-ray sources, the detectors have demonstrated the same energy resolution as obtained using discrete readout electronics. For example, the LaBr3:Ce detector has shown energy resolution (FWHM) of 4% at 662 keV and 2.5% at 1274 keV. The lowest detectable energy is limited by the dark current of the SiPM array and has been found to be just under 30 keV for the LaBr3:Ce detector at room temperature. Further measurements show that SIPHRA inputs can accommodate a capacitive load of at least 66 nF without a significant effect on the spectral performance, which indicates that as many as 16 SensL 6 mm SiPMs can be connected together to a single input channel.

Keywords: ASIC, silicon photomultiplier, SiPM, readout, gamma rays, IDE3380
Poster panel
(face) ID: 21


Poster Number:
N-03-011

A NIM Module for signals processing of the most common types of scintillators Detectors (#3667)

C. Boiano1, S. Brambilla1, S. Riboldi1, A. Giaz1, F. Camera1, 2

1 INFN, Sezione di Milano, Milano, Italy
2 Università degli studi di Milano, physics department, Milano, Italy

Content

The developed 16-channels NIM module allows to get Energy, Time and Pulse-Shape information from most of commonly available scintillators detectors. Each channel consists of three different sections; The energy section consists of an Integration Circuit with a programmable integration constant to match the decay time of the used scintillator. The timing section consist of an auto walk CFD with the possibility to program the width and delay of the output logic. The pulse-shape section consists of a circuit able to capture the maximum amplitude of the input signal and providing a shaped gaussian output proportional to this amplitude. The module is also equipped with a Pile-up rejection circuit that sends quickly in saturation the output signal whenever a pile-up event occurs within the time to peak window. The module is suitable for most common commercial scintillators such as NaI, CsI, BaF2, LaBr3, CeBr3, LaCl3:Ce, BGO, and all the organic scintillators detectors. Thanks to its pulse shape capability it is also suitable for phoswich detectors and for those scintillators detector characterized by different decay time.

Keywords: scintillators detectors, Pulse-Shape
Poster panel
(face) ID: 23


Poster Number:
N-03-012

4-bit, 25GSa/s Flash ADC (#4046)

P. K. Bikkina1, Y. Feng2, Y. Tang2, J. Chen2, E. O. Mikkola1

1 Alphacore, Inc., Tempe, Arizona, United States of America
2 University of Houston, Houston, Texas, United States of America

Content

This paper describes an ultra-high speed (25GS/s), 4-bit (ENOB > 3.5 bits), low-power (220mW core power), analog-to-digital converter (ADC) which is currently under development for use in remote sensing applications. The ADC has analog input bandwidth of >20GHz. The proposed ADC employs an innovative topology with high-bandwidth front-end sampling circuit combined with flash-type ADC. Novel and effective digital calibration is used to guarantee spurious free Nyquist frequency band. The sampling speed, ENOB and power have all been measured from netlists extracted from layouts. First iteration of the design has been fabricated and is being evaluated. The ADC has been developed in a 28nm CMOS technology.

Keywords: analog to digital converter, ADC, flash ADC architecture, high performance ADC
Poster panel
(face) ID: 25


Poster Number:
N-03-013

Alpha Particle X-ray Spectrometer onboard Chandrayaan-2 rover (#1090)

A. R. Patel1, M. Shanmugam1, S. K. Goyal1, N. P. S. Mithun1, S. V. Vadawale1, T. Ladiya1, H. Adalja1

1 Physical Research Laboratory, PLANEX, Ahmedabad, Gujarat (GJ), India

Content

The Alpha Particle X-ray Spectrometer (APXS) for the Chandrayaan-2 rover will be used to determine the elemental composition of lunar soil and rocks near the landing site. The objective of the instrument is to determine the elemental composition of lunar soil and rocks by detecting elements such as Mg, Al, Si, K, Ca, Ti, and Fe around the lunar landing site through the detection of characteristic X-rays emitted from PIXE and XRF. The solid state semi-conductor detectors such as Silicon Drift Detector (SDD) makes it possible to detect X-ray emissions from planetary surfaces with an energy resolution of <160 eV at 5.9 keV in the energy region 1 to 25 keV. This will be carried out by placing the APXS payload on the rover platform to view the moon sample. We have carried out laboratory experiments for measuring fluorescent X-ray spectrum from various known samples irradiated by the six source of 244Cm with each 5 mCi activity. It is shown that intensities of various characteristic X-ray lines are well correlated with the respective elemental concentrations. The detail about the instrument and experiment results will be presented during conference.

Keywords: APXS, SDD, PIXE, XRF
Poster panel
(face) ID: 27


Poster Number:
N-03-014

Tissue Equivalence of Diamond for Heavy Charged Particles (Z>2) (#1566)

J. A. Davis1, 2, P. Lazarakis1, M. L. F. Lerch1, 2, A. B. Rosenfeld1, 2, S. Guatelli1, 2

1 University of Wollongong, Centre for Medical Radiation Physics, Wollongong, N.S.W, Australia
2 University of Wollongong, Illawarra Health and Medical Research Institute, Wollongong, N.S.W, Australia

Content

A dedicated Geant4 study was utilised to determine a correction factor (C=0.32) to convert the energy deposition response in diamond and silicon to water for heavy charged ions, with atomic number (Z) greater than 2 with energies typical of hadron therapy and galactic cosmic rays. This work extends upon previous work specific to protons and alpha particles. This study has shown no Z dependence upon the correction factor in the energy regime of interest. Following the confirmation of a common correction factor for galactic cosmic rays, the energy deposition response within an ideal diamond based microdosimeter was modelled and converted into a microdosimetric spectrum. The simulation was then repeated, substituting diamond for water. It was shown that by applying the correction factor, the energy deposition and microdosimetric response in diamond could be matched to that of water. The effect of the correction factor for converting microdosimetric spectra in diamond to water for Galactic Cosmic Rays is also examined and will be presented in full. This result is extremely encouraging and indicative of the applicability of diamond for use in microdosimetric applications in space environments.

Keywords: Diamond, Microdosimetry, Galactic Cosmic Rays, Space
Poster panel
(face) ID: 29


Poster Number:
N-03-015

Study of the High Dynamic Range PMT for LHAASO Experiment (#2276)

X. Li1, Z. B. Tang1, C. Li1, X. K. Zhao1, Z. W. Li1, Z. Liu1

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

Content

The Large High Altitude Air Shower Observatory (LHAASO) project is scheduled to be built at elevation of 4410 m at Haizi Mountain in China. As a large scale complex of various detectors, its primary scientific goals include exploring the origin of cosmic ray, searching for very high energy gamma ray sources, and study new physicals like Lorentz invariance, dark matter and quantum gravity.

As a central detector of LHAASO, Water Cherenkov Detector Array (WCDA) is proposed to target gamma astronomy between 100 GeV and 30 TeV and will achieve the best sensitivity at this energy region. WCDA covers an area 78000 m2, is divided into 3000 units of detector. An 8-9 inches photomultiplier tube (PMT) is installed at the bottom-center of each cell to collect the Cherenkov light produced by shower particles crossing water. According to the physics goals and Monte Carlo simulation, PMTs require good single photoelectron (SPE) resolution (Peak-to-Valley ratio> 2.0), fast time response (TTS<4.0 ns), and most importantly, the large dynamic range (1 to 4000 PE). Muon Detector (MD), another important part of LHAASO, also uses the water Cherenkov detection technology to detect the muons in the air shower. The MD unit must achieve at least a dynamic range from 1 to 10000 muons (about 106PE) and the PMT output current should reach above 1600 mA.

To meet those requirements, we designed the base of large dynamic range for each of PMT candidates (XP1805, CR365 and R5912), and tested their performance including the gain, high voltage response, transit time spread, dark noise rate, afterpulse rate and non-linearity. The measurement results show that under the voltage divider in specially designed, each PMT candidate can achieve the linear dynamic range of 1~4000 PE within +/-5% , and is well qualified for WCDA, both of PMTs R5912 and XP1805 can meet the demands of MD .

Keywords: Large High Altitude Air Shower Observatory (LHAASO), Water Cherenkov Detector Array (WCDA), Muon Detector (MD), Photo-Multiplier Tube(PMT), Large dynamic range, Non-linearity
Poster panel
(face) ID: 31


Poster Number:
N-03-016

PixDD - A Fast Multi-Pixel, Integrated Silicon Detector-Read-out System for Focal Plane High Resolution X-ray Timing and Spectroscopy (#2387)

Y. Evangelista1, 2, M. Feroci1, 2, A. Tobia1, G. Zampa4, N. Zampa4, A. Rachevski4, A. G. Vacchi3, 4, D. Cirrincione3, 4, I. Rashevskaya5, G. Bertuccio6, M. Ahangarianabhari6, M. Gandola6, M. Fiorini7, C. Labanti8, R. Campana8, F. Fuschino8, P. Bellutti9, P. Malcovati10, M. Grassi10

1 INAF, IAPS, Rome, Italy
2 INFN, Roma Tor Vergata, Rome, Italy
3 INFN & Università di Udine, Dep of Mathematics, Computer Science and Physics, Udine, Italy
4 INFN, Trieste, Trieste, Italy
5 TIFPA - INFN, Trento, Povo (TN), Italy
6 Politecnico di Milano, Department of Electronic Engineering, Como, Italy
7 INAF, IASF Milano, MIlano, Italy
8 INAF, IASF Bologna, Bologna, Italy
9 FBK, Povo (TN), Italy
10 Università di Pavia, Dipartimento di Ingegneria Industriale e dell'Informazione, Pavia, Italy

Content

Multi-pixel fast Silicon detectors represent the enabling technology for the next generation of space-borne experiments devoted to high-resolution spectral-timing studies of low-flux compact cosmic sources. Several imaging detectors based on frame-integration have been developed as focal plane detectors for X-ray space-borne missions but, when coupled to large-area concentrator X-ray optics, these detectors can suffer of strong pile-up and dead-time effects, thus limiting the time and energy resolutions as well as the overall system sensitivity. The current technological gap in the capability to realize pixel Silicon detectors with fast response, asynchronously detecting and triggering on the individual X-ray photons while still offering nearly Fano-limited energy resolution and soft X-ray response, therefore translates in the unavailability of sparse read-out sensors suitable for high throughput X-ray astronomy applications. In the framework of the ReDSoX Italian collaboration, we developed a new, sparse read-out, pixelated Silicon drift detector which operates in the energy range 0.5-15 keV with nearly Fano-limited energy resolution (<150 eV FWHM @ 6 keV) at room temperature or with moderate cooling (~0 °C ÷ +20 °C). In this paper, we present the design and the laboratory characterization of the first 16-pixel (4x4) drift detector prototype (PixDD), read-out by individual ultra low-noise charge sensitive preamplifiers (SIRIO) and discuss the future development of a large area, 32x32 pixel Silicon Drift Detector.

Keywords: x-ray instrumentation, silicon drift detectors, pixel detectors, x-ray, high throughput astronomy
Poster panel
(face) ID: 33


Poster Number:
N-03-017

The EUSO-SPB mission (#2871)

V. Scotti1, G. Osteria1

1 INFN, Sezione di Napoli, Napoli, Italy

Content

EUSO-SPB (Extreme Universe Space Observatory - Super Pressure Balloon) is an experiment on board a super pressure balloon for a flight duration which may reach 100 days. The balloon was launched on April, 25th  2017 from Wanaka in New Zealand.

The instrument is an updated version of the EUSO-Balloon one. It includes a full original JEM-EUSO PDM (Photon Detection Module with 2304 pixels) and an optical system with two Fresnel lenses with a side of 1 meter covering a field of view of ±5.5 degrees.

The main scientific objective is the first observation and measurements of Ultra High Energy Cosmic Ray Air Showers by looking down from near space with a fluorescence detector. The EUSO-SPB will also search for Ultra Violet (UV) pulse like signatures from other objects as meteoroids, atmosphere Transient Luminous Events, Strange Quark Matter, and it will measure slowly varying UV light as airglow, bioluminescence events over the ocean.

Keywords: astroparticle, cosmic rays
Poster panel
(face) ID: 35


Poster Number:
N-03-018

SiPM Based Focal Plane Detectors Operated Alongside PMTs for Large Imaging Atmospheric Cherenkov Telescopes (#3272)

A. Hahn1, D. J. Fink1, D. Guberman3, D. Mazin2, R. Mirzoyan1, M. Teshima2

1 MPI fuer Physik, Munich, Bavaria, Germany
2 University of Tokyo, Institute for Cosmic Ray Research, Chiba, Japan
3 Universitat Autònoma de Barcelona, Institut de Física d'Altes Energies, Bellaterra (Barcelona), Spain

Content

MAGIC is a system of two 17 m diameter Imaging Atmospheric Cherenkov Telescopes used for gamma ray astronomy. In addition to the photomultiplier based active area of the cameras, six positions are available at the outside edge of each camera for comparative evaluation of alternative photo detection designs during regular observations. Here we describe the design and construction of two modules based on two different silicon photomultiplier (SiPM) detectors. Based on simulation results and initial prototypes, pixel detectors with an active area of 324 mm2 have been fabricated, along with their associated control electronics and specially designed light concentrators. A low-noise analog pulse summation circuit was used to implement rapid signal response (~2.5 nsec) for this detection area while maintaining resolution of individual photo-electron peak spectra used for calibration. Data recorded during camera operation is analyzed for comparison to the photomultiplier devices, and to laboratory characterization measurements done prior to installation.

Keywords: MAGIC Cherenkov PMT SiPM
Poster panel
(face) ID: 37


Poster Number:
N-03-019

Cherenkov Telescope Array: The Next Generation Gamma-ray Observatory (#3442)

N. Otte1

1 Georgia Institute of Technology, Atlanta, United States of America

On behalf of CTA-Consortium

Content

The Cherenkov Telescope Array (CTA) will be a new observatory to study very-high-energy gamma-ray sources. It is designed to achieve an order of magnitude improvement in sensitivity in the 20 GeV to 300 TeV energy band compared to currently operating instruments: VERITAS, MAGIC, and H.E.S.S. CTA will probe known sources with unprecedented sensitivity, angular resolution, and spectral coverage, while also detecting hundreds of new sources. This presentation will describe the science drivers for CTA and the status of the project.

Keywords: gamma-rays, astrophysics
Poster panel
(face) ID: 39


Poster Number:
N-03-020

Using Highly Triboluminescent EuD4TEA to Detect Debris Impacts and Space Radiation (#4232)

W. Hollerman1, J. Miller1, V. Bertrand1, P. Darby2, N. Pugh2, R. Fontenot3, N. Guardala3

1 University of Louisiana at Lafayette, Physics, Lafayette, Louisiana, United States of America
2 University of Louisiana at Lafayette, College of Engineering, Lafayette, Louisiana, United States of America
3 Naval Surface Warfare Center, Carderock Division, West Bethesda, Maryland, United States of America

Content

Recently, luminescent materials have been proposed for use in smart sensors to measure particle impacts and to monitor space radiation fluence. To sense particle impacts, triboluminescent (TL) materials are embedded in a composite host structure. When the damage/fracture occurs in the host structure, it leads to the fracture of the TL crystals resulting in light emission. This provides a warning that structural damage has occurred. TL emission from the material must be sufficiently bright, so it is strong enough to be detected. Most TL materials do not emit light with sufficient intensity to allow detection with compact and inexpensive detectors. Materials such as doped zinc sulfide (ZnS) and europium tetrakis dibenzoylmethide triethylammonium (EuD4TEA), have sufficient yield for the light emission to be easily observed with the naked eye. From 1990, the authors have found that the Birks and Black (1954) equation describes the reduction in emission yield for every tested luminescent material except lead phosphate glass due to proton irradiation. Recently, the authors determined that the half brightness fluence for EuD4TEA irradiated with 3 MeV protons was about one thousand times smaller than the value for manganese doped ZnS. According to Tribble (2003), a spacecraft at 1 AU from the Sun will receive a 1 MeV proton fluence of less than 1011 mm-2 from a large solar event or in the Earth’s radiation belts. For this reason, EuD4TEA could be used as a sensor material to monitor radiation fluence in space vehicles. The purpose of this presentation will provide an overview of all completed research from 1990 to the present. Particular emphasis will be placed on the development of a 1U CubeSat payload that will be launched in early 2018. Data from this CubeSat will help determine whether EuD4TEA be used as a real-time impact and space radiation sensor

Keywords: luminescent sensors, EuD4TEA, Half Brightness Fluence, CubeSat
Poster panel
(face) ID: 41


Poster Number:
N-03-021

Using Monte Carlo to explore 3D reconstruction to geological application: preliminary characterization of technique limitations (#1091)

G. Hoff1, 2, J. Sanchez1, J. T. de Assis1, A. Brunetti3

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

Content

It is a project under development. The main objective of this project is to define a methodology for sediments characterization of objects of test, imaging the material deposited in the tanks or in locu. In this project it is evaluated 3D reconstruction of the simulated images and the definition of limitations of the technique by simulating the sediment images using the Monte Carlo toolkit XRMC. The strategy defined was to use as base the acetylene and as object of contrast (OC) acetylene with 10% of barium. To estimate some limitations of the technique deterministic calculations were used to estimate the subject contrast (SC) and transmission (T). After that the Monte Carlo toolkit XRMC version 6.5.0-2 was used in “Transmission” mode to generate the planar images in centered geometry, simulating images in 360 degrees, in steps of 1 degree. The Feldkamp-David-Kress (TDK) reconstruction method, using 8 bit images, was used to generate the 3D images. The reconstructed images were evaluated (by using using automated macros in Fiji) considering the dimensions of the OC and the sign, sign-to-noise ratio among other characteristic of the image sing. The deterministic calculation guided the selection of realistic spectra giving an idea about the limitation of the technique. The simulated images confirmed the limitation for 30 kVp to image thickness larger than 30 cm. To larger thicknesses the Ir-192 spectra was used, with consistent results. The xrmc Monte Carlo toolkit proved to be an interesting and useful tool to generate geological images and guide on new strategies to image sediments. The preliminary results shows that FDK reconstruction method alone cannot be used for this image with low contrast and high noise.

Research developed with the partial support of the National Supercomputing Center (CESUP), Federal University of Rio Grande do Sul (UFRGS).

Keywords: Monte Carlo, XRMC toolkit, Geology, Imaging, Image reconstruction
Poster panel
(face) ID: 43


Poster Number:
N-03-022

Study of Counting Efficiency with Triple to Double Coincidence Ratio in Liquid Scintillation Counter by using Geant4 (#1595)

T. Aso1, T. Masuda2, M. Hara3, M. Shoji4, T. Furusawa2, T. Yoshimura2, Y. Kato2, Y. Higa1

1 National Institute of Technology, Toyama College, Electronics and Computer Engineering, Imizu, Toyama, Japan
2 Hitachi, Ltd., Mitaka-shi, Tokyo, Japan
3 University of Toyama, Hydrogen Isotope Center, Toyama, Toyama, Japan
4 Universityu of Toyama, Life Science Research Center, Toyama, Toyama, Japan

Content

Liquid scintillation counter (LSC) is one of radioactivity measurement techniques, which is suitable for low level and low energy beta decay radionuclide. LSC counts the number of flushes of scintillation lights by charged particles of decay products. However, the counting rate may be partly lost due to quenching that reduces the light output of the scintillator. Therefore, the compensation of the count rate loss is essential to determine the radioactivity. We previously reported on the study of counting efficiency in double coincidence events of two photomultipliers (PMTs) by using Geant4 Monte Carlo simulation. In this research, we have newly developed a simulation for LSC-LB7 manufactured by Hitachi, Ltd. that is equipped with three PMTs. The LSC system allows observation of double and triple coincidences. The triple and double coincidence ratio (TDCR) method is an interest for quantitative measurement in the field of radionuclide metrology, because the method does not require a series of standard quenched samples for estimating the detection efficiency.

For the purpose of studying the counting efficiency with TDCR, the simulation of LSC-LB7 system has been performed. The liquid scintillation cocktail was assumed to Ultima Gold of PerkinElmer Co. Ltd. The photon yield of scintillation cocktail was adopted from the previous result in LSC-5100, that had been determined in the series of standard quenched sample of C-14. The physics-list takes account for all physics processes such as radioactive decay, electromagnetic and optical photon processes. The quantum efficiency and photosensitivity of PMT was also taken into account. H-3, C-14, S-35 and P-32 were generated in scintillation cocktail in a glass vial, respectively.

As a result, efficiency and TDCR were calculated by counting events that satisfy the double and triple coincidence in three PMTs. We confirmed that the efficiency can be determined from TDCR in pure beta decay radionuclide.

Keywords: Liquid scintillation counter, Geant4, TDCR, Efficiency
Poster panel
(face) ID: 45


Poster Number:
N-03-023

Cosmic-ray Muon Backgrounds in the DEAP-3600 Dark Matter Search Experiment (#2288)

E. T. Rand1, V. Golovko1, O. Kamaev1

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

Content

There is an increasing need for highly-sensitive detector technologies to address today's non-proliferation and nuclear counter-terrorism concerns. The detector technology developed for recent dark matter search experiments, like the Dark matter Experiment using Argon Pulse-shape discrimination (DEAP), offers unparalleled performance in neutral particle detection. An assessment of these detector technologies suitable for nuclear forensics and security applications has been completed at the Canadian Nuclear Laboratories (CNL), which identified the DEAP-3600 detector technology as a strong candidate for special nuclear material (SNM) detection. The DEAP-3600 experiment is a state-of-the-art detector comprising of 3600 kg of liquid argon. The detector is located 2 km below the surface of the earth at the SNOLAB facility in Sudbury, Ontario, Canada. At this depth, background events originating from cosmic-rays are significantly reduced, therefore enabling the measurement of extremely rare interactions; such as the interactions theorized between ordinary matter and dark matter. To achieve this level of sensitivity, the detector is housed within a large ultra-pure water tank which serves as a radiation shield and a Cerenkov veto detector for cosmic-ray muons. In this work, we characterized the efficiency of the DEAP-3600 cosmic-ray muon veto system using the Reactor Analysis Tool (RAT) simulation software, and developed a stand-alone particle generator for both muons and neutrons. The cosmic-ray muon veto efficiency was found to be 96.56(9)% using a realistic triggering condition. The results from this work will contribute to CNL's development of a liquid argon detector for SNM identification, which will require a robust muon veto system capable of detecting the larger flux of lower energy muons at the surface of the earth. The DEAP-3600 muon veto efficiency results and preliminary simulation studies of the muon induced neutron background rates will be presented.

Keywords: Dark Matter, Cosmic-ray Muon, Monte Carlo, Simulation
Poster panel
(face) ID: 47


Poster Number:
N-03-024

Review of GAMOS/GEANT4 framework (#2846)

P. Arce1, J. I. Lagares1, L. Harkness-Brennan2, D. Perez-Astudillo3, M. Cañadas1, P. F. Rato1, M. de Prado4, Y. Abreu5, G. di Lorenzo6, M. Kolstein7, A. Díaz5, A. Glaser8, L. Desorgher4, A. Fernandez9

1 CIEMAT, Medical Applications Unit, Madrid, Spain
2 Liverpool, Oliver Lodge Laboratory, Liverpool, United Kingdom of Great Britain and Northern Ireland
3 Qatar Foundation, Qatar Environment and Energy Research Institute, HBKU, Qatar, Qatar
4 Paul Scherrer Institute, Villigen, Switzerland
5 CEADEN, Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, La Habana, Cuba
6 SAP SE, Walldorf, Germany
7 IFAE, Barcelona, Spain
8 Dartmouth College, Thayer School of Engineering, New Hampshire, United States of America
9 Centro Guadalinfo de Santisteban del Puerto, Jaén, Spain

Content

GAMOS (Geant4-based Application for Medical-Oriented Simulations) from its conception was meant to provide a framework not only easy to use, as other GEANT4-based frameworks, but also flexible, with the aim of avoiding a common problem: that the use of a framework prevents the user from taking advantage of all the potentiality that GEANT4 provides. We describe here the main functionality of GAMOS, paying special attention to the latest developments.

Keywords: Monte Carlo simulation, GEANT4, Nuclear Medicine, Radiotherapy, Radiation protection
Poster panel
(face) ID: 49


Poster Number:
N-03-025

Effects of Oblique Incidence in Pixel Detectors on Diffraction Experiments (#3230)

T. Rüter1, 2, S. Hauf1, M. Kuster1, L. Strüder2, 3

1 European X-Ray Free-Electron Laser Facility GmbH, Detector Development, Schenefeld, Schleswig-Holstein, Germany
2 Universität Siegen, Department Physik, Siegen, North Rhine-Westphalia, Germany
3 PNSensor GmbH, Innovative Radiation Detectors, München, Bavaria, Germany

Content

The European X-ray Free Electron Laser (XFEL.EU) is a high-intensity X-ray light source currently being constructed in the area of Hamburg/Schenefeld, Germany, that will provide spatially coherent X-rays in the energy range between 0.25 keV – 25 keV at an unprecedented peak brilliance. The high photon flux and the coherent X-ray radiation are paramount for diffraction experiments that rely on single-shot imaging and will increase the resolution for experimental techniques such as coherent X-ray diffraction. The LPD, DSSC and AGIPD detectors are being developed to provide megapixel imaging capabilities with a dynamic range spanning from single photon sensitivity to 105 photons per pixel.

Data analysis of Bragg diffraction experiments relies on the localization and indexing of diffracted X-rays in the detector image. Pixelated, two dimensional X-ray detectors however add uncertainty to localization, due to pixel size, scattering of diffracted photons in the detector and its entrance window, and charge diffusion, leading to incomplete signal collection.

Using X-ray Detector Simulation Pipelines (XDSPs) the correct attribution of the point of impact of diffracted photons on the detector's pixel matrix can be evaluated over the XFEL.EU's energy range. The method presented is easily adapted to a broad range of machine parameters, experimental conditions and detector configurations. We examplarily show that the effect is non-negligable for 10 keV photons, where pixel-misattribution can occur for angles of incidence larger than 31°.

Keywords: X-ray Detector, Simulation, XFEL, Diffraction
Poster panel
(face) ID: 51


Poster Number:
N-03-026

ReDecay, a method to re-use the underlying events to speed up the simulation in LHCb (#3514)

D. Mueller1, M. Rama2

1 The University of Manchester, School of Physics and Astronomy, Manchester, United Kingdom of Great Britain and Northern Ireland
2 Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, Pisa, Italy

On behalf of LHCb Collaboration

Content

With the steady increase in the precision of flavour physics measurements collected during LHC Run 2, the LHCb experiment requires simulated data samples of ever increasing magnitude to study the detector response in detail. However, relying on an increase of available computing power for the production of simulated events will not suffice to achieve this goal. The simulation of the detector response is the main contribution to the time needed to generate a sample, that scales linearly with the particles multiplicity of the event.

Of the dozens of particles present in the simulation only a few, namely those participating in the studied signal decay, are of particular interest, while all remaining ones, the so-called underlying event, mainly affect the resolution and efficiencies of the detector. This talk presents a novel development for the LHCb simulation software which re-uses the underlying event from previously simulated events.

This approach achieves an order of magnitude increase in speed and the same precision compared to the nominal simulation.

Keywords: Monte Carlo simulation, LHCb, Large Hadron Collider, Fast simulation
Poster panel
(face) ID: 53


Poster Number:
N-03-027

Advanced programming concepts for nuclear and particle physicists (#4210)

S. Kluth1, M. G. Pia2, P. Steinbach3

1 MPI für Physik, Munich, Bavaria, Germany
2 INFN, Sezione di Genova, Genova, Italy
3 MPI of Molecular Cell Biology and Genetics, Dresden, Saxony, Germany

Content

We report on the training program "Advanced Programming Concepts", which teaches the concepts, methods and techniques needed for efficient work with the software in nuclear and particle physics experiments. Software is essential in all phases of an experiment from the design based on detailed simulations, during data taking to collect, filter and reconstruct the interactions with the data from the detector to the final physics analysis. The intended audience for the school are students and young researchers performing regular tasks with the experiment software such as developing a physics analysis or improving a reconstruction algorithm. The participants are exposed to principles of object-oriented programming, design patterns, meta-template programming, optimisation strategies, and unit testing and refactoring. The emphasis is on working effectively with existing code and on providing a basis for self-improvement. We will present the guiding principles and methods of the "Advanced Programming Concepts" training, and show analysis of feedback by participants.  We intend to promote a discussion in the community about the responsability to prepare the students and young researchers in the collaborations more thoroughly for their daily work with the software and more widespread knowledge of advanced software methods and techniques could be beneficial for the collaborations.

Keywords: Software training refactoring object oriented programming
Poster panel
(face) ID: 55


Poster Number:
N-03-028

Synthesis of Radiation Counts for Networks of Detectors (#1781)

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

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

Content

Networks of radiation detectors are increasingly being deployed to detect and localize radiation sources in urban areas, special events, and border crossings. Practical deployments require the performance characterizations for a wide range of network configurations and source strengths, which in turn requires representative radiation measurements or counts from diverse scenarios. However, currently available measurements have been limited mostly to simulations and experiments under limited configurations with a select set of sources of certain strengths. We develop a data-driven, regression-based scaling method to synthesize radiation counts for a given source strength in a spectral bin by bootstrapping measurements from Domestic Nuclear Detection Office's Intelligence Radiation Sensors Systems (IRSS) tests. These counts not only “fill in” the gaps in existing configurations (in particular, IRSS tests), but also support comprehensive analysis and testing of current and next generation network solutions. In addition to counts, we also generate network messages using message-skeletons extracted from IRSS tests. Radiation counts generated by tools such as GADRAS do not incorporate network parameters, such as packet loss and clustered packet arrivals, and therefore require additional tools (e.g., network simulators) to generate network messages. We characterize the quality of generated counts using statistical measures based on chi-square significance test and distance metrics between the probability density functions of synthesized and original datasets. Also, we provide an analytical justification for our method based on Vapnik-Chervonenkis theory that guarantees probabilistically-bounded estimation error.

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

Keywords: detection networks, low-level source, source injection, network fusion algorithms
Poster panel
(face) ID: 57


Poster Number:
N-03-029

Artificial Neural Network for Unfolding Accelerator-based Neutron Spectrum by Means of Multiple Foil Activation Method (#2590)

T. Kin1, Y. Sanzen1, M. Kamida1, K. Aoki1, N. Araki1, Y. Watanabe1

1 Kyushu University, Department of Advanced Energy Engineering Science, Kasuga-shi, Fukuoka, Japan

Content

Recently, applications of accelerator-based neutron are widely spread to many fields. Among all, we have focused on the medical RIs production. In the study, accelerator-based neutrons are generated by 10- to 40-MeV deuteron induced reactions on thick target made of C or Be. For design of irradiation system and estimation of production rate and purity, double differential thick target neutron yields (DDTTNY) are required. There are, however, not sufficient available data. Therefore, in the medical RI production study, the DDTTNY is necessary to be measured. We adopted the multiple foil activation method for the measurement. It is appropriate for the medical RI production study, because the direct activation power of the neutron source can be obtained. The DDTTNY should be derived by an unfolding technique from measured yields of atoms produced via the activation reactions. Performances of conventional unfolding codes are strongly dependent on the initial guess spectrum and a human-inducible parameter of convergence condition. We have developed an unfolding code using artificial neural network (ANN) which requires no initial guess spectrum and no human-inducible convergence condition. Once the ANN is trained, neutron spectrum can be derived from inputting yields of atoms produced via the activation reactions only. To demonstrate the ability to derive the DDTTNY by the ANN unfolding code, we input yields of produced atoms obtained by a multiple foil activation experiment conducted at Kyushu University Tandem Laboratory.  The resultant DDTTNY is compared with that by GRAVEL code, which is one of the conventional codes. Since there is no large discrepancy, we found that the ANN unfolding code has same ability to GRAVEL code even without the initial guess spectrum.

Keywords: accelerator-based neutron, artificial neural network, mutiple foil activation method, neutron spectrum unfolding
Poster panel
(face) ID: 59


Poster Number:
N-03-030

Situational information guidance for revised detection limits (#3398)

K. Stadnikia1, A. Enqvist1, K. Henderson2, S. Koppal2

1 University of Florida, Nuclear Engineering, Gainesville, Florida, United States of America
2 University of Florida, Electrical and computer engineering, Gainesville, Florida, United States of America

Content

Detection limits for nuclear material detection have had numerous inconsistent limited definitions in literature historically. Currie provided a concise definition and framework as depending on background, errors of first and second kind, and then generating a critical level, detection limit and determination limit. In many critical search spaces the main detection mechanism is simply a gross counting detector of suitable time intervals that generates an alarm based on a suitable limit, but with no situational awareness or additional information. The deployment of various awareness and tracking sensors have enabled many situations where a more sophisticated detection limit algorithm could be devised. One that takes into account a priori situational information, such as movements in time of any non-stationary object/person in the vicinity of the radiation counter.

It is clear that the detection limit corresponding to the Currie limit  could be revised. The full paper will detail a realistic nuclear security detection scenario. And quantify the achievable benefit by incorporating various realistic dynamic scenes such as potentially encountered at a port of entry.

Keywords: Currie equation, Detection limit, Counting statistics
Poster panel
(face) ID: 61


Poster Number:
N-03-031

The Reorganize and Multiplex (RMU) front-end-trigger optical bridge for the JUNO experiment (#1158)

P. Branchini1, A. Fabbri1, D. Riondino1, A. Aloisio2, R. Giordano2, F. Dicapua2

1 INFN, Roma Tre, Roma, Italy
2 Università di Napoli Federico II, Fisica, Napoli, Italy

Content

The Jiangmen Underground Neutrino Observatory (JUNO) is a medium baseline reactor neutrino experiment under construction in Southern China. The main detector consists of a transparent sphere containing 20,000 tons of liquid scintillator, surrounded by approximately 17,000 photomultiplier tubes. The information delivered by 20 PMT stations is digitized continuously and aggregated at the RMU level. The main RMU task is to provide 20 input optical link at 0.5 Gbps and 1 at 10 Gbps optical output link running at fixed latency. A control implementing white rabbit is present on the the RMU. In this contribution we describe the full RMU architecure.   

Keywords: optical links, data acquisition system, trigger system
Poster panel
(face) ID: 63


Poster Number:
N-03-032

Frequency domain multiplexing of multiple organic scintillator detectors (#1385)

M. Mishra1, J. Mattingly1, J. Mueller1

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

Content

Anode pulses from multiple organic detectors can be multiplexed to a single digitizer channel using a simple circuit that converts the output from the photomultiplier tube to damped sinusoidal oscillations. This damped sinusoidal output gives a distinct frequency to each detector depending on the value of the passive components attached to the circuit. The frequency – domain analysis on the ringing pulse is performed to extract the information (time-of-arrival and charge collected) about the original anode pulse. The frequency associated with the waveform identifies the detector from which the pulse originated. The results show that the time-of-arrival of the anode pulse and charge collected under it can be calculated using the first amplitude and phase of the ringing waveform respectively. A linear relationship between the charge collected and the amplitude of the sinusoidal waveform is established. A linear relationship is established between the time-of-arrival of the anode pulse and phase of the sinusoidal waveform. Coincidence measurements were performed using Na-22 source where phase of the ringing waveform was used to calculate time-of-arrival of the coincident pulse. The results show an increase in FWHM of about 1 ns when the ringing waveform was used to estimate the timing information.

Keywords: Multiplexing, Fourier transform
Poster panel
(face) ID: 65


Poster Number:
N-03-033

FPGA-based Single Photon Counting and Timing from an Array of Superconducting Nanowire Single Photon Detectors (#1489)

N. Lusardi1, G. Bulgarini2, F. Garzetti1, A. Geraci1

1 Politecnico di Milano, DEIB - Department of Electronics, Milano, Italy
2 Single Quantum BV, Delft, Netherlands

Content

Counting single photons and measuring their arrival time is of crucial importance for imaging, computing or communication applications that use single photons or few photons to outperform classical techniques. Single photons or pair of photons can for instance be used to enhance the resolution of optical imaging techniques, or to transmit information with ultimate security using quantum cryptography. In order to maintain this performance gain in such applications, the exact number of photons and their arrival time must be measured and monitored. In this contribution, we present a method to measure the number of photons and their arrival time by using 16 Superconducting Nanowire Single Photon Detectors (SNSPDs) optically coupled to a weak laser via a fiber multiplexer.

Since a single SNSPD is not sensitive to the number of incoming photons, the optical signal multiplexing is necessary to measure photon correlations among the channels and thus reconstruct the statistics of the optical pulse. The readout and counting of the photon arrivals is performed with a fast multi-channel Asynchronous-Correlated-Digital-Counter (ACDC) [4] whereas the arrival time is measured by an high resolution multi-channel Time-to-Digital Converter (TDC) with resolution of 10 ps, full-scale-range of 640 ns and global precision guaranteed below 22 ps r.m.s. referred to each single channel.

Both of the ACDC and the TDC are implemented in the Programmable Logic (PL) of a Xilinx Zynq®-7 XC7Z030 Xilinx System-of-Chip (SoC) device hosted in a customized acquisition board interfaced outside by means of a USB 3.0 communication gate.

Keywords: SNSPD, ACDC, TDC, FPGA
Poster panel
(face) ID: 67


Poster Number:
N-03-034

Influence of Switch Queue Length on Data Acquisition System using DCB (#1558)

R. Imaike1, S. - N. Iwai1, Y. Nagasaka1

1 Hiroshima Institute of Technology, Graduate School of Science and Technology, Hiroshima-shi, Hiroshima, Japan

Content

A system has become to be used in the field of large-scale scientific experiments with the advance of information technology. Especially, in the DAQ system for a high energy physics experiment such as ATLAS experiment at CERN, a parallel processing via a large number of network switches is performed to enhance efficiency of acquiring and analyzing experimental data. In addition, many-to-one simultaneous communication is performed to gather vast amounts of data generated by a large number of detectors into one computer for analyses. A network traffic congestion, however, occurs in the network of the DAQ system due to the characteristics of the communication, and it results a decrease in the throughput because of packet losses. Therefore, it is required to avoid congestions and packet losses caused by many-to-one simultaneous communication. In order to solve this problem, the DCB (Data Center Bridging) technology which realize the lossless Ethernet is being studied. Since event fragments in the large-scale data acquisition system is, however, transmitted via a large number of network switches, it is considered that an influence of a buffer size of the network switch is big. Therefore, this study focuses on a queue of the network switch in the DAQ system using DCB and makes these influences for the system performance clear. Fairness and throughput of each flow in the many-to-one simultaneous communication system were measured. As a result, it was concluded that the maximum performance was achieved in case that the average queue length in the network switch was small.

Keywords: Data Acquisition System, Data Center Bridging, Network Switch
Poster panel
(face) ID: 69


Poster Number:
N-03-035

All in One Integrated Smart Photomultiplier Tube Readout Electronics with Gigabit Ethernet and POE (#1886)

T. Xue1, J. Zhu1, L. Wei2, Y. Luo1, J. Li1, K. Kang1, G. Gong1

1 Tsinghua University, Beijing, Beijing, China
2 Nuctech Company Limited, Beijing, Beijing, China

Content

Photomultiplier tubes (PMT) act main roles in physics experiments, especially in high energy physics and nuclear related experiments. Traditional data acquisition system use the discrete standard pulse shaping and FADC plug-in boards which are based on NIM or VME system to implement the readout function for photomultiplier tubes. In some applications, there are few PMTs used in whole system, or in some distributed applications, long distance analog cable with high voltage power cable are not allowed due to the larger distributed space. The all in one integrated readout electronics are designed for neutron scintillator detector runs in China Jinping underground Laboratory (CJPL). The detector ordinary design is using two terminals readout scheme and two channels pulse shaping and FADC plug-in VME boards combined with a trigger logic board for anti-coincidence. All of the pulse shaping analog circuit, analog to digital converter, real time trigger scheme, data buffering and transmission are integrated in the all in one integrated readout electronics with power over ethernet supported. Only one Gigabit unscreened twisted-pair cable are needed for over 700 Mbps data throughput and more than 10W power. This paper will illustrate the architecture, hardware and software development for these all in one integrated readout electronics.

Keywords: Photomultiplier tubes, readout electronics, POE
Poster panel
(face) ID: 71


Poster Number:
N-03-036

Pre-research on Jiangmen Neutrino Experiment Readout Data Flow Software (#2296)

Z. Tingxuan1, 2, L. Fei1, 2, Z. Kejun1, 2

1 University of Chinese Academy of Sciences, Institute of High Energy Physics, Beijing, Beijing, China
2 state Key Laboratory of Partical Detection and Eletronics, Institute of High Energy Physics, Beijing, Beijing, China

Content

The Jiangnan neutrino experiment will design, develop and run an international leading neutrino experimental station to determine the quality order of neutrinos, accurately measure the neutrino hybrid parameters, and carry out a number of other scientific frontier studies. The experimental station consists of detector system, electronics system and online data acquisition system. The detector system detects signals  and transports them to electronics system. The electronic system converts signals into binary data and send it to data acquisition system. The data acquisition system receives, processes and stores the converted binary data for offline analysis. The data acquisition system of the Jiangmen neutrino experiment needs to read out the event data generated by 20,000 photomultiplier tubes at the event rate of 1KHz, and needs to carry out event assembly and online data storage. The total readout bandwidth is about 320Gb/s. How to simulate the electronic board to send data, how to maximize the use of readout servers' network bandwidth to arrange as many connections as possible per node, and make sure that the transmission speed of each connection meet the experimental needs become difficult. The readout data flow software studied in this paper is to solve these problems. The workflow of the entire data flow software is divided into four parts: The simulation program that simulates the electronic board to send data, readout program, event building and storage. The simulation program supports 1KHz data transmission frequency and multi-node multithreaded concurrent sending. The readout section provides two modes. The first one is multi-threaded readout , each thread processes one connection. The second one opens fewer threads, each thread handles multiple connections concurrently. After testing, both readout mode can multithreading read out 1024 concurrent connections per node, and the readout bandwidth can reach 16.8Gb/s per node.

Keywords: Jiangmen neutrino experiment; data flow; readout; simulated electronics; multithreaded; transmission speed
Poster panel
(face) ID: 73


Poster Number:
N-03-037

A distributed data acquisition system for signal digitizers with on-line analysis capabilities (#2441)

C. L. Fontana1, M. Lunardon1, F. E. Pino1, L. Stevanato1, S. Moretto1

1 Università degli Studi di Padova, Dipartimento di Fisica ed Astronomia, Padova, Italy

Content

In this article we present a distributed Data Acquisition (DAQ) system developed for the C-BORD project. Many examples of DAQ systems are monolithic processes that run on a computer attached to the DAQ hardware. In this new DAQ, a different process is assigned to each task of the system (e.g. data acquisition, pre-processing, analysis, high-voltage management...). The communication between the processes is obtained through dedicated communication sockets. An important advantage of this approach is the possibility to distribute the system over several computers connected in a network, in order to distribute the computational load. The distributed nature of the system allows also the implementation of on-line data analysis processes that can be computationally intensive. Moreover the system is very versatile, as the different tasks can be dynamically activated or disabled, and robust, since a failure of one of the processes does not jeopardize the whole system. The system has been used in the project to acquire the data generated by fast signal digitizers. Excellent results were obtained, both in terms of performance (i.e. maximum acquisition rates) and stability.

The project entitled "effective Container inspection at BORDer control points" (C-BORD) is funded by the European H2020 program. Its aim is to develop a comprehensive set of technologies for the generalized Non-Intrusive Inspection (NII) of containers and large-volume freight at the EU border.

Keywords: distributed DAQ, C-BORD, digitizers
Poster panel
(face) ID: 75


Poster Number:
N-03-038

Front-end Readout Electronics for Micromegas Detectors in the ATLAS New Small Wheel (#2501)

K. A. Johns1, W. Hart1

1 University of Arizona, Tucson, Arizona, United States of America

On behalf of the ATLAS-Collaboration

Content

The design and implementation of demonstrator front-end readout electronics for Micromegas detectors to be employed in the New Small Wheel, an ATLAS muon spectrometer upgrade, are described.  The demonstrator electronics board accepts 512 Micromegas detector channels as input.  Amplification, shaping and digitization of each input signal is performed by eight custom ASIC’s developed by Brookhaven National Lab.  Configuration and control functions of the ASIC’s and Gigabit Ethernet readout functions are performed using an Artix-7 FPGA.  Design constraints and considerations for this small form factor board are discussed.  Measurements of the noise performance, both off- and on-detector, are presented.  Results using an Fe-55 source are also shown. Design changes for the final front-end readout electronics to be used in the ATLAS experiment are discussed. 

Keywords: LHC, ATLAS, muon detector, micromegas detector, front-end readout
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(face) ID: 77


Poster Number:
N-03-039

A Scalable Synchronized Timing System for Digital PET (#2683)

J. Wu1, 2, D. Xi1, X. Mei1, 2, C. Zeng1, 2, W. Liu1, R. Chen1, 2, P. Zhang1, 2, Y. Liu1, 2, P. Xiao2, 3, Q. Xie2, 3

1 Raymeasure Medical Technology Co., Ltd (Suzhou), Suzhou, JIangsu, China
2 Huazhong University of Science and Technology, Department of Biomedical Engineering, Wuhan, Hubei, China
3 Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei, China

Content

Having varieties of methods for sampling the scintillation pulse of a PET detector, there is a great interest in developing a modularized PET detector that directly outputs digital scintillation pulse. The information of an incoming Gamma photon can be extracted by analyzing the yielded digital scintillation pulse with a DSP method implemented in a computer or an embedded platform. Such PET detector can leverage the fast growing computer industry to lower cost, short development/upgrade cycle, and simplified electronics. Besides, developers can setup a PET system quickly by using several such modularized detectors and a standard computer. Previously, we have released such a PET detector (named Si-BDM 2550E) by employing the MVT (Multi-Voltage Threshold) method. Several demonstration systems have been developed by using the detectors. To get the correct coincidence events, all the detectors in the PET system are required to work in a same clock domain. Therefore, a clock distribution system for time synchronization is required for a PET system in such architecture. Unfortunately, the clock system tends be customized according to the number of detectors employed in the PET system. In this paper, we propose a standard clock distribution module. It can work in either master mode or slave mode and a slide switch is used for work mode selecting. In the master mode, the clock distribution module provides 12 channel synchronized clock and reset outputs. In the slave mode, an input clock and reset signal is required, it outputs 12 channel clock and reset signals, each of which is synchronized with the input signal. Thus, one clock distribution module work in master mode can drive a system using 12 digital detectors or less. Using one clock module working in master mode and several in slave mode, we can setup a synchronized clock system organized in a tree structure. it could support 144 detectors when its height is 2 and 1728 detectors when its height is 3.

Keywords: Digital PET, PET Detector Module, Multi-Voltage Threshold, Synchronized Timing System
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(face) ID: 79


Poster Number:
N-03-040
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DQM4HEP - A generic online monitor for particle physics experiments (#3010)

T. Coates1, R. Ete6, A. Pingault2, A. Irles3, D. Cussans4, M. Wing5

1 University of Sussex, Brighton, United Kingdom of Great Britain and Northern Ireland
2 Ghent University, Ghent, Belgium
3 LAL Orsay, Orsay, France
4 University of Bristol, Bristol, United Kingdom of Great Britain and Northern Ireland
5 University College London, London, United Kingdom of Great Britain and Northern Ireland
6 Institut de Physique Nucléaire de Lyon, Lyon, France

Content

There is currently a lot of activity in R&D for future collider experiments. Multiple detector prototypes are being tested, each one with slightly different requirements regarding the format of the data to be analysed. This has generated a variety of ad-hoc solutions for data acquisition and online data monitoring. We present a generic C++11 online monitoring framework called DQM4HEP, which is designed for use as a generic online monitor for particle physics experiments, ranging from small tabletop experiments to large multi-detector testbeams, such as those currently ongoing/planned at the DESY2 or CERN SPS beamlines. We present results obtained using DQM4HEP at several testbeams where the CALICE AHCAL, SDHCAL and SiWECAL detector prototypes have been tested. During these testbeams, online analysis using DQM4HEP's framework has been developed and used. We also present the currently ongoing work to integrate DQM4HEP within the EUDAQ tool. EUDAQ is a tool for common and generic data acquisition within the AIDA-2020 collaboration. This will allow these two frameworks to work together as a generic and complete DAQ and monitoring system for any type of detector prototype tested on beam tests, which is one of the goals of the AIDA-2020 project.

Keywords: data acquisition, online monitoring, AIDA-2020, testbeams
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(face) ID: 81


Poster Number:
N-03-041

Signal-to-Noise Analysis in Count Rate Dependent Adaptive Digital Pulse Processing for Gamma-Ray Spectroscopy (#3580)

S. Saxena1, A. I. Hawari1

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

Content

Digital techniques for nuclear spectroscopy are increasingly implemented in modern radiation detection systems, which allows consideration of the attributes of the generated signal on a pulse-by-pulse basis. High energy resolution and high throughput characteristics are of primary importance in radiation spectroscopy. In this work, theoretical limits of the count rate dependent signal-to-noise ratio (SNR) are established for time invariant (fixed) and time variant (adaptive) digital filters. The theoretical calculated results illustrate that the adaptive filter provides improved SNR for a given pulse throughput rate as compared to a fixed filter. Further analysis shows that the detector with low input capacitance is a preferable choice to achieve better SNR and improve performance at high count rates. The adaptive digital pulse shaping algorithms, based on digital trapezoid and cusp filters, are implemented using field programmable gate array (FPGA, Kintex 7) for real-time signal processing.  National Instruments (NI) NI 5761 14 bit, 250 MS/s adaptor module is used for digitizing an HPGe detector’s pre-amplifier pulses. The experimental results with coaxial HPGe with fixed and adaptive shaping show reasonable agreement with the theoretical calculations. At high count rates, the time-variant trapezoid shaping provides better SNR performance as compared to cusp shaping. At 700 kcps input count rate, with 50% throughput rate, with fixed trapezoid shaping the normalized SNR degrades to 6.2% (FWHM of 6.83 keV) for the 137Cs 662 keV gamma peak, whereas adaptive shaping shows a significant improvement in the normalized SNR (FWHM of 4.5 keV) for the same experimental conditions.

Keywords: Adaptive, digital, Signal to noise
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(face) ID: 83


Poster Number:
N-03-042

An Adaptive Coding for Fixed-Latency and Radiation-Tolerant Serial Data Transfers (#3707)

A. Aloisio1, 2, V. Izzo2, R. Giordano1, 2, S. Perrella1, 2

1 Università di Napoli, Dipartimento di Fisica, Napoli, Italy
2 INFN, Sezione di Napoli, Napoli, Italy

Content

High-speed serial links are key components of trigger and data acquisition systems of High Energy Physics (HEP) experiments.  Transmission protocols have been defined for protecting the data and guarantee a reliable transmission over noisy communication channels. Line codes ensure enough transitions in the serialized data and provide DC balance. Error correction codes improve the robustness of the link to burst or single bit errors. However, both line codes and error correcting codes generally add an overhead, which is not always acceptable. For instance, the 8B 10B code introduces an overhead of 25% and any error correcting code reduces the bandwidth available for the payload. Thus, since data-transfer rates continue to grow for trigger and data acquisition systems, in order to cope with the higher amount of data to read out, low-overhead coding alternatives have to be considered. Some examples are the scrambling technique used in 10-Gigabit Ethernet or in the CERN GBT project.

In this work, we present a proof of concept of a bidirectional data link running at 5 Gbps which uses a self-synchronizing scrambler for data randomization. In the view of the operation in radiation areas, our design supports adaptive forward error correction. The link is able to adjust the amount of redundancy in the serial stream according to the number of transmission errors detected per time unit. Moreover, the architecture is such to guarantee a low and deterministic latency often required by trigger systems.

We discuss an implementation of our architecture in a Kintex-7 FPGA and we show how it can be used for data readout from a JESD204B-compliant high-speed ADC. We describe the logic resources occupation of the design, its performances in terms of maximum operation frequency and power consumption. We also present the measurements of the serial data stream eye-diagrams and of latency stability.

Keywords: optical links, FPGAs, trigger, data acquisition, forward error correction, scrambling, radiation tolerance
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(face) ID: 85


Poster Number:
N-03-043

Development of Simple Benchmark Tool for Data Acquisition Network (#3889)

S. - N. Iwai1, R. Imake1, Y. Nagasaka1

1 Graduate School of Science and Technology, hiroshima institute of technology, Information Systems Science, Hirosima, Hirosima, Japan

Content

A data acquisition system of a high energy physics experiment such as ATLAS experiment is a parallel processing system to collect and process data on many source nodes efficiently. The architecture to collect the event fragments is a many-to-one communication one for each event. The architecture is very simple, but it causes packet losses in the system without any flow controls, less fairness, and less throughput of each flow. Many researches are performed to solve the problem by architecture and technology approaches. General-purpose network performance tools such as iPerf and Netperf  are used to evaluate data acquisition network in those researches. However, as the traffic of a data acquisition system isn’t general because many source nodes send data to one destination at the same time in the same timing, the tools can’t evaluate the specific traffic correctly. Then we developed a simple benchmark tool, DAQPerf, to evaluate the network for the specific traffic easily. DAQPerf consists of three parts, i.e., a trigger, a sender and a receiver. The trigger sends the trigger data to the sender, and the sender sends data like an event fragment to the receiver when it receives the trigger. The receiver receives data from each sender and measures time to calculate performances. We also measured errors of the interval time of triggers and the transmission time of data to evaluate the performance of DAQPerf itself. As a result, it was confirmed the error of the interval time of triggers is about 10 usec  and that of the transmission time of data is about 100 usec in the case of 10 kHz trigger .

Keywords: data acquisition systems, network switch
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(face) ID: 87


Poster Number:
N-03-044

Image-based Simulation of Internal Materials Decomposition with Dual Energy Gamma-ray CT system (#3922)

D. H. Lee1, C. Park2, C. H. Baek3, C. Lee2, S. J. Lee2, H. Song2, Y. H. Chung2

1 The University of Sydney, Faculty of Health Sciences and Brain & Mind Centre, Sydney, NSW, Australia
2 Yonsei University, Department of Radiation Convergence Engineering, Wonju, Gangwon-do, Republic of Korea
3 Dongseo University, Department of Radiological Science, Busan, Republic of Korea

Content

Gamma-ray computed tomography (CT) has been widely used to inspect cracks, obstructions, and fluid flow in pipes. Previous studies have shown that the inspection accuracy is limited when materials in the pipe have a similar density. To overcome this drawback, we investigated a method to discriminate small density differences using a dual energy gamma-ray CT. In this study, the performance of a gamma-ray CT system was simulated using GATE (Geant4 Application for Tomographic Emission) with three types of sources (Am-241, Co-57, and Cs-137). A PVC pipe containing oil and sludge was modeled as a phantom. Sparsely acquired data were reconstructed using filtered back-projection (FBP) and iterative total variation (TV) denoising algorithms. Each material discrimination procedure was performed with a post-reconstruction technique. Our results clearly showed that the gamma-ray CT imaging with Am-241 and Co-57 sources and the TV denoising reconstruction algorithm can be used to inspect the internal structures based on discriminated images. The calculated areas of discriminated oil and sludge were within an error margin of 2% (oil: 78.4% and sludge: 21.6%) compared with the simulated phantom (oil: 80% and sludge: 20%). For both gamma sources, the calculated contrast-to-noise ratio (CNR) values with the TV denoising algorithm were the highest values for all structures (Am-241/Co-57: 18.03/28.95 for oil vs. sludge, 41.67/31.53 for oil vs. PVC pipe, and 23.64/31.53 for sludge vs. PVC pipe). The feasibility of our approach and results indicates it usefulness for industrial fields that require internal obstruction inspections.

Keywords: gamma-ray CT, GATE simulation, material discrimination, filtered back-projection (FBP), total variation (TV) denoising, post-reconstruction
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(face) ID: 89


Poster Number:
N-03-045

Threshold Optimization in Multi-Voltage Threshold Digitizers for TOF PET detector (#4217)

Z. Deng1, 2, H. Wu1, 2, W. Xiong1, 2, A. Zhao1, 2, Y. Yang3, Z. Duan1, 2, P. Xiao1, 2, J. Tang1, 2, Q. Xie1, 2

1 Huazhong University of Science and Technology, Wuhan, China
2 Wuhan National Laboratory for Optoelectronics, Wuhan, China
3 Suzhou Science and Technology Town Hospital, Department of Nuclear Medicine, Suzhou, China

Content

Performance of time pickoff method, such as Leading Edge Discrimination (LED) and Multi-Voltage Threshold (MVT) digitization, is particularly sensitive to the threshold setting. Thus, targeting to improve the time resolving ability, we investigate the choice of threshold in LED and MVT. In this work, we analyze the time spectrum with information entropy theory. Based on the principle of Minimum Entropy (ME), we give the criterion of threshold choice. To evaluate the improvement of our threshold choice, we set up a pair of detectors to test the coincidence time resolution (CTR) under different threshold settings. For LED, we scan the test thresholds to find the ME thresholds; For MVT, problem about choosing K thresholds can be divided into K subproblems of threshold scanning by using Greedy Strategy (GS). The result shows that better CTR indeed can be obtained when the pickoff logic works with our optimized threshold. The optimized threshold setting generates a time performance 5 times better than the worst threshold setting in LED. And for MVT, our GS method obtains the threshold setting with an obviously better CTR compared with Uniform Distribution (UD) especially when the number of the used thresholds is small. All of these results demonstrate the adaptability and superiority of the strategys in time pickoff of MVT.

Keywords: Multi-Voltage Threshold (MVT) digitization, time pickoff method, coincidence time resolution, threshold
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(face) ID: 93


Poster Number:
N-03-047

Microhexcavity Plasma Panel Detectors: Development and Results (#2500)

P. S. Friedman1, M. Ausilio2, J. W. Chapman2, C. Ferretti2, D. S. Levin2, A. Mulski2, N. Ristrow2, A. Das3, M. Raviv-Moshe3, Y. Benhammou3, E. Etzion3, D. Reikher3, R. Yaacoby3

1 Integrated Sensors, LLC, Ottawa Hills, Ohio, United States of America
2 University of Michigan, Department of Physics, Ann Arbor, Michigan, United States of America
3 Tel Aviv University, Beverly and Raymond Sackler School of Physics and Astronomy, Tel Aviv, Israel

Content

We report here on the fabrication, staging and operation of the first small prototype microhexcavity detectors. The microhexcavity plasma panel sensor (µH-PPS) is a type of plasma panel detector inspired by plasma display panels (PDPs), the core component of flat panel plasma televisions. A PDP comprises millions of discrete cells per square meter each of which, when provided with a signal pulse, can initiate and sustain a plasma discharge. Configured as a detector, a pixel or cell is biased to discharge when a free-electron is generated in the gas. A µH-PPS functions as a highly integrated and dense array of pixel-elements each independently capable of detecting free-electrons deposited into the cell. The prototypes have a 16 by 16 matrix of 2 mm, closed packed hexagon pixels. Initial tests of these detectors, conducted with Ne based gases at atmospheric pressure, indicate that each pixel responds independently of its neighboring cells, producing volt level pulse amplitudes in response to ionizing radiation. Results will include the hit rate response to a radioactive beta source, cosmic ray muons, backgrounds from spontaneous discharge, pixel isolation and uniformity, and efficiency measurements.

Keywords: gaseous detectors, micropattern detectors, plasma panel detectors, plasma panel sensors, particle tracking detectors, charged-particle radiation detectors, gaseous particle detector, plasma panel radiation detectors, PPS, position-sensitive gas detector
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(face) ID: 95


Poster Number:
N-03-048

Construction of the drift tube chamber and drift time spectra research of the drift tubes (#2747)

Q. Chen1, Y. Wang1, L. Sun1

1 NUCTECH COMPANY LIMITED, Detector Technology Department, Beijing, Beijing, China

Content

Gas filled detectors provide practical and cost effective solution with wide range applications. They have the advantage of simple construction, decent energy resolution, and good position resolution.

Drift tube chamber, which consists of layers of regularly arranged drift tubes, can be used to track charged particles such as muons. When a charged particle causes hits in a drift tube, ionization electrons are drifting to the avalanche region around the anode wire. By measuring the drift time of the electrons (especially the fastest ones), the perpendicular distance between the wire and the charged particle track can be get. The drift tubes provide sub-millimeter position resolution perpendicular to the wire, which makes it possible to track charged particles in three-dimensions by placing the tubes in orthogonal layers.

Previously, the relationship between the drift time t and the perpendicular distance r should be studied. We use time integration method to obtain the r-t relationship.

We have designed and manufactured several drift tubes. And the research is in progress. The result of the r-t relationship will be shown on the poster.

Keywords: drift tube, track detector, drift time spectrum
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(face) ID: 97


Poster Number:
N-03-049

Design Studies for a TPC Readout Plane Using Zigzag Patterns with Multistage GEM Detectors (#3994)

B. Azmoun1, P. Garg3, T. K. Hemmick3, M. Hohlmann2, A. Kiselev1, M. L. Purschke1, C. Woody1, A. Zhang1

1 Brookhaven National Laboratory, Physics Department, Upton, New York, United States of America
2 Florida Institute of Technology, Department of Physics & Space Sciences, Melbourne, Florida, United States of America
3 Stony Brook University, Department of Physics and Astronomy, Stony Brook, New York, United States of America

Content

A new Time Projection Chamber (TPC) is currently under development for the sPHENIX experiment at RHIC. The TPC will be read out using multistage GEM detectors on each end and will be divided into approximately 40 pad layers in radius. Each pad layer is required to provide a spatial resolution of ~200 microns, which must be achieved with a minimal channel count in order to minimize the overall cost of the detector. The current proposal is to make the pads into a zigzag shape in order to enhance charge sharing among neighboring pads. This will allow for the possibility to interpolate the hit position to high precision, resulting in a position resolution many times better than the 2mm pitch of the readout pads. This paper discusses various simulation studies that were carried out to optimize the size and shape of the zigzag pads for the readout board for the TPC, along with the technical challenges in fabricating it. It will also describe the performance of the first prototype readout board obtained from measurements carried out in the laboratory using a highly collimated X-ray source.

Keywords: Zigzag readout, GEM, TPC, position resolution
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(face) ID: 99


Poster Number:
N-03-050

Installation and Commissioning of the CMS Hadron Forward Calorimeters Phase I Upgrade (#1526)

B. Biki1, 2, Y. Onel1

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

Content

The final phase of the CMS Hadron Forward Calorimeters Phase I upgrade was performed during the Extended Year End Technical Stop of 2016 – 2017. In the framework of the upgrade, the PMT boxes were reworked to implement two channel readout in order to exploit the benefits of the multi-anode PMTs in background tagging and signal recovery. The front-end electronics was also being upgraded to QIE10-based electronics which will implement larger dynamic range and a 6-bit TDC to provide additional handles to eliminate the background.

Following this major upgrade, the Hadron Forward Calorimeters are being commissioned for operation readiness in 2017. Here we describe the details and the components of the upgrade, and discuss the operational experience and results obtained during the upgrade and commissioning.

Keywords: CMS, hadron calorimetry, upgrade
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(face) ID: 101


Poster Number:
N-03-051

Characterization of the quartz surface quality with beta-source (#1594)

A. Natochii1, 2, F. Addesa3, O. Bezshyyko1, D. Breton2, L. Burmistrov2, V. Chaumat2, G. Cavoto3, S. Dubos2, M. Garattini4, Y. Gavrikov4, F. Iacoangeli3, J. Maalmi Di Bello2, S. Montesano4, V. Puill2, R. Rossi4, W. Scandale4, A. Stocchi2

1 Taras Shevchenko National University of Kyiv (TSNUK), Nuclear Physics Department, Kyiv, Ukraine
2 Linear Accelerator Laboratory (LAL), University of Paris-Sud/IN2P3, Orsay, France
3 Istituto Nazionale di Fisica Nucleare (INFN), Rome, Italy
4 European Organization for Nuclear Research (CERN), Geneva, Switzerland

Content

We present a method for characterizing the quality of the Cherenkov quartz radiator using beta-source. Two quartz (fused silica) bars (5x10x400 mm3) are fabricated and used for CpFM (Cherenkov detector for proton Flux Measurement) detector constructed for CERN-UA9 experiment. Due to the main goal of the detector - measurement of the proton number passing though the radiator, one of the dominant property of the device is the Cherenkov light collection produced by relativistic charge particle in the quartz. Thus the production quality of the radiator should be as high as possible to avoid light losses in the quartz. Current work presents the idea and implementation of the test to estimate quartz optical properties. The test is based on the scanning with 90Sr radioactive source (standard deviation is 1.17 mm) of the radiator surface and measurements of the Cherenkov light rate and amplitude, detected by the PMT attached to the quartz bars. This experimental data have been compared with a Monte-Carlo simulation which repeats the same experimental configuration. This method gives an upper estimate of the radiator parameters which are related to two different quantities: (1) probability of the total internal reflection; (2) ineffective area in the corner of the quartz bar. The obtained results based on fit the data with Monte-Carlo say us that 96.4 +/- 0.1 % and 95.9 +/- 0.1 % are total internal reflection probability for first and second bar respectively. The effect of the inefficient corner area for second bar is negligible and for first bar this area reaches 2.7 +/- 0.7 % from total surface area of the bar.

Keywords: Cherenkov radiation, Monte-Carlo simulation, Quartz quality
Poster panel
(face) ID: 103


Poster Number:
N-03-052

Gamma Polari-Calorimeter: Performing simultaneous polarization and energy measurements of gamma rays using the pair production process (#1776)

M. Cuciuc1, S. Ataman1, L. D'Alessi1, K. Homma2, 3, T. Moritaka4, Y. Nakamiya5, M. Rosu1, K. Seto1, O. Tesileanu1

1 Horia Hulubei National Institute of Physics & Nuclear Engineering, ELI-NP, Bucharest, Romania
2 Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
3 Ecole Polytechnique, International Center for Zetta-Exawatt Science and Technology, Palaiseau, France
4 National Central University, Dept Phys, Taoyuan, Taiwan
5 Kyoto University, Institute for Chemical Research, Kyoto, Japan

Content

This paper describes the Gamma Polari-Calorimeter, an instrument that is being developed for measuring both energy and polarization degree of gamma beams in the energy range of 100 MeV - 2 GeV at the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility. The instrument is being designed for performing these measurements using the polarization dependent cross-section of the pair production process. The electron-positron pair's kinematic properties are measured after being tracked using a magnetic field and thin pixelated silicon sensors, thus enabling the reconstruction of the incoming gamma photon that generated the pair. The degree of polarization of the beam can then be obtained from the amplitude of the modulation of the azimuthal distribution of the electron-positron pairs. Monte Carlo simulations show that for single incoming photons within the targeted energy range the energy resolution is below 15% and the analyzing power is greater than 0.5. Performance degrades when considering multiple photons arriving at the detector simultaneously but the energy resolution is still kept below 20% while simultaneously reconstructing as many as 12 photons per event.

Keywords: gamma ray, polarimetry, pair production, ELI-NP
Poster panel
(face) ID: 105


Poster Number:
N-03-053

Precision Measurements of Induced Radioactivity and Absolute Luminosity Determination with TPX Detectors in LHC Proton-Proton Collisions at 13 TeV (#2050)

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

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

Content

The measurements of absolute luminosity are performed with the van der Meer scan technique by separating the LHC proton beams and measuring the widths of the beams. These measurements are performed with low-intensity LHC proton-proton collisions. Therefore, the precision of measurements of the luminosity during the van der Meer scans strongly depends on the exact determination of the background. This background is largely due to induced radioactivity at the positions of the TPX devices in the ATLAS cavern. The activation at a given time depends on the history of the LHC operation. A detailed study of activation has been performed for the data taken at 13 TeV proton-proton collisions which allowed to reduce the uncertainty on the absolute luminosity determination.

Keywords: Induced radioactivity, absolute luminosity, pixel detectors
Poster panel
(face) ID: 107


Poster Number:
N-03-054

Development of Threshold-Type Aerogel Cherenkov Counter with A Low Mis-PID Rate (#2247)

T. Tanaka1, Y. Emoto2, K. Fujihara2, T. Ishikawa3, H. Ito2, H. Kawai2, S. Kimura2, H. Matsunaga1, A. Kobayashi2, T. Mizuno2, T. Nakamura2, M. Tabata2, T. Yuzawa1

1 Chiba University, Faculty of Science, Chiba, Chiba, Japan
2 Chiba University, Graduate School of Science, Chiba, Chiba, Japan
3 Tohoku Univesity, Research Center for Electron Photon Science, Sendai, Miyagi, Japan

Content

Charged particles sometimes produce knock-on electrons. The speed of an electron with the kinetic energy of 2 MeV is approximately 98% of the speed of light. Therefore, Threshold-type Cherenkov counters sometimes fail to identify particles because of knock-on electrons. It is difficult to distinguish Cherenkov light produced by original charged particles from Cherenkov light produced by knock-on electrons, when using a standard threshold-type Cherenkov counter which use a small number of large-area photomultiplier tubes (PMTs). We are developing a threshold-type Cherenkov counter. In a standard counter, charged particles enter to the radiator perpendicularly. In our counter, charged particles have a small incident angle to the radiator. The area of the radiator of our counter is larger than that of a standard counter. However, the required volume of the radiator of our counter is nearly the same as that of a standard counter, because the thickness of the radiator of our counter can be ruduced. In addition, the number of necessary PMTs of our counter is nearly the same as that of a standard counter, because PMTs of our counter are installed obliquely. In our counter, the PMT which most of the Cherenkov light produced by the original charged particles enter differs from the PMT which most of the Cherenkov light produced by the knock-on electrons enter. Therefore, the error rate of particle identification (PID) is greatly reduced. The mis-PID rate in standard threshold-type Cherenkov counters is 3 to 5%, and that in our counter is expected to be 0.5% or less.

Keywords: Cherenkov counter, particle identification, Silica aerogel, Photoproduction nuclear physics
Poster panel
(face) ID: 109


Poster Number:
N-03-055

The Upgrade of the CMS Pixel Detector for the High-Luminosity LHC (#2438)

C. Vernieri1, F. Fahim1

1 Fermilab, BATAVIA, United States of America

Content

The LHC is planning an upgrade program which will bring the luminosity to up to 7.5 x 1034 cm-2s-1 in 2028, with the goal of an integrated luminosity of 3000 fb-1 by the end of 2037. This High Luminosity scenario, HL-LHC, will present new challenges of higher data rates and increased radiation. In order to maintain its physics reach in the HL-LHC era, the CMS Collaboration is preparing an upgrade program of the detector known as the Phase-2 upgrade. The CMS Phase-2 Pixel upgrade will require a high bandwidth readout system and highly radiation tolerant sensors and on-detector ASICs. Serial powering schemes are under consideration to accommodate significant constraints on the system. The new CMS pixel detector concept, featuring a new layout that include very forward pixel discs with acceptance extended from |eta|<2.4 to |eta|<4, will be presented together with performance estimates. Concepts for lightweight detector mechanics will be introduced which will result in a significant reduction in the material budget with respect to the Phase-1 pixel detector.

The following requirements have been taken into account to  design the new pixel detector:  (i) a narrower pitch than the present pixel detector, for better transverse and longitudinal impact parameter resolution and lower occupancy under high pileup conditions to improve track separation in jets; (ii) geometrical coverage up to |eta|<4 to provide large forward acceptance and to mitigate pileup; (iii) capability to withstand a harsh radiation environment with negligible inefficiencies.

Keywords: CMS, pixel, tracker, LHC, radiation tolerant
Poster panel
(face) ID: 111


Poster Number:
N-03-056

An Front-End Test Stand for the Analog ASICs of the ATLAS LAr Calorimeter Phase-II Upgrade (#2594)

H. Liu1, H. Chen1, G. D. Geronimo2, 3, C. D. L. Taille5, F. Lanni1, H. Ma1, N. Morange4, N. Seguin-Moreau5, L. Serin4, S. Simion4

1 Brookhaven National Laboratory, Upton, New York, United States of America
2 Stony Brook University, Stony Brook, New York, United States of America
3 University of Michigan, Ann Arbor, Michigan, United States of America
4 Laboratoire de l'Accélérateur Linéaire, Orsay Cedex, France
5 OMEGA/Ecole Polytechnique/CNRS, Palaiseau, France

Content

This paper describes the development of a common front-end test stand for the analog ASICs, which are part of the effort to develop the front-end electronics for the ATLAS LAr Calorimeter Phase-II upgrade of HL-LHC. The common test stand consists of a front-end test board, a toy calorimeter, multiple ASIC mezzanine boards and the DAQ system. The front-end test board is the bridge between the DAQ system and the ASIC mezzanine, it integrates two 16-channel ADCs for digitizing the outputs of the analog ASIC and a calibration pulse generator for detector signal injection. The analog ASICs under test are mounted on the ASIC mezzanine boards, their outputs are connected to the front-end test board through an FMC
connector. A Xilinx ZC706 evaluation board is utilized as the DAQ board for this test stand, a Gigabit Ethernet link is implemented on the DAQ board for control, configuration and ADC data transmission. The test of two analog ASICs with this test stand is ongoing. The preliminary test results demonstrate that this test stand is suitable for the testing of the multi-channel analog ASICs developed for the LAr Calorimeter Phase-II upgrade. We will report on the design and complete characterization of the test stand with front-end ASICs.

Keywords: analog ASIC, electronic test stand, liquid argon calorimeter, ATLAS experiment
Poster panel
(face) ID: 113


Poster Number:
N-03-057
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ATLAS Muon-to-Central Trigger Processor Interface Upgrad (#2795)

M. V. Silva Oliveira1

1 STFC, Didcot, United Kingdom of Great Britain and Northern Ireland

Content

To cope with the higher luminosity and physics cross-sections for the third run of the Large Hadron Collider (LHC) and beyond, the Trigger and Data Acquisition (TDAQ) system of ATLAS experiment at CERN is being upgraded. Part of the TDAQ system, the Muon to Central Trigger Processor Interface (MUCTPI) connects the output of the barrel and endcap muon trigger to the Central Trigger Processor (CTP). It receives muon candidate information from each of the 208 muon trigger sectors and counts muon candidates for each transverse momentum threshold and sends it to the CTP; taking into account the possible overlap between trigger sector in order to avoid double counting of muon candidates. A full redesign and replacement of the existing MUCTPI is required in order to provide full-granularity muon position information at the bunch crossing rate·to the Topological Trigger processor (L 1Topo) and to be able to interface with the new sector logic modules. State-of-the-art FPGA technology and high-density ribbon fiber-optic transmitters and receivers will be used to receive, process and send detector information with low latency in a single AdvancedTCA blade. In comparison, the existing system requires a full 9U VMEbus shelf with 18 boards. The upgraded MUCTPI features over 270 multi-gigabit optical inputs/outputs with an aggregate bandwidth of over 2 Tbit/sec. In this presentation we will present the hardware design, the testing of the optical I/O, integration tests with the muon sector logic, and the results from the validation of the first prototype.

Keywords: trigger
Poster panel
(face) ID: 115


Poster Number:
N-03-058

Longitudinally segmented shashlik calorimeters with SiPM embedded readout (#2808)

A. Longhin1, A. Berra7, 8, M. Bonesini2, G. Catanesi5, G. Sirri3, G. De Rosa6, G. Ballerini7, R. Boanta2, C. Brizzolari2, 8, G. Brunetti1, S. Cecchini3, F. Cindolo3, A. Coffani2, 8, G. Collazuol1, E. Conti1, F. Dal Corso1, A. Gola11, R. Intonti5, C. Jollet13, 12, V. Mascagna7, 8, M. Laveder9, 1, L. Ludovici14, L. Magaletti5, G. Mandrioli3, A. Margotti3, N. Mauri3, A. Meregaglia12, 13, M. Mezzetto1, A. Paoloni15, M. Pari9, 1, L. Pasqualini3, G. Paternoster11, L. Patrizii3, C. Piemonte11, M. Pozzato3, M. Prest7, 8, F. Pupilli1, E. Radicioni5, C. Riccio6, 10, A. Ruggeri6, F. Terranova2, 8, E. Vallazza4, L. Votano15

1 INFN, Padova, Padova, Italy
2 Univ. Milano Bicocca, Milano Bicocca, Milano, Italy
3 INFN, Bologna, Bologna, Italy
4 INFN, Trieste, Trieste, Italy
5 INFN, Bari, Bari, Italy
6 INFN, Napoli, Napoli, Italy
7 Univ., Insubria, Como, Italy
8 INFN, Milano Bicocca, Milano, Italy
9 Univ., Padova, Padova, Italy
10 Univ. Federico II, Napoli, Napoli, Italy
11 Fondazione Bruno Kessler (FBK), Trento, Italy
12 CNRS, Strasbourg, Strasbourg, France
13 IPHC, Univ. Strasbourg, Strasbourg, France
14 INFN, Roma1, Roma, Italy
15 INFN, LNF, Frascati, Italy

ENUBET collaboration

Content

Shashlik calorimeters are sampling calorimeters using wavelength shifting fibers running perpendicularly to the scintillating/absorber plates for the light readout. These devices are cost-effective, easy to assemble, and characterized by a good flexibility in terms of energy resolution. On the contrary, the perpendicular optical fiber readout and the resulting fiber bundling to the photosensor pose a strong limitation to the longitudinal segmentation. Recently, the fast development of solid state photosensors allowed for the integration of the readout system directly in the bulk of the calorimeter, opening new possibilities in terms of longitudinal segmentation (SCENTT INFN R&D). In an ultra-compact module every single fiber segment is directly connected to a non-amplified SiPM; the SiPMs are arranged in arrays on custom PCBs and readout by a fast electronics based on waveform digitizers.This detector technology is the baseline option for ENUBET which is a 5 year project (2016-2021) funded by the European Research Council aiming to demonstrate the possibility of a complete instrumentation of the decay tunnel of conventional neutrino beam allowing a ten-fold reduction on the neutrino flux normalization error. In the talk we will present the results and a detailed performance assessment of the novel ultra-compact design obtained with a prototype of longitudinally segmented shashlik calorimeter, readout with SiPMs embedded in the calorimeter bulk. Tests performed at the CERN PS-T9 beamline in the 1-5 GeV energy range in November 2016 allowed to get results in terms of linearity, energy resolution and e/pi discrimination at various beam angles reproducing the grazing incident coinditions typical of neutrino beam decay tunnels. We will also present results on a neutron irradiation campaign of our Silicon Photomultipliers at the INFN-LNL CN accelerator allowing to test neutron fluences of O(10^12/cm^2) using 5 MeV protons on a Be target.

Keywords: shashlik calorimeter Silicon photomultibliers embedded readout testbeam, neutrino physics
Poster panel
(face) ID: 117


Poster Number:
N-03-059

The Layout and Performance of the Phase-II upgrade of the tracking detector of the ATLAS experiment (#3173)

X. Ai1

1 Chinese Academy of Sciences (CAS), Institute of High Energy Physics (IHEP), Beijing, China

On behalf of ATLAS Collaboration

Content

In the high luminosity era of the Large Hadron Collider (HL-LHC), the instantaneous luminosity is expected to reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. To cope with the resultant increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk), aiming to provide tracking coverage up to |η|<4. 

The ITk consists of an inner pixel and an outer strip detector, the design of which are careful compromises of the conflicting requirements of a low mass, mechanically stable tracker with sufficient number of high granularity sensors for high quality tracking.  The latest design and performance estimates of the ITk detector are presented and discussed.

Keywords: ATLAS, HL-LHC, silicon, tracking
Poster panel
(face) ID: 119


Poster Number:
N-03-060

Development of a Particle Identification System of Pions, Kaons, and Protons with the Momentum Range of 1 to 10 GeV/c (#3321)

T. Mizuno1, Y. Emoto1, H. Kawai1, A. Kobayashi1, A. Konaka2, T. Nakamura1, T. Sekiguchi3

1 Chiba University, Graduate School of Science, Chiba, Chiba, Japan
2 TRIUMF, Physical Science Division, Vancouver, British Columbia, Canada
3 High Energy Accelerator Research Organization (KEK), Institute of Particle and Nuclear Studies (IPNS), Tsukuba, Ibaraki, Japan

Content

A particle identification system of pions, kaons, and protons with the momentum range of 1 to 10 GeV/c is being developed. It is composed of 3 silica aerogel Cherenkov counters, 1 CO2 gas Cherenkov counter, 1 TOF counter, and 4 nuclear emulsions. The size of the detection surface is 20 cm by 20 cm. Using the relation expression of the refractive index and the threshold momentum of Cherenkov radiation for each particle, required refractive indices of Cherenkov radiators are determined. The refractive indices of the silica-aerogel tiles are around 1.049, 1.014, and 1.004 and that of the gas is around 1.0012. They are settled in this order toward the downstream of the beam line. The number of the Cherenkov counters which detect Cherenkov light indicates the candidate of the combination of the particle and its momentum range. The most upstream Cherenkov counter is a ring image Cherenkov counter (RICH), and the light is read out by silicon photomultipliers (SiPM) arranged in an array-form. Misidentified events by knocked out electrons can be rejected by searching the Cherenkov ring only around the particle track. In the other 3 Cherenkov counters, the light is read out by PMTs. The momentum of the particle is measured at the nuclear emulsions settled in the upstream side. Using the result of the measurement of the momentum and the Cherenkov light, the particle can be identified except 1 to 1.56 GeV/c kaons and protons. For these particles, the velocities measured at the TOF counter are used. This time, the Cherenkov counter using the silica aerogel with the refractive index around 1.004 is proposed, while the lowest refractive index of silica aerogel whose detection surface is equal to or greater than 20 cm by 20 cm and directly read out by PMTs has been 1.007. We are going to test several silica-aerogel tiles with different refractive indices around 1.004 and confirm which refractive index is suited for attaining enough Cherenkov photons and detection efficiency.

Keywords: PID, Cherenkov Counter, Silica Aerogel, Low Refractive Index
Poster panel
(face) ID: 121


Poster Number:
N-03-061

Search for Heavy Stable Charged Particles in the CMS Experiment using the RPC phase II upgraded detectors (#4084)

G. Ramirez2, C. Carrillo1

1 Universidad de los Andes, Physics Department, Bogotá, Colombia
2 CINVESTAV, Mexico, Mexico

CMS Collaboration

Content

Several theoretical models inspired in the idea of supersymmetry (SUSY) accommodate the possibility of HSCPs (Heavy Stable Charged Particles). The phase-II upgrade of the CMS-RPC system will allow the trigger and identification of these kind of slow moving particles exploiting the Time of Flight Technique with the improved time resolution that a new DAQ system will provide (~1ns). Moreover new RPC chambers will be installed to extend the acceptance coverage up to $\eta<2.1$ with similar time resolution and better space resolution to complement this search. 

In this talk a trigger strategy to detect HSCPs with the RPC detectors is presented, its performance is studied with Monte Carlo simulations and the expected results with the High Luminosity LHC data are shown.

Keywords: CMS Muon RPC HSCP
Poster panel
(face) ID: 123


Poster Number:
N-03-062

A Quick Radioactivity Measuring Instrument for Emergent Nuclear Pollution Detection in Body Of Water (#1321)

K. Song1, 2, J. Chen2, Y. Yang3, J. Liu4

1 University of Science and Technology of China, Modern Physics, Hefei, Anhui, China
2 State Key Laboratory of Particle Detection and Electronics, Hefei, Anhui, China
3 Hefei Guowei electronics Co.,Ltd., Hefei, Anhui, China
4 Ministry of Environmental Protection of Nuclear and Radiation Safety Center, Beijing, China

Content

This manuscript presents a portable Liquid Scintillation (LS) coincidence instrument for quick radioactivity measurement in water body, which is based on high speed Analog to Digital Converter (ADC) direct sampling. To meet the requirement of emergent water nuclear accident onsite detection, the instrument is designed to be portable and quick detection. Traditionally, water concentration and precipitation methods are necessarily used for measurement of radioactivity in body of water. It will take several hours to finish the several liters water concentration process. So it cannot be acceptable for emergent situation. The existing lab equipment for water radiation detection is generally bulk and unmovable. For quickly detecting the radioactivity, we research and design a portable Liquid Scintillation (LS) coincidence instrument without water concentration process.  It can greatly reduce the evaporation and detection time for  several hours.  The LS signal from PMT is sampled by a two-channel 12bit ADC with a speed of 800Msps. Data coincidence calculation implemented by a chip of Field Programmable Gate Array (FPGA). Test result shows that the instrument can count the total pulse number of alpha and beta particle radiation, and also can discriminate them satisfactorily. It’s novel and significant for quick and efficient onsite detection of environmental radioactive pollution in body of water.

Keywords: Liquid scintillation, Radionuclide, Radioactivity measurement, Onsite detection in body of water, Emergent situation
Poster panel
(face) ID: 125


Poster Number:
N-03-063

C-BORD - an overview of efficient toolbox for high-volume freight inspection (#1397)

P. Sibczynski1, M. Moszyński1, A. Dziedzic1, K. Grodzicki1, J. Iwanowska-Hanke1, L. Swiderski1, A. Syntfeld-Każuch1, D. Wolski1, A. Dołębska2, W. Gęsikowski2, J. Godlewski2

1 National Centre for Nuclear Research, Radiation Detector's Division, Otwock, Mazowieckie, Poland
2 Custof Office Gdynia, Gdańsk, Pomorskie, Poland

Content

For several years, detection of various threats on country borders plays a significant role in the frame of Homeland Security. Every year Custom Offices seizure significant amount of various illegal materials: starting from tobacco, alcohol, drugs, ending on explosives, weapons, and even radioactive or nuclear materials. The Custom Office requirements often vary from country to country, thus, adaptation of the non–intrusive inspection systems to fit the expectation is especially important. Unfortunately, until now observation of threat-like object in cargo leads to physical inspection, which is time  consuming and reduce cost-efficiency of the inspection process. Thus, investigation of novel systems supporting Custom Offices is extremely important. In this manuscript we would like to present an overview of the systems developed and upgraded in the frame of C-BORD project, funded by EU Horizon 2020 program. During the project, focused on inspection of high-volume cargo equipment, the upgrade covers existing commercial systems, like radiation portal monitors (RPM) and Smiths Detection HCVM-T X-ray scanner, as well as the evaporation based detectors, known also as an electronic SNIFFER. Meanwhile, new systems based on tagged neutron device for non-intrusive detection of tobacco, drugs and explosives, as well as photofission detectors for nuclear material detection is being developed. All these systems will be integrated in common interface, allowing for getting information from each device used one inspection sequence. All these technologies will be tested on real inspection sites in The Netherlands, Poland and Hungary in 2018.

Keywords: cargo inspection, homeland security, border monitoring, X-ray, rpm, neutrons, photofission, sniffer, gamma rays, prompt radiation, delayed radiation
Poster panel
(face) ID: 127


Poster Number:
N-03-064

Using Time-Correlated Neutron and Gamma-Ray Measurements to Distinguish Point-like Sources From Spatially Distributed Sources Without Imaging (#1606)

J. M. Mueller1, J. Mattingly1

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

Content

We have developed a novel technique to determine the spatial extent of a fissioning assembly for disarmament verification without the use of imaging techniques.  Our method is based on timing correlations between coincident neutrons and gamma rays.  Fast liquid scintillator detectors are placed on either side of an unknown assembly of special nuclear material (SNM).  The distance to the average fission location can be determined from the neutron energy deposition in the detector and the neutron time of arrival relative to the preceding gamma ray.  For a spatially distributed source of SNM, the distance to the average fission location changes if the gamma ray is detected on the same side or opposite side of the SNM as the neutron.  This difference in distance is related to the attenuation of the gamma ray through the SNM and the size of the source.  In principle, this technique could be used to estimate the radius of an unknown source of fissioning SNM and determine if the source is hollow or solid without imaging.  To demonstrate this technique, we will present MCNPX-PoliMi simulations and experimental measurements of a 4.5 kg sphere of 94% 239Pu weapons-grade plutonium metal.

Keywords: Disarmament verification, Special nuclear material, Liquid scintillators, Neutron imaging, Gamma-ray imaging
Poster panel
(face) ID: 129


Poster Number:
N-03-065

Discriminating Uranium Isotopes Based on Long-Lived Delayed Neutron Time Emission Profile (#1682)

J. Nattress1, K. Ogren1, F. Sutanto1, M. Sharma1, I. Jovanovic1

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

Content

In nuclear nonproliferation and safeguards, detecting and characterizing special nuclear material (SNM) endures as one of the greatest challenges. Timely and accurate SNM detection in complex configurations is frequently associated with relatively small signal-to-background ratios, requiring innovative approaches to overcome specific application constraints. Passive detection relies on the spontaneous radioactive decay, whereas active interrogation (AI) uses external probing radiation to identify and characterize the material. AI provides a greater signal intensity, providing a more viable method for SNM detection. We have shown in recent work that the fission of U-238 can be detected from the neutron buildup and decay originating from long-lived delayed neutron groups. Taking into account the time dependence of delayed neutron spectrum and energy-dependent detector efficiency, we have demonstrated the consistency of the measurement with the published nuclear data for U-238. Here we extend those measurements to U-235, with a goal to demonstrate a capability to also measure the isotopic composition of the material from the differences in the shape of the delayed neutron time emission profile. Custom-built capture gated detectors and PSD-capable commercial liquid scintillators are utilized for the experiment. We present the results from our prior work, preliminary Monte Carlo simulations, and the relevant details of the experimental approach.

Keywords: Delayed Neutrons, special nuclear material, active interrogation
Poster panel
(face) ID: 131


Poster Number:
N-03-066

Application of 2D convex polygon partitioning to radiation detection (#1854)

P. K. Soin1

1 AWE, Reading, Berkshire, United Kingdom of Great Britain and Northern Ireland

Content

The challenge of ensuring an area is completely searched can be encapsulated in “the art gallery” problem. Solutions must ensure all areas of the gallery are ‘covered’ or visible to at least one ‘guard’. By partitioning the space into convex polygons (triangles in our method) and locating one guard at each polygon centre, the entire area can be surveyed. In this paper we present work to extend the methodology for use in radiation detection; in particular adapting the convex polygon model to accommodate the reduction in source strength as an inverse square function of the distance from the source. The searchable area was an irregular space with the inclusion of obstacles. A pre-existing open source code was used to completely split the searchable area into triangles, this was combined with an algorithm developed to incorporate the inverse square effect. A gamma source and a gross counts detector, with a 360o field of view, were assumed. The triangle size was constrained by the detection distance required to give a 95% confidence using the Currie limit. Application of the triangle method divided the space into a series of search areas, these points were then combined via a travelling salesman approach allowing the creation of an optimised route for a handheld detector to travel through the area. It is believed that compared to existing radiation detection search methods, this approach offers advantages if the searchable area is irregular and filled with obstacles.

Keywords: gamma detection, homeland security, search algorithm
Poster panel
(face) ID: 133


Poster Number:
N-03-067

SiPM Readout of Stilbene Crystals for Safeguards Applications (#2265)

A. Di Fulvio1, K. A. Beyer1, T. H. Shin1, N. Giha1, S. D. Clarke1, S. A. Pozzi1

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

Content

We developed and tested a compact neutron detector, based on a cylindrical stilbene crystal, directly read out by a silicon photomultiplier (SiPM). We experimentally studied the effect of light guides to improve the light collection efficiency when coupling small SiPMs to large-area crystals. The use of the light guide for a crystal-SiPM area ratio of 14x increased the overall detection efficiency approximately 5%, compared to a direct coupling. This modest efficiency improvement hardly justifies the additional design complexity due to adding a light guide to the assembly. Based on a simple readout scheme, a pair of detectors was used to measure correlated emissions from laboratory fission sources (i.e. Cf-252). An amplified SiPM readout board is being developed. Detectors equipped with this readout device will be used in a multiplicity counter assembly to inspect special nuclear materials.

Keywords: Silicon Photomultiplier, SiPM, Stilbene, Organic Scintillators, Light Guide, Gamma-neutron Discrimination
Poster panel
(face) ID: 135


Poster Number:
N-03-068

Detection of gas bubbles in bitumen filled nuclear waste drums with Muon Scattering Tomography (#2505)

L. Frazao1, M. Dobrowolska2, C. Poole1, D. Kikola2, J. J. Velthuis1

1 University of Bristol, Bristol, United Kingdom of Great Britain and Northern Ireland
2 Warsaw University of Technology, Warsaw, Poland

Content

It is common for legacy nuclear waste to be stored in bitumen containers. Metals in these containers oxidise, forming hydrogen, which can accumulate in bubbles due to the impermeability of bitumen. These bubbles can make the waste in the drum expand, a situation that is already seen: 220 L drums that were originally filled with 180 L intermediate level waste have been observed to overflow. The hydrogen can accumulate in larger bubbles. The minimum volume of a hydrogen bubble needed to ignite the bitumen was estimated to be about 2 litres. Additionally, if hydrogen reacts with uranium it can form hydride, which is pyrophoric and could ignite if exposed to air. It is necessary to use non-invasive techniques to find these gas bubbles in nuclear waste. We developed a method to measure the volume of gas bubbles embedded in concrete using muon scattering tomography. Muons are highly penetrating and scatter in matter, with wider distributions for higher atomic numbers. So the scattering distribution will be different for muons that only cross bitumen than for the ones that also cross a gas bubble. We simulated bitumen volumes containing varying sizes of gas bubbles. Using an algorithm based on scatter angles, reconstructed scattering vertices and muon momentum, we have reconstructed the total amount of gas in a container for volumes bigger than 2 litres, achieving a volume resolution of 10%. We also determined if this volume of gas is in a single bubble or in separate bubbles. This is essential for risk assessment of the stored waste.

Keywords: Nuclear waste, Cluster finding methods, Muon tomography
Poster panel
(face) ID: 137


Poster Number:
N-03-069

Development of Spatial Dose Distribution measuring system of X-ray Beamline in Cargo container scanner using MV energy x-ray (#2744)

C. H. Lim1, J. - W. Park1, I. - H. Kim1, J. H. Lee1, Y. - K. Lim1, M. - K. Moon2, S. Lee3

1 Korea Research Institute of Ships & Ocean Engineering, Ocean System Engineering Research Division, Daejeon, Republic of Korea
2 Korea Atomic Energy Research Institute, Neutron Instrumentation, Daejeon, Republic of Korea
3 Daon Technology, Co., Ltd., Daejeon, Republic of Korea

Content

A cargo container scanner using X-ray generally inspects the interior of the container non-destructively using MV X-ray. Scanning system should be designed with a structure to minimize the leakage of X-ray dose. To do this, precise control of the incident direction and distribution of X-ray beam has to be performed. In order perform the control, precise alignment of the X-ray and image detector should be performed and accurate collimation of the X-ray beam should be performed. And the X-ray beam distribution by position must be accurately measured. In order to measure the x-ray spatial dose distribution, methods using ion chambers, diodes, plastic scintillators, etc. can be used. Among these methods, the method using diode is difficult to measure the dose accurately compared to the ion chamber, but it has a merit that the size of the pixel can be made relatively small, the manufacturing cost is low, and the maintenance is simple. For this reason, a dose measuring device using a diode is widely used for measuring the dose. So, we have developed the spatial dose distribution measuring system to measure the spatial dose distribution of cargo container scanner. The experimental evaluation of the developed X-ray spatial dose distribution measuring device was carried out in the cargo container scanner test bed developed by KRISO (Korea Research Institute of Ship and Ocean Engineering). Experiments were carried out on the high resolution spatial dose distribution and the linearity of the response signal. According to the result, it is confirmed that the source distribution is well represented in the high resolution mode, and the response characteristic of the system according to the dose change is linear.

Keywords: cargo container scanner, x-ray spatial dose distribution, diode array
Poster panel
(face) ID: 141


Poster Number:
N-03-071

Quantitative analysis of a nuclear reaction-based active interrogation imaging system (#3002)

J. Harms1, P. B. Rose Jr.1, A. S. Erickson1

1 Georgia Tech, Woodruff School of Mechanical Engineering, Atlanta, Georgia, United States of America

Content

The number of containers carrying cargo across borders has been steadily increasing over the past several years, leading to an ever increasing risk that special nuclear material (SNM) may be smuggled across the border. The industry standard for cargo scanning, bremsstrahlung interrogation beams and energy integrating detectors, can give adequate measurements of transmission, but bremsstrahlung is inherently poor at differentiating materials based on proton number, Z. Our group has been developing an imaging system based on quasi-monoenergetic γ-ray emissions from the 11B(d,nγ)12C reaction, with energy resolving Cherenkov detectors. We have previously shown that energy-dependent transmission measurements from this beam with Cherenkov detectors are possible, accurately differentiating materials of varying Z up to around 75.

In this research, we characterize the performance of this imaging system, via Geant4 simulations, according to ANSI standard N42.46. Specifically, we measure the penetration capabilities of the beam, the spatial resolution of our imaging array, and the contrast sensitivity as outlined in the report. Additionally, we measure the contrast-to-noise ratio and error of our Zeff calculation on a simulation phantom consisting of six materials immersed in a tub of water. All images are acquired with the reaction beam are compared to images acquired with a 9 MV bremsstrahlung beam. Because the contrast phantom images require dual-energy information for Zeff reconstruction, we also simulate 6 MV/9 MV dual-energy acquisition for comparison to the reaction-based beam.

Keywords: active interrogation, gamma imaging, Cherenkov detectors, nuclear reaction based sources, image quality
Poster panel
(face) ID: 143


Poster Number:
N-03-072

A Study On Development Of Cargo Inspection System For Improving Searching Efficiency (#3059)

J. Lee1, J. Park1, C. Lim1, I. Kim1, Y. Lim1

1 Korea Research Institute of Ships & Ocean engineering (KRISO), Ocean System Engineering Research Division, Daejeon, Republic of Korea

Content

This paper describes a cargo inspection system that distinguish of overlapped cargo and provides a Three-dimensional scanning image.

Normally, a cargo inspection system consists of one X-ray Generator and one Array detector. In this case, only the plane of the vehicle can be scanned because it uses a straight beam. Therefore, it is very difficult to distinguish of overlapped object. The Identification of the overlapped cargo is very important to identified dangerous materials and smuggled cargoes. For these reasons, we have developed a cargo inspection system for distinguish of overlapped cargoes. Our system consists of a x-ray generator, two array detector and three collimators with an adjustable angle. After scanned the cargo vehicle using two different angles, the overlapped cargoes can be identified using the parallax information of the stored data. Also, Three-dimensional images can be generated using the parallax information of the stored images. These image enables the easily identify the overlapped objects.

We conducted a scan test using real-cargo vehicle for performance verification. We used straight beam and 4 degree tilted beam for scan test. As a result, we confirmed that the overlapped objects can be identified.

Keywords: cargo inspection system, x-ray image Processing
Poster panel
(face) ID: 145


Poster Number:
N-03-073

Evaluation of the Directionality Performance of Detector Arrays Consisting of Non-Directional Radiation Detectors (#3396)

C. G. Britt1, B. Ayaz-Maierhafer1, E. Green2, C. E. Seifert3, H. Qi2, J. P. Hayward1

1 University of Tennessee, Departement of Nuclear Engineering, Knoxville, Tennessee, United States of America
2 University of Tennessee, Department of Electrical Engineering and Computer Sciences, Knoxville, Tennessee, United States of America
3 Pacific Northwest National Laboratory, Pacific Northwest National Laboratory, Richland, Washington, United States of America

Content

This paper proposes a method to characterize the directionality performance of detector arrays consisting of non-directional radiation detectors in ideal measurement scenarios. The method consists of generating detector responses via MCNP simulations, synthetically generating measurements with these simulations, training a classifier, then evaluating the classifier's performance. Results indicate that directionality performance is highly dependent on detector array geometry. Furthermore, the results suggest that array geometries which perturb the detector response into unique values will yield favourable directionality performance.

Keywords: Radiation, detector array, localization, directionality, supervised learning.
Poster panel
(face) ID: 147


Poster Number:
N-03-074

ACTM: Adaptive Computed Tomography with Modulated-Energy X-ray Pulses (#3434)

A. Arodzero1, 4, S. Boucher1, P. Burstein1, M. Frenkel2, A. Katsevich2, 3, S. V. Kutsaev1, R. C. Lanza4

1 RadiaBeam Technologies, LLC, Santa Monica, California, United States of America
2 iTomography Corporation, Houston, Texas, United States of America
3 University of Central Florida, Department of Mathematics, Orlando, Florida, United States of America
4 Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, Cambridge, Massachusetts, United States of America

Content

We present a new CT technology: Adaptive Computed Tomography with Modulated-energy X-ray pulses (ACTM). ACTM is based on adaptive intrapulse multi-energy cargo radiography techniques that have been developed over the last few years.  Key enabling ACTM techniques are:

  • Linear accelerator with deep energy control;
  • Multi-energy spectrum in each slice provided by packets of short X-ray pulses with end-point energy ramp up (> 1 MHz rate of energy switching);
  • Fast detectors with reduced sensitivity to scatter radiation;
  • Detector readout with silicon photomultipliers (SiPM) provides time-resolved measurement of short X-ray pulses;
  • Electronics and an algorithm for automatic, dynamic adjustment of SiPM responsivity in detector channels provides increased dynamic range of X-ray imaging;
  • Real-time algorithm for pulse-by-pulse linac output adjustment, based on: a) the immediately preceding measured X-ray attenuations; and b) selection of high and low energy windows for dual-energy material decomposition;
  • Filtered backprojection (FBP) helical reconstruction based on the efficient Katsevich algorithm.

The ACTM method for dual- (or, multi-) energy CT mitigates the main disadvantages of the conventional interlaced approach: 1) ambiguity and artifacts caused by sampling different regions due to motion of the object between interlaced pulses with distinct energies, and 2) small range of object thicknesses where material decomposition is valid.
The key advantage of the ACTM concept is that each elementary pencil beam (which makes up the cone beam) collects the multi-energy data.  This is different from the conventional dual-energy method with interlaced linac, where two energies are acquired by slightly offset beams. Thus, our approach has two benefits: 1) For the same accelerator pulse rate, the scan rate can be twice as fast (better throughput) or can be done with a lower dose; 2) Accurate multi-energy decomposition in the projection domain is possible.

Keywords: Homeland security, Industrial CT, Cargo inspection, Computed Tomography, X-ray radiography, Material decomposition
Poster panel
(face) ID: 149


Poster Number:
N-03-075

Cyclotron-based Monoenergetic Gamma Sources for Cargo Security (#3512)

H. Y. Lee1, S. J. Jepeal1, R. Nelson1, A. Danagoulian1, Z. S. Hartwig1, B. S. Henderson1, R. C. Lanza1

1 massachusetts institute of technology, Nuclear Science and Engineering, Cambridge, Massachusetts, United States of America

Content

Passive detection of special nuclear material (SNM) radiation signatures in commercial cargoes is difficult because of a weak signal which can be easily shielded. Hence, active interrogation and radiographic techniques are the most effective method for screening cargoes potentially containing shielded SNM. There are existing and implemented inspection systems utilizing dual-energy bremsstrahlung beams to determine the screening materials but requires high doses and may pose a radiation hazard to cargo or potential stowaways. We present a concept system using low energy nuclear reactions to produce multiple monoenergetic gamma rays (MMGR) which can then be used to perform a low-dose radiography to simultaneously measure the atomic number (Z) and the areal density of the cargo. Previous research showed that RFQ-based 3 MeV d+ beams can be used to produce 4.4 MeV and 15.1 MeV photons, using them in radiographic and active interrogation applications. Here, we describe a new system which uses ION-12(SC), a 12 MeV superconducting cyclotron, utilizing (p,pγ) reactions on various targets to produce MMGR. Current work involves investigation of suitable reactions to produce MMGR, thus further extending research on the use of MMGR in radiography. Unlike the RFQ-based MMGR system, the cyclotron’s Continuous Wave (CW) proton beam technology has the potential of leveraging neutron-less reactions leading to lower radiation doses. The use of superconducting technology has resulted in an accelerator which weights less than 2 tonnes.  Most importantly the proton-based nuclear reactions on 12C and 16O targets can result in gamma intensities of the order comparable to that of bremsstrahlung systems. These characteristics can enable mobile, low-dose systems which will achieve more accurate detection of SNM in commercial cargoes. Preliminary results involving spectral transmission data from the will be presented.  The cyclotron and the general concept will be presented and discussed.

Keywords: SNM, MMGR, multiple monoenergetic gamma rays, special nuclear material, cyclotron, neutron-less reactions, mobile, low-dose
Poster panel
(face) ID: 151


Poster Number:
N-03-076

A Portable Gamma/Neutron Detector for Characterization and Imaging of Nuclear Materials (#3544)

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

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

Content

Long-range detection and localization of dispersed or concentrated neutron and gamma-ray activity is needed to identify potential nuclear security or defense threats. A field-deployable neutron detector was recently developed, with directional and spectroscopic capability, based on a moderated array of boron coated straws (BCS). We present here a modified design that incorporates in addition a CsI-based gamma detector, for long-range imaging and characterization of gamma emitting nuclear materials. The detector can be manufactured at low cost, and operated reliably in the field with simple electronics, and lower power consumption, compared to CZT-based solutions. We present measurements and simulations that demonstrate the spectroscopic capability of the detector, and the application of a tomographic technique for long-range imaging of neutron and gamma radiation emitted by hidden nuclear materials.

This work was supported in part by the U.S. Defense Threat Reduction Agency (DTRA) under contract no. HDTRA1-14-P-0007. The views, opinions, and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government.

The image reconstruction algorithm has been developed with the help and guidance of Andrew Reader (King’s College, London). 

Keywords: boron-coated straws, neutron imaging, gamma imaging, long-range imaging
Poster panel
(face) ID: 153


Poster Number:
N-03-077

Nuclear Safeguards Assay of Spent Nuclear Fuel via Fission Product Analysis with Coincident LaBr3:Ce Gamma-ray Spectrometry (#3604)

A. Drescher1, S. Landsberger1, D. Haas1

1 University of Texas at Austin, Nuclear Engineering Teaching Lab, Austin, Texas, United States of America

Content

The development of a methodology for in situ measurements of spent nuclear fuel with coincident cerium-doped lanthanum bromide detectors is described in this paper.  Coincident measurements allow for de-convolution of the gamma-ray signatures from many fission products that are unidentifiable in the single detector spectra. Measurements were conducted on a series of three 20 mg uranium standards of varying enrichment (natural, 3% and 63% 235U) which were irradiated in the TRIGA reactor at The University of Texas at Austin for one hour at 500 kW. A time evolution study of the coincident spectra was conducted by performing measurements of all three samples a dozen times over the course of a month post-irradiation. The coincident signatures of the following fission products were identified in many of the spectra: 150Eu, 98Tc, 149Gd, 105Ag, 156Tb, and 134Cs. Additional investigations were performed on the magnitudes of the fission product coincidence photopeaks to determine the correlation to enrichment based on characteristic fission product yields of 235U and 238U. These results can be used to determine spent nuclear fuel enrichment or burnup for verification of operator declared operating history, and prevention of diversion of special nuclear materials.

Keywords: Uranium, Fission Products, Spent Nuclear Fuel, Coincidence, Lanthanum Bromide, Gamma-ray Spectrometry
Poster panel
(face) ID: 155


Poster Number:
N-03-078

Stilbene Cell Analysis for Radioxenon Monitoring (#3648)

C. Sivels1, J. McIntyre2, S. Clarke1, S. A. Pozzi1

1 University of Michigan, Ann Arbor, Michigan, United States of America
2 Pacific Northwest National Laboratory, Richland, Washington, United States of America

Content

Radioxenon monitoring is one component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty. The systems in the field use hollow plastic scintillators for beta detection and NaI(Tl) detectors for gamma detection, where the plastic cell also contains the radioxenon gas sample. To advance the current detection systems, a stilbene cell is being developed to replace the plastic cell. The benefits of developing a new detector that uses stilbene include increased resolution of the beta spectrum and removal of radon interferences using pulse shape discrimination. This work presents measurements made by a prototype stilbene cell to analyze the detector characteristics. These results are compared to the presently used plastic cell. The experiment was modeled using MCNPX-PoliMi and the simulations will be used to optimize the final design of the stilbene cell.

Keywords: Comprehensive Nuclear-Test-Ban Treaty, radioxenon monitoring, Radiation detection
Poster panel
(face) ID: 157


Poster Number:
N-03-079

Use of Backscatter Imaging for Detection of IEDs (#3944)

T. R. Barker1, C. R. Hughes1, J. E. Baciak1

1 University of Florida, Nuclear Engineering Program, Gainesville, Florida, United States of America

Content

Compton Backscatter Imaging (CBI) has proven effective, but slow in land mine detection when used in a pencil beam configuration. Additionally, recent research has shown CBI in a fan beam configuration can be effective in Pressure Plate Improvised Explosive Device (IED) interrogation, given the higher acquisition speeds. However, one of the simplistic questions presented with recent research is whether the original experimental design accounted for the realistic possibility of non-binary, non-ideal conditions.

When a pressure plate IED is detected in a combat environment, the pressure plate may come in multiple configurations in terms of wire diameter, angular orientation, or construction. Previous research has demonstrated that when scanned perpendicularly or parallel to the fan beam, a device can be detected within 35 s. These orientations allow for the most exposure of the device by each detector pixel, thus providing the greatest opportunity to overcome integration time within the detector. However, not every pressure plate will be detected or interrogated at an ideal angle with the greatest exposure.

This research has demonstrated that despite the angular orientation of the pressure plate target relative to the source fan beam and detector, a linear detector array can detect the presence of a pressure plate device under 3 cm of sand.

Keywords: Compton Backscatter Imaging, IED Detection
Poster panel
(face) ID: 159


Poster Number:
N-03-080

Improving the Radioisotope Detection Performance of KSr2I5:Eu2+ Scintillators (#4024)

E. D. Lukosi1, C. Melcher1

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

Content

This paper discusses the potential exploitation of the intrinsic radioactivity and light-trapping properties of Eu2+ activators in KSr2I5:Eu2+ scintillators. Utilizing the position-dependent transient light response of KSr2I5:Eu2+, the uniform distribution of background from 40K may be effectively discriminated against the non-uniform signals generated from moderate energy external gamma-rays.

Keywords: Potassium Strontium Iodide, Nuclear Security, Gamma Spectroscopy, Radioisotope Identification, Scintillation, KSr2I5
Poster panel
(face) ID: 161


Poster Number:
N-03-081

Design Optimization for a Wearable, Gamma-Ray and Neutron Sensitive, Detector Array with Directionality Estimation (#4128)

B. Ayaz-Maierhafer1, C. G. Britt1, A. J. August2, H. Qi2, C. E. Seifert3, J. P. Hayward1

1 University of Tennessee, Nuclear Engineering, Knoxville, Tennessee, United States of America
2 University of Tennessee, Electrical Engineering and Computer Science, Knoxville, Tennessee, United States of America
3 Pacific Northwest National Laboratory, Richland, Washington, United States of America

Content

In this study, we report on a constrained optimization and tradeoff study of a hybrid, backpack-based, detector array having directional sensing based upon gamma-ray occlusion. One resulting design uses CLYC detectors while the second feasibility design involves the coupling of gamma-ray-sensitive CsI scintillators and a LiCaAlF6 (LiCAF) neutron detector. The detector systems’ responses were investigated through simulation as a function of angle in a two-dimensional plane. The expected total counts, peak-to-total ratio, directionality performance, and detection of 40K for accurate gain stabilization were considered in the optimization. Source directionality estimation was investigated using Bayesian algorithms. Gamma-ray energies of 122 keV, 662 keV, and 1332 keV were considered. The equivalent neutron capture response compared with 3He was investigated for both designs.

Keywords: gamma ray detection, neutron detection, directionality, Monte Carlo, machine learning, Bayesian estimation
Poster panel
(face) ID: 163


Poster Number:
N-03-082

Bright Eu2+-activated polycrystalline ceramic neutron scintillators (#1288)

C. L. Wang1, M. P. Paranthaman2, R. A. Riedel1, J. P. Hodges1, J. J. Karlic2, R. A. Veatch2, L. Li2, C. A. Bridges2

1 Oak Ridge National Laboratory, Instrument and Source Devision, Oak Ridge, Tennessee, United States of America
2 Oak Ridge National Laboratory, Chemical Sciences Division, Oak Ridge, Tennessee, United States of America

Content

Scintillation properties of Eu2+-doped CaF2-AlF3-6LiF (Eu:CALF) polycrystalline ceramic thermal-neutron scintillators as a function of AlF3 concentration have been studied. The emission band peaked at a wavelength of 425-431 nm is due to the presence of Eu:CaF2 micro-crystallites. The highest light output from these samples is near 20,000 photons per thermal neutron, which is 3 times that of a GS20 6Li-glass scintillator. The pulse-decay lifetime and light output vs. AlF3 concentration may be understood using a radiation trapping model and the formation of Li3AlF6 phase. A neutron-gamma-discrimination (NGD) ratio of 9 x 108 was obtained from Principal Component Analysis (PCA) of digital waveforms, while Fisher Linear Discriminant Analysis (FLDA) can completely separate the thermal neutrons from the 60Co gamma rays within the limit of gamma event statistics used in this work. Our results suggest that Eu:CALF scintillators can potentially replace the GS20 scintillator in the Anger camera for thermal neutron imaging and in other neutron detection systems.              

Keywords: Neutron scintillator, light output; neutron-gamma discrimination
Poster panel
(face) ID: 165


Poster Number:
N-03-083

Optical fiber type neutron detector using eutectic LiF/CaF2 scintillator (#1933)

K. Watanabe1, K. Fukuda2, Y. Ikeda2, A. Ishikawa1, A. Yamazaki1, S. Yoshihashi1, A. Uritani1, T. Yanagida3

1 Nagoya University, Department of Applied Energy, Naogoya, Aichi, Japan
2 Tokuyama Corp., Shunan, Yamaguchi, Japan
3 Nara Institute of Science and Technology, Graduate School of Materials Science, Ikoma, Nara, Japan

Content

We are developing optical fiber type neutron detectors for relatively intense neutron fields, such as spallation neutron sources and irradiation fields of boron neutron capture therapy (BNCT).  For the detectors used in these fields, the detection efficiency or sensitivity is not so important but no gamma-ray sensitivity and no influence to the measured field are strongly required.  An optical fiber type neutron detector using a small piece of a bright neutron scintillator can suppress gamma-ray sensitivity preferentially to use difference in penetrating power between fast electrons and energetic charged particles generated in gamma-ray and neutron interactions, respectively.  Of course, a small detector has little influence to the measured field.  So far, we have applied a small piece of Eu:LiCaAlF6 scintillator for the optical fiber type neutron detector because of its high light yield and no hygroscopicity.  In this paper, we replace Eu:LiCaAlF6 to eutectic LiF/CaF2:Eu scintillator.  In this scintillator, LiF and CaF2 phases work as a converter from neutrons to energetic charged particles and a scintillator, respectively.  It is expected to have higher neutron sensitivity due to its higher 6Li content than the LiCaAlF6 scintillator.  We fabricated an optical fiber type neutron detector, in which a small piece of LiF/CaF2:Eu scintillator is mounted on a tip of an optical fiber.  The fabricated detector also shows a neutron peak in the spectrum.  Detectors showing a peak structure in the pulse height spectrum have advantages in stabilizing detector gain and assuring right operation.

Keywords: neutron detector, eutectic LiF/CaF2:Eu, optical fiber
Poster panel
(face) ID: 167


Poster Number:
N-03-084

The Development of Campbell integration system applied in high particle flux measurement (#2190)

W. Wang1, 2, J. Cao1, 2, X. Zhou1, 2, Z. Yin1, 2

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

Content

In this article, we present the design of a digital high speed, real-time Campbell integration neutron flux measurement system applied in the plasma diagnostic system in ITER.

Keywords: Campbell mode, signal pileup processing, neutron flux measurement
Poster panel
(face) ID: 169


Poster Number:
N-03-085

Probing of GAGG:Ce scintillation material for a fast neutron detection (#2210)

V. I. Dormenev1, A. Borisevich2, K. T. Brinkmann1, G. Dosovitskiy3, 4, A. Dosovitskiy5, A. Fedorov2, M. Korjik2, 4, D. Kozlov2, V. Mechinsky2, R. W. Novotny1, H. - G. Zaunick1

1 Justus-Liebig-University, II. Physical Institute, Giessen, Germany
2 Research Institute for Nuclear Problems, Minsk, Belarus
3 NRC “Kurchatov Institute” – IREA, Moscow, Russian Federation
4 National Research Centre “Kurchatov Institute”, Moscow, Russian Federation
5 “NeoChem” JSC, Moscow, Russian Federation

Content

An increase in the yield of scintillations in inorganic compounds with a garnet structure is achieved in mixed garnets, with partial or complete replacement of yttrium or lutetium ions by gadolinium ions, and aluminum ions with a pair of ions: aluminum and gallium upon activation of the compound by cerium ions. Single crystals of gadolinium-aluminum gallium garnet with the structural formula Gd3Al2Ga3O12, (GAGG), activated by cerium ions, can be used to detect neutrons. Natural gadolinium is a mixture of six stable isotopes: 154Gd (2.18%), 155Gd (14.8%), 156Gd (20.5%), 157Gd (15.7%), 158Gd (24.8%) and 160Gd (21.9%), two of which, 155Gd And 157Gd, have the highest of all known stable isotopes of the thermal neutron capture cross section, 61,000 and 254,000 barns, respectively. The capture of neutrons is accompanied by the emission of γ-quanta with a total energy of about 8 MeV:

n+155Gd→156Gd+γ(8.5 MeV)
n+157Gd→158Gd+γ(7.9 MeV),

The greatest yield among γ-quanta emitted due to the interaction has quanta with an energy of 76 keV and 179 keV. This energy release, as well as individual γ-quanta, can be detected by the same crystal in which the interaction takes place. Thus, this scintillation material can expand the possibilities for detecting neutrons in a wide energy range of neutrons. Here we describe results of the fast neutron detection, having energy more than 10 MeV, with GAGG crystal scintillator and PMT readout.

Keywords: Scintillator, Neutron detector, Garnet
Poster panel
(face) ID: 171


Poster Number:
N-03-086

Scintillation Glasses and Glass Ceramics containing Li, Be, Gd for Neutron Detection (#2399)

G. A. Dosovitskiy1, 2, O. V. Akimova1, 2, A. E. Dosovitskiy3, A. A. Fedorov1, 4, E. V. Gordienko1, 2, M. V. Korjik1, 4, D. Kozlov4, V. A. Mechinsky1, 4, E. Trat’siak4, E. Trusova5, P. A. Volkov1, 2, V. Dormenev6

1 National Research Centre “Kurchatov Institute”, Moscow, Russian Federation
2 NRC “Kurchatov Institute” – IREA, Moscow, Russian Federation
3 NeoChem JSC, Moscow, Russian Federation
4 Research Institute for Nuclear Problems, Minsk, Belarus
5 Belarus State Technological University, Minsk, Belarus
6 Justus-Liebig-University, II. Physical Institute, Giessen, Germany

Content

Among the variety of transparent inorganic materials, glasses have a unique position. Glass can be easily obtained in different forms in short times: from bulk to fibers. However, a disordered structure of glasses and presence of plurality of structural defects cause low efficiency transfer of electronic excitation to emitting centers, preventing an achievement of a high scintillation light yield (LY). Important application of scintillation glasses is thermal neutrons detection, which utilizes glass ability to include high content of 6Li isotope. One of the demonstrated approaches to improve their LY consists in forming a glass-ceramics based on glasses with close to stoichiometric composition, in particular lithium di-silicates (Li2O∙2SiO2, DSL) doped with Ce ions. It combines the luminescent properties of rare-earth ions in crystallites with advantages of the morphological properties of mother glass. LY of more than 7000 ph/neutron and energy resolution for thermal neutrons better than 8.5% was shown for this material. There are two important directions of further improvement of neutron sensitive scintillation glasses – light yield increase and providing a glass ability to detect neutrons with higher energies. Improvement of the epithermal and fast neutron detection efficiency can be achieved by addition of Be and/or Gd. Be nuclei introduce additional n-moderating properties whereas Gd implies an additional ability to capture higher energy neutrons.  In the present work we compare neutron detecting properties of DSL doped with Ce and Tb with glasses and glass ceramics of more complicated compositions, containing Be and/or Gd ions. The best light yield was obtained at the doping with Tb. Despite a rather slow scintillation kinetics due to the forbidden Tb3+ 4f-4f transitions, high light yield makes these materials very promising for threshold neutron detectors with high sensitivity. The work is supported by Russian Government grant № 14.W03.31.0004.

Keywords: scintillator, neutron, glass, glass-ceramics
Poster panel
(face) ID: 173


Poster Number:
N-03-087

A design study of a handy neutron energy spectrometer for BNCT daily QA procedure (#2535)

R. Kurihara1, A. Nohtomi1, G. Wakabayashi2, Y. Sakurai3, H. Tanaka3

1 Kyushu University, Department of Health Sciences, Fukuoka, Japan
2 Kindai University, Atomic Energy Research Institute, Osaka, Japan
3 Kyoto University, Research Reactor Institute, Kyoto, Japan

Content

In BNCT (boron neutron capture therapy), confirmation of an actual neutron energy spectrum is one of the important QA procedures. So, a handy neutron energy spectrometer is desirable, which is suitable for a routine quick check. Recently, we have proposed a neutron energy spectrometer using a CsI self-activation method. In the self-activation method, information of incident neutrons is derived from the activity of I-128 generated in a CsI scintillator. This method allows quick and user-friendly measurement for daily quick check of neutron energy spectra. In the present work, a design study of our proposed neutron energy spectrometer arrangement was carried out to obtain appropriate response functions. In addition to this, by using the calculated response functions, spectrum unfolding tests were also performed. Response functions calculations were performed by Monte Carlo simulation code PHITS.  The use of 4 CsI scintillators was assumed and they were placed along a neutron beam axis. To detect neutrons coming from beam direction selectively, these CsI crystals arranged in a neutron shield which consists of a polyethylene and Cd. Neutron moderators and neutron absorbers were inserted in front of each CsI crystal. The thickness of moderators and absorbers was adjusted by trial-and-error so that response functions have a high sensitivity only to a certain range in epi-thermal neutron region which is main component of recent BNCT neutron sources. To evaluate calculated response functions, spectrum unfolding simulations were carried out by a Bayesian unfolding method. Reasonable response functions were obtained by an appropriate spectrometer design. Unfolding results reasonably show good agreement with the true spectra. These results indicate that this spectrometer has good energy resolution for epi-thermal neutrons, so it is expected that a neutron energy spectrum of BNCT can be measured in adequate accuracy for a routine quick check.

Keywords: BNCT, CsI self-activation method, Neutron spectrometer
Poster panel
(face) ID: 175


Poster Number:
N-03-088

Super resolution for resonance absorption imaging by reconstruction with sub-pixel shifting (#2819)

J. Koide1, T. Uragaki1, N. Hagura2, J. Kawarabayashi2, K. - I. Mochiki2, H. Hasemi3, T. Kamiyama3, T. Sano4, D. Ito4, Y. Takahashi4, J. - I. Hori4, K. Nakajima4

1 Tokyo City University, Graduate School of Engineering, Setagaya-ku, Tokyo, Japan
2 Tokyo City University, Faculty of Engineering, Setagaya-ku, Tokyo, Japan
3 Hokkaido University, Faculty of Engineering, Sapporo, Hokkaido, Japan
4 Kyoto University, Research Reactor Institute, Sennan-gun, Osaka, Japan

Content

The neutron resonance absorption imaging by a pulsed neutron source is very useful technique in the non-destructive element analysis of highly activated materials such as an alternative nuclear fuel including trance uranic (TRU) material and fuel debris. This imaging system required 100 ns time resolution, 400 µm spatial resolution, and high detection efficiency to identify 400 µm plutonium (Pu) spots. A gas electron multiplier (GEM) detector was selected as a time resolved imaging detector. However, its spatial resolution of 0.8 mm is not enough to recognize the Pu spots. Therefore, we are developing super resolution system with a detector shifting equipment and reconstructing algorism to obtain fine image by sub-pixel shifting technique. Experiments were made using a compact accelerator-driven neutron source at Hokkaido University and Kyoto University using a thin-GEM detector and a thick-GEM detector, respectively. To improve the intrinsic 0.8 mm resolution of the GEM detector, data taking of sub-pixel shifted images and reconstruction were carried out according to the following steps. The first step was an acquisition of four sub-pixel shifted transmission images step by step shifting the inspecting object by a half of pixel pitch. These processing and reconstruction was worked well in the preliminary experiment with an X-ray source and a CCD camera. The sensitivity of the GEM detector, however, was not stable to the change of temperature. To suppress the effect of the sensitivity shift caused by temperature change sensitivity correction was necessary. The correction factors had been estimated itself by a part of local area outside of the inspecting object one by one for each acquired image.  In the reconstructed image by MLEM method suppression of the non-stability was recognized. This procedure will be applied to sub-pixel shifted data set obtained using a pulsed-neutron source of Kyoto University.

Keywords: neutron absorption imaging, sub-pixel shifting, GEM detector
Poster panel
(face) ID: 177


Poster Number:
N-03-089

Target and shielding design of accelerator-driven transportable neutron source (#2912)

Y. Kushima1, T. Kobayashi2, Y. Ikeda2, N. Hayashizaki3, N. Hagura1, J. Kawarabayashi1, Y. Otake2

1 Tokyo City Univercity, Graduate School of Engineering, Setagaya-ku, Tokyo, Japan
2 RIKEN, Neutron Beam Technology Team, Wako-shi, Saitama, Japan
3 Tokyo Institute of Technology, Laboratry for Advanced Nuclear Energy, Meguro-ku, Tokyo, Japan

Content

The deterioration of social infrastructure is an urgent issue in our society and technical development of nondestructive inspection of large concrete structures such as bridges is needed. We have started prototyping of a portable neutron source aimed at on-site use. The project is based on experimental results obtained at RIKEN accelerator driven compact neutron source (RANS). The purpose of this study is to develop a prototype of portable neutron source (RANS2) and also to develop an imaging technique of internal structure of concretes using fast neutron. According to neutron yield calculation, we adopted 2.49 MeV proton for incident particle and Li for target. In this paper, the angular distribution of neutron with 7Li (p, n) 7Be reaction, the shielding performance of several commercially available candidate materials, and attenuation of fast neutrons in concrete were evaluated using a Monte Carlo calculation. The boron-added polyethylene (BPE, 10 wt% B2O3) is the most effective material for neutron shielding. However, the flexibility of boron-added rubber (50 wt%, B4C) is very attractive. No significant difference was found in the results of BPE and PE. This will be because the neutron capture cross section by boron atom is smaller at high-energy region. The target station will be designed also considering the gamma shielding. The depth profile of the neutron spectra in concrete the neutron flux decreased to one-tenth at every 10 cm distance. The fast component more than 100 keV became about 10-3 after passing through 30 cm thick concrete. It would be the limit of the thickness for transmission imaging. We will forward the design of the target and shielding along with the setup of the accelerator and ion source.

Keywords: Compact neutron source, Accelerator, Monte Carlo calculation, Li
Poster panel
(face) ID: 179


Poster Number:
N-03-090
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The research on the suppression of spurious neutrons for a neutron detector array that may be used in the neutron scattering (#2931)

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

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

Content

In the neutron scattering, the angular distribution of neutrons scattered by the tested sample is measured to calculate the momentum transfer in the scattering process, to understand the microstructure information of the tested material. Because of the existence of structural materials in the neutron detector array, spurious neutrons may undergo collisions with atoms in the structural materials before they are measured by the detector array. Thus, a background is introduced to the angular distribution of neutrons scattered by the tested sample, leading to a deteriorated interpretation of the microstructure of the tested material. The RT/S, which reflects a ratio between the non-collided neutrons and spurious neutrons, is researched for various boron-lined gaseous detectors. A newly-designed boron-lined honeycomb converter based gaseous neutron detector is introduced in this paper to provide a higher RT/S, benefitting from its anisotropy of neutron sensitivity. Based on the simulation (GEANT4 and Garfield) and preliminary experimental results, a 3 to 10 times improvement for the RT/S can be realized with this newly-designed neutron detector. The suppression of spurious neutrons can significantly improve the analyzing quality of microstructure information for the tested material.

Keywords: boron-lined detector, anisotropy of neutron sensitivity, spurious neutron, suppressing
Poster panel
(face) ID: 181


Poster Number:
N-03-091

Validation of Detailed Geant4 Model for Thermal Neutron Scattering using the Results of Multi-Grid Detector Prototype Test at CNCS at SNS (#3062)

E. Dian1, 2, A. Khaplanov2, K. Kanaki2, X. X. Cai2, 4, G. Ehlers5, R. Hall-Wilton2, 6, T. Kittelmann2, 4, P. Zagyvai1, 3

1 Hungarian Academy of Sciences, Centre for Energy Research, Budapest, Hungary
2 European Spallation Source ESS ERIC, Lund, Sweden
3 Budapest University of Technology and Economics, Institute of Nuclear Techniques, Budapest, Hungary
4 Technical University of Denmark, DTU, Lyngby, Denmark
5 Oak Ridge National Lab, Oak Ridge, Tennessee, United States of America
6 Mid-Sweden University, Sundsvall, Sweden

Content

The European Spallation Source (ESS) aspires to be the world’s leading neutron source of the upcoming decades. Numerous large-scale instruments will be installed. ESS sets the scope on replacing 3He tube detectors where it is reasonably achievable, so advanced neutron detectors are needed that are competitive with 3He tubes and satisfy scientific requirements. The Multi-Grid detector, an Ar/CO2-filled proportional chamber based on solid 10B4C converter, is the most potent replacement technology for chopper spectroscopy. Since the inelastic signals are orders of magnitude smaller than the elastic ones, for these instruments the low background is essential. This study reproduces in a detailed Geant4 geometry of a neutron scattering instrument the data from the Multi-Grid demonstrator detector. The objective is to introduce the measured results of one of the newest prototypes of the Multi-Grid detector, that has been tested for a ~1 year period, installed side-by-side to the 3He tubes at the CNCS instrument at SNS. The prototype was compared to a group of the neighbouring 3He tubes. For the further understanding of the background of the detector, Monte Carlo simulations were performed with the ESS Coding Framework, using a Geant4 version extended with NXSG4 and NCrystal, that is capable to handle the crystal structure of specific materials, therefore the effects of neutron absorption, elastic and inelastic scattering were treated properly for crystalline materials. A detailed and realistic model of the prototype was built and was validated via comparison against measured data. With this model, different sources of neutron scattering were determined and studied separately, providing a better understanding of the scattered neutron background. Due to these capabilities the model will be used in the further optimization of the detector, especially for the background reduction via shielding, which will lead to instruments with better signal-to-background ratio by design.

Keywords: B4C, B10, CNCS, ESS, Geant4, Monte Carlo, Multi-Grid, Neutron Detector, NXSG4
Poster panel
(face) ID: 183


Poster Number:
N-03-092

Characterization of 3D Neutrons Silicon detectors filled with 10B (#3377)

R. Mendicino1, 2, G. - F. Dalla Betta1, 2, A. Bagolini3, M. Boscardin3, 2

1 University of Trento, DII, TRENTO, Italy
2 TIFPA, trento, Italy
3 FBK, trento, Italy

Content

Solid-state sensors fabricated with 3D technologies and coupled to different neutron converter materials have been developed by several groups as direct replacement of 3He gas detectors, mainly for homeland security applications. In the framework of the INFN HYDE (HYbrid Detectors for neutrons) project, we have designed a new microstructured sensor aimed at thermal neutron detection and imaging, e.g., with a Medipix read-out chip, and featuring a good efficiency (~30%) while minimizing the process complexity. At the conference, we will recall the main design and technological aspects for these sensors, and report selected results from their characterization with radioactive sources and under thermal neutron beams.

Keywords: Solid state neutron detector, Device characterization
Poster panel
(face) ID: 185


Poster Number:
N-03-093

Scintillation Properties of Benzoic-acid-Based Crystals for Neutron Scintillator Grown by the Bridgeman Method (#3470)

S. Kurosawa1, 2, A. Yamaji3, S. Yamato3, T. Horiai3, S. Kodama3, Y. Ohashi1, K. Kamada1, 4, Y. Yokota1, A. Yoshikawa1, 4

1 Tohoku University, New Industry Creation Hatchery Center, Sendai, Miyagi, Japan
2 Yamagata University, Faculty of science, Yamagata, Yamagata, Japan
3 Tohoku University, Institute for Materials Research, Sendai, Miyagi, Japan
4 C&A, Sendai, Miyagi, Japan

Content

Neutrons are/can be used in several applications, and we have developed fast neutron scintillator. In this paper, as a material search, we show the crystal growth for benzoic-acid-based crystals and stilbene grown by the self-seeding vertical Bridgeman technique. Moreover, scintillation properties of these materials were investigated. As a result, benzoic-acid had around 80%-light output of stilbene.

Keywords: Scintillator, organic crsytal
Poster panel
(face) ID: 187


Poster Number:
N-03-094

A two-dimensional scintillation neutron detector module for a new protein single crystal neutron diffractometer at J-PARC MLF (#3868)

T. Nakamura1, K. Toh1, N. Tsutsui1, M. Ebine1, A. Birumachi2, K. Sakasai1

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

Content

A position-sensitive scintillation detector module for a new protein neutron diffractometer was developed by using a scintillator / wavelength shifting (WLS) fiber technology. The detector module has a spatial resolution of 2.5 mm with a neutron-sensitive area of 320 x 320 mm2. The WLS fibers are arranged in a regular pitch of 2.5 mm in x and y direction and those arrays are placed diagonally. The light reflecting grid is inserted in between the fibers in order for optical isolation and for mechanical support of the fiber. The detector implemented flat 6Li/ZnS screens up and downstream of the WLF fiber arrays. The detector exhibited a detection efficiency of 30-50% for thermal neutron (depending on gamma-ray sensitivities) and a count uniformity of ~13%. In this paper detailed detector design and experimental results obtained using a pulsed neutron beam are presented.

Keywords: position-sensitive neutron detector, wavelength-shifting fiber, scintillation detector
Poster panel
(face) ID: 189


Poster Number:
N-03-095

Characterization of Stilbene Scintillation Detectors with Light Guide Coupling and Silicon Photomultiplier Readout (#3880)

K. Beyer1, A. Di Fulvio1, S. A. Pozzi1

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

Content

We experimentally investigated the low energy pulse shape discrimination (PSD) capabilities of four cubic stilbene crystals with 6mm, 10 mm, 15 mm, and 20mm sides. We used a 6 × 6 mm^2 silicon photomultiplier (SiPM) for readout, and coupled the crystals both with and without light guides, optimizing light guide wrapping for PSD. We compared the crystals’s figure of merit (FOM) dependence on light output. For the smaller three crystals, direct coupling provided better PSD (roughly 116% FOM of the guided at 100 − 150 keVee). For the 10 mm sided crys- tal the trend was reversed and the light guide became advantageous (105% FOM of the direct at 100 − 150 keVee). 

Keywords: gamma neutron discrimination, pulse shape discrimination, stilbene, light guide, Silicon photomultiplier
Poster panel
(face) ID: 191


Poster Number:
N-03-096

Single-Volume Neutron Scatter Camera Simulation Results (#4196)

J. Braveman1, E. Brubaker1, B. Cabrera-Palmer1, S. A. Czyz2, A. Nowack1, M. Sweany1, E. Woods1

1 Sandia National Laboratories, Livermore, United States of America
2 Oregon State University, Corvallis, United States of America

Content

In order for passive neutron imaging to provide value in nuclear security applications, we need to improve on existing systems by making them smaller and more efficient. We present simulation results of a very compact double-scatter fission-energy neutron imager, aimed at localization and characterization of special nuclear material. The imager relies on the detection and resolution of two neutron scatters within a single contiguous scintillator volume. Our simulation is informed by experimental studies of system components.

Neutron imaging characterizes the spatial distribution of neutron emitters, providing information that is valuable in arms control and emergency response. Current neutron imagers, such as the SNL Neutron Scatter Camera and the ORNL/SNL Fast Neutron Coded Aperture Imager, have demonstrated imaging with up to ~1 cm spatial resolution at close range. These systems are large and heavy, making them difficult to deploy; and their sensitivity is limited by geometrical efficiency and a requirement of distance between the source and imager. We are working toward a new compact neutron imager that is easy to transport and deploy, has high efficiency, and can be placed near a threat object to increase sensitivity and spatial resolution.

Advances in photodetector (PD) technology have enabled coverage of large areas (hundreds of cm2) with good spatial resolution (few mm) and excellent time resolution (tens of ps) for individual optical photon arrivals. This allows us to consider imaging systems that acquire and process data from the scintillation photons due to interactions in the material. We present simulations that demonstrate the feasibility of using the photon positions and times at the faces of a (10 cm)3 active volume to reconstruct multiple neutron scatter to sub-cm and sub-ns accuracy, which allows the reconstruction of the neutron energy and direction.  In the absence of PSD discrimination, we discuss ways to discriminate neutron and gamma events. 

Keywords: neutron imaging, neutron scatter camera, emergency response, special nuclear materials
Poster panel
(face) ID: 193


Poster Number:
N-03-097

Neutron and X-ray transmission measurements using a Li-glass scintillation detector (#2676)

K. Y. Hara1, H. Sato1, T. Kamiyama1, T. Shinohara2

1 Hokkaido University, Faculty of engineering, Sapporo, Hokkaido, Japan
2 Japan Atomic Energy Agency, J-PARC center, Naka-gun, Ibaraki, Japan

Content

We have developed a complementary imaging method using a composite source system of neutron and X-ray in the 45-MeV electron linear accelerator facility at Hokkaido University. By switching the production target on the electron beam axis, the composite source system allows us to alternatively use the thermal neutron or keV X-ray beam. When combined with the source system and a dual-use detector for the both beams, the neutron and X-ray transmission images for a sample can be measured without changing the sample and detector setup positions. In a previous work, we measured the neutron and X-ray radiographs using a two-dimensional neutron detector which consisted of a neutron color image intensifier (TOSHIBA, UltimageTM-nγ-04) and a digital camera (CANON, EOS 5D Mark II). In this work, a Li-glass scintillation detector was applied in order to test the complementary imaging with the time-of-flight (TOF) technique, where the detector consists of 256 Li-6 glass scintillators and a multi-anode type photo-multiplier tube (PMT: HAMAMATSU, H9500). The PMT of detector was used at the bias voltage of -760 V for neutron and -900 V for X-ray. The TOF and pulse-height spectra for the neutron and X-ray beams were measured using samples of metal and carbon plates. The measured neutron and X-ray transmission rates are in agreement with the calculated ones within 4% at 0.03 eV and 2 MeV, respectively, where the monochromatic and pencil-like beams were defined in the calculation with the PHITS code. The energy distribution of X-ray beam will be calculated because a thick lead block was put on the flight path to avoid the saturation of PMT output in the measurements with the X-ray beam.

Keywords: neutron, X-ray, imaging, Li-glass scintillation detector
Poster panel
(face) ID: 195


Poster Number:
N-03-098

Shielded Nuclear Material Identification via Combined Fast-Neutron/Gamma-Ray Computed Tomography (FNGCT) (#2918)

M. Licata1, 2, M. J. Joyce1

1 Lancaster University, Department of Engineering, Lancaster, United Kingdom of Great Britain and Northern Ireland
2 Next Generation Nuclear, Centre for Doctoral Training, Manchester, United Kingdom of Great Britain and Northern Ireland

Content

A Monte Carlo study on the feasibility to discern nuclear materials using a combined neutron-gamma tomography technique is described. The presence of materials, such as uranium, plutonium and related compounds, may be obscured from non-destructive identification when hidden inside materials with similar densities, atomic number or cross sections. It will be shown that, via a combination of gamma and neutron tomography, the potential exists to distinguish some of these materials from one another that are otherwise challenging to distinguish using either g-ray or neutron tomography in isolation. A tomography system has been simulated with MCNPX. It comprises an americium-beryllium source and an array of 13 organic scintillation detectors. The AmBe source produces fast neutrons and 4.4 MeV g-rays; this mixed radiation field is collimated into a fan beam and is directed towards the sample to be investigated. The detectors are located 51 cm from the sample and 90 cm from the source. The sample is scanned over a range of different positions by which neutrons and gammas are retained simultaneously by the detectors, through the Monte Carlo tool used. An algebraic reconstruction technique suitable for this particular system geometry is applied to reproduce sets of both neutron and gamma-ray tomographic projections, and the final n-g combined tomography image. The results presented in this paper will demonstrate that via this combined technique, spheres of plutonium oxide of 2 cm diameter and plutonium metal are identifiable when shielded and hidden inside an 8 cm lead cuboid, in turn located in a 2 cm thick polyethylene box, and similarly for spheres of 3 cm of uranium, uranium carbide and uranium trioxide when located into 5 cm lead cuboid. The method has potential for in-situ assessments for nuclear security and safeguards applications, particularly when solo-neutron or solo-gamma computed tomography are not able to provide a conclusive identification of these materials.

Keywords: combined neutron gamma tomography, nuclear materials, image reconstruction
Poster panel
(face) ID: 197


Poster Number:
N-03-099
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The Design of the Photoneutron Convertor Used for Energy Selective Neutron Imaging (#3000)

I. Lu1, 2, X. Wang1, 2, Y. Yang1, 2, Z. Zhang1, 2

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

Content

Neutron imaging plays an important role in the industrial applications, such as turbine blade manufacturing, fuel cell research, and nuclear fuel quality inspection. As isotopic neutron sources and neutron generators cannot provide high-intensity neutron beams, and neutron beamlines of research reactors or spallation neutron sources are very rare, a cost-effective neutron source with high neutron yield and long life-span should be researched. The e-LINAC driven photoneutron source, which converts X-rays to photoneutrons, has been proved to be a robust neutron source that can realize neutron yield ranging from 1010 to 1015n/s. Hence it is a promising neutron source to provide neutron beams used for the neutron imaging. Because the e-LINAC works at a pulsed mode and the photoneutrons have a continuous energy spectrum, energy selective neutron imaging can thus be realized with the e-LINAC driven photoneutron source, with the aid of time of flight (TOF) technique. In this research, an e-LINAC driven photoneutron source is researched to strike the compromise between the neutron flux and the energy resolution. With a well-designed heavy water photon-to-neutron convertor, a 10 MeV/ 20 KW e-LINAC can provide a thermal neutron flux of 7.28×104n/cm2/s at 10 meters away from the electron target, with energy resolution less than 20%. By using a low temperature (10K) moderator, the cold neutron flux at the same position can be 2.13×104n/cm2, and the energy resolution is less than 2%. The study in this research can help realize the energy selective neutron imaging with an e-LINAC driven photoneutron source.

Keywords: photoneutron source, energy selective neutron imaging, TOF
Poster panel
(face) ID: 199


Poster Number:
N-03-100

Computational Design and Evaluation of a Compact, High Efficiency Neutron Scatter Camera (#3281)

K. Weinfurther1, J. Mattingly1, E. Brubaker2

1 North Carolina State University, Raleigh, North Carolina, United States of America
2 Sandia National Laboratories, Livermore, California, United States of America

Content

We evaluated design alternatives for a compact, high efficiency neutron scatter camera using simulation. The device consists of a contiguous volume of scintillator internally optically segmented into long, narrow pillars. Optical segmentation confines scintillation light to propagate in the long dimension of each pillar. An air gap surrounds each scintillator pillar, enabling total internal reflection of light. Escaping light is reflected back into the pillar using a specular reflector lining the channel walls. Photodetectors are affixed on opposing ends of each pillar to collect scintillation light. We showed neutron scintillation position and proton recoil energy reconstruction root mean square (RMS) errors for multiple combinations of scintillator, photodetector and pillar dimensions. Scintillators and photodetectors that were evaluated include EJ-204, EJ-232Q, and stilbene in conjunction with a microchannel plate photomultiplier (MCP-PM) and a silicon photomultiplier (SiPM). The highest precision estimates of scintillation position were obtained for the scintillator/photodetector combination that exhibited the smallest temporal spread of charge carriers. The highest precision estimates of proton recoil energy were obtained for the scintillator/photodetector combination that produced the greatest number of charge carriers. Consequently, the best combination we identified, EJ-204/MCP-PM, produced a scintillation position RMS error of less than 5 mm and proton recoil energy RMS error of less than 50 keV for 2 MeV proton recoils.

Keywords: Neutron, Scatter Camera, Scintillator, Photodetector, Imaging
Poster panel
(face) ID: 201


Poster Number:
N-03-101

Performance of Stilbene Bars Coupled to Silicon Photomultipliers Using Different Reflectors (#3540)

W. M. Steinberger1, M. L. Ruch1, S. A. Pozzi1

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

Content

Two 6-mm by 6-mm by 50-mm bars of stilbene were each coupled to a silicon photomultiplier (SiPM) and evaluated for signal-to-noise ratio (SNR) and time resolution using specular and diffuse reflectors. To evaluate the SNR at 478 keV, a Cs-137 source was placed between both bars and measured. The average SNR was 38% lower using a specular reflector as compared to using a diffuse reflector. The coincidence resolving time, measured with a Na-22 source, improved by 32% for standard output pulses and 40% for fast output pulses.  These results suggest that neutron energy uncertainty from time-of-flight (TOF) measurements using stilbene bars coupled to SiPMs could be improved by utilizing a specular reflector.

Keywords: Silicon Photomultipliers, Stilbene, Characterization
Poster panel
(face) ID: 203


Poster Number:
N-03-102

Directional gamma-ray imaging using stacked edge-on silicon strip detector (#4069)

Y. Yoshihara1, K. Shimazoe1, H. Takahashi1, M. Kaburagi2, T. Torii2

1 University of Tokyo, Department of Nuclear Engineering and Management, Bunkyo, Tokyo, Japan
2 Japan Atomic Energy Agency (JAEA), Collaboration Laboratories for Advance Decommissioning Science (CLADS), Naka, Ibaraki, Japan

Content

The decommissioning of Fukushima Daiichi Nuclear Power Plant has been conducted in Japan since the accident of March 11, 2011. Portable gamma-ray cameras, which can be mounted on remote control robots, are necessary for visualizing the contamination distribution inside the nuclear power plant. We have been developing a stacked edge-on silicon strip detector based on hetero-junction technology. Each layer of silicon strip detector has 48 readout aluminum strips in single side with the pitch of 1 mm. The thickness of fully depleted layer is 0.5 mm under the applied back-bias voltage of 120 V. The directionality of the stacked silicon strip detector was evaluated analytically and experimentally.

Keywords: Silicon strip detector, Directional gamma-ray imaging, Gamma camera, decommissioning
Poster panel
(face) ID: 205


Poster Number:
N-03-103

Development of a fiber optic radiation monitor for severe accidents using a near-infrared photon counting method (#1582)

T. Tadokoro1, S. Hatakeyama1, K. Ueno1, Y. Ueno1, K. Nebashi2, M. Koyama2

1 Hitachi, Ltd., Hitachi, Ibaraki, Japan
2 Hitachi-GE Nuclear Energy, Ltd., Hitachi, Ibaraki, Japan

Content

The earthquake, tsunami and subsequent accident at Tokyo Electric Power Company’s Fukushima Dai-ichi Nuclear Power Plant resulted in severe situations under which it was difficult to measure important parameters for monitoring plant conditions, and these measurement difficulties continue even now. The dose rate in the primary containment vessel (PCV) is one of the key parameters to understand the plant condition. Hitachi and Hitachi-GE have been developing a fiber optic radiation monitor using a near-infrared photon counting method.

We chose a commonly used neodymium-doped yttrium aluminum garnet crystal (Nd:YAG) as the light emission element for the radiation monitor. When gamma-rays are irradiated onto the Nd:YAG, Nd transits to the 4F3/2 excited state or upper excited states of the 4F3/2. A part of the upper excited states of Nd soon transit to the 4F3/2, and the 4F3/2 soon transits to the 4I11/2 excited state. During this last transition, a 1064 nm photon is emitted and only one 1064 nm photon seems to be emitted when many gamma-rays are irradiated onto the Nd:YAG. That is why Nd:YAG can be used to measure high dose rates. When the photon emission rate is proportional to the absorbed energy value in the Nd:YAG, the dose rate can be measured by measuring the counting rate of photons.

We fabricated a prototype monitor and carried out its performance evaluation. We confirmed that the monitor had a capability for measuring dose rates from 10-2 Gy/h to 6.1x104 Gy/h and the monitor satisfied the requirements of variation of response with photon radiation energy and angle of incidence of the IEC 60532-2010 standard. We also confirmed dose rate linearity was within ±4% of full scale after an 84-h heat (300 oC) and pressure (1x106 Pa) resistance test. These results confirmed the fiber optic radiation monitor using a near-infrared photon counting method could be applied to measurements under severe accident circumstances.

Keywords: Radiation monitor, Severe accident, Fiber optic, Photon counting, Nd:YAG
Poster panel
(face) ID: 207


Poster Number:
N-03-104

A Multi-Purpose Test Station to Characterize Fast Neutron Scintillators for the TREAT Fuel Motion Monitoring System (#1898)

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

1 Idaho National Laboratory, Global Security & International Safeguards, Idaho Falls, Idaho, United States of America

Content

The Transient Reactor Test Facility (TREAT) at Idaho National Laboratory is designed to evaluate reactor fuels and structural materials under conditions that simulate various types of transient overpower and under-cooling situations in a nuclear reactor. The TREAT reactor is equipped with a time-resolved neutron imaging system, a neutron “hodoscope”, a key instrument that monitors the motion of test fuel within the core. The technique generates coarse images of this test fuel by measuring fast neutrons, produced by fission in the test fuel, as they escape the core through engineered streaming paths. The neutrons travel through a void slot in the core and then through a set of collimator channels, impinging on a 360-channel detector array. The hodoscope is designed to allow for pre-, during-, and post-transient imaging of test fuel in a TREAT test loop in the center of the reactor core. The hodoscope can aide in studying time resolved mechanisms of fuel failure, metal-water reactions, thermal interaction between overheated fuel and coolant, and the transient behavior of ceramic fuel for high-temperature systems. Due to the age of the instrument, a refurbishment of the hodoscope’s fast neutron detection capability is necessary for experiment data collection in the restart of the TREAT reactor to test new nuclear fuel in transient conditions. Described here is a Multi-Purpose Test Station (MPTS) that was designed to simultaneously qualify and characterize up to eight photo-multiplier tubes using a distributed LED light source or a neutron-emitting radioisotope source. The MPTS also provides a means to characterize up to eight fast neutron detector assemblies consisting of ZnS(Ag) scintillators coupled to photo-multiplier tubes housed inside phenolic shrouds.

Keywords: TREAT, Fuel Motion Monitoring System, Multi-Purpose Test Station, photo-multiplier tubes, ZnS(Ag)
Poster panel
(face) ID: 209


Poster Number:
N-03-105

development of all directional gamma-ray imager with fine bar-type scintillators (#2773)

J. Kawarabayashi1, D. Matsui2, Y. Fuwa2, T. Takahashi2, H. Tomita2, T. Iguchi2, E. Takada3

1 Tokyo City University, Department of Nuclear Safty Engineering, Setagaya, Tokyo, Japan
2 Nagoya University, Department of Quantum Engineering, Nagoya, Aichi, Japan
3 National Institute of Technology, Toyama College, Department of Electrical and Control Systems Engineering, Toyama-shi, Toyama, Japan

Content

We have been developed a stacked scintillator detector based on Compton scattering gamma camera in order to detect the incident direction of radiations emitted from released radioactive material rapidly in order to protect workers and to evacuate citizens in the case of severe accident of nuclear power station such as Fukushima Dai-ichi accident. An important performance required for this purpose is to operate in high dose rate environment, because in the severe accident of Fukushima Dai-ichi Power Station in 2011, the dose rate increased up to 12 mSv/h at the entrance gate of the site. The Compton camera needs two interaction position to derive incident angle of the gamma-ray. In order to reduce the chance coincidence, the detector was composed of some stacked fine scintillator bars which ends were connected to photon sensors and each scintillator bar worked individually. The interaction positions were derived from the positions of the bar itself and the light output ratio at the two ends of the bar whereas the deposited energy was derived from summing the two light outputs of the bar. The symmetric geometry of this detector provided a rapid detection sensitive in all directions. We stacked 64 fine scintillator bars and the performace was evaluated experimentally. After energy and position calibration which was carried out with 511keV annihilation gamma-ray and 662keV gamma-ray by 22Na and 137Cs sources, respectively, a experimental demonstration was successfully made to find the radioactive source (137Cs). It was confirmed that this detector was sensitive for all directions and the angular resolution was 60 degree for 662keV gamma-ray. The upper limit of dose rate was estimated by Monte-Carlo simulations. It was 10 mSv/h to reconstruct corresponding image for a point source of 137Cs. This detector was applicable for the outdoors use in the severe accidents of nuclear power stations.

Keywords: gamma camera, scintillatior
Poster panel
(face) ID: 211


Poster Number:
N-03-106

Evaluation, Refurbishment, and Characterization of Fast Neutron Scintillators for the TREAT Fuel Motion Monitoring System (#3392)

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

1 Idaho National Laboratory, Global Security & International Safeguards, Idaho Falls, Idaho, United States of America

Content

This paper details work being performed to evaluate, refurbish, and characterize proton-recoil scintillator (PRS) assemblies being used in a 360 channel array for the measurement of fast neutrons in the Fuel Motion Monitoring System (FMMS) at the Transient Reactor Test Facility (TREAT). The TREAT FMMS measures the real time movement and displacement of experimental fuel during transient experiments, correlating fast-neutron signals to the mass of fuel in each of the 360 pixels at the center of the reactor’s core. The detectors in the FMMS have stood dormant for over 20 years and significant degradation must be addressed before the system can be brought back to operational status. The PRS refurbishment process began by decoupling the scintillators from their matched photo multiplier tubes (PMTs) and treating the PRSs with ethanol. This process cleans the surfaces, removing paint and legacy labels/ markings. During this procedure many physical variations were observed. After cleaning, the PRSs were physically measured using a digital caliper and the dimensions documented. Following this, a well-controlled fiber-coupled 280-nm light-emitting diode light source was used to stimulate the PRSs to produce an emission spectrum inside a light integration sphere. This emission spectrum was measured using a ultra-violet light enhanced optical spectrometer. Spectral measurements were recorded from 185 nm to 580 nm in 0.4 nm steps. The PRSs were then lightly sanded on the non-PMT mating surfaces and painted with commercially available reflective paint. A final emission spectrum was recorded for each PRS after painting.

Keywords: PRS, FMMS, TREAT, Detector, refurbishment
Poster panel
(face) ID: 213


Poster Number:
N-03-107

Ionization Chambers to Measure Neutron and Gamma-Ray Kerma in a Research Reactor (#3683)

J. Radtke1, P. DeLuca1, L. Bartol1, A. Maile2, R. Agasie2, T. Trumbull3, E. Grant3, P. Brooks2, M. Anderson2, W. Culberson1

1 University of Wisconsin, Department of Medical Physics, Madison, Wisconsin, United States of America
2 University of Wisconsin, Madison, Department of Engineering Physics, Madison, Wisconsin, United States of America
3 Knolls Atomic Power Laboratory, Niskayuna, New York, United States of America

Content

Ionization chambers were designed and constructed to measure the kerma rates (heating) in various materials within several centimeters of a TRIGA reactor core operating at 1 MW. Wall thickness, collection gap and fill gas pressure were chosen to satisfy Bragg-Gray criteria, so that measured ionization current across the collection gap was proportional to the kerma in the wall material. Chamber wall materials comprised of low mass number elements, including hydrogen-rich C552 air-equivalent plastic and beryllium, were selected to measure the kerma due to fast neutron elastic scattering. By operating these neutron sensitive chambers coincidentally with relatively neutron insensitive chambers composed of aluminum and Zircaloy-4, we were able to measure the relative heating due to neutrons and gamma rays in a material. Chamber collection volumes were initially determined using NIST-traceable kerma rates and a cobalt-60 source. All chambers were sealed with argon gas to provide thermal and compositional stability. Chamber collection gas mass, stability and saturation curves were determined using the 60Co source. Chambers were operated for approximately 30 minutes and the integrity of gas seals was subsequently verified by repeating the measurement with the 60Co source.

Keywords: ionization chamber, kerma rate, heating rate, neutron/gamma ratio, TRIGA reactor
Poster panel
(face) ID: 215


Poster Number:
N-03-108

Development of Radiation Resistant Camera System (#3867)

T. Takeuchi1, N. Otsuka1, T. Watanabe2, S. Tanaka3, O. Ozawa3, H. Komanome3, S. Ueno4, K. Tsuchiya1

1 Japan Atomic Energy Agency, Oarai Research and Development Center, Oarai, Ibaraki, Japan
2 Brookman Technology, Inc., Hamamatsu, Shizuoka, Japan
3 Ikegami Tsushinki Co., Ltd., Ohta-ku, Tokyo, Japan
4 Tokyo Nuclear Services Co., Ltd., Taito-ku, Tokyo, Japan

Content

During the Fukushima Daiichi Nuclear accident, it was failed to monitor the plant situation because almost all the instruments were broken down. In response to the lesson of the accident, we started a development of a radiation-resistant CMOS color camera system. In order to develop the desired camera, ensuring the radiation resistance of the camera components, namely optical system, electric parts and image sensor, was addressed.

About the optical system, trial radiation-resistant prism and zoom lens composed of quartz and calcium fluoride were fabricated and irradiated. The results showed that the both components had enough performance after 1 MGy irradiation. About the electric parts, the gamma irradiation tests were performed for commercially available devices. The results revealed that only few of the electric parts had less than 100 kGy radiation resistances. According to these results of irradiation test of a ready-made camera, dark current in image sensor increased and the camera didn’t work only less than one hundred Gy. Therefore, about the image sensor, several different approaches in order to reduce dark current were considered. Firstly, the number of transistor, one of main source of dark current, was reduced to three from four. Secondly, to suppress irradiation-induced charging, a photo gate type instead of normal photo diode type of photoelectric conversion structure was used. Finally, the configuration of electrodes and the driving voltage of the sensor were optimized. As a result, the sensor was usable after 200 kGy irradiation. On the basis of these results, a trial radiation-resistant camera system equipped with shielding structure around the image sensor and electric parts was fabricated. The gamma irradiation test confirmed the system achieved over 900 kGy radiation resistance.

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

Keywords: Camera, Radiation resistance, CMOS, Severe accident
Poster panel
(face) ID: 217


Poster Number:
N-03-109

Detector response function of a HPGe detector to photon energies between 200 keV and 1.5 MeV for Gamma-ray nondestructive assay instrument instrument (#1183)

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

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

Content

A semi-empirical detector response function (DRF) model of HPGe detector was proposed to fit gamma-ray nondestructive assay transmission spectra. The model for each single peak contained a step function, a Gaussian function, and an exponential tail function. The Gaussian standard deviation obtained by electronic noise and Fano factor, so our DRF only had 4 parameters and they were obtained by the weighted nonlinear least-squares fitting method. In the application, 152Eu spectra were obtained by using the 30%, 50%, 70% HPGe detector, and fitted by the established DRF model. Reduced chi-square values were at the interval of 0.039-0.202. Its validity that the model had good versatility, can be applicable to different detection efficiency of HPGe detectors.

Keywords: detector response function, Gaussian standard deviation, Fano factor, weighted nonlinear least square, chi-square
Poster panel
(face) ID: 219


Poster Number:
N-03-110

A new method to stabilize scintillation detectors using a miniature X-ray generator (#1507)

Q. Lecomte1, M. Bakkali1, D. Chambellan2, J. Dumazert1, R. Coulon1, S. Garti1, M. Becht1, F. Carrel1

1 CEA, LIST/DM2I/LCAE, Gif sur Yvette, France
2 CEA, LIST/DISC/LITT, Gif sur Yvette, France

Content

Temperature dependence of scintillation detector response, notably in thallium doped sodium iodide NaI(Tl) is a well-known phenomenon. Effective detector stabilization is of crucial importance for many outdoor applications in the field of homeland security. Most of these sensors must operate in environments where strong and rapid changes of the ambient temperature may occur. The approach of the scheme is to pile-up X-ray photons on the scintillator to generate a high energy peak in the spectrum. The system includes a miniature X-ray generator, a brass disk with a thin slit rotated by a motor and placed in front of the X-ray window, and a collimator placed in front of the scintillation detector to reduce the time of alignment between the scintillation detector and the X-ray generator. The rotating brass disk placed between the X-ray source and the collimator is deployed as a high-frequency obturator. If, during a time duration lower than the integration time of the scintillation detector, a large number of photons interact with the scintillator, the energy is added and the spectrometer records this energy as the contribution of a high energy single photon. Measurements were carried out with two different supply voltages and rotation speeds of the disk: X-ray generator powered at 22.2 kV, 100 µA and rotation speed of 10000 rpm, and powered at 30kV, 60 µA and a rotation speed of 4500 rpm. The two measurements highlight satisfactory results, with a width of the X-ray peak at the half maximum about 200 keV at 662 keV. Experimental results underlines a tangible proof of concept for a self-calibration device, which will be valuable for the correction of the temperature drift in the scintillator-photomultiplier pair.

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Keywords: method, temperature stabilization, scintillation detectors, X-rays
Poster panel
(face) ID: 221


Poster Number:
N-03-111

Development of an alpha particle spectrometer based on a GPS scintillator plate for high-reliable dust monitor (#1590)

Y. Morishita1, J. H. Kaneko2, M. Higuchi2, K. Izaki1, T. Yajima3, M. Matsuura3

1 Japan Atomic Energy Agency, Radiation control department, Tokai-mura, Naka-gun, Ibaraki, Japan
2 Hokkaido University, Graduate School of Engineering, Sapporo, Hokkaido, Japan
3 Advanced Fusion Technology, Co., Ltd., Chiyoda-ku, Tokyo, Japan

Content

For detecting airborne contamination of 238Pu and 239Pu released by the accident, a dust monitor with a silicon surface barrier detector (SSBD) is introduced at a site of nuclear fuel facility. However, SSBD frequently produces a false alarm triggered by an electromagnetic noise generator. For high-reliable dust monitoring, we developed an alpha particle spectrometer based on the GPS scintillator plate with PMT. Our developed spectrometer consists of a cerium doped Gd2Si2O7 (GPS) scintillator plate and a Photomultiplier Tube (PMT). The GPS scintillator plate was hexagonal in shape and 50 mm in diameter and a scintillator layer was approximately 40 μm. An output signal from PMT was amplified by a preamp and transferred to a MCA. An energy spectrum was displayed in real-time. An 241Am source with 5.5 MeV alpha particle, Rn progeny collected air filter, and PuO2 particle were measured by our developed spectrometer. The energy resolution for 5.5-MeV alpha particles was ~11.9 ± 0.2 % FWHM. The radon progeny nuclide reduction ratio (Rratio) was improved compared with ZnS(Ag) based alpha spectrometer, so that Pu and Rn progeny can be effectively distinguished. Thus, our developed alpha spectrometer will be high-reliable dust monitor for detecting Pu contamination.

Keywords: GPS scintillator plate, Dust monitor, Alpha particle, Plutonium, Radon progeny
Poster panel
(face) ID: 223


Poster Number:
N-03-112

A Smart adjustable Nuclear Interactions Counter based on compact Arduino control system and readout. (#2000)

F. Iacoangeli1, A. Natochii2, Y. Gavrikov3, M. Garattini2, G. Cavoto1, F. Addesa1

1 INFN, Roma, Rome, Italy
2 CERN, Geneva, Switzerland
3 National Research Centre “Kurchatov Institute”, Petersburg Nuclear Physics Institute, Gatchina, Russian Federation

Content

We realized a new, fine, easy to install detector for nuclear interaction based on twin plastic scintillators, ArduSiPM prototype readout, and remote handling system for adjustment of pair gap.

The system made up of two small scintillators (5x10x25 mm3 of BC-408) as nuclear interaction counters.

Signal readout is provided by the ArduSiPM prototype system, which makes available four pairs of bias voltage channel and analog readout channel for as many 3x3mm2 SiPMs.

Two Hamamatsu SiPMs are coupled with each scintillator to get readout redundancy and to use coincidence strategy for minimizing the system noise.

A constant fraction system allows getting fine timing coincidence both between scintillators and between beam’s trigger signal and scintillators to minimize the fake counts on radiative environment.

Remote gap adjustment make possible to set the nuclear scattering angle of measurement as well as to make an angular scan.

The detector was proposed as new nuclear interaction counter for the H8 telescope of the UA9 experiment.

This CERN-SPS experiment aim to test the crystal assisted collimation for both protons and lead ion beam collimation in the LHC.  The NID fulfil the precise measurements of nuclear interactions probability between crystal and particles in the various channeling regimes (channeling, volume reflection etc.)

Keywords: SiPM, MPPC, Arduino, ArduSiPM, Nuclear Interaction, Beam Collimation, UA9, Crysbeam
Poster panel
(face) ID: 225


Poster Number:
N-03-113

Very high performance stabilization and data acquisition systems for the COSINUS experiment (#3076)

P. Carniti1

1 INFN and University of Milano Bicocca, Milano, Italy

On behalf of the COSINUS collaboration

Content

The COSINUS collaboration aims to develop a cryogenic scintillating calorimeter for the search of dark matter, using undoped sodium iodide crystals as target. The simultaneous measurement of the phonon and light signal – both read out by Transition Edge Sensors (TESs) – allows to discriminate between signal and background events. For proper functioning, TESs have to operate close to their characteristic transition temperature, hence there is a need for a programmable, very stable and high resolution working point stabilization and biasing system. For this purpose, we designed a flexible 2-channel custom board, which is able to generate a programmable current with a 12-bit resolution. Current full-scale ranges can be further selected with 5 bits, for better flexibility during detector characterization. Each of the channels can be used for both TES biasing and TES temperature stabilization via a dedicated heater. The same board is also able to inject custom-shaped current pulses into the heater, in order to periodically calibrate the energy response of the detector. The thermal drifts are compensated using a calibrated 8-bit trimmer, reaching a stability over temperature of less than 1 ppm/°C. The board is based on a Cortex-M3 microcontroller and is remotely controlled through an optically coupled CAN bus. We also conducted a development study on a prototypal signal filter and digitization system, designing a 6-channel 6-pole Bessel filter board with programmable cut-off frequencies between 250 Hz and 25 kHz. An onboard 250 kHz ADC with an effective RMS resolution of 19.8 bits is responsible of the signal digitization. In this contribution, we present the design solutions and performance of these two electronic apparatus: the stabilization system for the COSINUS detector and a prototype signal filtering and digitization system.

Keywords: dark matter, bolometric detector, tes, stabilization system
Poster panel
(face) ID: 227


Poster Number:
N-03-114

Development of a new photon tagging system for GeV-gamma beam line (#3233)

M. Sasaki1, T. Ishikawa2, M. Iwasa1, M. Miyabe2, N. Muramatsu2, H. Shimizu2, A. O. Tokiyasu2, Y. Tajima1, H. Yamazaki3, H. Y. Yoshida1

1 Yamagata Univercity, Department of Physics, Yamagata, Yamagata, Japan
2 Tohoku University, Research Center for Electron Photon Science, Sendai, Sendai, Japan
3 High Energy Accelerator Research Organization, Institute of Particle and Nuclear Studies, Tsukuba, Ibaraki, Japan

Content

A new photon tagging system which determines the energy of each photon in the bremsstrahlung process has been development. The photon beam is generated by inserting a diameter of 11 um carbon fiber into circulating electrons in the 1.3 GeV electron synchrotron at the Research Center for Electron Photon Science (ELPH), Tohoku University.

 Moller scattering particles from the window frame of the beam cause to make worse energy resolution of the current tagging system. To overcome this problem, the angular resolution  less than 5 degree is required to separate the post bremsstrahlung electrons from the Moller scattering electrons. Furthermore, the timing resolution  less than 200 ps is required  to identify the beam bunches of the circulating electrons.  To achieve this values, the new system is designed with a combination of a multi-wire drift chamber (MWDC) and a plastic scintillator hodoscope.  

The frame of MWDC take an arc shape along the circulation electron  and has a size of ~ 1000 mm × 136 mm.  A sense wire is surrounded by 6 potential wires arranged in a hexagonal structure.  And the sense wire spacing is 6 mm so that the MWDC can also be used as a MWPC. The MWDC has three x-planes to measure directions of scattered electrons precisely, and equipped with the hodoscope which is used to measure timing of these electrons. The diameter of the sense wire is 20 um, the potential wire and the sweep wire have diameters of 50 um.  The signals from sense wires are obtained by using 32 ch RAINER board made by REPIC, on which the drift time is measured with a TDC of 1 ns resolution on the FPGA and the signal charge is measured with a 31.25 MHz FADC, respectively. We studied a detection efficiency and an angular resolution of the MWDC using the positron beam with a momentum range from 100 and 900 MeV/c.  As the result, we achieved more than 99% of efficiency and less than 5 degree of angular resolution.

Keywords: MWDC, Photon tagging counter
Poster panel
(face) ID: 229


Poster Number:
N-03-115

Recent Progress in Ultra Low-Noise, Large Volume HPGe detectors (#3645)

V. Marian1, M. Ginsz1, J. - B. Legras1, B. Pirard1, J. Flamanc1, P. Quirin1, M. - O. Lampert1

1 Mirion Technologies, Lingolsheim, France

Content

Large Volume High Purity Germanium (HPGe) detectors with ultra-low electronic noise have increasing interest in low background physics experiment, searching for weakly interacting particles like neutrino or WIMPs. These experiments require reaching the lowest energy threshold, which is equivalent to having the lowest energy resolution. MIRION TECHNOLOGIES has provided several detectors for the last decade, pushing forward simultaneously the HPGe volume and the electronic resolutions. This paper shows results of a mechanically cooled 1.5 kg HPGe Detector achieving 60eV FWHM pulser resolution.

Keywords: HPGe, Ultra Low Resolution, Electrical Cooler, Low Background
Poster panel
(face) ID: 231


Poster Number:
N-03-116

Instrumentation Development to Measure a Rare Decay of 40K (#3996)

E. D. Lukosi1

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

On behalf of the KDK collaboration: N. Brewer, K. Dering, P. Di Stefano, A. Fijalkowska, R. Grzywacz, D. Hamm, P. Lechner, Y. Liu, E. Lukosi, C. Melcher, J. Ninkovic, F. Petricca, B.C. Rasco, F. Retiere, K. Rykaczewski, P. Squillari, L. Stand, D. Stracener, M. Stukel, M. Wolińska-Cichocka, I. Yavin

Content

This paper discusses the development of two detection systems aimed at experimentally measuring the rare electron-capture decay of potassium-40 to argon-40 going directly to the ground state. Calculations suggest that this decay path occurs 0.2% of the time. Experimental verification of this calculation is necessary to investigate the longstanding, but controversial, claim of detection of dark matter by the DAMA experiment. Current progress on detection system development and implementation will be presented.

Keywords: K-40, MTAS, K-40 decay, dark matter
Poster panel
(face) ID: 233


Poster Number:
N-03-117

High-performance DIRC Detector for the Future Electron Ion Collider Experiment (#4235)

G. Kalicy1

1 CUA, Nuclear Physics, Washington DC, Maryland, United States of America

On behalf of PID Consortium for an integrated program for Particle Identification (PID) at a future Electron-Ion Collider.

Content

A radially-compact subsystem providing particle identification (e\pi, pi/K, K/p) over a wide momentum range is an essential requirement for the central detector of an Electron-Ion Collider (EIC). With a radial size of only a few cm, a detector based on the Detection of Internally Reflected Cherenkov light (DIRC) principle is a very attractive solution for the barrel region of the detector.

The R&D undertaken by the EIC PID consortium has demonstrated the feasibility of a high-performance DIRC that would extend the momentum coverage well beyond state-of-the-art, providing 3~standard deviations separation of pi/K up to 6GeV/c, e/K up to 1.8~GeV/c and p/K up to 10GeV/c.

This contribution presents the latest design of the high-performance DIRC for the EIC detector, including the performance in the Geant4 simulation as well as results of experimental tests of key elements in the laboratory and with particle beams. 

Keywords: Cherenkov detectors, Electron Ion Collider, DIRC
Poster panel
(face) ID: 235


Poster Number:
N-03-118
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Silicon photomultiplier multichannel arrays for the LHCb scintillating fibre tracker (#2111)

O. G. Girard1, G. J. Haefeli1, A. K. Kuonen1, M. E. Stramaglia1

1 EPFL, SB / IPHYS / LPHE1, Lausanne, Vaud, Switzerland

Content

For the LHCb detector upgrade in 2019, a large scale scintillating fibre tracker read out with silicon photomultipliers is under construction. The harsh radiation environment (neutron and ionising radiation), the 40MHz read-out rate of the trigger less system and the large detector surface of 320m2 impose many challenges. We present the results from lab tests with 1MeV electrons and from the SPS test facility at CERN for the mulitchannel SiPM array that combines peak photo-detection efficiency of 48% and extremely low correlated noise. The measurements were performed with detectors irradiated with neutrons up to a fluence of 12*1011 neq/cm2 and single photon detection was maintained. First results of the characterization of the pre-series of 500 detectors delivered by Hamamatsu and irradiation studies on a large sample will be included.

Keywords: SiPM, Scintillating fibre, LHCb, SciFi tracker, Multichannel array, Neutron irradiation, Single photon detection
Poster panel
(face) ID: 237


Poster Number:
N-03-119

Tests of single photon counting at sub-nanosecond precision for next generation RICH detectors (#2929)

M. Calvi1, 2, P. Carniti1, 2, L. Cassina1, 2, C. Gotti1, 2, C. Matteuzzi1, 2, G. Pessina1, 2

1 INFN, Milano Bicocca, Milano, Italy
2 University of Milano Bicocca, Dipartimento di Fisica G. Occhialini, Milano, Italy

Content

Comparative measurements of the timing resolution to single photons of SiPM, Ma-PMT and MCP-PMT from several manufacturers are presented. Their timing resolution is studied down to the 10-ps range, as a means to resolve single Cherenkov photons from background in the high luminosity conditions foreseen at future colliders. The performance of a low power ASIC for single photon counting named CLARO is compared with that of discrete, wide-bandwidth operational amplifiers.

Keywords: RICH detectors, single photon counting, photodetectors, SiPM, MCP, PMT
Poster panel
(face) ID: 239


Poster Number:
N-03-120

Direct temperature measurement of SiPM microcell junctions (#3194)

A. Ivan1, S. Dolinsky1

1 GE Research, Niskayuna, New York, United States of America

Content

The temperature-dependent performance of silicon photomultipliers (SiPM) is mitigated in light detector systems by maintaining a constant thermal environment. When the light has large and/or rapid variations, the thermal equilibrium fails and it becomes essential to determine the actual junction temperature for accurate light detection.
The present work proposes a new measurement method based on the relation between forward current-voltage (I-V) diode characteristic and the junction temperature. First, a device-specific calibration table is determined from forward I-V characteristics of the SiPM at different constant temperatures. After calibration, the normal SiPM operation in reverse bias is rapidly switched at the power supply to forward bias in current source mode. The forward voltage readout and the calibration look-up provide the instantaneous local temperature.
For demonstration, we performed a set of calibration measurements on commercial SiPM devices. As intense light source, a picosecond-pulsed laser triggered simultaneously avalanches in all of the SiPM microcells to produce a common temperature-time profile. After illumination, the forward voltage Vf readouts tracked the junction temperature decay, based on the prior calibration. For further proof-of-concept study, we exposed the SiPMs to different light illumination patterns by varying the laser frequency or the total illumination time.

Keywords: Silicon photomultiplier, semiconductor-based photosensor
Poster panel
(face) ID: 241


Poster Number:
N-03-121

Comprehensive Characterization of Silicon Photomultipliers for Nuclear Security Applications (#3278)

M. Wonders1, M. Flaska1, D. L. Chichester2

1 Pennsylvania State University, Department of Mechanical and Nuclear Engineering, University Park, Pennsylvania, United States of America
2 Idaho National Laboratory, Idaho Falls, Idaho, United States of America

Content

This paper reports on the characterization of many different silicon photomultipliers with an emphasis on characteristics relevant to nuclear nonproliferation and safeguards. Such characteristics include noise, wavelength responsivity, time response, and the ability to detect and identify neutrons when coupled with organic scintillators using pulse shape discrimination. The dependence of these characteristics on overvoltage is determined, and damage resulting from elevated temperatures and high radiation fields is also investigated. Silicon photomultipliers of different pixel and microcell sizes have been acquired from various manufacturers: SensL, Hamamatsu, Ketek, First Sensor, and AdvanSiD. This work will result in a comprehensive assessment of the performance of current state-of-the-art of silicon photomultipliers, where silicon photomultipliers are compared to traditional photomultiplier tubes for different applications.

Keywords: Silicon Photomultipliers, neutron detection, semiconductor, photodetector
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(face) ID: 243


Poster Number:
N-03-122

Large Plastic Scintillators with Efficient SiPM Readout (#3522)

M. R. Kusner1, P. R. Menge1

1 Saint-Gobain Crystals, Hiram, Ohio, United States of America

Content

Large monoliths (~5x40x200 cm3) of plastic scintillator are routinely used for detection (via gamma rays) of illicit nuclear materials in applications such as cargo scanning, wide area monitoring, and vehicle border crossings. Silicon photomultipliers (SiPMs) are attractive replacements for photomultiplier tubes (PMTs) due to their compactness and low power draw. However, SiPMs can pose a problem for these large scintillator applications. When large areas of SiPMs are used, the dark count noise and cost increase proportionally with the surface area covered. Moreover, as of 2017, SiPMs are roughly 5x the price of PMTs on a per cm2 basis. When too few SiPMs are used, the low fraction of scintillation light collected reduces the sensitivity and the detectability of gamma rays. This problem gets even worse when applied to advanced plastics containing high-Z additives or high fluor concentrations. These plastics have increased optical scattering and attenuation. A potential method to reduce the SiPM coverage requirements is to pass rods of wavelength shifting (WLS) plastic through the bulk of the large monolith and couple each rod end to an SiPM. Such a method improves the situation in two ways. First, the number of potential absorptions by the surface reflector is fewer. Second, the average photon pathlength through the monolith is reduced. This is especially important for advanced plastics (e.g. spectroscopic or neutron-detecting) which have high optical extinction coefficients. Simulations show that as few as eight standard SiPMs (6x6 mm2) coupled to four WLS rods are sufficient to emulate the performance attained with PMTs on large monoliths. Results of ongoing experiments will be presented.

Keywords: plastic scintillator, SiPM, large detector, portal monitor, wide area monitoring
Poster panel
(face) ID: 245


Poster Number:
N-03-123

Improvement of SDD-Maia Detector for X-ray Fluorescence Detection (#3611)

W. Chen1, D. Elliott1, G. Giacomini1, A. Kuczewski1, A. K. Rumaiz1, D. Pinelli1, D. P. Siddons1, G. Smith1

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

Content

A new SDD-Maia detector is being currently developed, consisting of an array of 384 silicon drift detectors (SDDs), each having a surface area of 1 mm2. The shape of each individual pixel is square in order to coincide with the footprint of the diode-based Maia detector. Each SDD pixel is made of 8 concentric “rings” that supply a voltage gradient to form the drift field within the silicon. The detector has a new double metal scheme that supplies biases to the single SDD rings. All 384 anodes of SDDs are connected to individual electronic channels. This effort was motivated by the need of improving the energy resolution and the throughput of existing diode-based Maia detectors. The first batch of SDD-Maia showed reasonable sensitivities for detecting 55Fe X-rays, achieving the same noise performance as the diode-based Maia detector at a lower shaping time. From the inputs of the first fabrication batch, a second batch has solved many of the issues. The spectroscopic test will soon be carried out. The improvement and test results will be presented in the conference.

Keywords: Silicon Drift Detector
Poster panel
(face) ID: 247


Poster Number:
N-03-124

An active high QE photocathode (#3691)

H. van der Graaf1, 2

1 Nikhef, Detector R&D, Amsterdam, NH, Netherlands
2 TU Delft, RST, Delft, ZH, Netherlands

Content

We propose to perform a theoretical study aiming for a highQE photocathode.

The quantum efficiency of photocathodes has asymptotically reached a value of 0.4. New available technology may change this situation:

  • the absorption/conversion layer could be sandwiched by two single layers of i.e. graphene: by applying a potential difference between these layers, a drift field could push electrons in the conduction band towards the emission side of the layer;
  • With Atomic Layer Deposition (ALD), the conversion layer could, in principle, take the form of a stack of individual ALD layers, combining, for instance, a multiple of alkali and -oxide monolayers
  • With available ab initio routines like the Vienna Ab initio Simulation Package VASP, electron density, energy distributions and work functions can be calculated, providing parameters needed for a full simulation of the conversion layer
  • The electron affinity of the emitting surface can be lowered by adding termination atoms onto the graphene at the emission side
  • The positive effect of the static extracting field can be maximised

Such a stack should first be designed, simulated and analysed: after that, the rapidly expanding ALD technology is consulted for a next project to realise such a photocathode.

This project is a pure theoretical solid-state physics study.

Keywords: Photocathode, Quantum Efficiency, Active photocathode
Poster panel
(face) ID: 249


Poster Number:
N-03-125

Comparative study of ruggedness and reliability of gamma ray detectors based on a commercial rugged PMT and a Schlumberger PMT at temperatures up to 185°C (#3941)

I. Shestakova2, O. Philip2, J. Weidemann1, A. Headley1

1 Schlumberger, Princeton Technology Center, Princeton Junction, New Jersey, United States of America
2 Schlumberger, Houston Formation Evaluation, Sugar Land, Texas, United States of America

Content

We have evaluated gamma ray detectors built with a rugged YAP(Ce) scintillator and two kinds of photomultiplier devices: a commercial rugged PMT designed for 200°C operation and a rugged ceramic PMT with a 1-in. diameter window designed and built in house at the Schlumberger Princeton Technology Center for use in the Schlumberger oil exploration tools. For oilfield applications, gamma ray detectors require reliable and stable performance during hundreds of hours of operation in the harsh well-logging environment (high shock levels and high temperature). Therefore, the focus of this evaluation was on the characterization of the photomultiplier reliability under these conditions. The measurement techniques and results will be presented.

Keywords: rugged photodectors, lifetime of photomultipliers, oilfield logging environment, custom photomultipliers
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(face) ID: 251


Poster Number:
N-03-126

Advances in Radiation-Hard Scintillator and Wavelength-Shifter Developments (#1527)

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

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

Content

Unprecedented radiation conditions are projected for future circular and linear colliders as well as the Large Hadron Collider in the High-Luminosity era. Scintillator tiles are common active media in particle detectors as well as beam monitors in all of these experiments. In this context, we have developed radiation-hard scintillator materials and wavelength shifting fibers such as quartz variants with various surface coatings and plastic polymers and elastomers. Here we describe the recent advances in these developments and discuss past and projected measurements including radiation tests.

Keywords: radiation hard scintillators
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(face) ID: 253


Poster Number:
N-03-127

Radiation Charaterization of a Swiched Capacitor Array Readout ASIC for Time Projection Chamber (#1988)

X. Zhao1, 2, Z. Deng1, 2, Y. Liu1, 2, W. Hajdas3

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

Content

The paper present the radiation test results of a readout ASIC (CASCA: Charge Amplifier with Switched Capacitor Array) for a TPC based X-ray polarimeter. It integrated 32 channel full-chain signal processing circuits and was fabricated in 0.18μm CMOS process. Each channel consisted of a charge sensitive preamplifier, a CR-RC shaper with a peaking time of 25 ns, a baseline holder, a discriminator and a 64-cell switched capacitor array (SCA). Both TID and SEE tests of CASCA would be taken. In the TID test, three samples were irradiated to 10Krad (Si), 20Krad (Si) and 100Krad (Si) with dose rate of 10rad (Si)/s respectively. The electrical test results of their analogue front-ends and switch capacitor arrays both before and after irradiations were given and discussed. The SEE tests of the ASIC with different energy of protons are undergoing, which will mainly focus on its performance against SEL and SEU. The detailed radiation test methods, data analysis and test results will be present in this paper.

Keywords: readout ASIC, radiation effects, TID, SEE
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(face) ID: 255


Poster Number:
N-03-128

Modeling Radiation Damage to Pixel Sensors in the ATLAS Detector (#2078)

C. Troncon1

1 INFN, Milano, Italy

Content

Pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC). As the closest detector component to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the High-Luminosity LHC (HL-LHC), the innermost layers will receive a fluence in excess of 1015 neq/cm2 and the HL-HLC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is critical in order to make accurate predictions for current future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects to the ATLAS pixel sensors for the first time. In addition to thoroughly describing the setup, we present first predictions for basic pixel cluster properties alongside early studies with LHC Run 2 proton-proton collision data.

Keywords: radiation damage, silicon pixel detector
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(face) ID: 257


Poster Number:
N-03-129

Radiation Effects in IGZO Semiconductor Based Switch Used for Flat Panel Detector (#2430)

Y. Otaka1, 2, K. Shimazoe2, A. Koyama2, H. Miyoshi3, T. Iimoto4, H. Takahashi2, K. Inoue1, M. Fukushi1

1 Tokyo Metropolitan University, Department of Radiological Sciences, Higashiogu, Arakawa-ku, Tokyo, Japan
2 The University of Tokyo, Department of Bioengineering, Hongo, Bunkyo-ku, Tokyo, Japan
3 Sharp Corporation, Research Division, Takumi-cho, Sakai-ku, Sakai City, Osaka, Japan
4 The University of Tokyo, Division for Environment, Health and Safety, Hongo, Bunkyo-ku, Tokyo, Japan

Content

In this paper, radiation resistance of Indium Gallium Zinc Oxide - Thin Film Transistor (IGZO-TFT) was investigated using industrial X-ray generator. Since the IGZO-TFT has low leakage characteristics when it is OFF, the contribution of noise is small and the signal-to-noise ratio is high when used as a switching device of the Flat Panel Detector (FPD). Therefore, it is possible to perform low- dose X-ray imaging than FPD using conventional amorphous-silicon-TFT. However, since there is almost no precedent case regarding radiation resistance of IGZO-TFT, resistance evaluation will be carried out in this research and reported. The evaluation of radiation effects using OFF current (Ioff), ON current (Ion), mutual conductance (gm), field effect mobility (μfe) and subthreshold swing(SS) of fundamental character. In the method, X-ray with a tube voltage of 120 kV / tube current of 2 mA which is the maximum output was irradiated equivalent to 450 Gy for 88 minutes to the IGZO-TFT. Gate voltage-drain current characteristics (I-V characteristics) required for derivation of Ioff, Ion, gm, μfe and SS were measured before and after X-ray irradiation. Further measurements were taken after a certain period from irradiation, and changes over time were examined. As a result, neither Ioff, Ion, gm, μfe and SS increased to an extent not affecting switching characteristics. Assuming that the IGZO-TFT can be considered in the same way as the Metal Oxide Semiconductor Field Effect Transistor (MOSFET) made of silicon, part of the holes generated in the gate insulator by X-ray irradiation is captured in the gate oxide film, so due to performed the positive charged trapping oxides. As time elapsed, the trapped holes escaped from the oxide film as carriers, so did not affect the switching characteristics. Therefore, from this result IGZO-TFT provided sufficient X-ray stability for FPD.

Keywords: IGZO, FPD
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(face) ID: 259


Poster Number:
N-03-130

Investigation of Environmental Cosmic-ray Muon Spectrum in Low Energy Region (#2791)

H. Sato1, T. Kin1, Y. Watanabe1

1 Kyushu University, Department of Advanced Energy Engineering Science, Kasuga-shi, Fukuoka, Japan

Content

Recently, potential of soft errors by cosmic-ray muon has been pointed out for state-of-the-art high-integrated devices. Since low energy muon can deposit sufficient energy even in the small sensitive region of the device, cosmic-ray muon spectrum in low energy region is important to estimate error rate. However, no measurement has been reported below 100 MeV. We have developed a muon detector system consists of plastic scintillators (PSs) to measure the low-energy cosmic-ray muon energy spectrum. The main cubic PS was sandwiched vertically by two plate-shaped PSs. To eliminate natural background radiation and electric noises, recorded events were filtered by coincidence condition of the main and upper PSs. The bottom PS was used as a veto detector to reject the muons penetrating the main PS. Under these conditions, signals by a muon stopped in the main PS were only acquired. The detectable maximum zenith angle and energy was limited by the detector geometry and the values are 45 degrees and 75 MeV, respectively. The experiment with the detector system was carried out at Chikushi Campus of Kyushu University. The energy dependent efficiency was derived by PHITS simulation to obtain absolute energy spectrum from measured counting rate. The obtained spectrum is in good agreement with the predicted one with EXPACS around 75 MeV in magnitude and shape. In lower energy region, however, the present flux is larger. Since our detector system cannot reject cosmic-ray electrons completely, their events are possibly included in the region. In the future, detection geometry will be improved to absorb or scatter the cosmic-ray electrons.

Keywords: Cosmic-ray, Energy spectrum, Soft error
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(face) ID: 261


Poster Number:
N-03-131

Dose and dose rate dependency of radiation-induced transient absorption in pure silica optical fibers under gamma irradiation (#4164)

M. Baydjanov1, 2, M. Ashurov2, I. Nuritdinov2, K. Saidakhmedov2, T. Shikama3

1 Turin Polytechnic University in Tashkent, Tashkent, Uzbekistan
2 Institute of Nuclear Physics, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan
3 Hachinohe Institute of Technology, Hachinohe, Japan

Content

The optical losses spectra in 300-800 nm region of silica core fibers with high and low OH-group content is measured in-situ and after 10 minutes of irradiation by γ-rays of 60Co source. In-situ optical losses are separated to fast annealing (transient) and residual (stable) parts in order to analyze behavior of transient color centers with the change of dose and dose rate. The linear dependence of the magnitude of transient absorption caused by transient color centers is observed as a function of dose and its saturation at the dose ~5∙107 Rad in silica core silica clad fiber is achieved. The saturation of transient color centers in silica core polymer clad fibers is achieved at ~107 Rad. The dependence of radiation-induced optical losses on dose rate is linear within the observed values 6-360 R/s.  It’s shown that creation mechanism and concentration of transient color centers depend on OH-group content as well as core diameter and preliminary defects in fibers.

Keywords: radiation effects in fibers, silica fibers, induced absorption, color centers, radiation damage of fibers, radiation resistance of fibers, optical fibers in radiation environment
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(face) ID: 263


Poster Number:
N-03-132

Lu3Al5O12:Ce Transparent Polycrystalline Ceramic and Single Crystal Scintillators: Microstructure and Performance (#1017)

A. A. Trofimov1, T. DeVol2, L. G. Jacobsohn1, 3

1 Clemson University, Department of Materials Science and Engineering, Clemson, South Carolina, United States of America
2 Clemson University, Environmental Engineering and Earth Sciences Department, Anderson, South Carolina, United States of America
3 Clemson University, Center for Optical Materials Science and Engineering Technologies – COMSET, Anderson, South Carolina, United States of America

Content

Polycrystalline ceramic scintillators have received increasing attention due to a number of advantages over single crystals, including faster and lower cost fabrication methods and easier fabrication of materials with high melting temperatures. Nevertheless, scintillation performance of polycrystalline ceramics is commonly inferior to single crystals. In this work, a comparative investigation between a LuAG:Ce transparent polycrystalline ceramic and a single crystal scintillators was executed in terms of their microstructure, as well as optical and luminescent properties to gain insight into the factors influencing their scintillation performance. The polycrystalline ceramic was prepared by high temperature vacuum sintering, and the single crystal was grown by the Czochralski method with Ce content of ~0.06 and ~0.04 at.%, respectively. Results showed enhanced self-optical absorption and a higher degree of structural disorder in the polycrystalline ceramic. Radioluminescence (RL) and photoluminescence measurements indicated the presence of defect bands, including F+-type centers and antisite defects. RL results indicated a 7 times higher content of defects in the single crystal than in the polycrystalline ceramic. TL results within the 50-400 oC range showed the presence of 6 glow peaks in the single crystal and 4 glow peaks in the polycrystalline ceramic, all with first-order kinetics. Trap depths of glow peaks at the same temperature were ~1.2-1.6 times deeper in the single crystal than in the polycrystalline ceramic. The scintillation response was evaluated by means of differential pulse height distribution measurements and yielded the luminosity relative to BGO. Both LuAG:Ce forms presented a linear behavior of the energy response, with the relative luminosity of the single crystal being 1.7 times that of the polycrystalline ceramic at 662 keV.

Acknowledgements: This material is based upon work supported by the National Science Foundation under Grant No. 1207080.

Keywords: LuAG:Ce, ceramic, microstructure, thermoluminescence
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(face) ID: 265


Poster Number:
N-03-133

Characterization of Large Diameter Tl2LiYCl6 Scintillation Detectors (#1119)

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

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

Content

Large diameter (⌀1") Tl2LiYCl6: Ce (TLYC), a new, thallium-based equivalent of CLYC, is recently grown and analyzed at Radiation Monitoring Devices, Inc. (RMD). Growth of 1" crack-free single crystals has been accomplished. Gamma-ray light yield of 25,000 ph/MeV and energy resolution better than 4% at 662 keV are achieved with a crack-free ⌀1"×1.2" crystal. The gamma equivalent energy (GEE) produced by thermal neutron is 1.89 MeVee, along with a neutron induced light yield of 47,000 ph/n. This work describes crystal growth, scintillation properties and potential applications of large diameter TLYC. Non-proportionality data, gamma-ray and neutron decay time measurements, as well as pulse shape discrimination (PSD) results from large diameter TLYC crystals will also be reported.

Keywords: Tl2LiYCl6, Elpasolite, Crystal Growth, Dual Mode Scintillator, Gamma-ray Detection, Neutron Detection
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(face) ID: 267


Poster Number:
N-03-134

Thermal Neutron Detection with LiF:W Single Crystal Scintillator (#1191)

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

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

Content

Scintillation properties of LiF:W were investigated comparing with LiCaAlF6:Eu and GS20 (Ce doped lithium silicate glass). As results of photoluminescence and X-ray induced luminescence spectra, LiF:W showed emission peak at the wavelength of 440 nm. From X-ray induced decay curve, decay time of LiF:W was estimated at approximately 43 μs that was rather lower than LiCaAlF6:Eu and GS20. Pulse heigt spectra of LiF:W were successfully obtained under themal neutrons or gamma-ray irradiation. Finally, the light yield of LiF:W was estimated at approximately 90 photons/neutron by comparison with GS20.

Keywords: Thermal neutron, Neutron scintillator, Scintillator, Single crystal, Fluoride
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(face) ID: 269


Poster Number:
N-03-135

Scintillation and Dosimetric Properties of Aluminum Nitride Ceramics Sintered with Strontium Fluoride Additive (#1193)

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

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

Content

In this study, we synthesized undoped AlN and SrF2-added AlN (AlN-SrF2) ceramics by Spark Plasma Sintering (SPS), and we characterized their scintillation and dosimetric properties. The prepared undoped AlN ceramic had gray color and visually non-transparent whereas, with an addition of SrF2, the transparency improved and became translucent. The addition of SrF2 decreased the scintillation intensity. Thermally-stimulated luminescence (TSL) showed good linear response from the milli-gray range to over 10 Gy. The sensitivity seems to decrease by an addition of SrF2 as it suppresses structural defect centers which are responsible for dosimeter properties. However, the main TSL glow peak position shifts to higher temperature with the addition of SrF2, which indicates that inclusion of SrF2 improves the TSL signal stability.

Keywords: Scintilltior, Dosimeter, AlN, Nitride, Ceramic
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(face) ID: 271


Poster Number:
N-03-136

Characterization of the Anisotropic Scintillation Response of Stilbene Using Monoenergetic Neutron Beams and Elastic Scatter Kinematics (#1204)

R. A. Weldon1, J. Mueller1, J. Mattingly1

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

Content

Stilbene is a crystalline organic scintillator known to have an anisotropic scintillation response to neutrons dependent on the proton recoil direction in the crystal. We have conducted experiments using the Triangle Universities Nuclear Laboratory (TUNL) tandem Van de Graaff accelerator with the goal of characterizing the anisotropic scintillation response of stilbene to neutrons. The results of two sets of measurements are presented here. The first set of measurements characterized the response for 7 proton recoil directions in two 1 cc stilbene crystals using a 5 MeV neutron beam. The proton recoil directions were in the a-b plane and the a-c' plane of the stilbene crystals and cover an energy range of 400 keV to 4.7 MeV. The second set of measurements were performed with the goals of (1) testing the reproducibility of the first set of measurements and (2) determining if the scintillation response can be characterized over a full hemisphere of a stilbene crystal using vector decomposition of the proton recoils measured in the major axes planes and at specific directions in theta and phi.

Keywords: stilbene, crystalline scintillator, anisotropic scintillation response, neutrons
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(face) ID: 273


Poster Number:
N-03-137

Efficiency calibration of CeBr3 scintillator in close-geometry: Simulations and measurements (#1542)

A. K. Gourishetty1, A. Bhagwat1, S. Panwar1, S. Sharma1, V. Ranga1, S. Rawat1, M. Dhibar1

1 Indian Institute of Technology Roorkee, Radiation Detectors and Spectroscopy laboratory, Department of physics, Roorkee, Uttarakhand, India

Content

CeBr3 is emerging as one of the best scintillation detectors having properties similar to Cerium doped lanthanum halide detectors. The experimental determination of efficiency calibration of CeBr3 detector for close source-to-detector geometry is useful in gamma-ray spectroscopy. In the present work, we have made realistic Monte Carlo simulations of the response of a 1² ´ 1² CeBr3 scintillation detector using mono energetic gamma emitter 137Cs and radioactive sources emitting two gamma rays in cascade, namely, 60Co, 94Nb, 46Sc and 24Na by considering the source on the top of the detector surface. These simulations were done using GEANT4 toolkit that include radioactive decay module, low energy EM package and general particle source (GPS) module. Energy spectra were generated for each of these double gamma emitters and absolute efficiencies (both total detection and full energy absorption) so obtained have been corrected for coincidence summing using the method proposed by Vidmar et al. [Nucl. Instr. and Meth. A 508 (2003) 404]. The simulations have also been carried out for the same energies assuming mono-energetic point sources, for comparison. Experimental measurements have also been carried out using calibrated point sources of 137Cs and 60Co. The simulated and the experimental results are found to be in good agreement. This demonstrates the reliability of the correction method, originally proposed for HPGe detector, for efficiency calibration of CeBr3 detector.

Keywords: CeBr3, coincidence summing, GEANT4 Simulation, Efficiency
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(face) ID: 275


Poster Number:
N-03-138

Resolving x-ray microbeams using a water-equivalent scintillator dosimeter (#1591)

J. Archer1, E. Li1, M. Petasecca1, 3, A. Dipuglia1, M. Cameron1, A. Stevenson2, C. Hall2, D. Hausermann2, A. Rosenfeld1, 3, M. Lerch1, 3

1 University of Wollongong, Centre for Medical Radiation Physics, Wollongong, New South Wales, Australia
2 Australian Synchrotron, Imaging and Medical Beam-Line, Clayton, Victoria, Australia
3 University of Wollongong, Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia

Content

Synchrotron microbeam radiation therapy (MRT) is a novel external beam therapy under investigation for its application in the treatment of brain tumours. Key characteristics of these x-ray microbeams is their high flux, high spatial fractionation and large dose rates. For clinical quality assurance, the dose rate in the microbeams (peaks) and between them (valleys) must be measured accurately. In this work, we present a water-equivalent plastic scintillator dosimeter with an optimal one-dimensional spatial resolution of 50 μm (0.157 mm3 sensitive volume). The scintillator is linear, energy independent, and radiation hard. The dosimeter is able to perform real time relative dosimetry. Whereas the probe design itself is not novel, this is the first use of a plastic scintillator dosimeter to resolve microbeams. The sub-millimetre spatial resolution is the highest found in available literature for a dosimeter of this type. The intrinsic microbeam profile was measured using this dosimeter at the Australian Synchrotron on the Imaging and Medical Beam-Line. The microbeam collimator defined a microbeam field 30 mm × 2.014 mm, with microbeam width 50 μm and peak-to-peak separation of 400 μm. The mean microbeam full width at half maximum was measured using our dosimeter to be (63 ± 2) μm. The mean peak-to-valley dose ratio was measured to be (19 ± 3). Further, a synchrotron x-ray broadbeam percent depth dose was measured and compared to ionisation chamber results. The dosimeter consistently over-responded compared to the ionisation chamber results at low depth. This work demonstrates the applicability of this dosimeter design in MRT, and we intend to develop a probe with even higher spatial resolution.

Keywords: microbeam radiation therapy, scintillators, x-ray dosimetry, synchrotrons, fibre optic
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(face) ID: 277


Poster Number:
N-03-139

Luminescence properties of organic–inorganic layered perovskite-type compounds under vacuum ultraviolet irradiation (#1638)

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

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

Content

We investigated luminescence properties of organic–inorganic layered perovskite-type compounds under vacuum ultraviolet irradiation. A single crystal of (C6H5C2H4NH3)2PbBr4 was fabricated by poor-solvent diffusion method. Exciton emissions from the inorganic layer was observed at 410 nm under ultraviolet irradiation (Exc. 180 and 300 nm). Rise time behavior of luminescence decay curves was quite similar among the excitation wavelength of 60–300 nm. In addition, no peak (1A1g1E1u) of benzene in a vacuum ultraviolet energy region was observed in the excitation spectra with the wavelength of exciton emissions from the inorganic layer. These results indicate that the effect of energy transfer from the organic to the inorganic layer has negligible influence on the luminescence properties of the organic–inorganic layered perovskite-type compounds.

Keywords: excitons, quantum confinement effect, VUV
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(face) ID: 279


Poster Number:
N-03-140

Progress on Metal-loaded Plastic Scintillators for Nuclear Security Applications (#1716)

U. Shirwadkar1, E. van Loef1, G. Markosyan1, M. McClish1, K. S. Shah1, J. Glodo1, P. Feng2, N. Myllenbeck2, R. Dhaoui2

1 Radiation Monitoring Devices, Inc., Watertown, Massachusetts, United States of America
2 Sandia National Laboratories, Livermore, California, United States of America

Content

Nuclear non-proliferation applications and monitoring of special nuclear materials (SNMs) prefer low-cost detector solutions that provide efficient gamma-ray and neutron detection in combination with neutron/gamma pulse shape discrimination (PSD). Plastic scintillators with excellent PSD can be produced in large sizes at low cost.  Unfortunately, due to their low density and effective Z, gamma-ray detection is limited to gross counting. In this paper we report on the fabrication and characterization of large (up to 4” diameter) metal-loaded plastic scintillators developed at RMD and SNL.  We will show that these metal-loaded plastic scintillators have a high light output, a fast scintillation decay, and exhibit very good neutron-gamma PSD with a Figure of Merit (FOM) of about 2 at 1 MeVee.  Pulse height spectra collected using a 137Cs source show energy resolutions of about 10-12% (FWHM) at 662 keV. The non-proportionality, measured in the energy range 60 keV - 1275 keV, shows a 5% deviation from linear response at lower energies. A systematic study was performed of tin and PPO concentrations to investigate their effect on the scintillation properties. Clear trends have been observed, which are useful in selecting optimal compositions for specific application needs. Samples were fabricated with up to 90% tin- and 40% lead-compounds. Photopeak efficiencies have been compared among samples with different loading. We have constructed a permanent detector probe consisting of a 2” x 2” tin-loaded plastic scintillator for handheld applications. Its efficiency has been compared to a commercial detector such as CLYC. The data on these metal-loaded plastic scintillators is presented in this paper.   

Keywords: Plastic scintillators, metal-loaded plastic scintillators, Nuclear non-proliferation, pulse shape discrimination, Gamma-ray spectroscopy
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(face) ID: 281


Poster Number:
N-03-141

Radio-photoluminescence (RPL) in Sm:CsBr (#1772)

G. Okada1, Y. Fujimoto2, S. Kasap3, N. Kawano1, N. Kawaguchi1, T. Yanagida1

1 Nara Institute of Science and Technology, Graduate School of Materials Science, Ikoma, Nara, Japan
2 Tohoku University, Department of Applied Chemistry, Sendai, Miyagi, Japan
3 University of Saskatchewan, Electrical and Computer Engineering, Saskatoon, SK, Canada

Content

Radio-photoluminescence (RPL) is a  phenomenon seen in luminescent materials in which the appearance of new photoluminescence (PL) emission is induced by an incident ionizing radiation such as x-rays; and the signal is stable even after the irradiation and during the PL measurement. Since the induced PL intensity is proportional to the irradiation dose, the RPL can be used in radiation measurements. The distinct advantage of RPL over the conventional thermally- or photo-stimulated luminescence (abbreviated as TSL or PSL) dosimeters is the stability of response signal. With an RPL detector, it allows us to readout the signal multiple times without signal fading. In this work, we have discovered that CsBr:Sm shows an RPL phenomenon by X-ray irradiation, and we have characterized this new material as an RPL detector. While the sample shows PL emissions mainly in the visible range, after an X-ray irradiation additional emissions can be observed in the red to near-infrared range around 650-850 nm and 900-1000 nm and longer. The RPL response is fairly stable overall, but very interestingly the 650-850 nm signal slightly increases while the 900-1000 nm decreases during PL readout. The dynamic range was confirmed over 1 – 104 mGy with linear response.

Keywords: Radio-photoluminescence (RPL), Sm, CsBr
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(face) ID: 283


Poster Number:
N-03-142

NIR-Emitting Scintillators based upon Rare-Earth-Doped Garnet Crystals (#1775)

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

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

Content

The paper reports experimental results towards a development of near-infrared (NIR) emitting scintillators based on rare-earth-doped garnet crystals which was performed as a part of collaborative research with the Nuclear Power Safety Technology Research Center, Chubu Electric Power Co., Inc. A series of garnet scintillators (YAG and YAGG doped with rare earth elements (Nd, Sm, Ho, Er, Tm, and Yb) at varying concentrations (0.5, 1.0, 2.0, 5.0, and 10.0 mol.%) were synthesized by the floating zone method and systematically characterized for NIR-emitting scintillator applications. Among all the samples, 5%Nd-doped YAG showed the highest scintillation intensity (integration mode). Taking spectral responsivity of photodetector and attenuation of optical light guide into consideration, a combination of 5%Yb-doped YAG and InGaAs detector expected to give the highest detectable signal. The scintillation intensity effectively depends on the photoluminescence quantum yield and energy transfer efficiency, which is not effectively correlated with the quality of crystal but the type of rare-earth ion doped.

Keywords: NIR, Scintillator, YAG, YAGG
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(face) ID: 285


Poster Number:
N-03-143

Effect of simultaneous Ca, Mg – doping on the scintillation properties and crystal growth stability of large size Ce:Gd3Al2Ga3O12 crystals (#1841)

V. Kochurikhin1, K. Kamada1, 2, Y. Shoji1, 2, S. Kurosawa2, 3, Y. Yokota2, A. Yamaji2, M. Yoshino1, 2, A. Yoshikawa1, 2

1 C&A (Crystals and Applications) Corp., Sendai, Japan
2 Tohoku University, Institute for Materials Research, Sendai, Japan
3 Yamagata University, Faculty of science, Yamagata, Japan

Content

Ce-doped Gd3Al2Ga3O12 (GAGG) bulk crystals with simultaneous co-doping by Mg2+ and Ca2+ ions were grown the Czochralski technique up to 3 inch in diameter. Production of Ce:GAGG with big size has a serious limitation due to the high growth instabilities and, as a result, change of growing crystal shape from straight into the spiral one. At the same time it is known that the adding of small amount of divalent ions to the melt suppresses such phenomenon effectively. However, appearance of even small amount of extraneous impurity in one of crystallographic sublattices cases the formation of stresses in the crystal and cracking as a result. In this study, 2 different size divalent ions (Mg2+, Ca2+) in the amount up to 1000 ppm each were added to the melt simultaneously for the suppression of growth instabilities. Additionally, the adding of divalent ions has positive effect on the scintillation properties as notable acceleration of decay time. The effect of such double doping on the growth stability, the distribution of dopant ions by the crystallographic sites, and the influence on the scintillation properties will be discussed.

Keywords: single crystal growth, Oxides, scintillator materials
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(face) ID: 287


Poster Number:
N-03-144

Simulation of scintillation signal as a help in phoswich systems conception (#1845)

R. Coulon1, M. Becht1, J. Dumazert1, Q. Lecomte1, S. Garti1

1 CEA, LIST, Sensors and Electronic Architecture Laboratory, Gif-sur-Yvette, France

Content

Pulse shape analysis is commonly implemented into nuclear detection systems notably dealing with phoswich structures addressing for instance beta or neutron discrimination from gamma rays. Particle transport codes such as MCNP, TRIPOLI or GEANT are useful tools to help designing phoswich systems. However, the basic calculation is focused on the estimation of the deposited energy per particle history into scintillator parts. The new model proposed by the CEA LIST enables to process scintillation light production, collection, conversion, and thereafter pulse shape simulation at the output of a photomultiplier.

The approach is based on the decomposition of the signal with: the scintillation signal from interaction, the thermal noise (Johnson-Nyquist), and the dark noise (thermo-ionic emission). Knowing, for each particle histories, the quantity of energy deposed by charged particles into each cells of the phoswich system (MCNP-PTRAC), the light yield corresponding to each scintillator, the light collection efficiency and quantum efficiency of the conversion system; a number of photoelectrons is generated by sampling into a Poisson distribution according to the purely stochastic process of fluorescence emission. Thus, the scintillation signal model uses continuous illumination function (sum of exponential functions parametrized with time constant of scintillators) in order to provide the expected numbers of photoelectron as a function of the time. A discrete Dirac brush is obtained by processing the inhomogeneous Poisson process of photoelectron arrivals. The time interval between photoelectrons is generated by random sampling into an exponential distribution parametrized with the corresponding period given by the illumination function. The scintillation signal is finally obtained thanks to the convolution of the Dirac brush with the photomultiplier impulse response (centered Gaussian shaped function parametrized with the photomultiplier spread time).

Keywords: Scintillation; Phoswich; Simulation;
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(face) ID: 289


Poster Number:
N-03-145

Evaluation of new semiconductor scintillator Gallium oxide (#1858)

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

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

Content

We report distinct scintillation properties of well-known Ga2O3 semiconductor material. Under UV excitation, photoluminescence (PL) emission peak appeared around 380 nm with the quantum yield of 6%, and fast decay of 8 and 793 ns were observed. In contrast, X-ray induced scintillation spectrum also showed an intense emission band around 380 nm, which of decay curve was reproduced by two exponential decay components with the time constants of 8 and 977 ns. The pulse height spectrum of 137Cs g-rays measured using measured Ga2O3 showed a clear photoabsorption peak with a light yield of 15000 ± 1500 ph/MeV.

Keywords: Scintillator, Ga2O3
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(face) ID: 291


Poster Number:
N-03-146

Development of LuAG based infrared emitting scintillator (#1860)

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

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

Content

Lu3Al5O12 (LuAG) single crystals co-doped with Nd and Ce were grown by the Floating Zone (FZ) method to evaluate their scintillation properties particularly in the near infrared (NIR) wavelength. When X-ray was irradiated, the scintillation due to Nd3+ 4F3/24I11/2 transition was observed at 1064 nm. By changing the irradiation dose from 10-1000 mGy, we evaluated the relation between the scintillation intensity and the X-ray dose, and the relation was approximately linear. The scintillation decay time profiles were approximated by two or three exponential decay functions. The observed decay times were100 ns due to Ce3+, 0.6-1.0μs due to the garnet host and few μs due to Nd3+.

Keywords: scintillator, near infrared, LuAG
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(face) ID: 293


Poster Number:
N-03-147

Non-proportionality and energy resolution of LuxY1-xAG:Pr and LuAG:Pr,Mo crystals (#2029)

K. Brylew1, P. Sibczynski1, M. Moszyński1, W. Drozdowski2, J. Kisielewski3

1 National Centre for Nuclear Research, Radiation Detector Physics Division, Otwock-Świerk, Poland
2 Nicolaus Copernicus University, Faculty of Physics, Astronomy and Informatics, Toruń, Poland
3 Institute of Electronic Materials Technology, Department of Functional Materials, Warsaw, Poland

Content

Recently, there has been an increased interest in the scintillators belonging to the family of garnet crystals. Praseodymium activated LuAG (Lu3Al5O12:Pr) shows decent properties in terms of light output, energy resolution and emission fast emission originating from 5d14f1 → 4f2 transitions in Pr3+, peaking at 310 nm. Since the material shows potential for application as a detector in PET imagining, there have been attempts to improve the properties of this crystal.

Previously published results show that the aim to enhance light yield and energy resolution has been successful and in this communication we report extended and detailed study of the influence of crystal composition on non-proportionality characteristics and energy resolution. A wide array of radiation sources emitting gamma radiation in the range between 14.4 to 1274 keV were used to perform measurements on a series of mixed (LuxY1-x)3Al5O12 crystals, where x = 0.00, 0.25, 0.50, 0.75 1.00 and on LuAG:Pr co-doped with trace amounts of molybdenum (Mo at 0.005, 0.0009 and 0.0005 % mol.). The measurements were performed at 3 and 10 μs shaping times to study the impact of the material composition on longer decay components of the pulse shape and on linearity of the scintillation response.

Keywords: garnet, scintillator, energy resolution, non-proportionality, praseodymium, band-gap engineering
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(face) ID: 295


Poster Number:
N-03-148

Array of Silicon Photomultipliers coupled to EJ-299-34 for neutron detection with gamma discrimination: system qualification and performance (#2093)

R. Santoro1, M. Caccia1, L. Malinverno1, A. Martemiyanov1, M. Ellis2, C. Allwork2

1 Universita’ degli Studi dell’Insubria, Dipartimento di Scienza e Alta Tecnologia, Como, Italy
2 AWE, Aldermaston, United Kingdom of Great Britain and Northern Ireland

Content

Silicon Photomultipliers (SiPMs) are a new class of photon sensor featuring high detection efficiency, single photon sensitivity and extended dynamic range. Two main strategies have been evaluated by different SiPM producers to obtain large area sensors, namely the monolithic or the array production. The latter making it possible to have large sensors made of an array of SiPMs connected to the same substrate using the Through Silicon Vias (TSV) process. This paper reports the studies performed with an array of 16 SiPMs each with 3x3 mm2 area coupled to a novel plastic scintillator sensitive to fast neutrons with gamma discrimination: a possible option for handheld instrumentations suitable to detect radioactive material at borders. The array of SiPMs provides 16 individual outputs but, in this application, a single signal proportional to the total amount of light seen by the sensor is required. Two different Front-End Electronics (FEE) circuits have been considered to sum the analogue signals whilst minimising the impact on the output shape. This is a crucial requirement to preserve the scintillation time profile used in all Pulse Shape Discrimination (PSD) algorithms to distinguish neutron events from gamma events. A comparison of the considered FEE circuits will be discussed together with the performance obtained for the neutron-gamma discrimination. A Figure of Merit (FoM) of 2.56 in the energy window of 1 - 1.5 MeV has been measured, demonstrating that arrays of SiPMs are a viable solution for handheld instrumentation. The system qualification will be also discussed.

Keywords: Arrays of SiPM, EJ-299-34, fast neutron detection with gamma discrimination, PSD
Poster panel
(face) ID: 297


Poster Number:
N-03-149

Growth and Applications of large size Gd3Al2Ga3O12 Single Crystals (#2183)

Y. Shoji1, 2, K. Kamada3, 1, S. Hayasaka1, V. Kochurikhin1, S. Kurosawa3, 4, Y. Yokota3, M. Yoshino1, Y. Ohashi3, A. Yamaji2, A. Yoshikawa2, 3

1 C&A Corporation, Sendai, Japan
2 Tohoku University, Institute for Materials Research, Sendai, Japan
3 Tohoku University, New Industry Creation Hatchery Center,, Sendai, Japan
4 Yamagata University, Department of Physics, Yamagata, Japan

Content

3 inch diameter Ce doped Gd3Al2Ga3O12 (GAGG) single crystals and Mg co-doped GAGG (GFAG) were grown by the Czochralski (Cz) method. Because of the requirement of the large size GAGG and GFAG is increasing in recent years. The concentration of Ce and Mg was optimized for future use of positron emission tomography and various applications. The scintillation properties (light output, energy resolution, decay time, timing resolution) were evaluated from 5x5x5mm3 size of 3inch GAGG and GFAG. These crystals performed the stable and good characteristics at any part of the crystal.

Keywords: Crystal growth, Scintillators
Poster panel
(face) ID: 299


Poster Number:
N-03-150

A Comparison of Calcium Codoping in Lu­2­Si2O7: Ce and Lu2SiO5: Ce (#2196)

C. Foster1, 2, M. Koschan2, Y. Wu1, 2, C. L. Melcher1, 2

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

Content

Improvement in the properties of inorganic scintillators via codoping is an ongoing topic of interest to the field of scintillator material research. In this study, we explore the mechanisms behind the differing effects of calcium codoping on two members of the rare-earth silicate family, Lu2SiO5: Ce (LSO: Ce) and Lu2Si2O7: Ce, (LPS: Ce). It has previously been reported that calcium codoping has the ability to improve scintillation characteristics of LSO: Ce, in particular light yield and decay time. Our research aims to discover how the structural differences of these elementally similar scintillators affect performance when codoped with calcium. Here, single crystals of LPS: 0.2% Ce, LPS: 0.2% Ce, 0.1% Ca, and LPS: 0.25% Ce, 0.25% Ca were grown via the Czochralski method. Absorbance measurements were carried out to determine whether calcium codoping promoted the presence of stable Ce4+, and thermo-stimulated luminescence was utilized to determine the presence and depth of traps in the scintillator. These results were combined with decay time and light yield measurements to clarify the effect of calcium codoping on LPS: Ce and LSO: Ce, and further explain their differences in the scintillation mechanism.

Keywords: Scintillator, Codoping, LSO, LPS
Poster panel
(face) ID: 301


Poster Number:
N-03-151

Intrinsic resolution of NaI(Tl) using PIXIE-4 data acquisition system (#2233)

V. Ranga1, S. Sharma1, S. Rawat1, M. Dhibar1, A. K. Gourishetty1

1 Indian Institute of Technology Roorkee, Radiation Detectors and Spectroscopy laboratory, Department of Physics, Roorkee, Uttarakhand, India

Content

The study of interaction of gamma radiation with matter is crucial in understanding the working of scintillators. It also contributes to the understanding and development of new scintillators. With the hope of getting more insight on how scintillators respond to gamma radiation, we have used PIXIE-4 advanced data acquisition system to find out the intrinsic resolution of 2"×2" NaI(Tl) detector by employing Compton Coincidence Technique (CCT). Advantage of CCT lies in studying the response of scintillators to gamma rays generated only due to the Compton effect. The intrinsic resolution of NaI(Tl) was obtained for different gamma energies. PIXIE-4 advanced data acquisition system doesn’t require pulse processing units such as amplifier and coincidence unit separately. This makes the whole setup very compact. The results were compared with those reported in the literature and were found to be in agreement.

Keywords: NaI(Tl), intrinsic resolution, Compton effect
Poster panel
(face) ID: 303


Poster Number:
N-03-152

Quality Assurance on Un-Doped CsI Crystals for the Mu2e Experiment (#2264)

C. Hu1

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

Content

The Mu2e experiment is constructing a calorimeter consisting of 1,348 un-doped CsI crystals in two disks. Each crystal has a dimension of 34×34×200 mm3, and is readout by a large area SiPM array. A series of technical specifications on mechanical and optical parameters was defined according to the calorimeter physics requirements. Pre-production CsI crystals were procured from three firms: Amcrys, St. Gobain and SICCAS. We report the quality assurance on crystal’s scintillation properties and their radiation hardness against ionization dose and neutrons. The results confirm that the quality of mass produced un-doped CsI crystals in the market satisfies the Mu2e requirements.

Keywords: Mu2e, Scintillators, CsI crystals, Quality Assurance
Poster panel
(face) ID: 305


Poster Number:
N-03-153

Development of Czochralski growth process for highly hygroscopic alkali-earth halide scintillators (#2375)

E. Galenin1, O. Sidletskiy1, C. Dujardin2, A. Gektin1

1 Institute for Scintillation Materials NAS of Ukraine, Kharkiv, Ukraine
2 Institut Lumière Matière, UMR55306 Université Claude Bernard Lyon 1-CNRS, Villeurbanne CEDEX, France

Content

This report represents the Czochralski growth of alkali-earth halides crystals with diameters of up to 50 mm on example of SrI2:Eu2+. Czochralski method is optimal from the point of scaling up of crystal growth technology. The development of this process for highly hygroscopic substances includes the optimized conditions of raw materials preparation and their loading into the growth chamber, including a precise control over admixture content in the raw materials and growth atmosphere. Compositions, as well as optical and scintillation parameters of SrI2:Eu crystals grown by the Bridgman and Czochralski methods are compared. The Czochralski process provides a uniform distribution of Eu2+ across the crystals within +/-5 %. The latter factor favors a high energy resolution within 3.6-3.7 % at 662 keV obtained in detectors fabricated from different parts of Czochralski-grown crystals. Such values of the energy resolution are similar to those obtained with SrI2:Eu2+ grown by the Bridgman method both in this work, and in other laboratories. This certifies a high purity and a good quality of the Czochralski grown crystals and demonstrates a feasibility to successfully produce SrI2:Eu2+, as well as other highly-hygroscopic halide scintillation crystals by the Czochralski method.

The work is supported by the NATO multiyear Science for Peace Project NUKR.SFPP 984958 "New sensor materials and detectors for ionizing radiation detection"

Keywords: scintillator, crystal growth, Czochralski method, alkali earth halides
Poster panel
(face) ID: 307


Poster Number:
N-03-154

Scintillation characterization for light-scattering samples with complicated shape of Ce-activated garnet phosphors (#2413)

G. A. Dosovitskiy1, 2, A. A. Fedorov2, 3, E. V. Gordienko1, 2, E. Radiuk4, E. Petina1, 2, D. E. Kuznetsova1, 2, P. V. Karpyuk1, 2, V. A. Mechinsky2, 3, V. M. Retivov1, 2, A. L. Mikhlin1, A. E. Dosovitskiy5, M. V. Korjik2, 3, V. Dormenev6

1 NRC “Kurchatov Institute” – IREA, Moscow, Russian Federation
2 National Research Centre “Kurchatov Institute”, Moscow, Russian Federation
3 Research Institute for Nuclear Problems, Minsk, Belarus
4 Radiation Instruments and New Components, Minsk, Belarus
5 NeoChem JSC, Moscow, Russian Federation
6 Justus-Liebig-University, II. Physical Institute, Giessen, Germany

Content

Some existing and potential applications of scintillators allow their use in a form of light scattering materials, e.g. phosphor screens or translucent ceramics for CT. Moreover, powder samples could be used to express-test scintillation properties of materials with new compositions. Light yield is one of the most important characteristics for scintillator performance, so adequate method to control it is needed. Widely used method to estimate the scintillation light yield consists in comparison of pulse height spectra, measured with the material under study and a reference material with well-known light yield. Typically, such measurements are performed with optically transparent materials, but strongly light scattering samples could deteriorate measurements results, because large fraction of the emitted light will not be collected by PMT. A new approach was proposed, which consists in two main experimental details: 1) α-particle source (241Am, 5 MeV) is used as a probe; 2) in measurement geometry PMT and excitation source are placed on the one side of the sample. So, scintillations are excited in the surface layer of the material (tens of microns), and light path in the material is decreased together with the effect of a light scattering. This approach has allowed to measure amplitude spectra for strongly light scattering powdered samples, and YAG:Ce single crystal with grinded surface was sued as a reference. Good correlation with photoluminescence intensity was found for YAG:Ce powder samples. LY was shown to be dependent on composition and co-doping of GGAG:Ce powders, which is in accordance with other studies. The same measurement technique was applied to YAG:Ce translucent ceramics in shape of tablets and complex 3D-printed structures. The described LY measurement approach was shown to be useful instrument for express estimation of scintillator compound performance. The work is supported by MES of Russia grant № 14.625.21.0033, project ID RFMEFI62515X0033.

Keywords: scintillator, light yield, YAG, GGAG, powder, garnet, ceramics
Poster panel
(face) ID: 309


Poster Number:
N-03-155

Free carrier dynamics in GAGG:Ce scintillation crystal with aliovalent codoping (#2467)

E. Auffray1, M. Korjik2, M. Lucchini1, V. Mechinsky2, S. Nargelas3, G. Tamulaitis3, A. Vaitkevicius3

1 CERN, EP/CMX/DA, Geneva, Switzerland
2 RINP, Minsk, Minsk, Belarus
3 Vilnius University, Vilnius, Lithuania

Content

The recent studies of fast processes in scintillators, including the study of the influence of aliovalent codoping on the time of build up of luminescence response of self-activated and Ce-doped scintillators and the demonstration of coincidence time resolution bellow 50 ps, show that the carrier dynamics in scintillating materials has to be investigated in more detail. In this study, we exploit the free carrier absorption at selective photoexcitation by femtosecond laser pulses to investigate the carrier dynamics in Ce-doped gadolinium gallium aluminum garnet Gd3Al2Ga3O12 (GAGG), which is prospective scintillator for radiation detectors in PET and high-energy physics applications. The study is focused on the influence of aliovalent codoping on the carrier dynamics. We demonstrate that the gadolinium sublattice plays a significant role in the transfer of both free electrons and holes, which are generated in the valence band after relaxation from the Gd ground state located by 1.05 eV in the valence band. The diagrams of energy levels are compiled and used to explain the excitation transfer in different garnet crystals and the fast build up of the scintillation in aliovalently codoped crystals containing Ce as activator. The influence of of Mg-codoping on the excitation transfer is discussed. The codoping facilitates the excitation transfer from the matrix to Ce ions but introduces defects acting as nonradiative recombination centers.

Keywords: GAGG, fast timing
Poster panel
(face) ID: 311


Poster Number:
N-03-156

Thermal Variance Investigation of Cs2LiLa(Br,Cl)6:Ce (#2489)

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

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

Content

Elpasolites are a promising family of inorganic scintillators for dual-mode neutron and gammaray detection, often offering better gamma-ray energy resolution than traditional scintillators such as NaI, sensitivity to thermal neutrons through capture on 6 Li, and the ability to distinguish between neutron and gamma events through pulse shape discrimination (PSD). We have investigated the thermal variance of Cs2LiLa(Br,Cl)6:Ce (CLLBC), an elpasolite that exhibits better gamma-ray energy resolution and higher density than Cs2LiYCl6:Ce (CLYC), which is currently the most well-known elpasolite scintillator. By collecting digitized waveforms, we examine the thermal variation in CLLBC response to neutrons and gamma-rays, focusing on the time profile of the light response, gamma-ray energy resolution, and PSD separation between neutron and gamma-ray events.

Keywords: Elpasolite, CLLBC, scintillator, neutron, gamma-ray
Poster panel
(face) ID: 313


Poster Number:
N-03-157

Radiation-induced luminescence properties of Pr:CaSiO3 crystals (#2552)

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

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

Content

We investigated the photoluminescence (PL), radioluminescence (RL) and thermoluminescence (TL) properties of Pr:CaSiO3 crystals grown by the floating zone method. In both the PL and RL spectra, a broad emission band are observed around 300 nm due to the 5d-4f transitions of Pr3+, whose decay time constants are 16-20 ns and 140-260 ns. In TL, multiple glow peaks are observed over 50-250 °C, and the response intensity increases linearly proportional to the X-ray dose. Among the present samples, the 3% and 1% Pr-doped samples show the high sensitivity and cover from 0.1 to 10000 mGy.

Keywords: scintillator, dosimetry, thermoluminescence
Poster panel
(face) ID: 315


Poster Number:
N-03-158

Luminescent and scintillation properties of Al-rich Ce:Tb3Al5O12 crystals (#2555)

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

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

Content

Tb3Al5O12 (TAG) crystalline materials doped with different Ce concentrations were prepared by the floating zone (FZ) method to evaluate their luminescent and scintillation properties. In photoluminescence (PL), a broad emission due to the 5d-4f transition of Ce3+ appeared around 550 nm, and the decay time was approximately 44 nsec, 1.7 μsec and 4.9 μsec. Under X-ray exposure, the scintillation due to the 5d-4f transitions of Ce3+ was also observed around 550 nm, but the decay time is similar to those in PL. The pulse height spectroscopy analyses revealed that 3% Ce-doped TAG shows the highest light yield of 57,000 ph/MeV under 137Cs γ-ray irradiation among the samples synthesized in this study.

Keywords: scintillator, dosimetry, radioluminescence, thermoluminescence
Poster panel
(face) ID: 317


Poster Number:
N-03-159

Investigation of scintillation properties of BaF2 Transparent Ceramic (#2557)

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

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

Content

Inorganic scintillators, which convert high energy ionizing radiation to thousands of visible photons, have been playing a major role in many fields of radiation detection, including medical, security, oil-logging, environmental monitoring, astro- and particle physics. Barium fluoride (BaF2) crystal is known as a potential scintillator material. In the 1970s, Farukhi et al. have first reported scintillation by BaF2 crystal due to auger-free luminescence (AFL) and self-trapped excitation (STE), which appear around 190-220 and 310 nm, respectively. In particular, BaF2 has considerably large effective atomic number (Zeff = 52.7), so it has a great advantage to be used for γ-ray detections.

In this study, we developed the undoped BaF2 transparent ceramics and characterized scintillation properties in relation with AFL. Specifically, the synthesis of BaF2 transparent ceramics was carried out by the spark plasma sintering (SPS) method, and the optical and scintillation properties were characterized.

When X-ray was irradiated, all the samples showed an emission at 320 nm due to the STE luminescence. Subsequently, we measured scintillation spectra of ceramic samples in VUV range, and emission peaks were detected at 190 and 220 nm, which are due to the AFL. Pulse height spectra were measured under 137Cs exposure. Clear photoabsorption peaks were detected in transparent ceramic. The absolute light yield was determined as 6,000 ph/MeV.

Keywords: scintillator
Poster panel
(face) ID: 319


Poster Number:
N-03-160

Fabrication of hybrid small size dosimeter system using Eu:BaFBr and Ce:CaF2 for quenching effect correction (#2656)

Y. Hirata1, K. Watanabe1, A. Uritani1, A. Yamazaki1, S. Yoshihashi1, Y. Koba2, N. Matsufuji2, T. Yanagida3, K. Fukuda4

1 Nagoya University, Engineering, Nagoya, Aichi, Japan
2 National Institute of Radiological Sciences, Inage, Chiba, Japan
3 Nara Institute of Radiplogical Sciences, Ikoma, Nara, Japan
4 TOKUYAMA corporation, Shunan, Yamaguchi, Japan

Content

Particle radiotherapies can form fine and complex dose distribution and attack almost only a target organ or tumor.  However, in fine irradiation, misalignment of an irradiation position might cause a significant accidental exposure to normal organs.  In order to accurately estimate the irradiation dose, it is desired to insert a dosimeter into an affected region in a patient body.  For this purpose, we are developing a small size dosimeter using optically stimulated luminescence (OSL) elements and an optical fiber, which has higher signal-to-noise ratio than scintillator based small size dosimeters.  The OSL small size dosimeters showed quenching effects when irradiated by high linear energy transfer (LET) particles, such as carbon ions.  The degree of quenching effect depends on OSL materials.  The luminescence efficiency, that is also a correction factor for the quenching effect, can be determined from the luminescence ratio of the different OSL materials.  In order to determine the luminescence ratio, we fabricated a hybrid small dosimeter probe, which is adhered with two types of OSL materials of Ce:CaF2 and Eu:BaFBr on a tip of a single optical fiber.  We have already confirmed that this correction procedure using the hybrid probe can correct the quenching effect when the probe was irradiated with carbon ions with an energy of 290 MeV/u at Heavy Ion Medical Accelerator in Chiba (HIMAC).  However, so far, we separately measured the signal intensities for the both OSL materials.  This means that we measured two times at the same position for each OSL material.  In this paper, we fabricated the OSL readout system for the hybrid small dosimeter probe in order to determine the luminescence ratio in a single measurement.  We evaluate some characteristics on the hybrid probe measurement system.

Keywords: Dosimetry, Particle radiotherapy, Optically Stimulated Luminescence, Optical fiber
Poster panel
(face) ID: 321


Poster Number:
N-03-161

Bulk Single Crystal Growth of Ca(F, Cl, Br, I)2 Scintillators (#2957)

K. Kamada1, 2, T. Iida3, T. Ohata4, M. Yoshino1, 2, S. Hayasaka2, Y. Shoji1, 2, S. Sakuragi5, S. Kurosawa1, 6, Y. Yokota1, Y. Ohashi1, A. Yoshikawa1, 2

1 Tohoku University, Sendai, Miyagi, Japan
2 C&A, Sendai, Miyagi, Japan
3 University of Tsukuba, Osaka, Osaka, Japan
4 Osaka University, Tsukuba, Ibaraki, Japan
5 Union Materials Inc,, Tone, Ibaraki, Japan
6 Yamagata University, Yamagata, Yamagata, Japan

Content

CANDLES (Calcium fluoride for the study of Neutrinos and Dark matters by Low Emery Spectrometer) have been developed in Kamioka underground observatory, Japan and is an experiment to search for the double beta decay of 48Ca with undope CaF2 scintillator coupled with photo multiplayer tubes (PMTs). The sum of the kinetic energy of the two electrons emitted by neutrino-less double beta decay of 48Ca is 4.27 MeV, the largest Q value among all the double beta isotope candidates. The Q value for the double beta reaction is the amount of energy released by the reaction. Because this Q value is higher than the environmental radiation (b-rays and γ-rays), it has the advantage of being easier to perform a measurement in very low-background condition. The undope CaF2 have 3.18 g/cm3 of density and 16.5 of Zeff. CaF2 exhibits emission of triplet self-trapped excitons at 280 nm with around 10,000 photon/MeV of light yield and 960 ns of scintillation decay time. In general, heavy and high Zeff materials are required to absorb high energy photons. It can be thought that CaI2 is one of the best candidates for research of the double beta decay with 48Ca because of its scintillation performance such high density, high Zeff, high light yield, high energy resolution even it is hygroscopic.

In this research, scintillation performance of undope CaF2, CaCl2, CaBr2 and CaI2 was evaluated. Crystal growth was performed by Bridgman–Stockbarger (BS) method at each melting points. Investigations of their crystal phases, luminescence and scintillation properties such light yield, energy resolution decay time were performed. In addition, linearity of gamma-ray response in 32-1275 keV range were also evaluated.

Keywords: Scintillator, Bridgman–Stockbarger, Single crystal growth
Poster panel
(face) ID: 323


Poster Number:
N-03-162

Stabilization of EJ-309 liquid scintillator detectors (#3049)

V. Astromskas1, M. J. Joyce1

1 Lancaster University, Engineering Building, Lancaster, United Kingdom of Great Britain and Northern Ireland

Content

Multi-element scintillator systems are commonly used in medical and industrial applications and each element is required to operate identical to each other. However, a significant difference in the performance of the scintillator material, the photomultiplier tubes and/or the quality of the coupling are typically observed. Normally, the detectors are calibrated using laboratory-based radioactive gamma sources to account for the differences in performance, but ignoring gain discrepancies. The focus of this study is to investigate the normalisation of the performance of a multi-element scintillator detector system as well as the stability with respect to time and temperature. Seven EJ-309 organic liquid scintillators coupled to a photomultiplier tube were characterised individually. The high voltage was supplied and data was readout using a mixed field analyser developed by Hybrid Instruments Ltd, Lancaster, UK. Each of the detectors were connected in turn to the same single-channel mixed field analyser. Laboratory-based cesium-137, sodium-22 and cobalt-60 radioactive sources were used for characterisation as the emitted characteristic gamma-rays range from 511 keV to 1332.5 keV. The preliminary stability measurements indicate that the detectors require 30 to 60 minute warm-up period before a stable performance in terms of gain. The energy linearity investigation revealed that the difference in the resolved channel of the same gamma peak differs more as the energy increased. Also, a difference in gain amongst the detectors of ±23 % has been observed, thus, a further investigation into the source and its effect on long term operation is required. The study will investigate the temperature, time and scintillator material dependence on the stability and warm-up period, the effect of resetting the applied high voltage on the stability of performance. Furthermore, the methodology to ensure stable multi-element detector system performance will be presented.

Keywords: Scintillator, Detectors, EJ-309, Stability
Poster panel
(face) ID: 325


Poster Number:
N-03-163

Synthesis and Properties of Polycrystalline Ceramic SrI2:Eu (#3081)

J. P. Smith1, C. Delzer1, L. Boatner2, C. L. Melcher1

1 University of Tennessee Knoxville, Scintillation Materials Research Center, Knoxville, Tennessee, United States of America
2 Oak Ridge National Lab, Synthesis and Properties of Novel Materials Group, Oak Ridge, Tennessee, United States of America

Content

Europium doped strontium iodide (SrI2:Eu) is a promising scintillator for nuclear security applications including gamma-ray spectroscopy because of its high light yield, good energy resolution and proportionality. Single crystal growth of SrI2:Eu is a slow and expensive process, which could be alleviated with the development of a reproducible method of producing optically transparent polycrystalline ceramic SrI2:Eu using faster and more economic techniques such as the hot isostatic pressing (HIP) and spark plasma sintering (SPS) methods. In this work, polycrystalline SrI2:Eu ceramic pellets were sintered by both hot pressing and the spark plasma sintering (SPS) method. Subsequent heat treatment and hot isostatic pressing was investigated to remove residual porosity to increase the optical quality of the ceramics. Scintillation characterization of the ceramics was performed and the light yield, optical transmission, energy resolution, decay time and afterglow of the polycrystalline ceramics were compared to that of a single crystal.

Keywords: strontium iodide, scintillator, ceramic, hot press, spark plasma sintering
Poster panel
(face) ID: 327


Poster Number:
N-03-164

Crystal growth and analysis of 38mm and 50mm diameter KCaI3:Eu (#3243)

M. Loyd1, 2, M. Folsom3, M. Koschan1, C. Melcher2, 1, M. Zhuravleva2, 1

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

Content

Much research in the last ten years has been focused on developing scintillator materials that are suitable in gamma-ray spectroscopy applications.  These materials must have strong performance capabilities and the ability to be grown at large sizes (38 mm diameter and larger).  KCaI3:Eu is one such scintillator that has promising performances of >70,000 ph/Mev and <4% E.R. at 662 keV. In this work we show the first simultaneous growth of both two and four 38 mm diameter crystals of KCaI­3:Eu utilizing a multi ampoule growth station.  Additionally, a 50 mm diameter crystal was grown and characterized.  Two of the 38 mm diameter crystals, and the 50 mm diameter crystal, were hermetically sealed in different package geometries.  One package utilized a traditional close wrapped Teflon reflector, while another included an air gap surrounded by a quartz ring wrapped in Teflon to help light collection and reduce self-absorption of emitted light.  Simulations of light transport in both packages using GEANT4 are compared to measured results from the crystal.  To better understand radial homogeneity in these large crystals, a slab was cut from a 38 mm crystal and pixelated.

Keywords: Scintillator, Crystal Growth
Poster panel
(face) ID: 329


Poster Number:
N-03-165
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Scintillation properties of high-resolution La(BrxCl1-x)3:Ce and high-sensitivity CeBr3 crystals (#3264)

M. Selle1, S. Petrak1, K. McKinny2

1 Hellma Materials GmbH, Jena, Germany
2 GE, Twinsburg, Ohio, United States of America

Content

In the past years, Ce3+ activated halide-lanthanide scintillators such as LaBr3:Ce, LaCl3:Ce and CeBr3 have generated much interest in the radiation detection community. These scintillators are distinguished by very high energy resolution and ultrafast detection of gamma rays. We present a new embodiment in this group of scintillators, where the matrix material contains a mixture of two halides, lanthanum bromide and lanthanum chloride, that form a solid solution in the uranium tri-chloride lattice type. The scintillation properties of the new La(BrxCl1-x)3:Ce material are discussed and compared with other lanthanide scintillators. We report on several aspects relevant to gamma-ray spectrometry up to 3 MeV, such as scintillation characteristics, energy resolution, intrinsic activity, decay time, non-proportionality of the response, and gamma-ray detection performance at high temperatures. The unique advantages of La(BrxCl1-x)3:Ce and CeBr3 are discussed in the context of specific detector requirements for high energy resolution and/or high detection sensitivity.

Keywords: halide-lanthanide scintillators, La(BrxCl1-x)3:Ce, CeBr3, gamma-ray spectrometry
Poster panel
(face) ID: 331


Poster Number:
N-03-166

Optimizing the Performance of Extruded Scintillator for the Mu2e Cosmic-Ray Veto (#3285)

A. Pla-Dalmau1

1 Fermilab, Batavia, Illinois, United States of America

On behalf of Mu2e CRV Group

Content

Cosmic-ray muons are a potential background source for the Mu2e experiment and must be suppressed to achieve the sensitivity required by Mu2e. An active veto detector will be used to identify penetrating cosmic‑ray muons. The Mu2e cosmic‑ray veto (CRV) detector will consist of four layers of extruded plastic scintillator strips with aluminum absorbers between each layer. Wavelength-shifting (WLS) fibers embedded in the center of the strips will be used to capture and transport the scintillation light to the silicon photomultipliers at each end. The extruded scintillator will be produced at Fermilab using the FNAL-NICADD Extrusion Line Facility which has been in operation since 2003. The scintillator counters will be extruded with a rectangular profile (5 cm x 2 cm), two holes in the center for the WLS fibers, and a titanium dioxide (TiO2) coating. Since the CRV detector must have a 99.99% efficiency, extensive work both in computer simulations and in component testing has been performed. Here we report the results of studies carried out to optimize the CRV scintillator bars including: a) shape control during extrusion to minimize gaps; b) the TiO2 percentage in co‑extruded capstocking; c) the scintillator dopant concentration; and d) the scintillator dopant composition. These different parameters were separately checked during extrusion and the scintillation light yield differences were measured using a 137Cs radioactive source. Based on these preliminary results, performance of the scintillator counters was studied at the Fermilab Test Beam Facility with the appropriate photodetectors and electronics. The major enhancement in light yield was attributed to the doubling of the TiO2 quantity (30% by weight) in the reflective coating. Less significant increases were observed with the changes in dopant and dopant concentration.

Keywords: cosmic-rays, muons, scintillator, veto detector
Poster panel
(face) ID: 333


Poster Number:
N-03-167
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Improved Detector Energy Resolution via Wavelength-shifted Hygroscopic Scintillator Emission (#3397)

H. D. Suitts1, S. R. Tornga1

1 Los Alamos National Laboratory, Intelligence and Space Research, Los Alamos, New Mexico, United States of America

Content

Small, light-weight, photodetection devices such as silicon avalanche photodiodes (SiAPDs) have attracted attention as potential alternatives to bulky photo-multiplier tubes for use in applications limited by size, weight and power, such as hand-held or space-based detector systems. However, the peak emission of many high-performance scintillators is often poorly matched with the spectral response of high-efficiency readout devices. In previous research, we have developed methods of applying wavelength-shifting dye-doped polymers to non-hygroscopic scintillator crystals to shift light emission into a region that is more compatable with high-efficiency solid-state readout devices. We present here our optimization of these methods as well as applying this approach to several hygroscopic crystals, including Cesium Iodide. The appropriate dye coating for a given scintillator is determined via our developed figure-of-merit spectrum convolution software that utilizes manufacture-provided quantum efficiency figures, scintillator emission spectra, and a database of absorption and emission spectra for a variety of dyes. The shift of scintillation light is confirmed via radioluminescence spectroscopy, and gamma ray spectroscopy measurements are made to determine increase in photoelectron light collection. In addition, several measurements are taken to verify repeatability in our dye application and coupling techniques. Currently, we have observed increases in photoelectron collection efficiency of ~52% for a SiAPD-coupled YAP:Ce crystal and 7.6% for a SiAPD-coupled CsI:Na crystal, as well as improved energy resolution, by applying the most suitable wavelength-shifting dye as determined by our software. We have also optimized variable parameters such as dye thickness and concentration. Results using other hygroscopic crystals will be presented.

Keywords: hygroscopic, scintillator, wavelength-shifting, photodetector
Poster panel
(face) ID: 335


Poster Number:
N-03-168

A Diffusive Model of Scintillation Light in Monolithic Crystal Gamma Cameras (#3562)

M. Galasso1, A. Fabbri1, C. Borrazzo1

1 INFN, Sezione Roma Tre, Roma, Italy

Content

In gamma rays imaging the typical detector is a scintillation crystal coupled, through a light guide, to a photodetector system. Performance of a gamma camera mainly depend on the features of the photodetector and on the combination of characteristics of the other components such as type and width of the crystal, number, type and width of the light guides, etc. Monte Carlo simulations typically perform accurate simulations of such optical systems. However, the computational requirements are very high and the investigation of large number of types of optical systems is often unpractical. Experimentally, many surface treatments are used in monolithic crystals, especially for the radiation entrance face of the scintillator, in order to make the photodetector collect more light or to preserve the light distribution shape. Therefore, the choice of the optimal surface treatment turns out to be difficult because of the trade-off between the amount of collected optical photons and the width of the light distribution. In this work, we propose a model that consider Snell-Descartes reflection, refraction effects and Lambertian diffusion interactions on the crystal top surface. This model will help to design a gamma camera allowing for fast evaluation of many detector configurations. Scintillator top surface treatments can be investigated as well as their effects on the spatial linearity, spatial resolution and energy resolution. In order to validate the model, the computed light distributions have been compared with light distributions obtained from accurate GEANT4 MC simulations for the same system configurations. The results demonstrate a good agreement between the proposed model and MC simulation. Finally, the use of estimation methods of scintillation position applied to modelled data, rather than simulated data, leads to a low computational time performance evaluation of the crystal/light guides/photo-detector system in terms of linearity and intrinsic spatial resolution.

Keywords: model, monte carlo, simulation, scintillator
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(face) ID: 337


Poster Number:
N-03-169

Study of Position Sensitivity of Large LaBr3:Ce Scintillators Readout by SiPMs (#3627)

M. Carminati1, 2, G. Cozzi1, 2, C. Fiorini1, 2, M. Massara1, A. Morozov3, M. Occhipinti1, 2, V. Solovov3

1 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
2 INFN, Sezione di Milano, Milano, Italy
3 University of Coimbra, LIP-Coimbra, Dept. of Physics, Coimbra, Portugal

Content

Cerium-doped Lanthanum Bromide (LaBr3:Ce) is regarded as a very attractive material for scintillation detectors for spectroscopy measurements in nuclear physics thanks to its excellent energy resolution (3% at 662 keV). In some experiments, in order to correct for the Doppler broadening effect, some degree of position sensitivity is required in addition to this spectroscopy capability. However, the typical geometry of such crystals, designed to enhance their efficiency (crystal thickness usually in the same order of diameter), and the use of diffuse reflectors on all surfaces but the exit window to the photodetectors (to enhance energy resolution), make position sensitivity in such crystals quite challenging. In this work we propose a study on a reference 3”× 3” LaBr3:Ce scintillator readout by arrays of SiPMs to evaluate its position sensitivity all over the full volume of the crystal. The reconstruction of the 3D interaction coordinates of the gamma-ray in the scintillator is performed by means of maximum likelihood method provided by the recently developed ANTS2 toolkit. Capability of reconstructing position of interaction with estimation of spatial resolution in the various positions of the crystal volume are performed by means of simulations and the results, together with preliminary experimental tests, will be presented in this work.

Keywords: position sensitivity, Doppler effect, statistical methods, 3D reconstruction
Poster panel
(face) ID: 339


Poster Number:
N-03-170

Influence of Au co-doping on scintillator properties of BaBrCl:Eu singe crystal (#3852)

T. Shalapska1, R. dos Reis2, A. Canning1, S. Dwaraknath1, D. Perrodin1, G. Bizarri1, E. Bourret1

1 LBNL, Berkeley, California, United States of America
2 National Center for Electron Microscopy, Molecular Foundry, LBNL, Berkeley, California, United States of America

Content

We report on the effect of Au co-dopant on the scintillator performance of BaBrCl:Eu. The luminescence and scintillation properties of BaBrCl:Eu, Au are investigated as a function of Eu and Au concentrations. We found that 0.1% Au co-doping significantly impacts the light output of BaBrCl:Eu. increasing by 3.5 times for low Eu concentrations (0.5%Eu). Similar light output to BaBrCl:Eu doped at 5-8% level is achieved by 3% Eu and 0.1% Au co-doping. Concurrently, the fraction of light decaying in the 300-500ns range increases by 50%. Thermostimulated luminescence studies show that incorporation of Au co-dopant in BaBrCl:Eu significantly suppressed the trapped charge population. From the density-of-states plots of BaBrCl:Eu,Au, we calculated the energy levels of Au ion in various configurations. This data suggests that Au mitigates the detrimental effect of F centers in BaBrCl. Atomic configuration and chemical environment of Au and Eu dopants are qualitatively addressed by high-resolution scanning transmission electron microscopy and electron energy-loss spectroscopy.

Keywords: scintillator, light output, BaBrCl:Eu, single crystal, Au co-dopant
Poster panel
(face) ID: 341


Poster Number:
N-03-171

Gamma-ray and Alpha-ray Response for Pure and Na-doped Cs2HfCl6 (#4013)

S. Kurosawa1, 2, S. Kodama3, A. Yamaji3, J. Pejchal5, R. Kral5, S. Yamato3, Y. Ohashi1, K. Kamada1, 4, Y. Yokota1, A. Yoshikawa1, 4, M. Nikl5

1 Tohoku University, New Industry Creation Hatchery Center, Sendai, Miyagi, Japan
2 Yamagata University, Faculty of science, Yamagata, Yamagata, Japan
3 Tohoku University, Institute for Materials Research, Sendai, Miyagi, Japan
4 C&A, Sendai, Miyagi, Japan
5 CAS, Institute of Physics, Prague, Czech Republic

Content

Scintillation properties for pure and Na-doped CsHfCl6 excited by gamma and alpha rays were investigated, and these samples were grown by the vertical Bridgman technique. At room temperature, the light output of the 1-mol% Na-doped sample was up to 38,000 photons/MeV. On the other hand, pure sample had light outputs of approximately 43,000 photons/MeV. Both pure and Na-doped sample had faster decay times for alpha-ray irradiation than gamma-ray irradiation.

Keywords: Scintillator, Cs2HfCl6
Poster panel
(face) ID: 343


Poster Number:
N-03-172

Crystal Growth, Characterization, and Fabrication of Radiation Detectors Based on Ultra-Fast Scintillators (#4149)

C. Oner1, T. A. Chowdhury1, K. C. Mandal1

1 University of South Carolina, Department of Electrical Eng., Columbia, South Carolina, United States of America

Content

Recently there has been considerable interest in ultra-fast and bright scintillators for medical imaging, gamma-ray spectroscopy, nuclear non-proliferation, high-energy astrophysics, and environmental monitoring. In our effort at the University of South Carolina (USC), we have grown large volume single crystals of LaBr3: Ce (0.5 – 10% by mole) and CeBr3 in vacuum sealed carbon coated quartz ampoules by a specially designer vertical gradient freeze technique. A finite element based simulation was performed to assess the temperature distribution inside the furnace and the ampoule wall to visualize temperature gradient evolution between the two temperature zones. These grown moisture sensitive inorganic scintillators are carefully processed in an argon controlled glove box and characterized through X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Energy dispersive X-ray spectroscopy (EDS), and Raman measurements. The well characterized crystals are used in fabricating high-resolution gamma-ray spectrometers. Both crystals have shown very high light outputs of ~85,000 and ~68,000 photons/MeV, respectively, with excellent light yield proportionality, and fast principle decay constants of < 30 ns. The emission wavelength for the LaBr3: Ce and CeBr3 are λmax = 360 nm and 380 nm, respectively. At room temperature, both materials have shown excellent energy resolutions (full width at half maximum, FWHM, over the peak position) of ~ 3% at 662 keV γ-ray irradiation from 137Cs radiation source. We will present our results on the growth, characterization, and scintillation properties of completely crack-free and highly transparent Ce-doped LaBr3 and undoped CeBr3 crystals. We will also present in-details processing parameters and critical handling procedures for these moisture and oxygen sensitive scintillator materials.

Keywords: Scintillators, Gamma-ray spectroscopy, Lanthanum bromide, Cerium bromide, Crystal growth, High light yield, Ultrafast
Poster panel
(face) ID: 345


Poster Number:
N-03-173
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Numerical simulation of charge multiplication in Ultra-Fast Silicon Detectors and comparison with experimental data (#1379)

M. Mandurrino1, N. Cartiglia1, A. Staiano1, R. Arcidiacono1, 2, M. Ferrero1, 3, F. Cenna1, 3, V. Sola1, M. Costa1, 3, R. Bellan1, 3, V. Monaco1, 3, M. Boscardin4, G. Paternoster4, L. Pancheri5, G. - F. Dalla Betta5

1 INFN, Sezione di Torino, Torino, Italy
2 Università del Piemonte Orientale, Novara, Italy
3 Università di Torino, Torino, Italy
4 Fondazione Bruno Kessler (FBK), Trento, Italy
5 Università di Trento, Trento, Italy

Content

We present results from numerical investigation on different silicon Low-Gain Avalanche Diode (LGAD) detectors intended for space-time particle tracking in high-energy physics experiments, manufactured by Fondazione Bruno Kessler (FBK, Italy), Centro Nacional de Microelectronica (CNM, Spain) and Hamamatsu Photonics K.K. (HPK, Japan). Simulations are performed by including the well-known avalanche formalisms by Massey, van Overstraeten-de Man and Okuto-Crowell into a drift-diffusion modeling framework. Our calculations on devices with either 50- and 300-um thick active regions provide very good agreement with gain and most probable charge measurements taken in a wide range of applied bias and operating temperatures, as well as before and after irradiation with neutrons and pions. Thus, at the end of the present paper, we propose a robust and reliable simulation setup which is highly predictive in the field of research and development of LGADs, especially important in view of future LHC detectors.

Keywords: silicon detectors, carrier multiplication, numerical simulations
Poster panel
(face) ID: 347


Poster Number:
N-03-174

Study of a CMOS pixel sensor for high-precision silicon tracker (#1824)

J. Liu1, L. Zhang1, M. Wang1

1 Shandong University, School of Physics, Jinan, China

Content

The tracking system of the Circular Electron Position Collider (CEPC) proposed by the Chinese particle physics community includes a high-precision silicon tracker. The silicon tracker is complementary to the continuous tracking provided by the Time Projection Chamber (TPC). The single point resolution of the silicon tracker should be less than 7 µm in order to achieve the required high-precision tracking. A new CMOS pixel sensor is under development for the CEPC tracker by using a 180 nm CMOS technology. This technology could offer a high resistivity epitaxial layer, which results in better charge collection efficiency and improved radiation hardness. The prototype is aimed at the investigation of the charge collection efficiency depending on various pixel geometries and pitches. The size of the prototype is 2 mm by 7.88 mm. The prototype consists of 9 different pixel flavors with respect to the size of charge collection diode and the pitch of pixel. The in-pixel electronics is implemented with self-biased 3-Transistor circuit. The analog output signals are read out in a so-called rolling shutter mode. In order to explore the electric properties for this CMOS technology, the two dimensional and three dimensional Technology Computer Aided Design (TCAD) simulations have been performed carefully. The simulations have been carried out to investigate the depletion, breakdown voltage, leakage current, capacitance as well as the charge collection behaviors. Both the Non Ionizing Energy Loss (NIEL) and the Total Ionizing Dose (TID) effects are introduced into the simulation in order to investigate the sensor property degradation. The above mentioned prototype design and the simulation results will be shown in details. The characterization of the prototype is in process. The first measurement results of the prototype will also be addressed.

Keywords: Position sensitive particle detectors, Silicon radiation detectors, Numerical simulation, Sensor phenomena and characterization
Poster panel
(face) ID: 349


Poster Number:
N-03-175
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Performance of Front-end ASIC and its evaluation with Silicon Strip Sensor for J-PARC Muon g-2/EDM Experiment (#2801)

Y. Sato1, H. Ikeda4, M. Ikeno1, T. Ito2, K. Kawagoe2, T. Kishishita1, T. Kohriki1, T. Kume5, M. Matama2, T. Mibe1, T. Murakami1, T. Nagasaka2, S. Nishimura6, N. Saito1, 7, O. Sasaki1, S. Shirabe2, M. Shoji1, T. Suehara2, M. Tanaka1, J. Tojo2, T. Uchida1, K. Ueno1, H. Yasuda6, T. Yoshioka3

1 High Energy Accelerator Research Organization, Institute of Particle and Nuclear Studies, Tsukuba, Ibaraki, Japan
2 Kyushu University, Department of Physics, Faculty of Sciences, Fukuoka, Fukuoka, Japan
3 Kyushu University, Research Center for Advanced Particle Physics, Fukuoka, Fukuoka, Japan
4 Japan Aero Space Exploration Agency, Institute of Space and Astronautical Science, Sagamihara, Kanagawa, Japan
5 High Energy Accelerator Research Organization, Mechanical Engineering Center, Tsukuba, Ibaraki, Japan
6 University of Tokyo, Physics Department, Bunkyo-Ku, Tokyo, Japan
7 J-PARC center, Naka, Ibaraki, Japan

Content

The muon anomalous magnetic moment (g-2)μ and electric dipole moment (EDM) are sensitive to new physics beyond Standard Model. There is a discrepancy between the (g-2)μ measured by E821 collaboration at Brookhaven National Laboratory and the Standard Model prediction at more than 3σ level. Our goal is to measure (g-2)μ with a precision of 0.1 parts per million and search for EDM with a sensitivity of 10-21 e・cm, respectively.

In this experiment, we use a silicon strip detector with high granularity and fast response to detect positrons from muon decay. The readout ASIC is required to tolerate high hit rate of 1.4 MHz per strip, to be stable to the change of hit rate by a factor of 1/150, and to have deep memory for the period of about 40 μs with 5 ns resolution. The prototype readout ASIC ``SliT128A'' has been fabricated using the Silterra 0.18-μs CMOS process. We mount the SliT128A on the board by wire-bonding and estimate the performance such as gain, dynamic range, pulse width, time-walk, noise level, and hit rate capability. We confirm the SliT128A has the performance close to the requirement for muon g-2/EDM experiment at J-PARC. We also connected the SliT128A with silicon strip sensor and tested it with muon beam at J-PARC. We succeeded in observing positrons from muon decay. We report the performance of the prototype ASIC itself and the combined performance with silicon strip sensor.

Keywords: silicon strip detector, muon, front-end ASIC, g-2/EDM
Poster panel
(face) ID: 351


Poster Number:
N-03-176

Characterization of lateral spatial resolution in high purity germanium double-sided strip detectors as a function of the strip-to-gap ratio for a fixed strip pitch (#3188)

M. Folsom1, J. P. Hayward1, 3, K. - P. Ziock2, 3

1 University of Tennessee, Knoxville, Department of Nuclear Engineering, Knoxville, Tennessee, United States of America
2 University of Tennessee, Knoxville, Department of Physics and Astronomy, Knoxville, Tennessee, United States of America
3 Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America

Content

Interpolation based on signals from strips neighboring the one directly over an interaction can be used to obtain spatial resolution in double sided strip detectors (DSSD) that is better than the width of a single strip. At a fixed strip pitch, the signal-to-noise ratio of the transient signals from the neighboring electrodes used to perform the interpolation should be a function of the ratio of the strip and gap widths, indicating that an optimum ratio may exist. However, typically such detectors minimize the inter-strip gap size to minimize incomplete charge collection. Results obtained using a finely collimated gamma-ray beam from a 133Ba source show improved spatial resolution from a DSSD with a 2.5 mm gap compared to detectors with 0.5 mm and 0.125 mm gaps. In all cases the strip pitch is 5 mm. The results agree with calculated signals obtained using charge transport calculations and weighting potentials validating the calculated signals which can be used to design a detector with an optimum gap width.

Keywords: germanium, double-sided strip detector, HPGe
Poster panel
(face) ID: 353


Poster Number:
N-03-177

Fabrication and testing of monolithic 384 Germanium strip detector with highly integrated readout (#3379)

A. K. Rumaiz1, D. P. Siddons1, A. J. Kuczewski1, J. Mead2, A. Miceli3, T. Krings4, E. Vernon2, D. Pinelli2

1 Brookhaven National Laboratory, NSLS II, Upton, New York, United States of America
2 Brookhaven National Laboratory, Instrumentation Division, Upton, New York, United States of America
3 Argonne National Laboratory, Advanced Photon Source, Argonne, Illinois, United States of America
4 Semikon Detector GmbH, Julich, Illinois, Germany

Content

We have constructed a monolithic 384 Germanium strip array using trenches to provide isolation between adjacent pixels. The read out has been accomplished using a custom CMOS application specific integrated circuit (ASIC). This ASIC will be referred to as multi-element amplifier and readout system or MARS. The detector has 384 pixels each 0.1 mm X 5 mm, arranged as series of strips. It is connected by wirebonds to twelve 32 channel ASIC. MARS is capable of measuring time of arrival of the events; this enables us to address the issue of charge sharing between adjacent pixels. The design, fabrication details and initial test result will be presented in the conference.

Keywords: Germanium Detector
Poster panel
(face) ID: 355


Poster Number:
N-03-178

Lower Temperature Silicon Drift Detectors for Faster Signal Rise Times (#3500)

J. Douwen1, S. Benichou2, C. Cohen2, M. Kocsis2, M. Morelle1

1 Mirion Technologies, Canberra, Olen, Belgium
2 ESRF, Grenoble, France

Content

The  advent  of  fast  low  noise  CMOS  based  preamplifiers  and new  digital  pulse  processing  techniques  have dramatically  increased the  resolution and throughput  of  SDD  based spectroscopy  systems  at  very  high  count  rates.   This paper  describes  recent  improvements  on  the charge collection  speed  on  Silicon  Drift  Detectors  (SDD’s)  to  obtain  faster signal  rise  times  out  of  the  preamplifier  and further  increase  the  throughput  which  can  be  achieved with  these  SDD systems.   A  key  parameter in  the charge collection  speed  of  SDD’s  is  the  operating  temperature  of  the  detector.   With multi-stage  and  cascaded thermo-electric  coolers  or  compact,  low-noise cryogenic coolers  detector temperatures  from  -50°C  to below  -100°C  can  be  obtained.   A  set  of  SDD  designs  with active  areas  from  15-80  mm²  have  been  characterized over this  temperature range.   Signal  rise time  distributions  from  10-25  ns  with  an  average  below  20  ns  have  been  achieved. 

Keywords: SDD, rise time, temperature, Cryocooler
Poster panel
(face) ID: 357


Poster Number:
N-03-179

Timing Resolution Measurements of Ultra-Fast Silicon Detectors vs. Temperature, Fluence, Thickness (#3858)

H. Sadrozinski1, M. Ferrero2

1 SCIPP, UC Santa Cruz, Santa Cruz, California, United States of America
2 INFN Torino, Torino, Italy

on behalf of Ultra-fast Silicon Detector Collaboration

Content

We report on the performance of UFSD (Ultra-Fast Silicon Detectors) from two vendors CNM (LGAD thickness 45μm) and HPK (LGAD thickness 50 and 80μm).

We will report measurements pre-rad and post-rad with neutron fluences between 6e14 and 6e15 n/cm2 of: the leakage current, gain, time jitter, time resolution and the value of Landau fluctuations. The pre-rad measurements were performed at three temperatures (+20C, 0C, -20C) and the post-rad measurements at -20C.

We find that LGAD with higher initial doping concentration achieve post-rad higher gain and better time resolution. 

We find an advantage of using the thinner LGAD because of the reduced contribution of the Landau Fluctuation to the time resolution.

Keywords: Fast Silicon tracking detectors, Radiation damage HL-LHC Instrumentation
Poster panel
(face) ID: 359


Poster Number:
N-03-180

High channel density germanium detector demonstrator for high throughput X-ray spectroscopy (#1400)

N. Tartoni1, S. Chatterij1, R. Crook1, T. Krings2, L. Bombelli3, A. Alborini3

1 Diamond Light Source ltd., Didcot, United Kingdom of Great Britain and Northern Ireland
2 Forschungszentrum Jülich GmbH, Institut für Kernphysik, Jülich, North Rhine-Westphalia, Germany
3 XGlab SRL, Milano, Italy

Content

The development of germanium detector systems for X-ray spectroscopy in synchrotron research applications with a throughput capable of coping with the photon flux is a problem that is still unresolved. The attempt to increase the throughput by increasing the number of channels with a fine segmentation of the germanium detector and by miniaturizing the front-end electronics has been tried in the past. A demonstrator was built and characterized with encouraging results a few years ago [1].

The aim of this work consisted in building and characterizing a second demonstrator along the same guidelines of the abovementioned work. However this time the construction of the demonstrator tried to move towards criteria that are expected to be applied in a full scale detector. The detector was fabricated with the back contact segmented as a hexagonal matrix of 19 pads. The apothem of each pad is 1 mm. The front-end electronics consists in integrated charge sensitive preamplifiers (CUBE [2]) that work in hole-collection. The electrical contact between the preamps and the detector pads is realized through pogo pins installed on the preamp carried board and pressed against the pads.

The new demonstrator was tested with radioactive sources and with the synchrotron X-ray beam to assess its spectroscopic capabilities, the amount of charge sharing between neighbouring channels, and the stability of the detector parameters. In addition by emulating a digital pulse processor procedures to identify and suppress the charge sharing have been investigated. The results of our measurements and investigations are reported in this talk.

[1] Nicola Tartoni, R. Crook, T. Krings, D. Protić, C. Ross, L. Bombelli, R. Alberti, T. Frizzi, and V. Astromskas

IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 62, FEBRUARY 2015 387-394 10.1109/TNS.2014.2381492

[2] L. Bombelli, C. Fiorini, T. Frizzi, R. Alberti, A. Longoni

Nuclear Science Symposium Conference Record, 2011, N40-5

Keywords: germanium detector, X-ray spectroscopy
Poster panel
(face) ID: 361


Poster Number:
N-03-181

Monolithic CMOS Active Pixel Sensor Development for Low Energy X-Ray Detection at Synchrotron Light Source (#2243)

F. Orsini1, J. Baudot2, G. Bertolone2, M. Bordessoule1, A. Dawiec1, K. Desjardins1, J. Heymes2, A. Himmi2, C. Hu-Guo2, M. Kachel2, B. Kanoute1, C. Menneglier1, M. Winter2

1 Synchrotron SOLEIL, GIF SUR YVETTE, France
2 Université de Strasbourg, IPHC/UMR 7178, STRASBOURG, France

Content

Several beamlines of the SOLEIL synchrotron light source are successfully exploiting soft and tender energy X-rays, over the energy range from several 100 eV up to 5 keV, with different techniques, where 2D imaging is compulsory. The scientific methods requires demanding performances for the detector: single photon sensitivity, no background noise, fast readout and large dynamic range that allows registering signals with difference in intensity up to a few orders of magnitude. Currently a relatively low number of developments are tackling this technological difficulty.

MIMOSA-22SX is a CMOS Monolithic Active Pixel Sensor prototype dedicated to low energy X-rays counting applications at the Synchrotron SOLEIL. The circuit was fabricated in a commercial 180 nm CMOS technology process and features a small matrix of 128 × 256 square pixels, which are 22 × 22 μm2 large. One of the main goals of this prototype consists to maximize the sensitive volume. The concept relies on a high resistive substrate where High Voltage (HV) is applied and the sensitive volume targets a thickness of about 50 µm, fully depleted and back-illuminated, allowing an almost 100% quantum efficiency for required X-ray energies. The micro-electronic architecture, the post-processing of the prototype and first in-laboratory tests have already been described in another recent paper.

In this paper, new tests results in laboratory are presented (noise level, discriminators threshold dispersion, charge collection, etc). Moreover, a new test set-up has been prepared for the chip prototype characterization tests on a low energy beam line at the synchrotron SOLEIL. Preliminary tests will be performed at the time being of the conference. A proof of concept for low energy detection, with the required performances and this given architecture, is expected. Depending on the beamline test results, the perspective of a larger surface sensor of about 1 cm2 with optimized architecture will be discussed.

Keywords: Soft X-rays, Single photon counting, CMOS Monolithic Active Pixels Sensors, Back-illumination
Poster panel
(face) ID: 363


Poster Number:
N-03-182

Deposited Charge Measurements with the Instant Retrigger Technology: Calibrating the IBEX ASIC for Time over Threshold Applications (#2820)

C. Disch1, S. De Carlo1, C. Hoermann1, P. Livi1, B. Luethi1, P. Trueb1

1 Dectris Ltd., Baden-Dättwil, Aargau, Switzerland

Content

The instant retrigger technology was introduced in the PILATUS3 ASIC to cope with the incredibly high photon fluxes at third generation synchrotrons. Additionally it enables the determination of the deposited charge in each pixel by measuring the Time over Threshold (ToT) of the amplified pulses. As proof of principle of this operating mode, a vacuum compatible prototype detector with a silicon sensor bump bonded to four IBEX ASICs has been built. The IBEX ASIC is a new readout chip with a pixel size of 75x75 μm2 and extends the functionality of the EIGER ASIC by implementing multiple energy thresholds as well as the instant retrigger technology. Detailed simulations have been performed to find optimal detector settings providing the best possible energy resolution in ToT mode.  After threshold equalization, the ToT of each pixel has been calibrated with high statistics as a function of photon energy. The response is found to be very linear in the energy range from 5.5 keV to 43 keV. Finally, electron diffraction patterns have been acquired, which demonstrate the good detector uniformity after applying the ToT calibration. The calibration profits from the high frame rate capability of the IBEX ASIC. The pixel merging mode with pixels of 150x150 μm2 size together with the electron collection mode will allow the construction of IBEX based prototypes with CdTe sensors in the future.

The developed Time over Threshold (ToT) calibration transforms photon counting detectors into devices with spectroscopic capabilities. Deposited charge measurements can be used to infer the position of single events with significantly improved subpixel resolution by using charge interpolation algorithms or to determine the number of photons in very short X-ray pulses with known photon energy. Thus, the ToT mode opens the way to new applications like Transmission Electron Microscopy or pump and probe experiments at high photon flux.

Keywords: ToT, Time Over Threshold, PILATUS, IBEX, Silicon sensor, Spectroscopy, Electron Microscopy, Diffraction, Pump and Probe, Charge Measurements, ASIC
Poster panel
(face) ID: 365


Poster Number:
N-03-183

Gotthard-II: A ultra-fast Silicon Microstrip Detector with on Chip digital Image Memory (#2985)

X. Shi1, D. Mezza1, A. Mozzanica1, B. Schmitt1, J. Zhang1, M. Andrä1, R. Barten1, A. Bergamaschi1, M. Bruechner1, R. Dinapoli1, E. Froejdh1, D. Greiffenberg1, C. Lopez-Cuenca1, M. Ramilli1, S. Redford1, M. Ruat1, D. Thattil1, C. Ruder1, G. Tinti1, M. Turcato2, S. Vetter1, M. Kuster2

1 Paul Scherrer Institute, Villigen PSI, Aargau, Switzerland
2 European X-Ray Free-Electron Laser Facility GmbH, Schenfeld, Hamburg, Germany

Content

Gotthard-II is a microstrip detector developed for the European X-ray Free-Electron Laser (XFEL.EU). The applications include but are not limited to: energy dispersive experiments at 4.5 MHz frame rate, and veto signal generation for EU XFEL. In Gotthard-II a silicon microstrip sensor with a pitch of 50 μm or 25 μm is wire-bonded to readout ASICs. The ASIC is implemented with the adaptive gain Pre-Amplifiers (PA), the Correlated-Double-Sampling (CDS) amplifiers, the 12-bit Analog-to-Digital Converters (ADC) as well as the memory implemented with Static Random-Access Memory (SRAM) capable of storing all 2700 images in an XFEL bunch train. Several prototype designs of the analogue front-end (AGPA and CDS) and ADC prototypes have been fabricated in UMC110nm CMOS technology. The last prototype, which was submitted in March 2017, consists of a full signal chain (PA + CDS + ADC + memory). The measurement results for these prototypes will be presented and the key issues which have to be solved in the final chip will be discussed.

Keywords: X-ray Detector, XFEL, Microstrip, SAR ADC, adaptive gain, charge integrating
Poster panel
(face) ID: 367


Poster Number:
N-03-184

Qualification of charge collection time in the DSSC sensor as a function of the deposited energy (#3252)

A. Castoldi1, C. Guazzoni1, S. Maffessanti1, M. Porro2, S. Schlee2, G. Weidenspointner2

1 Politecnico di Milano and INFN, Milano, Italy
2 European X-Ray Free-Electron Laser Facility GmbH, Schenefeld, Germany

Content

The X-ray imagers under development for the European XFEL are requested to fulfil a set of challenging specifications, the main ones being the high dynamic range (up to 1:10,000 X-ray photons) and the ability to readout frames up to a burst frequency of 4.5 MHz. The readout strategy of the DSSC instrument - a 1 Mpixel camera under development for the detection of low-energy X-rays (< 6 keV) - is particularly challenging as digitization and storage to the in-pixel memory must be performed within the same 220ns period. The DSSC time sequence must be accurately trimmed in order to accommodate the necessary timing signals for anode reset, charge transport, analog processing by a trapezoidal filter, sampling, digitization and storage.

It becomes therefore relevant to study charge collection effects as a function of the deposited charge and its sensitivity to experimental conditions (e.g. incident position within the pixel, time sequence, sensor bias, ASIC configuration). The goal of this work is two-fold, i) to extract the true time profile of the collected charge cloud in a wide range of experimental conditions, ii) optimize the impact of charge collection effects on the fastest 4.5 MHz DSSC operating mode.

We carried out a measurement campaign on a MM4 sensor matrix, based on a monolithic array of hexagonal silicon drift detector pixels (236 x 204 µm2) bump-bonded to a 8x16 pixel readout ASIC which provides also an analog output. In the so-called Day-0 version, the final DSSC sensor will be based on 256x128 pixel sensors bump-bonded to 64x64 pixel readout ASICs. Experimental measurement were carried out using an IR pulsed laser (705 nm, absorption length equivalent to about 1.4 keV X-ray).

The results of these measurements will be critically summarized and discussed.

Keywords: X-ray imager, FEL, DSSC, charge collection
Poster panel
(face) ID: 369


Poster Number:
N-03-185

A monolithic 64-channel germanium strip detector system with integrated circuit readout for energy dispersive X-ray diffraction (#3694)

R. Woods1, J. Almer1, J. Baldwin1, T. Krings4, A. Kuczewski2, T. Madden1, J. Mead2, A. Miceli1, J. Okasinski1, O. Quaranta1, A. K. Rumaiz2, D. P. Siddons2, S. Stock3

1 Argonne National Laboratory, Argonne, United States of America
2 Brookhaven National Laboratory, Upton, United States of America
3 Northwestern University, Evanston, United States of America
4 Forschungszentrum Jülich GmbH, Jülich, North Rhine-Westphalia, Germany

Content

We present performance results of a monolithic 64-channel germanium strip detector system, with integrated circuit readout for energy dispersive X-ray diffraction. At the heart of this detector system are the low-noise integrated circuit for spectroscopy developed at Brookhaven National Laboratory and high-quality monolithic germanium sensor from FZ Jülich. In particular, this detector system consists of 3-mm-thick germanium sensor with 64 strips on a 0.5-mm pitch. An energy spectrum is measured from each strip simultaneously; the energy resolution is ~500 eV. The system cooling (operation temperature 87 K) and control was developed at Argonne National Laboratory using a Joule-Thomson cryocooler, commercially available instruments and in-house developed software which fully automates the operation of the detector. Currently, the maximum energy of this system is ~60 keV, but new readout electronics being developed at Brookhaven will extend the energy range beyond 100 keV. Nonetheless, this detector system has enabled at Argonne National Laboratory a new x-ray imaging technique based on energy dispersive diffraction. This new technique provides spatially-resolved diffraction data including phase fractions and strains on cm-sized specimens. Applicable to more geometries than standard tomography techniques (e.g. high aspect ratio samples), with target areas including batteries, bone implants and aerospace components. The new imaging mode was accomplished with a slit and single translation across the sample, and applied to a three-dimensional printed bone phantom to confirm accuracy.

Keywords: germanium, X-ray, synchrotron, detector, ASIC