A relatively new branch of science-nuclear forensics,aiming at providing the nature,origin,history and possible trafficking route of seized nuclear materials/devices,has been established and rapidly developed over dec...A relatively new branch of science-nuclear forensics,aiming at providing the nature,origin,history and possible trafficking route of seized nuclear materials/devices,has been established and rapidly developed over decades to screen illicit nuclear activities.This highly interdisciplinary science is built upon a foundation of analytical chemistry,radiochemistry,nuclear physics,material sciences,geology,and other scientific disciplines,within which radiochemical methodologies and radioanalytical techniques play a key role.The present review provides a brief overview about the crucial aspects of nuclear forensics,including basic content,procedure,concerned elements,common separation,analytical method,and so on.The state of the art and recent progresses of nuclear forensics by research communities in China are reviewed,while selected examples and practical applications are emphasized.The challenges associated with this new area and on-going developments are highlighted and discussed.展开更多
Purpose The Germanium Gamma-ray Imager(GeGI)is a planar high-purity germanium(HPGe)imaging detector developed by PHDS Co for far-field imaging.This research investigates the detector’s ability for measuring heterogen...Purpose The Germanium Gamma-ray Imager(GeGI)is a planar high-purity germanium(HPGe)imaging detector developed by PHDS Co for far-field imaging.This research investigates the detector’s ability for measuring heterogeneous sources in the near field,placed directly on the detector’s faceplate,to perform isotopic mapping for nuclear forensic missions.Methods The intrinsic efficiency is strongly dependent on where the photons interact within the germanium.The efficiency varies by up to 20%within the sensitive volume of the detector.The efficiency was mapped using eight different photons from 123 to 1274 keV emitted from a collimated 154Eu photons.These were measured at 108 locations to interpolate the efficiency at any point on the detector’s face.Results The position and energy dependence are uncorrelated,and thus,the absolute efficiency at any position and for any gamma-ray energy can be calculated by the convolution of the spatial and energy efficiencies.Conclusion The results on this research show that detection efficiency for a planar two-sided strip HPGe is spatially dependent and shows typical energy dependence.The spatial dependence,which does not have any additional energy dependence,can be corrected.A 154Eu source was used in this research and was able to spatially calibrate for photon energies ranging from 100 to 1300 keV.This method is applicable for sources with higher gamma energies.The advantages of the method demonstrated that after initial in-laboratory calibration,a single measurement in the field can be used to efficiently calibrate the HPGe as a function of photon interaction on the crystal.展开更多
Purpose The performance of a scintillation detector based on an MAPD-type SiPM and LaBr_(3)(Ce)for detecting gamma rays over a wide energy range is investigated.Methods This paper proposes the use of an MAPD-type SiPM...Purpose The performance of a scintillation detector based on an MAPD-type SiPM and LaBr_(3)(Ce)for detecting gamma rays over a wide energy range is investigated.Methods This paper proposes the use of an MAPD-type SiPM with a pixel pitch of 15μm,a total pixel number of 1,063,877 pixels and a PDE of 30% for the preparation of scintillation detectors operating in a wide energy range.The scintillation detectors prepared with this method can theoretically detect gamma rays with an energy of 25 MeV.Results The performance of a LaBr_(3)(Ce)-based scintillation detector with a 16-element MAPD array was characterized for gamma-ray spectroscopy in the 0.1-7 MeV range.The detector exhibited excellent linearity and high energy resolution,successfully resolving the 1.173 MeV,1.332 MeV,and 1.460 MeV gamma lines with resolutions of 3.45%,3.11%,and 1.99%,respectively.It also identified multiple gamma-ray peaks from thermal neutron capture reactions induced by an AmBe source,detecting emissions from hydrogen,sodium,chlorine,and carbon.Despite challenges related to scintillator size and low gamma-ray intensity,the detector effectively provided spectral information on various elements.Conclusion The study demonstrates the potential of the LaBr_(3)(Ce)-MAPD scintillation detector for high-resolution gamma-ray spectroscopy over a broad energy range.The detector's excellent linearity,high light output,and ability to resolve multiple gamma-ray peaks make it a promising candidate for applications in industry,space exploration,and security.Future improvements,such as increasing the LaBr_(3)(Ce)scintillator size and investigating higher-density scintillators like BGO and LSO,could further enhance its performance,enabling even more precise and efficient gamma-ray detection.展开更多
基金the financial support from the Science Challenge Project(No.TZ2016004)National Natural Science Foundation of China(No.21906153)the Presidential Foundation of CAEP(No.YZJJLX2020002)。
文摘A relatively new branch of science-nuclear forensics,aiming at providing the nature,origin,history and possible trafficking route of seized nuclear materials/devices,has been established and rapidly developed over decades to screen illicit nuclear activities.This highly interdisciplinary science is built upon a foundation of analytical chemistry,radiochemistry,nuclear physics,material sciences,geology,and other scientific disciplines,within which radiochemical methodologies and radioanalytical techniques play a key role.The present review provides a brief overview about the crucial aspects of nuclear forensics,including basic content,procedure,concerned elements,common separation,analytical method,and so on.The state of the art and recent progresses of nuclear forensics by research communities in China are reviewed,while selected examples and practical applications are emphasized.The challenges associated with this new area and on-going developments are highlighted and discussed.
文摘Purpose The Germanium Gamma-ray Imager(GeGI)is a planar high-purity germanium(HPGe)imaging detector developed by PHDS Co for far-field imaging.This research investigates the detector’s ability for measuring heterogeneous sources in the near field,placed directly on the detector’s faceplate,to perform isotopic mapping for nuclear forensic missions.Methods The intrinsic efficiency is strongly dependent on where the photons interact within the germanium.The efficiency varies by up to 20%within the sensitive volume of the detector.The efficiency was mapped using eight different photons from 123 to 1274 keV emitted from a collimated 154Eu photons.These were measured at 108 locations to interpolate the efficiency at any point on the detector’s face.Results The position and energy dependence are uncorrelated,and thus,the absolute efficiency at any position and for any gamma-ray energy can be calculated by the convolution of the spatial and energy efficiencies.Conclusion The results on this research show that detection efficiency for a planar two-sided strip HPGe is spatially dependent and shows typical energy dependence.The spatial dependence,which does not have any additional energy dependence,can be corrected.A 154Eu source was used in this research and was able to spatially calibrate for photon energies ranging from 100 to 1300 keV.This method is applicable for sources with higher gamma energies.The advantages of the method demonstrated that after initial in-laboratory calibration,a single measurement in the field can be used to efficiently calibrate the HPGe as a function of photon interaction on the crystal.
基金supported by the Azerbaijan Science Foundation-Grant №AEF-MGC-2024-2(50)-16/04/1-M-04received funding from the European Union’s Horizon 2021 Research and Innovation Programme under the Marie Sklodowska-Curie’s INNMEDSCAN project(grant agreement ID 101086178).
文摘Purpose The performance of a scintillation detector based on an MAPD-type SiPM and LaBr_(3)(Ce)for detecting gamma rays over a wide energy range is investigated.Methods This paper proposes the use of an MAPD-type SiPM with a pixel pitch of 15μm,a total pixel number of 1,063,877 pixels and a PDE of 30% for the preparation of scintillation detectors operating in a wide energy range.The scintillation detectors prepared with this method can theoretically detect gamma rays with an energy of 25 MeV.Results The performance of a LaBr_(3)(Ce)-based scintillation detector with a 16-element MAPD array was characterized for gamma-ray spectroscopy in the 0.1-7 MeV range.The detector exhibited excellent linearity and high energy resolution,successfully resolving the 1.173 MeV,1.332 MeV,and 1.460 MeV gamma lines with resolutions of 3.45%,3.11%,and 1.99%,respectively.It also identified multiple gamma-ray peaks from thermal neutron capture reactions induced by an AmBe source,detecting emissions from hydrogen,sodium,chlorine,and carbon.Despite challenges related to scintillator size and low gamma-ray intensity,the detector effectively provided spectral information on various elements.Conclusion The study demonstrates the potential of the LaBr_(3)(Ce)-MAPD scintillation detector for high-resolution gamma-ray spectroscopy over a broad energy range.The detector's excellent linearity,high light output,and ability to resolve multiple gamma-ray peaks make it a promising candidate for applications in industry,space exploration,and security.Future improvements,such as increasing the LaBr_(3)(Ce)scintillator size and investigating higher-density scintillators like BGO and LSO,could further enhance its performance,enabling even more precise and efficient gamma-ray detection.
