In the field of nuclear radiation detection, sodium iodide (NaI(Tl)) and lanthanum bromide (LaBr<sub>3</sub>) are the primary scintillation crystals used for energy spectrum detectors. Furthermore, energy ...In the field of nuclear radiation detection, sodium iodide (NaI(Tl)) and lanthanum bromide (LaBr<sub>3</sub>) are the primary scintillation crystals used for energy spectrum detectors. Furthermore, energy spectrum detectors based on gadolinium gallium aluminum garnet (Ce:GAGG) scintillation crystals are minor. In this work, a 1-inch Ce:GAGG and Silicon Photomultipliers (SiPMs) are employed to construct a detector, and the coupled medium was silicone oil. An optimal SiPMs quantity scheme for the energy resolution was determined by varying the number of SiPMs coupled to Ce:GAGG and studying the effect of the different number of SiPMs on the energy resolution of the detector. Energy-resolution contrast experiments between Ce:GAGG and NaI(Tl) were performed using this scheme. The experimental results demonstrate that increasing the number of SiPMs enhances the energy resolution of the detector significantly. Notably, the energy resolution of the Ce:GAGG detector is comparable to that of the NaI(Tl) detector. Additionally, both detectors exhibit an energy linearity exceeding 99.9%. .展开更多
A newly developed digital data acquisition system,which is based on the digital pulse processor Pixie-16 modules by XIA LLC,was tested with the c-ray detector array of the China Institute of Atomic Energy using the cr...A newly developed digital data acquisition system,which is based on the digital pulse processor Pixie-16 modules by XIA LLC,was tested with the c-ray detector array of the China Institute of Atomic Energy using the cray source and in-beam c-rays.A comparison between this digital data acquisition system and the conventional analog data acquisition system was made.At a low count rate,both systems exhibit good and comparable energy resolutions.At a high count rate above 8.8 k/s,while the energy resolution obtained by the analog system deteriorates significantly,the energy resolution obtained by the digital system is nearly unchanged.Meanwhile,experimental data with higher statistics can be collected by the digital system.The advantage of this digital system over the conventional analog system can be ascribed to its excellent capability of handling pile-up pulses at higher count rates,and the fact that it has nearly no dead time in data transmission and conversion.展开更多
Measurements of the potassium content of samples of food, performed with High Purity Germanium detectors, are presented in this paper. The potassium content was measured by identifying the 1460 keV photons produced in...Measurements of the potassium content of samples of food, performed with High Purity Germanium detectors, are presented in this paper. The potassium content was measured by identifying the 1460 keV photons produced in the decay of the isotope 40K. Samples were selected, for which a high potassium content was expected. The measurements confirmed the expectations qualitatively, but not always quantitatively. Especially the expected dependence of the potassium content of chocolate on the listed percentage of cacao could not be confirmed.展开更多
Various methods are available for calculating the TOC of shale reservoirs with logging data, and each method has its unique applicability andaccuracy. So it is especially important to establish a regional experimental...Various methods are available for calculating the TOC of shale reservoirs with logging data, and each method has its unique applicability andaccuracy. So it is especially important to establish a regional experimental calculation model based on a thorough analysis of their applicability.With the Upper Ordovician Wufeng Fm-Lower Silurian Longmaxi Fm shale reservoirs as an example, TOC calculation models were built by useof the improved DlgR, bulk density, natural gamma spectroscopy, multi-fitting and volume model methods respectively, considering the previousresearch results and the geologic features of the area. These models were compared based on the core data. Finally, the bulk density method wasselected as the regional experimental calculation model. Field practices demonstrated that the improved DlgR and natural gamma spectroscopymethods are poor in accuracy;although the multi-fitting method and bulk density method have relatively high accuracy, the bulk density methodis simpler and wider in application. For further verifying its applicability, the bulk density method was applied to calculate the TOC of shalereservoirs in several key wells in the Jiaoshiba shale gas field, Sichuan Basin, and the calculation accuracy was clarified with the measured dataof core samples, showing that the coincidence rate of logging-based TOC calculation is up to 90.5%-91.0%.展开更多
This study presents a mathematical model for the peak efficiency of a coaxial high-purity germanium detector using the Monte Carlo code(MCNP),based on data provided by the manufacturer.Consequently,the detector’s mod...This study presents a mathematical model for the peak efficiency of a coaxial high-purity germanium detector using the Monte Carlo code(MCNP),based on data provided by the manufacturer.Consequently,the detector’s model is optimized using a trial-and-error methodology,either by increasing/decreasing the dead layer thickness,aligning the peak efficiency results with experimental measurements.Results indicate that,over 15 years of continuous operation,the dead layer is approximately twice as thick as initially quoted by the manufacturer.Therefore,the dead layer results would confirm that it is crucial to regularly optimize the dead layer over time,as the operator needs to address potential occasional changes.The results indicate that the optimized MC model is suitable for calculating the activity of point/volumetric radioactive sources,with relative errors of 4.40 and 3.23%,respectively.Moreover,this work discusses the different factors that affect the accuracy of the absolute efficiency calibration of gamma spectrometers.展开更多
We used the PW high-repetition laser facility VEGA-3 at Centro de Láseres Pulsados in Salamanca,with the goal of studying the generation of radioisotopes using laser-driven proton beams.Various types of targets h...We used the PW high-repetition laser facility VEGA-3 at Centro de Láseres Pulsados in Salamanca,with the goal of studying the generation of radioisotopes using laser-driven proton beams.Various types of targets have been irradiated including in particular several targets containing boron to generateα-particles through the hydrogen–boron fusion reaction.We have successfully identifiedγ-ray lines from several radioisotopes created by irradiation using lasergeneratedα-particles or protons including^(43)Sc,^(44)Sc,^(48)Sc,^(7)Be,^(11)C and^(18)F.We show that radioisotope generation can be used as a diagnostic tool to evaluateα-particle generation in laser-driven proton–boron fusion experiments.We also show the production of^(11)C radioisotopes,≈6×10~6,and of^(44)Sc radioisotopes,≈5×10~4per laser shot.This result can open the way to develop laser-driven radiation sources of radioisotopes for medical applications.展开更多
文摘In the field of nuclear radiation detection, sodium iodide (NaI(Tl)) and lanthanum bromide (LaBr<sub>3</sub>) are the primary scintillation crystals used for energy spectrum detectors. Furthermore, energy spectrum detectors based on gadolinium gallium aluminum garnet (Ce:GAGG) scintillation crystals are minor. In this work, a 1-inch Ce:GAGG and Silicon Photomultipliers (SiPMs) are employed to construct a detector, and the coupled medium was silicone oil. An optimal SiPMs quantity scheme for the energy resolution was determined by varying the number of SiPMs coupled to Ce:GAGG and studying the effect of the different number of SiPMs on the energy resolution of the detector. Energy-resolution contrast experiments between Ce:GAGG and NaI(Tl) were performed using this scheme. The experimental results demonstrate that increasing the number of SiPMs enhances the energy resolution of the detector significantly. Notably, the energy resolution of the Ce:GAGG detector is comparable to that of the NaI(Tl) detector. Additionally, both detectors exhibit an energy linearity exceeding 99.9%. .
基金supported by the National Key R&D Program of China(No.2018YFA0404403)the National Natural Science Foundation of China(Nos.12035001,12075006,11675003)the State Key Laboratory of Nuclear Physics and Technology,PKU(No.NPT2020KFY18)。
文摘A newly developed digital data acquisition system,which is based on the digital pulse processor Pixie-16 modules by XIA LLC,was tested with the c-ray detector array of the China Institute of Atomic Energy using the cray source and in-beam c-rays.A comparison between this digital data acquisition system and the conventional analog data acquisition system was made.At a low count rate,both systems exhibit good and comparable energy resolutions.At a high count rate above 8.8 k/s,while the energy resolution obtained by the analog system deteriorates significantly,the energy resolution obtained by the digital system is nearly unchanged.Meanwhile,experimental data with higher statistics can be collected by the digital system.The advantage of this digital system over the conventional analog system can be ascribed to its excellent capability of handling pile-up pulses at higher count rates,and the fact that it has nearly no dead time in data transmission and conversion.
文摘Measurements of the potassium content of samples of food, performed with High Purity Germanium detectors, are presented in this paper. The potassium content was measured by identifying the 1460 keV photons produced in the decay of the isotope 40K. Samples were selected, for which a high potassium content was expected. The measurements confirmed the expectations qualitatively, but not always quantitatively. Especially the expected dependence of the potassium content of chocolate on the listed percentage of cacao could not be confirmed.
基金National Key Science&Technology Project“Shale Gas Resource Evaluation and Regional Selection in Upper Yangtze and Dian(Yunnan)-Qian(Guizhou)-Gui(Guangxi)”(No.14B12XQ151001).
文摘Various methods are available for calculating the TOC of shale reservoirs with logging data, and each method has its unique applicability andaccuracy. So it is especially important to establish a regional experimental calculation model based on a thorough analysis of their applicability.With the Upper Ordovician Wufeng Fm-Lower Silurian Longmaxi Fm shale reservoirs as an example, TOC calculation models were built by useof the improved DlgR, bulk density, natural gamma spectroscopy, multi-fitting and volume model methods respectively, considering the previousresearch results and the geologic features of the area. These models were compared based on the core data. Finally, the bulk density method wasselected as the regional experimental calculation model. Field practices demonstrated that the improved DlgR and natural gamma spectroscopymethods are poor in accuracy;although the multi-fitting method and bulk density method have relatively high accuracy, the bulk density methodis simpler and wider in application. For further verifying its applicability, the bulk density method was applied to calculate the TOC of shalereservoirs in several key wells in the Jiaoshiba shale gas field, Sichuan Basin, and the calculation accuracy was clarified with the measured dataof core samples, showing that the coincidence rate of logging-based TOC calculation is up to 90.5%-91.0%.
文摘This study presents a mathematical model for the peak efficiency of a coaxial high-purity germanium detector using the Monte Carlo code(MCNP),based on data provided by the manufacturer.Consequently,the detector’s model is optimized using a trial-and-error methodology,either by increasing/decreasing the dead layer thickness,aligning the peak efficiency results with experimental measurements.Results indicate that,over 15 years of continuous operation,the dead layer is approximately twice as thick as initially quoted by the manufacturer.Therefore,the dead layer results would confirm that it is crucial to regularly optimize the dead layer over time,as the operator needs to address potential occasional changes.The results indicate that the optimized MC model is suitable for calculating the activity of point/volumetric radioactive sources,with relative errors of 4.40 and 3.23%,respectively.Moreover,this work discusses the different factors that affect the accuracy of the absolute efficiency calibration of gamma spectrometers.
基金supported by COST(European Cooperation in Science and Technology)through Action CA21128 PROBONO(PROton BOron Nuclear Fusion:from energy production to medical applicati Ons)funding from the European Union’s 2020 research and innovation program under grant agreement No.101008126(RADNEXT project)United States Department of Energy under grant#DEFG02-93ER40773+3 种基金SMILEI simulations were performed thanks to granted access to the HPC resources of TGCC under allocation No.2023-A0140514117 made by GENCIfinancial support of the Id Ex University of Bordeaux/Grand Research Program‘GPR LIGHT’and of the Graduate Program on Light Sciences and Technologies of the University of BordeauxL.G.and V.K.acknowledge the support of the Czech Science Foundation through grant No.GACR24-11398Ssupport of HB11 Energy,Ltd.,Australia,through its Collaborative Science Program.H.L.and M.H.
文摘We used the PW high-repetition laser facility VEGA-3 at Centro de Láseres Pulsados in Salamanca,with the goal of studying the generation of radioisotopes using laser-driven proton beams.Various types of targets have been irradiated including in particular several targets containing boron to generateα-particles through the hydrogen–boron fusion reaction.We have successfully identifiedγ-ray lines from several radioisotopes created by irradiation using lasergeneratedα-particles or protons including^(43)Sc,^(44)Sc,^(48)Sc,^(7)Be,^(11)C and^(18)F.We show that radioisotope generation can be used as a diagnostic tool to evaluateα-particle generation in laser-driven proton–boron fusion experiments.We also show the production of^(11)C radioisotopes,≈6×10~6,and of^(44)Sc radioisotopes,≈5×10~4per laser shot.This result can open the way to develop laser-driven radiation sources of radioisotopes for medical applications.
