467 results on '"Gamma ray detection"'
Search Results
2. Investigating the Interpretability of ML-Guided Radiological Source Searches
- Author
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Gregory R. Romanchek and Shiva Abbaszadeh
- Subjects
Gamma ray detection ,interpretability ,machine learning ,reinforcement learning ,source localization ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
The coupling of reinforcement learning (RL) and deep neural networks (DNN) has demonstrated promising results in many task-oriented scenarios, including radiological source localization. However, these black box approaches present an issue from the user’s perspective – the non-interpretably of results both during and after task completion. In this work, an RL-based convolutional neural network (CNN) for single-detector, radiological source localization is augmented with a system-feedback strategy which provides users with real-time information on estimated search progress, confidence in search termination, and a projection of future actions. In this Q-learning network, the agent is a single, mobile detector; the environment is a 2D simulated space, including background, attenuating obstacles, and source; the actions are (from a top-down view) {left, right, up, down, and stop search}. At each step, the agent moves and records a gamma-ray measurement, the search maps are updated, and the CNN is activated, yielding the action with the greatest q-value (reward). In addition, at each step, system-feedback is generated by virtually probing the network at all locations for q-values. The system-feedback sets are: 1) the confidence in taking each action at the given location, 2) a map of future movements, and 3) a map of stopping likelihood. The information these three sets provide helps the user better understand why a given action was taken and what to expect going forward. The combination of confidence measures, count rate, and pathing does provide interpretable information for discerning current and future actions.
- Published
- 2022
- Full Text
- View/download PDF
3. Dual particle imaging: Applications in security and environmental imaging.
- Author
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Pozzi, S.A., Lopez, R., Marleau, P., and Clarke, S.D.
- Subjects
- *
NUCLEAR counters , *GAMMA rays , *NEUTRON counters , *IMAGE converters , *AUGMENTED reality , *SOFT errors - Abstract
Radiation imaging detectors have been applied in a variety of fields for detection, localization and characterization of radioactive sources. In this work, we describe a handheld detection system (H2DPI) that can simultaneously image neutrons and gamma rays, and reconstruct the energy spectra of the incident particles. This system was applied to the detection and characterization of a plutonium metal source in experiments performed at the National Criticality Experiments Research Center, where the 4.5 kg plutonium source was placed approximately 60 cm from the H2DPI. Neutron and gamma-ray images were measured that show good agreement with the known location of the source. Furthermore, the H2DPI was also used to measure the neutron spectrum, which shows the expected shape of a Watt fission spectrum, and the gamma-ray energy spectrum, which shows the energies common to plutonium metal. Lastly, we describe the application of the H2DPI in augmented reality, whereby real-time neutron and gamma-ray imaging data can be streamed to the Microsoft HoloLens to allow the user to visualize the source locations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Comparison of theoretical and machine learning models to estimate gamma ray source positions using plastic scintillating optical fiber detector
- Author
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Jinhong Kim, Seunghyeon Kim, Siwon Song, Jae Hyung Park, Jin Ho Kim, Taeseob Lim, Cheol Ho Pyeon, and Bongsoo Lee
- Subjects
Plastic scintillating optical fiber ,Gamma ray detection ,Position estimation ,Machine learning ,Nonlinear regression ,Nuclear engineering. Atomic power ,TK9001-9401 - Abstract
In this study, one-dimensional gamma ray source positions are estimated using a plastic scintillating optical fiber, two photon counters and via data processing with a machine learning algorithm. A nonlinear regression algorithm is used to construct a machine learning model for the position estimation of radioactive sources. The position estimation results of radioactive sources using machine learning are compared with the theoretical position estimation results based on the same measured data. Various tests at the source positions are conducted to determine the improvement in the accuracy of source position estimation. In addition, an evaluation is performed to compare the change in accuracy when varying the number of training datasets. The proposed one-dimensional gamma ray source position estimation system with plastic scintillating fiber using machine learning algorithm can be used as radioactive leakage scanners at disposal sites.
- Published
- 2021
- Full Text
- View/download PDF
5. Growth of Cd 0.9 Zn 0.1 Te 1– y Se y Single Crystals for Room-Temperature Gamma Ray Detection.
- Author
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Kleppinger, Joshua W., Chaudhuri, Sandeep K., Roy, Utpal N., James, Ralph B., and Mandal, Krishna C.
- Subjects
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NUCLEAR counters , *GAMMA rays , *SINGLE crystals , *ENERGY dispersive X-ray spectroscopy , *SEMICONDUCTOR detectors , *SELENIUM - Abstract
Quaternary Cd0.9Zn0.1Te1–ySey (CZTS) single crystals, a novel room-temperature nuclear radiation detector semiconductor material, have been grown using a modified vertical Bridgman method (VBM) and a traveling heater method (THM). The percentage concentration of selenium in the VBM-grown crystal was 3% and that in the THM-grown crystal was 2%. While the THM Frisch collar detector ($4.4\times 4.4\times10.7$ mm $^{3}$) produced a highly resolved pulse height spectra (PHS) with a resolution of ~1.06% for 662-keV gamma rays without any correction, the VBM-grown detector ($10\times 10\times 2$ mm $^{3}$) offered a high-energy resolution of ~2% after the application of a digital bi-parametric correction. The high-resolution performance of these detectors has been attributed to the addition of Se in the Cd0.9Zn0.1Te (CZT) matrix. Ab-initio calculations based on density functional theory (DFT) also confirmed that the addition of Se in the CZT matrix helps to reduce the formation of TeCd and the TeZn antisites. The VBM-grown crystals were characterized using powder X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). While the XRD results revealed sharp diffraction peaks confirming the crystalline nature of the grown crystal, the EDS results confirmed the targeted stoichiometry of the elemental composition. The bulk resistivity of the grown crystal was calculated to be $\sim 3\times 10^{10}\,\,\Omega$ -cm from the current–voltage characteristics recorded at room temperature in a planar configuration, ensuring that the grown CZTS crystals have low dark current as required for detector-grade crystals. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
6. Signal Amplification of Fiber Integrated X-Ray Detector and Energy Independence.
- Author
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Debnath, Sree Bash Chandra, Darreon, Julien, Tallet, Agnes, Goncalves, Anthony, Tonneau, Didier, and Fauquet, Carole
- Abstract
We developed a high spatial resolution and sensitive detector particularly suitable for radiation dose measurements in radiotherapy at small fields and X-ray imaging applications. The detector is based on a silica optical fiber whose sensitive terminal is functionalized by grafting Ag-doped ZnS scintillating materials that emit blue luminescence under X-ray irradiation. Due to the small scintillating head of the detector, the acquisition signal is quite low, and it is measured by a sensitive photon counter plugged at the other terminal of the fiber. The weaker signal can be enhanced significantly by adding a metal coating over the scintillator. Therefore, this study presents the effect of metal thickness and density on the signal amplification at high irradiation energies of 6 MeV and 15 MeV using a Linear Accelerator (LINAC). In addition, the stem effect was characterized for regular to small field beam size and shows that the detector is almost free from stem contribution during high energy irradiation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
7. Correlation of Space Charge Limited Current and γ-Ray Response of CdxZn1-xTe1-ySey Room-Temperature Radiation Detectors.
- Author
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Chaudhuri, Sandeep K., Sajjad, Mohsin, Kleppinger, Joshua W., and Mandal, Krishna C.
- Subjects
NUCLEAR counters ,WIDE gap semiconductors ,SEMICONDUCTOR detectors ,ELECTRON traps ,SPACE charge ,ALPHA rays ,CHARGE carriers - Abstract
In this letter we report a direct correlation between the space charge limited current flow and radiation detection properties of CdxZn1-xTe1-ySey (CZTS) detector. CZTS is a recently discovered quaternary wide bandgap semiconductor for room-temperature gamma photon detection. The CZTS single crystals have been grown in-house using a modified Bridgman technique. Planar detectors were fabricated and characterized in terms of charge carrier flow and radiation detection measurements. An anomalous current flow falling outside the Lampert’s triangle in $\textit {logJ}-\textit {logV}$ plot, has been observed which is not generally seen in semiconductor detectors governed by space-charge limited current flow mechanism. The anomalous behavior has been attributed to the presence of electron traps. The devices were tested for their radiation detection properties by acquiring pulse height spectra using 241Am and a 137Cs isotopes as a source of alpha particles and gamma photons, respectively. It was further noticed that the only detectors which worked satisfactorily as radiation detectors, did not exhibit the anomalous current flow mechanism. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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8. Growth of Large-Area Cd₀.₉Zn₀.₁Te Single Crystals and Fabrication of Pixelated Guard-Ring Detector for Room-Temperature γ-Ray Detection.
- Author
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Sajjad, Mohsin, Chaudhuri, Sandeep K., Kleppinger, Joshua W., and Mandal, Krishna C.
- Subjects
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SINGLE crystals , *DETECTORS , *NUCLEAR counters , *SEMICONDUCTOR detectors , *TELLURIUM , *METAL tailings - Abstract
Large-volume detector-grade Cd0.9Zn0.1Te (CZT) single crystals were grown using a vertical Bridgman technique. The bulk resistivity of the as-grown crystal was found to be ~ 5 × 1010 Ω-cm from current–voltage measurements. A 19.0 ×19.0 × 5.0 mm3 block of the crystal was used to fabricate a detector with 10 × 10 pixelated anode configuration integrated with interpixel guard rings. The detector was tested for its radiation detection properties using 662-keV gamma rays from a 137Cs source. The pixels exhibited well-resolved gamma pulse-height spectra (PHS) with percentage energy resolution ~1.6% at 662 keV. A few pixels exhibited tailing of the photopeak on the lower energy side indicating the presence of hole traps. Biparametric plots (BPs) were obtained from digitally recorded preamplifier pulses. The BPs showed anomalous behavior, which was correlated with the gamma interactions in the active region of the detector in virtual Frisch grid configuration. The BPs also enabled to extract PHS free from the extensive tailing of the photopeak. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
9. Proximity-Based Sensor Fusion of Depth Cameras and Isotropic Rad-Detectors.
- Author
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Henderson, Kristofer, Liu, Xiaomeng, Stadnikia, Kelsey, Martin, Allan, Enqvist, Andreas, and Koppal, Sanjeev J.
- Subjects
- *
GAMMA ray detectors , *PROXIMITY detectors , *DETECTORS , *NUCLEAR counters , *KALMAN filtering - Abstract
Finding and tracking radioactive sources have numerous security applications in civilian energy installations, military facilities, and ports of entry. The price of radiological sensors varies proportionally to size and imaging characteristics such as angular resolution, and the cheapest devices are nearly isotropic–i.e., they integrate radiation from a sphere of directions centered at the sensor. While many radiation sensors have high aspect ratios or odd shapes, the sensors used here are right cylinders, with a near identical directional efficiency such that for analysis purposes, other aspects, such as counting statistics, would make nonisotropy of the sensor negligible. In this article, we propose a simple and robust way to integrate measurements from both isotropic radiological sensors and depth sensors, whose reliability and resolution benefit from recent advances in computer vision and imaging. Our key idea is to convert all sensor measurements into proximity signals based on radial distance variations over time. Based on this sensor fusion model, we show that for moving radiological sources even a simple Kalman filter can trade-off the complementary strength of high-resolution depth sensors and isotropic radiological sensors. We show novel results with a LIDAR sensor and a thermal stereo pair, and demonstrate applications such as tracking and rendering non-line-of-sight imagery behind obstacles and detecting multiple radiological sources in the same scene. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
10. 小型伽马射线检测系统的设计.
- Author
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童云坤, 陶玲, 李韪韬, 黄海鹏, and 李怡燃
- Abstract
Copyright of Chinese Medical Equipment Journal is the property of Chinese Medical Equipment Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
- Full Text
- View/download PDF
11. Organic photoelectric materials for X-ray and gamma ray detection: mechanism, material preparation and application
- Author
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Wenping Hu, Cong Wang, and Mingxi Chen
- Subjects
Materials science ,Detector ,Energy conversion efficiency ,Materials Chemistry ,X-ray ,Nanotechnology ,General Chemistry ,Photoelectric effect ,Thin film ,Particle detector ,Gamma ray detection ,Ionizing radiation - Abstract
In recent years, with the increasing demands of high-energy physics, medical diagnosis, radiochemistry, and industrial non-destructive testing, ionizing radiation detectors have received more and more attention. Organic photoelectric materials have been used in ionizing radiation detection for nearly hundred years. Until recently, the novel molecular design, progressive preparation technology and further mechanism exploration have once again greatly expanded their application field, as well as showing a short response time, low limitation of dose rate and high sensitivity, which can be used as candidate materials for next-generation high-energy radiation detectors owing to their low-cost processing techniques, flexible properties and promising low detection limit. Based on a brief description of the detection mechanism, this review investigates the recent research of X-ray and gamma ray detection based on organic thin films, single crystals, polymers and liquid materials. It focuses on the advantages of these materials, bottlenecks encountered, and relatively effective solutions in recent years. This article aims to provide readers with a deeper understanding of the comprehensive approach to design organic materials and improve the conversion efficiency for future ionizing radiation detection.
- Published
- 2021
12. Gamma ray detection: building a didactic proposal
- Author
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Sergej Faletič, Marisa Michelini, and Lorenzo Santi
- Subjects
spectra ,formative assessment ,teaching sequence ,General Physics and Astronomy ,gamma ray detection ,students’ difficulties - Abstract
A simple and economic scintillator kit in combination with a computer-based oscilloscope was used to develop a learning experience, comprised of a set of activities to introduce students in an interactive way to the physics of gamma-ray detection. The proposal for secondary school and university students is built by means of frequent on-the-fly formative assessment to collect difficulties of students and ways to overcome them. Internal decays of Lutetium–yttrium oxyorthosilicate (LYSO) crystals already present in the scintillator kit are used as sources of gamma rays, so no external sources were needed. In addition, the use of LYSO crystals offers a reason to discuss coincidence measurements, because of the inherent beta background present in the internal decay, which can be at least partially removed with coincidence measurements. The goal of the learning experience is to experience how gamma-ray detection is actually done, discussing the physics involved, motivated by the current frontline research on the detection of gamma-ray bursts.
- Published
- 2023
13. Strontium Iodide Instrument Development for Gamma Spectroscopy and Radioisotope Identification
- Author
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Solodovnikov, D [Northrop Grumman SYNOPTICS, North Carolina]
- Published
- 2014
14. Advances in the growth of alkaline-earth halide single crystals for scintillator detectors
- Author
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Bhattacharya, P. [Fisk University, Nashville]
- Published
- 2014
15. Performance of 3D printed plastic scintillators for gamma-ray detection
- Author
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Yong-Hyun Kim, Tae Hoon Kim, Junesic Park, Yong Kyun Kim, Kihong Pak, Sangmin Lee, Dong Geon Kim, and Jaebum Son
- Subjects
3d printed ,Materials science ,Physics::Instrumentation and Detectors ,020209 energy ,3D printing ,02 engineering and technology ,Electron ,Scintillator ,Detection efficiency ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Optics ,0202 electrical engineering, electronic engineering, information engineering ,Energy resolution ,Decay time ,Plastic scintillator ,business.industry ,Resolution (electron density) ,Gamma-ray detection ,lcsh:TK9001-9401 ,Nuclear Energy and Engineering ,lcsh:Nuclear engineering. Atomic power ,Digital Light Processing ,business ,Energy (signal processing) ,Gamma ray detection - Abstract
Digital light processing three-dimensional (3D) printing technique is a powerful tool to rapidly manufacture plastic scintillators of almost any shape or geometric features. In our previous study, the main properties of light output and transmission were analyzed. However, a more detailed study of the other properties is required to develop 3D printed plastic scintillators with expectable and reproducible properties. The 3D printed plastic scintillator displayed an average decay time constants of 15.6 ns, intrinsic energy resolution of 13.2%, and intrinsic detection efficiency of 6.81% for 477 keV Compton electrons from the 137Cs γ-ray source. The 3D printed plastic scintillator showed a similar decay time and intrinsic detection efficiency as that of a commercial plastic scintillator BC408. Furthermore, the presented estimates for the properties showed good agreement with the analyzed data.
- Published
- 2020
16. Bulk Organic–Inorganic Methylammonium Lead Halide Perovskite Single Crystals for Indirect Gamma Ray Detection
- Author
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Zhengyun Wu, Jiafa Cai, Bo Liang, Qiang Xu, Jun Liu, Bo Liu, Zhichao Zhu, Wenyi Shao, Xiao Ouyang, and Ouyang Xiaoping
- Subjects
Photomultiplier ,Photon ,Materials science ,Physics::Instrumentation and Detectors ,business.industry ,Physics::Optics ,02 engineering and technology ,Methylammonium lead halide ,Scintillator ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Ionizing radiation ,chemistry.chemical_compound ,chemistry ,Optoelectronics ,General Materials Science ,0210 nano-technology ,Spectroscopy ,business ,Perovskite (structure) ,Gamma ray detection - Abstract
Scintillators that convert ionization radiation photons to UV-visible photons have attracted extraordinary attention. Traditional scintillators are associated with a vacuum photomultiplier tube that faces strict constraints of fragility, magnetic fields, and operated voltage, or coupled to a silicon photomultiplier (SiPM) with optical silicone grease. Here, we report a high-performance radiation detector with an indirect photon-to-photon conversion radiation detection model based on perovskite single crystals (SCs), where perovskite SCs have been directly integrated into the window of SiPM by using the solution growth method at low temperature. Tunable X (γ)-ray excited light emission in the range of 414 to 600 nm is obtained with different concentrations of Br doping, which greatly matches the response wavelength of SiPM. Small Br-doped CH
- Published
- 2019
17. Efficiency calibration of NaI (Tl) detector for disc source using point source experimental technique and Monte Carlo simulations
- Author
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Azhar H. Malik, Muhammad Rizwan, and Rizwan Ahmed
- Subjects
Physics ,Point source ,Monte Carlo method ,Detector ,Gamma ray detectors ,Calibration ,Radius ,Computational physics ,Gamma ray detection - Abstract
The detection efficiency of a gamma ray detector should be calibrated prior to the measurement of activity in samples. The aim of this research is to develop a simple experimental technique to calibrate the efficiency of detectors for geometrical sources by replicating their responses from virtually equivalent sources (VES) constructed from a collection of Standard Point Source (SPS) measurements. Experiments were performed to replicate the response of a disk source of 5.2 cm radius by equivalent disk sources (EDS) reconstructed from a collection of 19, 91 and 169 SPS measurements to optimize the number of measurements, response of detector for radially symmetric SPS locations was verified through Absolute Peak Efficiency (APE) calculations. APE was calculated experimentally for the actual disk source and EDS as well as using EGS5 simulations. The difference between experimentally measured and simulated APE for 5.2 cm EDS was observed to be about 7.8 %, 5.2 % and 5.4 % for 137Cs and about -1.3 %, 1.3 % and 2.7 % for 22Na for the EDS constructed from 19, 91- and 169 SPS measurements respectively
- Published
- 2021
18. NEUTRON AND GAMMA RAY DETECTION FOR BORDER SECURITY APPLICATIONS
- Author
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Kouzes, Richard
- Published
- 2010
- Full Text
- View/download PDF
19. Layered shielding design for an active neutron interrogation system.
- Author
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Whetstone, Zachary D. and Kearfott, Kimberlee J.
- Subjects
- *
NEUTRON counters , *PHOTON flux , *MODULAR design , *DEUTERIUM , *TRITIUM , *NUCLEAR engineering - Abstract
The use of source and detector shields in active neutron interrogation can improve detector signal. In simulations, a shielded detector with a source rotated π/3 rad relative to the opening decreased neutron flux roughly three orders of magnitude. Several realistic source and detector shield configurations were simulated. A layered design reduced neutron and secondary photon flux in the detector by approximately one order of magnitude for a deuterium–tritium source. The shield arrangement can be adapted for a portable, modular design. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
20. Maximum Likelihood Localization of Radioactive Sources Against a Highly Fluctuating Background.
- Author
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Bai, Er-wei, Heifetz, Alexander, Raptis, Paul, Dasgupta, Soura, and Mudumbai, Raghuraman
- Subjects
- *
RADIATION sources , *MAXIMUM likelihood statistics , *GAMMA rays , *STOCHASTIC convergence , *ITERATIVE methods (Mathematics) , *COMPUTER simulation - Abstract
This paper considers the use of maximum likelihood estimation to localize a stationary source from total gamma ray counts, in an open area setting with a highly fluctuating background. As this turns out to be a highly nonconcave maximization, convergence rates of global convergent algorithms, such as simulated annealing, can be very slow and iterative algorithms such an Newton’s method for maximization can be captured by local maxima while fast. Thus, the selection of the initial estimate is critical to how well they perform. This paper proposes a way to generate such an initial estimate using an averaging process that is shown to be asymptotically convergent to the maximum likelihood source estimate. This ensures that with a sufficiently large number of samples, the initial estimate is indeed within of the basin of attraction of such iterative algorithms. Analytical results are supported by numerical simulations based on a measured background data and synthetically injected source data. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
21. Signal amplification of fiber integrated X-ray detector and energy independence
- Author
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D. Tonneau, Anthony Gonçalves, Agnès Tallet, Sree Bash Chandra Debnath, Julien Darreon, Carole Fauquet, Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU), Institute Paoli-Calmettes, Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC), Centre de Recherche en Cancérologie de Marseille (CRCM), Aix Marseille Université (AMU)-Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), This project has received funding from the EuropeanUnion’s Horizon 2020 Research and Innovation Programunder the Marie Skłodowska-Curie grant agreementNo.713750. It has also been carried out with the financialsupport of the Regional Council of Provence- Alpes-Côted’Azur and with the financial support of the A*MIDEXproject funded by the French Government, managed by theFrench National Research Agency (ANR)(n° ANR- 11-IDEX-0001-02, Investissements d'Avenir). This work was alsosupported by Initiative d'Excellence d'Aix-MarseilleUniversité - A*Midex AMX-18-UNT-018., European Project: 713750,H2020,H2020-MSCA-COFUND-2015,DOC2AMU(2016), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Paoli-Calmettes, and Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Aix Marseille Université (AMU)
- Subjects
Optical fiber ,Materials science ,Luminescence ,Physics::Instrumentation and Detectors ,X-ray detector ,Gamma ray detection ,Particle beam measurements ,Scintillator ,01 natural sciences ,Signal ,Particle detector ,law.invention ,Radiation dosage ,[SPI]Engineering Sciences [physics] ,law ,Biomedical applications of radiation ,Dosimetry ,X-rays ,Optical fiber devices ,Irradiation ,Electrical and Electronic Engineering ,Instrumentation ,ComputingMilieux_MISCELLANEOUS ,[PHYS]Physics [physics] ,business.industry ,010401 analytical chemistry ,Detector ,Optical fiber sensors ,X-ray detectors ,0104 chemical sciences ,Radiation detectors ,Oncology ,Optoelectronics ,Luminescent devices ,Photonics ,business - Abstract
International audience; We developed a high spatial resolution and sensitive detector particularly suitable for radiation dose measurements in radiotherapy at small fields and X-ray imaging applications. The detector is based on a silica optical fiber whose sensitive terminal is functionalized by grafting Ag-doped ZnS scintillating materials that emit blue luminescence under X-ray irradiation. Due to the small scintillating head of the detector, the acquisition signal is quite low, and it is measured by a sensitive photon counter plugged at the other terminal of the fiber. The weaker signal can be enhanced significantly by adding a metal coating over the scintillator. Therefore, this study presents the effect of metal thickness and density on the signal amplification at high irradiation energies of 6 MeV and 15 MeV using a Linear Accelerator (LINAC). In addition, the stem effect was characterized for regular to small field beam size and shows that the detector is almost free from stem contribution during high energy irradiation.
- Published
- 2021
22. 6Li210B4O7 NPs-loaded plastic scintillators for fast/thermal neutron and gamma ray detection
- Author
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Jonathan Dumazert, Clément Lynde, Guillaume H. V. Bertrand, Eva Montbarbon, Amélie Grabowski, Matthieu Hamel, Romain Coulon, Camille Frangville, and Amélie Venerosy
- Subjects
Materials science ,Radiochemistry ,Nanoparticle ,Context (language use) ,02 engineering and technology ,Scintillator ,Thermal neutron detection ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Neutron temperature ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,General Materials Science ,Polystyrene ,POPOP ,0210 nano-technology ,Gamma ray detection - Abstract
We report herein the synthesis of a new series of plastic scintillators (PSs) loaded with 6Li210B4O7 nanoparticles (NPs), as new radioluminescent sensors for fast/thermal neutron and gamma ray detection in the critical context of homeland security. This study aims to evaluate the benefit of such nanoparticles towards thermal neutron detection in a fast neutrons/gamma discriminating PS composition. First, a size-controlled synthesis of Li2B4O7 NPs assited with poly(N-vinylpyrrolidone) (PVP) is performed. Then enriched 6Li210B4O7 NPs (65 ± 22 nm) are dispersed in clear PSs mainly composed of polystyrene and standard fluorophores (20 wt% PPO, 0.03 wt% POPOP). For the first time, a triple nthermal/nfast/gamma discrimination is presented with a NP-loaded plastic scintillator, where both 6Li(n,α) and 10B(n,α) are observed.
- Published
- 2019
23. PRECISE COMPACT SYSTEM FOR IONIZING RADIATION DETECTION AND SIGNAL PROCESSING WITH ADVANCED COMPONENTS INTEGRATION AND ELECTRONIC CONTROL.
- Author
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Navařík, Jakub, Novák, Petr, Pechoušek, Jiří, Machala, Libor, Jančík, Dalibor, and Mašláň, Miroslav
- Subjects
- *
SYSTEMS theory , *IONIZING radiation , *SIGNAL processing , *ELECTRONIC control , *NUCLEAR physics - Abstract
Quality and performance of a detection system are the crucial parameters in all nuclear physics experiments. This system serves as a source of all signals and noises to be processed. Better performance, higher amplification and lower noises occurrence simplify subsequent signal analysis. In the field of Mössbauer spectroscopy, the spectrum quality and Mössbauer effect are crucial parameters which are affected especially by the quality of the detection system. These parameters were evaluated for different types of a detection setup. Finally an improvement of the spectrum quality by 15% and Mössbauer effect by 7% has been achieved for the natural iron reference absorber measurement in comparison with previous version of the detection system. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
24. Technical Review of the Domestic Nuclear Detection Office Transformational and Applied Research Directorate’s Research and Development Program
- Author
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Slakey, Francis
- Published
- 2013
- Full Text
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25. Semiconductor detectors for gamma-ray detection
- Author
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David Jenkins
- Subjects
Materials science ,business.industry ,Optoelectronics ,business ,Semiconductor detector ,Gamma ray detection - Published
- 2020
26. Applications of gamma-ray detection for society, medicine and other areas of science
- Author
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David Jenkins
- Subjects
Physics ,Optics ,business.industry ,business ,Gamma ray detection - Published
- 2020
27. Development and Characterization of a Directional Gamma-ray Detector.
- Author
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Cormier, Felix, Georgin, Marcel, Koelbl, Stephen, and Oda, Robert
- Subjects
- *
GAMMA rays , *SILICON research , *PHOTOMULTIPLIERS , *RADIOACTIVITY , *SCINTILLATORS , *SIGNAL-to-noise ratio - Abstract
Background: This work characterizes the first generation of detectors from the Hanna Laboratory to implement Silicon Photomultipliers and a heptagonal scintillator conguration. The purpose of the device is to determine the angle at which a radioactive source is located. Methods: The development of the detector consisted of three phases: construction(September 2012- December 2012), simulation and characterization (April 2013). The experimental portion of the work consisted of placing a 55137 Cs source at an arbitrary location, measuring the count rates in each scintillator panel and analysing the results. Results: The detector's function was validated by confirming the inverse square law with a radioactive source moving away from the detector. Furthermore, with a x² summation method of analysis the angular position of a source was determined with an accuracy of 10° and a precision of 12°. With a normalisation method of analysis the angular position of a source was found with an accuracy of 2° and a corresponding precision of 2°. Limitations: The quality of the electronics handling the signal from the silicon photomultipliers limited our resolution. Occasional double counts occur when a large amount of energy is imparted to the scintillator. Furthermore, the custom-built circuitry lowered the signal-to-noise ratio such that large distances were not feasible due to electronic noise constraints. Finally, simulation data analysis showed that the break of one circuit only had a small effect on the x² method of analysis. Conclusions: In conclusion, the design of the detector and the analysis techniques were shown to be suitable for short range angular resolution of a gamma-ray source. Both distance trials and a simulation of the detector prototype confirmed the validity of our design and of the analysis methods used. These promising results at short distances motivate further work in electronic circuit design to improve the range while maintaining both accuracy and precision. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
28. The gamma ray detection threshold temperature of different superheated droplet detectors
- Author
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Rupa Sarkar, Barun K. Chatterjee, and Prasanna Kumar Mondal
- Subjects
Radiation ,Materials science ,010308 nuclear & particles physics ,Detector ,Gamma ray ,01 natural sciences ,030218 nuclear medicine & medical imaging ,Computational physics ,Superheating ,03 medical and health sciences ,0302 clinical medicine ,Linear relationship ,Threshold temperature ,0103 physical sciences ,Phenomenological model ,Limit (mathematics) ,Gamma ray detection - Abstract
The response of superheated droplet detectors (SDD) loaded with four different active liquids, R-12 (CCl2F2), R-114 (C2Cl2F4), R-134a (C2H2F4) and R-610 (C4F10) have been studied to obtain the gamma ray detection threshold temperature (Tγ) of the respective detectors. A 137Cs gamma ray source is used for this study. To obtain Tγ from the experimental data a phenomenological model has been used. Result indicates that Tγ maintains a linear relationship with the limit of superheat (Tlim) of different active liquids used in SDD. It indicates that the limit of superheat of a liquid can be used for the prediction of its gamma ray detection threshold temperature.
- Published
- 2018
29. Investigations on Detecting Potential Nuclear Material Diversion from a Pyroprocessing Facility
- Author
-
Seung Min Woo, Sunil S. Chirayath, Heukjin Boo, and Keunhong Jeong
- Subjects
Nuclear and High Energy Physics ,Nuclear fission product ,020209 energy ,Nuclear engineering ,technology, industry, and agriculture ,chemistry.chemical_element ,02 engineering and technology ,Nuclear material ,Uranium ,Pyroprocessing ,Nuclear reactor ,Condensed Matter Physics ,complex mixtures ,law.invention ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Nuclear Energy and Engineering ,chemistry ,law ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,Gamma ray detection - Abstract
Under normal operating conditions, a pyroprocessing facility removes highly radioactive and nonradioactive fission product waste from used nuclear reactor fuel to recycle the remaining uranium (U),...
- Published
- 2018
30. Algorithm Implementation for a Prototype Time-Encoded Signature Detector
- Author
-
Wyatt, Cory
- Published
- 2007
- Full Text
- View/download PDF
31. Multi-scale Functional Nanomaterials for the Spectroscopic Detection of Ionizing Radiation and Characterization of Complex Structural Networks
- Author
-
Vecchio, Drew
- Subjects
- Multi-scale functional nanomaterials, Gamma ray detection, Quantum dots, Self-assembly, Nanocomposites, Graph Theory
- Abstract
Materials exhibiting unique properties in the nanoscale have potential to solve challenges that the macroscopic world faces. Translation of nanoscale effects into macroscopic solids is difficult because it requires the ordering of millions of precisely synthesized nanomaterials across multiple lengths scales without losing their spatial confinement. Multi-scale functional nanomaterials seek to combine the advantageous properties of nanoscale subunits with hierarchical organization to target specific applications. One such application that multi-scale functional nanomaterials can provide specific benefit is in the field of ionizing radiation detection. Nanoscale semiconductor materials can achieve high resolution gamma ray detection through efficient rates of multi-exciton generation and the suppression of optical phonons. Solid-state gamma ray detectors require macroscale thickness and pathways of organized semiconductors for charge percolation. This work advances our understanding and capability for nanoscale interactions with gamma rays through investigating new nanosemiconductor materials and approaches for assembling macroscale ordered solids from the nanoparticle subunits. Radiation detector performance was evaluated through the spectroscopic response of each material to a barium-133 gamma ray source, and measuring the peak resolution as the primary quantifiable metric. The first successful material approach utilized a robust aramid nanofiber matrix derived from Kevlar as a scaffold, and nanoparticles of cadmium telluride were grafted onto the polymer backbone to form efficient percolation networks. These aramid nanofiber composites measure tens-to-hundreds of micrometers in thickness, and successfully detect gamma rays with resolution < 1% at 81 keV, comparable to current commercial devices. The cadmium telluride/aramid nanofiber nanocomposites additionally demonstrated mechanical flexibility and resilience, with no degradation of performance up to 1000 bending cycles. Several formulations of aqueously colloidal lead telluride nanoparticles were investigated and developed to replace cadmium telluride in the nanocomposites in order to improve the materials’ stopping power and phonon suppression. The lead telluride/aramid nanofiber nanocomposites demonstrated gamma ray sensitivity, but the higher dielectric constant and limited device thickness constrained their performance with noise due to high capacitance. An alternative nanoparticle system was invented that showed lead telluride nanoparticles spontaneously self-assemble into macroscale transparent hydrogels consisting of a percolating nanoscale network. Graph theory was used as a tool to quantify network structure and develop correlations between electrolyte concentration/composition, the topological descriptor average nodal connectivity, and the rheological and electrical properties of the hydrogels. Functional detectors are prepared by reinforcing the spanning lead telluride networks with crosslinked polymers, which demonstrate scalability to several millimeters without exhibiting any apparent limitation to achieve thicknesses of several centimeters. The lead telluride polymer nanocomposites are shown to preserve the 3D nanoscale network in the macroscale devices and demonstrated resolved detection of the prominent 356 keV gamma ray from barium-133. The findings of this work prove the utility of nanosemiconductors for high-resolution gamma-ray detection, and provide a methodology for producing large-scale functional solids with conserved nanoscale features that retain desirable functionality. The goal of producing percolating networks of semiconducting nanoparticles that span macroscale volumes was demonstrated.
- Published
- 2022
32. PO-1728: Development of a new prompt gamma ray detection system for full 3D proton range verification
- Author
-
Michael Taylor, P. Costanza, Ranald I Mackay, and Karen J. Kirkby
- Subjects
Range (particle radiation) ,Materials science ,Oncology ,Proton ,Analytical chemistry ,Radiology, Nuclear Medicine and imaging ,Hematology ,Gamma ray detection - Published
- 2020
33. Determination of Plutonium Isotopic Content by Microcalorimeter Gamma-Ray Spectroscopy.
- Author
-
Hoover, Andrew S., Winkler, Ryan, Rabin, Michael W., Vo, Duc T., Ullom, Joel N., Bennett, Douglas A., Doriese, William B., Fowler, Joseph W., Horansky, Robert D., Schmidt, Dan R., Vale, Leila R., and Schaffer, Kathryn
- Subjects
- *
PLUTONIUM , *CALORIMETERS , *GAMMA ray spectrometer , *GAMMA ray detectors , *SUPERCONDUCTING photodetectors - Abstract
Microcalorimeter detectors provide unprecedented energy resolution for gamma-ray spectroscopy. One application is measuring the isotopic composition of plutonium-bearing samples by non-destructive gamma-ray spectroscopy to support nuclear safeguards and nonproliferation efforts. When measured with conventional high-purity germanium (HPGe) detectors, data from these samples contain significant peak overlaps requiring spectral deconvolution for analysis. The improved energy resolution of the microcalorimeter detector reduces peak overlaps leading to improvement in the statistical error component of the total measurement uncertainty. In this paper, we describe analysis code that was developed for spectral peak fitting and isotopic content determination from microcalorimeter and HPGe data. We apply the code to data collected from several plutonium standards to quantify the improvement of the statistical error derived from the improved energy resolution. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
34. The Gamma-Ray Imaging Framework.
- Author
-
Benson, Austin R., Bandstra, Mark S., Chivers, Daniel H., Aucott, Timothy, Augarten, Ben, Bates, Cameron, Midvidy, Adam, Pavlovsky, Ryan, Siegrist, James, Vetter, Kai, and Yee, Ben
- Subjects
- *
GAMMA rays , *GAMMA ray detectors , *COMPUTER memory management , *ELECTROMAGNETIC waves , *IONIZING radiation - Abstract
The Gamma-Ray Imaging Framework (GRIF) is an open source (LGPL) software framework for creating real-time gamma-ray imaging applications. GRIF is written in C++ using Qt, and uses ROOT and the Boost Graph Library. GRIF provides automatic multi-threading and data management to make it easy to quickly develop power gamma-ray imagining applications. The model for application developers is built around the separation of data acquisition (DAQ) and analysis units. Users are expected to use the APIs for the DAQ and analysis units to build their applications. Memory and data are managed by GRIF, so the user does not need to worry about allocating and de-allocating memory for data or thread management and locking schemes. The user only needs to post data to and read data from the GRIF memory manager. GRIF uses XML configuration files for determining data dependences between DAQ and analysis units in the system. We will give an overview of the first release of GRIF, as well as show example applications that have been built using the framework. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
35. Study on Background Gamma-Ray Reduction Using a Compton Backscattering Coincidence Technique.
- Author
-
Takagi, Takashi, Watanabe, Kenichi, Yamazaki, Atsushi, and Uritani, Akira
- Subjects
- *
GAMMA rays , *MONTE Carlo method , *GAMMA ray detectors , *NUCLEAR counters , *SCINTILLATORS - Abstract
We proposed a Compton Backscattering Coincidence (CBC) Technique to reduce background gamma-rays. Properties of the CBC technique were investigated with the EGS5 Monte Carlo simulation code and basic experiments. In this method, a sensitive area can be confined between two detectors while in a conventional method a sensitive area can't be confined because the sensitivity decreases as the solid angle decreases. Two detector configurations using two \ LaBr3 scintillators or HPGe-pure \ CaF2 scintillators were tested to validate the feasibility of the proposed technique. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
36. Upgrade of the CMD-3 BGO Endcap Calorimeter.
- Author
-
Grigoriev, Dmitry Nikolaevich, Akhmetshin, Ravel R., Kazanin, Vassili F., Kuzmenko, Anastasia E., and Yudin, Yury V.
- Subjects
- *
CALORIMETERS , *PHOTODIODES , *SILICON , *MAGNETIC fields , *CRYSTALS - Abstract
The BGO endcap calorimeter was successfully operated in the CMD-2 detector at the VEPP-2M collider. It consists of 680 BGO crystals, each with a size of 25\times 25\times 150~mm^3, arranged in two identical endcaps, with a total weight of 450 kg. The light readout used vacuum phototriodes. The endcap calorimeter has been now upgraded to operate in the CMD-3 detector at the new VEPP-2000 collider. The major part of the endcap calorimeter, BGO crystals, remains the same. The main upgrade is the use of silicon PIN photodiodes and new electronics. The reason of changing a photosensitive device is a strong non-uniform magnetic field in the endcap calorimeter volume making the operation of the vacuum photosensitive devices impossible. We also had to reduce the space available for the endcap calorimeter. Hamamatsu PIN photodiodes S3590–08 were chosen as optimal devices as they are insensitive to magnetic fields and are both compact and stable. An order of magnitude larger capacitance of silicon photodiodes requires a design and production of the new custom electronics. The upgrade is expected to bring an overall improvement of the calorimeter parameters. The endcap calorimeter has been installed in the detector and operated during the data taking that started in 2010. Data analysis shows an improvement of the energy resolution compared to the CMD-2 detector. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
37. Trends and Patterns of Scintillator Nonproportionality.
- Author
-
Khodyuk, Ivan V. and Dorenbos, Pieter
- Subjects
- *
PHOTON detectors , *SCINTILLATORS , *OXIDES , *HALIDES , *REFRACTION (Optics) , *NUCLEAR science - Abstract
Data on the photon nonproportional response of 33 inorganic scintillation materials are systemized and analyzed. The main trends of nonproportionality for different groups of inorganic scintillators, especially for oxides and halides, are highlighted. The dependence of the shape and degree of photon nonproportional response versus chemical composition, dopant type, index of refraction and other fundamental properties of the materials is studied. Better proportionality appears to be correlated with higher index of refraction of the compound. Another related factor is the width of the valence band in halide compounds. With larger valence band width from fluorides, to chlorides, to bromides, and to iodides, a better proportionality is observed. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
38. Scintillation Properties of Transparent Ceramic Pr:LuAG for Different Pr Concentration.
- Author
-
Yanagida, Takayuki, Fujimoto, Yutaka, Kamada, Kei, Totsuka, Daisuke, Yagi, Hideki, Yanagitani, Takagimi, Futami, Yoshisuke, Yanagida, Satoko, Kurosawa, Shunsuke, Yokota, Yuui, Yoshikawa, Akira, and Nikl, Martin
- Subjects
- *
CERAMICS , *SINTERING , *SINGLE crystals , *SCINTILLATION counters , *GAMMA rays - Abstract
We manufactured transparent optical ceramic of Pr 0.2–1% doped Lu3Al5 O12 (Pr:LuAG) by the sintering method. We compare its optical and scintillation properties with the single crystal counterpart grown by the conventional Czochralski method. So far the scintillation ceramic of Pr:LuAG appeared inferior to its single crystal analog especially in terms of light yield. However, in the present case our ceramic Pr 0.25%-doped sample exhibited by 20% higher light yield compared to single crystal under \gamma-ray excitation. Furthermore, in the ceramic sample the slower scintillation decay components were suppressed and the defect related host emission as well. The optimized technology of optical ceramics thus appears very competitive to single crystals and opens great practical prospectives for the former materials in the field of fast scintillators. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
39. A Comprehensive Model to Predict the Timing Resolution of SiPM-Based Scintillation Detectors: Theory and Experimental Validation.
- Author
-
Seifert, Stefan, van Dam, Herman T., Vinke, Ruud, Dendooven, Peter, Lohner, Herbert, Beekman, Freek J., and Schaart, Dennis R.
- Subjects
- *
SCINTILLATION counters , *PHOTOMULTIPLIERS , *POSITRON emission tomography , *NUCLEAR medicine , *PROBABILITY density function - Abstract
Silicon photomultipliers (SiPMs) are expected to replace photomultiplier tubes (PMTs) in several applications that require scintillation detectors with excellent timing resolution, such as time-of-flight positron emission tomography (TOF-PET). However, the theory about the timing resolution of SiPM-based detectors is not yet fully understood. Here we propose a comprehensive statistical model to predict the timing resolution of SiPM-based scintillation detectors. It incorporates the relevant SiPM-related parameters (viz. the single cell electronic response, the single cell gain, the charge carrier transit time spread, and crosstalk) as well as the scintillation pulse rise and decay times, light yield, and energy resolution. It is shown that the proposed model reduces to the well-established Hyman model for timing with PMTs if the number of primary triggers (photoelectrons in case of a PMT) is Poisson distributed and crosstalk and electronic noise are negligible. The model predictions are validated by measurements of the coincidence resolving times (CRT) for 511 keV photons of two identical detectors as a function of SiPM bias voltage, for two different kinds of scintillators, namely LYSO:Ce and LaBr3:5%Ce. CRTs as low as 138\,ps \pm 2 ps FWHM for LYSO:Ce and 95\,ps \pm 3 ps FWHM for LaBr3:5%Ce were obtained, demonstrating the outstanding timing potential of SiPM-based scintillation detectors. These values were found to be in good agreement with the predicted CRTs of 140 ps FWHM and 95 ps FWHM, respectively. Utilizing the proposed model, it can be shown that the CRTs obtained in our experiments are mainly limited by photon statistics while crosstalk, electronic noise and signal bandwidth have relatively little influence. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
40. Study of the Effects of Edge Morphology on Detector Performance by Leakage Current and Cathodoluminescence.
- Author
-
Crocco, J., Bensalah, H., Zheng, Q., Dierre, F., Hidalgo, P., Carrascal, J., Vela, O., Piqueras, J., and Dieguez, E.
- Subjects
- *
NUCLEAR counters , *ELECTRIC leakage , *CATHODOLUMINESCENCE , *ELECTRIC resistance , *ZINC telluride , *COMPLEMENTARITY (Physics) , *SURFACE defects , *GAMMA ray spectrometry , *SURFACE roughness - Abstract
The Vertical Gradient Freeze (VGF) method has been used to grow high resistivity Cadmium Zinc Telluride (CZT) for high energy radiation applications. In this work, the effect of lapping and polishing the lateral edges of planar detectors is studied. Expectations that improved surface morphology of the edges should correlate with reduced surface leakage current are shown to be erroneous. The effect of various types of lateral edge treatments on detector performance was observed before and after each surface modification. Complementary results were obtained using I-V, Cathodoluminescence (CL), and gamma ray response measurements using 133Ba. As a result, a quick and easy method is reported which minimizes leakage current and actually enhances detector performance through the introduction of surface defects. It is demonstrated that the introduction of radiative recombination centers helps reduce surface leakage current in the detector by a factor of up to 200%, depending on the surface treatment. The purpose of this work is to identify material processing steps for fabricating planar devices based on CZT for gamma ray spectroscopy. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
41. Fabrication and Properties of Translucent SrI_2 and Eu:SrI_2 Scintillator Ceramics.
- Author
-
Podowitz, Stephen R., Gaume, Romain M., Hong, Wesley T., Laouar, Atlal, and Feigelson, Robert S.
- Subjects
- *
SCINTILLATION counters , *MICROFABRICATION , *CERAMIC materials , *STRONTIUM compounds , *GAMMA ray detectors , *GAMMA ray spectrometer , *IODIDES , *THERMAL analysis - Abstract
Preparation of SrI_2 and Eu:SrI_2 ceramics is reported on for the first time. Translucent ceramics were sintered by hot-pressing. Thermal analysis on SrI_2 and EuI_2 starting powders was used to identify dehydration temperatures and informed the choice of sintering conditions. Optical transmission was found to decrease with increasing temperature and time. Microstructure studies (grain size and texture) were used to evaluate variations in optical transmission between samples. Scintillation characterization was carried out on 5 wt% Eu:SrI_2 ceramics. X-ray radio-luminescence spectra showed both the characteristic Eu^2+ emission band and a lower-intensity, broad emission in the visible. Scintillation lifetimes were shorter than those previously reported for single-crystal samples, and afterglow was substantially lower. A light yield of 21 000 ph/MeV was calculated from the photopeaks under \gamma-irradiation. Like single-crystal samples, Eu:SrI_2 ceramics were found to have a very proportional response with \gamma-ray energy. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
42. Light Pulse Shapes in Liquid Scintillators Originating From Gamma-Rays and Neutrons.
- Author
-
Szczesniak, Tomasz, Moszynski, Marek, Syntfeld-Kazuch, Agnieszka, Swiderski, Łukasz, Wolski, Dariusz, Grodzicka, Martyna, Pausch, Guntram, Stein, Juergen Robert, Kniest, Frans, Kusner, Michael R., Schotanus, Paul, and Hurlbut, Chuckn
- Subjects
- *
LIQUID scintillators , *PARTICLES (Nuclear physics) , *THERMAL neutrons , *GAMMA ray detectors , *BORON , *PERFORMANCE evaluation , *DATA analysis , *ELECTRONIC pulse techniques - Abstract
Liquid scintillators loaded with boron-10 or lithium-6 are capable to detect gamma rays, fast neutrons and also thermal neutrons. One of the popular methods applied in order to distinguish events originating from different particles is the pulse shape discrimination (PSD). The previously presented study of boron-10 loaded liquid scintillators using the PSD method showed different discrimination performance in scintillators such as BC523A, BC523A2, EJ339A2 and EJ309B5. It triggered a further study of the light pulse shapes in these scintillators originating from events related to gamma rays, fast and thermal neutrons. The light pulse shapes, measured using the single photon method, were recorded together with the 2-dimensional n/gamma discrimination data. Next, the recorded light pulses were gated using energy and the PSD information to extract pulses characteristic of the only one kind of particles. Finally, the analysis of the light pulse shapes with multi-exponential fits and calculation of decay time constants and intensities of components were performed. The results were compared with the data obtained for liquid scintillators not sensitive to thermal neutrons BC501A, EJ301 and EJ309. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
43. Expanding the detection efficiency of silicon drift detectors
- Author
-
Schlosser, D.M., Lechner, P., Lutz, G., Niculae, A., Soltau, H., Strüder, L., Eckhardt, R., Hermenau, K., Schaller, G., Schopper, F., Jaritschin, O., Liebel, A., Simsek, A., Fiorini, C., and Longoni, A.
- Subjects
- *
SILICON diodes , *NUCLEAR counters , *FORCE & energy , *BACKGROUND radiation , *LIGHT sources , *GAMMA ray detectors , *SCINTILLATORS - Abstract
Abstract: To expand the detection efficiency Silicon Drift Detectors (SDDs) with various customized radiation entrance windows, optimized detector areas and geometries have been developed. Optimum values for energy resolution, peak to background ratio (P/B) and high count rate capability support the development. Detailed results on sensors optimized for light element detection down to Boron or even lower will be reported. New developments for detecting medium and high X-ray energies by increasing the effective detector thickness will be presented. Gamma-ray detectors consisting of a SDD coupled to scintillators like CsI(Tl) and LaBr3(Ce) have been examined. Results of the energy resolution for the 137Cs 662keV line and the light yield (LY) of such detector systems will be reported. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
44. Using a simple scintillator kit to experience gamma ray detection
- Author
-
Lorenzo Santi, Sergej Faletič, Marisa Michelini, and Mario Gervasio
- Subjects
Physics ,History ,Optics ,Simple (abstract algebra) ,business.industry ,Scintillator ,business ,Computer Science Applications ,Education ,Gamma ray detection - Abstract
A simple scintillator kit developed by Ian Bearden [1] was used to prepare a learning experience on gamma ray detection for secondary students. The goal is to offer an opportunity to collect gamma spectra, analyse data and understand how coincidence measurements are useful in space physics and in many other applications.
- Published
- 2021
45. Gamma‐Ray Detection Using Bi‐Poor Cs 2 AgBiBr 6 Double Perovskite Single Crystals (Advanced Optical Materials 8/2021)
- Author
-
Zheng Zhang, Ge Yang, Zhengjie Huang, Dali Sun, Evgeny O. Danilov, Da Cao, and Ching-Chang Chung
- Subjects
Materials science ,business.industry ,Optical materials ,Optoelectronics ,Double perovskite ,business ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Gamma ray detection - Published
- 2021
46. A Comparison of Fast Inorganic Scintillators for Thermal Neutron Analysis Landmine Detection.
- Author
-
McFee, J. E., Faust, A. A., Andrews, H. R., Kovaltchouk, V., Clifford, E. T., and Ing, H.
- Subjects
- *
SCINTILLATORS , *GAMMA ray detectors , *NUCLEAR counters , *GAMMASPHERE , *ENGINEERING instruments , *LUMINESCENCE , *NUCLEAR reactors , *IONIZING radiation , *ELECTROMAGNETIC waves , *PHYSICS instruments - Abstract
The Improved Landmine Detector System, a militarily fielded, teleoperated vehicle-mounted multi-sensor landmine detector, uses a thermal neutron analysis (TNA) detector to con- firm the presence of a mine by detecting the bulk nitrogen in its explosives. To improve the nitrogen sensitivity or measurement times of the TNA detector, higher gamma ray rates will be required. The chief bottleneck to achieving the maximum possible performance from the present TNA or future versions is the relatively slow fluorescent decay time of the NaI(Tl) scintillators which are currently used. An experimental investigation was undertaken to compare a number of modern, fast inorganic scintillators to NaI(Tl) with respect to parameters relevant to TNA landmine detection, including efficiency, energy resolution, linearity, avail- able size and cost. This paper presents results in the context of the high-rate, high-gamma-energy environments expected in such a TNA application. Large (7.62 cm x 7.62 cm) LaBr3 :Ce scintillators, and to a lesser degree LaCl3 :Ce, were found to stand-out as as the principal candidates for the detector upgrade to the TNA confirmation system. Their properties also make them ideal candidates for fast neutron analysis and associated particle imaging bulk explosives detectors. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
47. Algorithm Implementation for a Prototype Time-Encoded Signature Detector.
- Author
-
Mercier, Theresa M., Runkle, Robert C., Stephens, Daniel L., Hyronimus, Brian J., Morris, Scott J., Seifert, Allen, and Wyatt, Cory R.
- Subjects
- *
DETECTORS , *ALGORITHMS , *GAMMA rays , *CESIUM iodide , *SCINTILLATORS , *NOISE - Abstract
The authors constructed a prototype Time-Encoded Signature (TES) system, complete with automated detection algorithms that can be used to detect point-like gamma-ray sources in search applications where detectors observe large variability in background count rates beyond statistical (Poisson) noise. The person-carried system consists of two cesium iodide scintillators placed on opposite sides of a lead shield. This geometry mitigates systematic background variation and induces a unique signature upon encountering point-like sources. This manuscript focuses on the development of detection algorithms that identify point-source signatures while remaining computationally simple. The latter constraint derives from the instrument's mobile (and thus low power) operation. The authors evaluated algorithms using both simulated and field data. The results of this analysis demonstrate the capability to detect sources at a wide range of source-detector distances using computationally simple algorithms. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
48. High-Resolution Compton-Suppressed CZT and LaC13 Detectors for Fission Products Identification.
- Author
-
Aryaeinejad, Rahmat, Hartwell, John K., and Scates, Wade W.
- Subjects
- *
DETECTORS , *HIGH resolution spectroscopy , *FISSION products , *NUCLEAR fission , *RADIOACTIVE substances , *SEMICONDUCTORS - Abstract
Room-temperature semiconductor CdZnTe (CZT) detectors are currently limited to total detector volumes of 1-2 cm³, which is dictated by poor charge transport characteristics. Because of this size limitation, one of the problems in accurately determining isotope identification is the enormous background from Compton scattering events. Eliminating this background will not only increase the sensitivity and accuracy of measurements, but will also help to resolve peaks buried under the background and peaks in close vicinity to others. We are currently developing a fission products detection system based on Compton-suppressed CZT and LaCl3 (Ce) detectors. In this application, the detection system is required to operate in a high radiation field. Therefore, a small 10 mm × 10 mm × 5 mm CZT and Φ13 mm × 15 mm LaCl3 detector are placed inside the center of a well-shielded Φ76 mm by 76 mm long Na! detector. So far, we have been able to successfully reduce Compton background by a factor of 3.7 to 4.0 for a 137Cs spectrum. In this work, we will discuss the performance of this detection system using both CZT and La Cl3 detectors. The results are compared with MCNP calculations. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
49. Cadmium telluride and cadmium zinc telluride
- Author
-
Andrea Zappettini
- Subjects
Cadmium Telluride Cadmium Zinc Telluride Crystal growth Electrooptics Gamma-rays detectors Inclusions Infrared imaging Solar cells Thermal treatments X-ray detectors ,chemistry.chemical_compound ,Materials science ,chemistry ,business.industry ,Photovoltaics ,Optoelectronics ,business ,Cadmium telluride photovoltaics ,Gamma ray detection ,Cadmium zinc telluride - Abstract
CdTe and CdZnTe crystals are employed for several applications such as IR imaging, X- and gamma ray detection, optical devices, and photovoltaics. These applications require that crystals show peculiar properties. On the other hand, phase diagrams suggest possible growth technologies. In this chapter, the most important synthesis and growth technologies for CdTe and CdZnTe crystals are described together with the post-growth treatments that were adopted for improving material properties. Finally, state of the art of CdTe and CdZnTe crystals are reviewed, problems still open are evidenced and, thus, few indications about possible future developments are summarized.
- Published
- 2019
50. Upgrading Plan Towards Multi-messenger Observation with LHAASO
- Author
-
M.J. Chen, H.C. Li, Zhengguo Cao, and Z.G. Yao
- Subjects
Physics ,Sky ,media_common.quotation_subject ,QC1-999 ,Astronomy ,Detector array ,media_common ,Gamma ray detection - Abstract
LHAASO is planning to enhance its sensitivity at energies around 100 GeV by utilize MCP staffed 20” PMT in the Water Cherekove Detector Array. The effective area for gamma ray detection will reach to 1800 m2 and differential sensitivity to 0.2 CU at 50 GeV. It will be the very useful survey detection for transient phenomena at 50 GeV in the northern sky. LHAASO is expected to play an important role in the multimessenger observation with the upgrading.
- Published
- 2019
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