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arXiv 2023年

作者： Karmakar, Annesha Pal, Anikesh Kumar, G. Anil Bhavika Anand, V. Tyagi, Mohit Nuclear Engineering and Technology Program Indian Institute of Technology Kanpur India Department of Mechanical Engineering Indian Institute of Technology Kanpur India Radiation Detectors and Spectroscopy Laboratory Department of Physics Indian Institute of Technology Roorkee India Technical Physics Division Bhabha Atomic Research Centre Mumbai India

This study shows an implementation of neutron-gamma pulse shape discrimination (PSD) using a two-dimensional convolutional neural network. The inputs to the network are snapshots of the unprocessed, digitized signals from a BC501A detector. By exposing a BC501A detector to a Cf-252 source, neutron and gamma signals were collected to create a training dataset. The realistic datasets were created using a data-driven approach for labeling the digitized signals, having classified snapshots of neutron and gamma pulses. Our algorithm was able to successfully differentiate neutrons and gammas with similar accuracy as the CI approach. Additionally, the independent dataset accuracy for our suggested 2D CNN-based PSD approach is 99%. In contrast to the traditional charge integration method, our suggested algorithm with data augmentation, is capable of extracting features from snapshots of the raw data based on the signal structures, making it computationally more efficient and also appropriate for other types of neutron detectors. Copyright © 2023, The Authors. All rights reserved.

关键词： Neutrons

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Thickness Dependent Sensitivity of GAGG:Ce Scintillation detectors for Thermal Neutrons: GEANT4 Simulations and Experimental Measurements

arXiv

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arXiv 2023年

作者： Karmakar, Annesha Kumar, G. Anil Tyagi, Mohit Pal, Anikesh Nuclear Engineering and Technology Program Indian Institute of Technology Kanpur India Radiation Detectors and Spectroscopy Laboratory Department of Physics Indian Institute of Technology Roorkee India Technical Physics Division Bhabha Atomic Research Centre Mumbai India Department of Mechanical Engineering Indian Institute of Technology Kanpur India

In the present work, we report extensive GEANT4 simulations in order to study the dependence of sensitivity of GAGG:Ce scintillation crystal based detector on thickness of the crystal. All the simulations are made considering a thermalised Am-Be neutron source. The simulations are validated, qualitatively and quantitatively, by comparing the simulated energy spectra and sensitivity values with those obtained from experimental measurements carried out using two different thicknesses of the crystal from our own experiment (0.5mm and 3mm) and validated with three other thicknesses (0.01mm, 0.1 mm and 1 mm) from literature [1]. In this study, we define sensitivity of GAGG:Ce as the ratio of area under 77 keV sum peak to 45 keV peak. The present studies clearly confirm that, while it requires about 0.1 mm thickness for the GAGG:Ce crystal to fully absorb thermal neutrons, it requires about 3 mm to fully absorb the thermal neutron induced events. Further, we propose an equation, that can be used to estimate the thickness of the GAGG:Ce crystal directly from the observed sensitivity of the GAGG:Ce crystal. This equation could be very useful for the neutron imaging community for medical and space applications, as well as for manufactures of cameras meant for nuclear security purposes. Copyright © 2023, The Authors. All rights reserved.

关键词： Binary alloys

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Quantum frequency mixing using an N-V diamond microscope

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Physical Review Applied 2024年第6期22卷 064051-064051页

作者： Samuel J. Karlson Pauli Kehayias Jennifer M. Schloss Andrew C. Maccabe Adam Libson David F. Phillips Guoqing Wang Paola Cappellaro Danielle A. Braje Massachusetts Institute of Technology (MIT) Lincoln Laboratory Lexington Massachusetts 02421 USA Department of Nuclear Science and Engineering Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Current affiliation: Quantum Science and Engineering Program Harvard University Cambridge Massachusetts 02138 USA. Department of Physics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA

Wide-field magnetic microscopy using nitrogen-vacancy (N-V) centers in diamond can yield high-quality magnetic images of dc and ac magnetic fields. The unique combination of micron-scale spatial resolution of scalar or vector fields at room temperature and parallel camera readout make this an appealing technique for applications in biology, geology, condensed-matter physics, and electronics. However, while N-V magnetic microscopy has achieved great success in these areas, historically the accessible frequency range has been limited. In this paper, we overcome this limitation by implementing the recently developed technique of quantum frequency mixing. With this approach, we generate wide-field magnetic images of test structures driven by alternating currents up to 70 MHz, well outside the reach of dc and Rabi magnetometry methods. With further improvements, this approach could find utility in hyperspectral imaging for electronics power-spectrum analysis, electronics diagnostics and troubleshooting, and quantum computing hardware validation.

关键词： Quantum computers

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Quantifying Environmental Radiation: Comparative Analysis of Monitoring Tools in Indonesia's Highest Radiation Area

SSRN

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SSRN 2024年

作者： Abdullah, Adi Rahmansyah Amir Permana, Sidik Srigutomo, Wahyu Maulana, Alan Seno, Haryo Purnama, Dikdik Sidik Rasito Humolungo, Ismail Zulfahmi Doctoral Program in Nuclear Engineering Department Bandung Institute of Technology Jl. Ganesha No. 10 Bandung Indonesia Master Program in Nuclear Science and Engineering Department Bandung Institute of Technology Jl. Ganesha No. 10 Bandung Indonesia Physics Department Bandung Institute of Technology Jl. Ganesha No. 10 Bandung Indonesia Indonesia’s National Research and Inovation Agency Jl. Tamansari No. 71 Bandung Indonesia

We employed three radiation detection devices: NaI(Tl) Scintillator, Geiger Muller Counter (GMC), and Electronic Personal Dosimeter (EPD) in highest natural background radiastion area in Inonesia. Direct measurements conducted with these three devices were validated by measuring radionuclide activities in the soil using HPGe Gamma Spectrometry. Among these three devices, two of them measure ambient dose equivalent (H*(10)), while one measures personal dose equivalent (Hp(10)). The measurement results indicating average H*(10) values of 0.457 µSv/h from NaI(Tl) Scintillator data and 0.769 µSv/h from GMC data, while the average Hp(10) value measured by EPD shows 0.986 µSv/h. The measurement of H*(10) by GMC is 45% higher than that of the NaI(Tl) Scintillator. This difference is also evident from the degenerate 2D map, where GMC data highlights locations of high flux gamma ray anomalies more clearly. This suggests that both devices exhibit different efficiencies under high gamma radiation exposure, with GMC showing better efficiency. However, under conditions of high radiation exposure, phenomena such as saturation may affect the performance of the device. The difference in measurement results does not indicate that one device is superior to the other;the naturally high radiation exposure conditions in the research environment affect the performance of both devices. Meanwhile, in the measurement of Hp(10) by EPD, it was found that the Hp(10) readings are higher than H*(10), which should not happen considering Hp(10) depends on the incident angle of radiation. The EPD detector type allows for the detection of radiation at low energies, but if it is not calibrated at this energy level, it might cause overreading when lower energy radiation, such as X-rays, is detected. Dead time and saturation may occur in environments with high background radiation, causing the detector readings to be less than ideal. © 2024, The Authors. All rights reserved.

关键词： Gamma rays

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Highly Compact and Scalable 100 ps CTR + 3D Positioning TOF-PET Detector Sub-Unit

Highly Compact and Scalable 100 ps CTR + 3D Positioning TOF-...

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IEEE Symposium on nuclear Science (NSS/MIC)

作者： S. Pourashraf D. Innes J. W. Cates C. S. Levin Radiology Stanford University California United States of America Lawrence Berkeley National Laboratory Applied Nuclear Physics Program Berkeley California United States of America Bioengineering Physics and Electrical Engineering Stanford University California United States of America

We have developed a highly compact design for TOF-PET detector modules employing side-readout of scintillation crystal elements to achieve 100 ps CTR and 3D positioning of 511 keV interactions. Detector modules comprise 16 layers, each containing 4 sub-units. Each detector layer sub-unit is a 2×4 array of 3×3×10 mm 3 LGSO elements side-coupled to a 6×4 array of 3×3 mm² SiPMs. To achieve high packing fraction, the electronic readout is implemented with a 4-layer rigid FR4 PCB that is only 0.4 mm thick and has a width matching the 6×4 SiPM array (13.3 mm). Among many features, the circuit multiplexes 24 SiPM timing channels into 1 to reduce the readout complexity. In new configuration reported here, all external connectors have been removed and replaced with 0.4 mm pitch fine connectors for scalable signal routing at the detector module level. The timing performance of this 24:1 multiplexed readout was measured in coincidence with a reference detector, resulting in average 107±1.3 ps FWHM CTR. Thus the proposed side-readout of scintillation crystal elements and readout electronics are now configured in a layer topology and achieve the performance that are scalable to large area detector modules for a ~100 ps CTR TOF-PET system.

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Perovskite detectors for x-ray imaging and gamma spectroscopy: Overview and current state-of-The-Art 23

Perovskite detectors for x-ray imaging and gamma spectroscop...

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Hard X-Ray, Gamma-Ray, and Neutron Detector physics XXIII 2021

作者： Cao, Lei R. Pan, Lei Kandlakunta, Praneeth Nie, Wanyi Nuclear Engineering Program Department of Mechanical and Aerospace Engineering The Ohio State University ColumbusOH43210 United States Center for Integrated Nanotechnology Materials Physics and Application Division Los Alamos National Laboratory Los AlamosNM87545 United States

ISBN: (数字)9781510645158

ISBN: (纸本)9781510645141

Perovskites are a family of semiconductor materials with molecular formula ABX3 [where A+ = Cesium (Cs), methylammonium (MA or CH3NH3) or formamidinium (FA or CH(NH2)2), B-site is metal, and X-= chlorine (Cl), bromine (Br) or iodine (I)] that have recently seen a surged interest for X-ray and gamma-ray detection. The all inorganic version, CsPbBr3, grown by high temperature melt method has been demonstrated with an impressive gamma-ray energy resolution of 1.4%@662 keV, while the solution grown CsPbBr3 showed the best achievable resolution of 5.5% at the same energy from a 137Cs source. This paper gives an overview of the development of perovskite in both X-ray detection and gamma spectroscopy, including the most recent advancement with perovskite single crystal grown by low temperature inverse temperature method for solid-state X-ray detector. The crystal shows a decent long carrier diffusion length that is ideal for charge collection, while their mobilities are still not on par with CdZnTe. We also reported our most recent development on clarifying the concepts around X-ray detection limits. The X-ray sensitivity and the lowest detectable dose rate (i.e., X-ray detection limits) of several MAPbI3 detectors made of single crystal were experimentally measured. The best achieved X-ray sensitivity is ∼2.5E4 μC/Gyair/cm2 under 15.4 V/mm, which is comparable to the current state-of-The-Art MAPbI3based X-ray detectors (∼ 2.3E4 μC/Gyair/cm2 under 4.2 V/mm for GAMAPbI3 (GA=guanidinium) single crystal detector). The best achieved lowest detectable X-ray dose rate for the same MAPbI3 detector is ∼61 nGyair/s under 15.4 V/mm, and decreased to ∼24 nGyair/s under 3.8 V/mm. The good performance of the MAPbI3 detectors further proves their great potential as the next generation low-cost X-ray detector. © COPYRIGHT SPIE.

关键词： X ray detectors

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Dosimetric Investigation of Six Ru-106 Eye Plaques by EBT3 Radiochromic Films and Monte Carlo Simulation

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Journal of Biomedical physics and engineering 2023年第4期13卷 309-316页

作者： Arjmand, Mojtaba Ghassemi, Fariba Rafiepour, Payman Zeinali, Reyhaneh Riazi-Esfahani, Hamid Beiki-Ardakani, Akbar Ocular Oncology service Farabi Eye Hospital Tehran University of Medical Sciences Tehran Iran Retina & Vitreous Service Ocular Oncology Service Farabi Eye Hospital Tehran University of Medical Sciences Tehran Iran Department of Nuclear Engineering Shiraz University of Medical Sciences Shiraz Iran Department of Medical Physics Tabriz University of Medical Science Tabriz Iran Retina Service Farabi Eye Hospital Tehran University of Medical Sciences Tehran Iran Radiation Medicine Program Princess Margaret Cancer Centre University Health Network TorontoON Canada

Background: Ophthalmic brachytherapy using radioactive plaques is an effective technique for the treatment of uveal melanoma. Ru-106 eye plaques are considered as interesting issue due to their steep gradient dose. The pre-planning evaluation of dosimetric parameters is essential for the treatment planning system. Objective: The current study aims at providing dose distributions of six Ru-106 eye plaques (CCA, CCB, CGD, CIB, COB and COD) using radiochromic EBT3 film, Geant4 Monte Carlo toolkit and the treatment planning software (Plaque Simulator). Material and Methods: In this experimental study, an in house phantom was employed for depth dose measurements with EBT3 films. Also, Geant4.10.5 scoring mesh was implemented to obtain the 2D dose distribution of the plaques. The results were compared with Plaque Simulator software and the manufacturer’s (BEBIG) data. The gamma index criterion (3%/3 mm) was used to evaluate dose distributions obtained by the film measurements and Geant4 simulation. Results: A good agreement was achieved between simulation and experimental re-sults. Gamma index passing rate was 94.2%, 89.3%, 88.2%, 82.2%, 92.2% and 90.1% for CCA, CCB, CGD, CIB, COB and COD plaques, respectively. Absolute dose rate (mGy/ min) obtained by EBT3 film at the depth of 2 mm was 79.4 mGy/min, 81.0 mGy/min, 78.6 mGy/min, 62.2 mGy/min, 75.2 mGy/min and 81.2 mGy/min for CCA, CCB, CGD, CIB, COB and COD plaques, respectively. Conclusion: The measured dose distributions and lateral dose profiles may be utilized in the treatment planning system to cover clinical volumes such as the clinical target volume and the gross tumor volume. © 2023, Shiraz University of Medical Sciences. All rights reserved.

关键词： Monte Carlo methods

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Radon exhalation rate from the latex pillows and its potential exposure to users

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Radiation Medicine and Protection 2024年第4期5卷 238-242页

作者： Phachirarat Sola Kanokporn Boonsirichai Santi Raksawong Ritiron Samran Pimprapa Chaijak Hirofumi Tazoe Chutima Kranrod Rawiwan Kritsananuwat Sattawat Jongjitklang Vichai Puripunyavanich Masahiro Hosoda Waleeporn Pongkua Shinji Tokonami Thailand Institute of Nuclear Technology(Public Organization) Sai MunOngkharakNakhon Nayok26120Thailand Physics Program Faculty of Science and TechnologyMuban Chombueng Rajabhat UniversityRatchaburi70150Thailand Department of Biology Faculty of ScienceThaksin UniversityPhatthalung93210Thailand Institute of Radiation Emergency Medicine Hirosaki UniversityHirosaki Aomori036-8564Japan Nuclear Engineering Chulalongkorn UniversityPatumwanBangkok10330Thailand

Objective:To develop a new system to accurately measure the radon exhalation from the latex pillows,and to estimate its potential exposure to ***:The new system is composed of two loops,the first loop is designed to trap background radon and thoron until their levels are nearly zero,and the second loop is the measurement loop to detect radon and thoron exhalation rates from the ***:The results showed that mass radon exhalation rated ranged from 0.18 Bq·kg^(-1)·h^(-1) to 0.78 Bq·kg^(-1)·h^(-1),with an average of(0.36±0.17)Bq·kg^(-1)·h^(-1) in the 9 *** average annual effective dose to users in a model room was estimated to be(15.51±12.69)μSv by assuming two pillows was ***:These results demonstrate that the new system can effectively measure radon exhalation rates in latex pillows,and the potential exposure to radon exhalating from the pillows is very low.

关键词： Radon exhalation Latex pillow Annual effective dose

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Internal dose assessment of lymphoma 18F-FDG Positron Emission Tomography (PET) scan

Internal dose assessment of lymphoma 18F-FDG Positron Emissi...

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2023 National physics Seminar, SNF 2023

作者： Murat, H. Karim, M.K.A. Kechik, M.M.A. Amer, M.F. Razak, H.R.A. Kamal, I. Chew, M.T. Department of Physics Faculty of Science Universiti Putra Malaysia Selangor Serdang Malaysia Department of Nuclear Medicine Hospital Sultanah Aminah Johor Bahru Johor Malaysia Medical Imaging Program College of Medicine and Health St Luke's Campus University of Exeter DevonEX1 2LU United Kingdom Medical Imaging Department KPJ Healthcare University Nilai Negeri Sembilan Malaysia Research Centre for Applied Physics and Radiation Technologies School of Engineering and Technology Sunway University Petaling Jaya Malaysia

This study aimed to assess the internal radiation exposure of patients who have undergone a Positron Emission Tomography (PET) scan using 18F-FDG radiopharmaceutical. A total of 24 patients (8 men, 16 women, with an average age of 43.88 ± 18.57 years and weight of 57.54 ± 13.04 kg) who had been diagnosed with lymphoma were administered with 300.80 ± 23.09 MBq of 18F-FDG for a PET scan of the whole body. The IDAC-Dose 2.1 program, developed by the International Commission on Radiological Protection (ICRP), was used to measure absorbed and effective doses. The organs selected for absorbed dose analysis were the breast, kidneys, adrenals, liver, and brain, with the brain receiving the highest absorbed dose and the breast receiving the lowest absorbed dose. The effective dose for all patients was 4.85 ± 0.37 mSv, and the ratio of the effective dose to the administered activity was 1.611 × 10-2 mSv/MBq. The safety of the current practice using 18F-FDG PET scan was ascertained, given that the ratio of effective dose to administered activity was lower than 1.9 x 10-2 mSv/MBq. © Published under licence by IOP Publishing Ltd.

关键词： Positron emission tomography

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Dynamic Time-Over-Threshold Readout for Improved Energy Linearity in PET Detectors that Achieve 100 ps CTR

Dynamic Time-Over-Threshold Readout for Improved Energy Line...

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2021 IEEE nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2021

作者： Pourashraf, Shirin Gonzalez-Montoro, Andrea Cates, Joshua W. Zhao, Zhixiang Won, Jun Yeon Sung Lee, Jae Levin, Craig S. Stanford University Department of Radiology StanfordCA94305 United States Berkeley National Laboratory Applied Nuclear Physics Program at Lawrence BerkeleyCA94720 United States Shanghai Jiao Tong University School of Biomedical Engineering Shanghai China Seoul National University Department of Nuclear Medicine and Biomedical Sciences Seoul110-744 Korea Republic of Stanford University Molecular Imaging Program Departments of Radiology Bioengineering Physics and Electrical Engineering StanfordCA94305 United States

ISBN: (纸本)9781665421133

We have embedded a dynamic time-over-threshold (DynTOT) block in our scalable TOF-PET detector readout electronics to linearize the multiplexed energy spectra while keeping 100 ps FWHM Coincidence Time Resolution (CTR) performance. This DynTOT block is constructed by off-the-shelve components and consumes only 20 mW power per detector 'layer' in our design. Using 3×3×10 mm3 "LGSO"crystals coupled to arrays of 3×3 mm² SiPMs, energy resolution of 13.8±0.1%, 13.9±0.3%, and 17.1±0.6% were experimentally achieved for conventional pulse height, DynTOT, and conventional TOT methods, respectively. Including the DynTOT method, coincidence data were experimentally acquired using a low jitter FPGA-based TDC, and 103.6 ± 1.1 ps FWHM CTR was achieved, demonstrating the robustness of our novel and scalable timing electronic chain. © 2021 IEEE.

关键词： Medical imaging

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