The assessment of activated concrete is particularly difficult during the decommissioning of an accelerator facility.Destructive analysis by core boring is the only method of investigating the activity of concrete mat...The assessment of activated concrete is particularly difficult during the decommissioning of an accelerator facility.Destructive analysis by core boring is the only method of investigating the activity of concrete material.To address this problem,an in-situ and nondestructive analysis method was developed to determineγ-ray-emitting nuclides and their specific activities in the concrete walls and floor by using a portable germanium semiconductor detector.In this work,we examined a substitute for Ge detector to establish a simpler and more convenient method.As candidates,we focused on some scintillation type spectrometers,and the possibility of a substitute for a Ge detector was examined by both simulation and experiment.The detection limits were roughly estimated through Monte Carlo simulation for various scintillation crystals,and it was found that 1.5-inch LaBr3,CeBr3,and SrI2 could distinguish the clearance level.It was confirmed that the 1.5-inch LaBr3 could reproduce the calibration curve of the Ge detector in the experiment.The required thickness and length of the radiation shield for suppressing the background radiation during the measurement was also determined for the convenience of an actual decommissioning work.展开更多
The paper builds the high-current plasma beams model under different dimensions (1D, 2D, and 3D) by continuum (magnetohydrodynamics MHD) and statistical (Monte Carlo MC) mechanics under conditions of low pressures (10...The paper builds the high-current plasma beams model under different dimensions (1D, 2D, and 3D) by continuum (magnetohydrodynamics MHD) and statistical (Monte Carlo MC) mechanics under conditions of low pressures (10<sup>-3</sup> Pa). After detailed presentation of the model, two methods firstly have been analyzed in terms of plasma beam properties. Then, we compare the simulation results of MHD numerical simulation with MC stochastic particles simulation. Finally, through further analysis, it is demonstrated that integrated hybrid MHD and MC method (IMHDMC) provides an innovative practical tool to capture essential properties of high-current plasma beams.展开更多
To estimate the physical dose of skin and key organs in a case of overexposure during a cardiac interventional procedure.Methods The female patient aged 50 suffered from owerexposure during ardiac interventional thera...To estimate the physical dose of skin and key organs in a case of overexposure during a cardiac interventional procedure.Methods The female patient aged 50 suffered from owerexposure during ardiac interventional therapy in a hospital,Xinxiang city,Henan province,China in January 2020.The mesh-type phantom for the patient was constructed based on the adult mesh-type reference computational phantoms(MRCPs)released by the International Comission on Radiological Protection Publication 145 (ICRP145)and phantom deformation technology.Models of exposure scenario were constructed and simulated with particle and heavy ion transport code system(PHTTS)according to exposure conditions.Resuts:The maximum absorbed dose of key organs/tissues under iradiation in posteroanterior(PA)and 30°left anterior oblique directions(LOA)was 632.4 and 305.6 mGy,respectively.The let lung,heart,and left mammary gland received a larger dose under both iradiation conditions.The ratio of the absorbed dose with and without shielding was a lculated,and the relative difference in most organs was<1%between two directions.The iso-dose curve of the back skin revealed the ditribution of the absorbed dose(0.1-5.2 Gy).The dose estimate of key tssues/organs was higher than the conventional level,especially the local skin,up to 5.2 Gy.Concusions The interventional procedure in this ase resulted in a higher dose.Monte Carlo codes combined with the MRCPs can be employed to estimate physical dose to individuals in concrete irradia tion scenarios.展开更多
文摘The assessment of activated concrete is particularly difficult during the decommissioning of an accelerator facility.Destructive analysis by core boring is the only method of investigating the activity of concrete material.To address this problem,an in-situ and nondestructive analysis method was developed to determineγ-ray-emitting nuclides and their specific activities in the concrete walls and floor by using a portable germanium semiconductor detector.In this work,we examined a substitute for Ge detector to establish a simpler and more convenient method.As candidates,we focused on some scintillation type spectrometers,and the possibility of a substitute for a Ge detector was examined by both simulation and experiment.The detection limits were roughly estimated through Monte Carlo simulation for various scintillation crystals,and it was found that 1.5-inch LaBr3,CeBr3,and SrI2 could distinguish the clearance level.It was confirmed that the 1.5-inch LaBr3 could reproduce the calibration curve of the Ge detector in the experiment.The required thickness and length of the radiation shield for suppressing the background radiation during the measurement was also determined for the convenience of an actual decommissioning work.
文摘The paper builds the high-current plasma beams model under different dimensions (1D, 2D, and 3D) by continuum (magnetohydrodynamics MHD) and statistical (Monte Carlo MC) mechanics under conditions of low pressures (10<sup>-3</sup> Pa). After detailed presentation of the model, two methods firstly have been analyzed in terms of plasma beam properties. Then, we compare the simulation results of MHD numerical simulation with MC stochastic particles simulation. Finally, through further analysis, it is demonstrated that integrated hybrid MHD and MC method (IMHDMC) provides an innovative practical tool to capture essential properties of high-current plasma beams.
基金National Natural Science Foundation of China(No.12105200,12175161,U186720)Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions+1 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),ChinaNuclear Energy Development Project,China(No.2016-1295).
文摘To estimate the physical dose of skin and key organs in a case of overexposure during a cardiac interventional procedure.Methods The female patient aged 50 suffered from owerexposure during ardiac interventional therapy in a hospital,Xinxiang city,Henan province,China in January 2020.The mesh-type phantom for the patient was constructed based on the adult mesh-type reference computational phantoms(MRCPs)released by the International Comission on Radiological Protection Publication 145 (ICRP145)and phantom deformation technology.Models of exposure scenario were constructed and simulated with particle and heavy ion transport code system(PHTTS)according to exposure conditions.Resuts:The maximum absorbed dose of key organs/tissues under iradiation in posteroanterior(PA)and 30°left anterior oblique directions(LOA)was 632.4 and 305.6 mGy,respectively.The let lung,heart,and left mammary gland received a larger dose under both iradiation conditions.The ratio of the absorbed dose with and without shielding was a lculated,and the relative difference in most organs was<1%between two directions.The iso-dose curve of the back skin revealed the ditribution of the absorbed dose(0.1-5.2 Gy).The dose estimate of key tssues/organs was higher than the conventional level,especially the local skin,up to 5.2 Gy.Concusions The interventional procedure in this ase resulted in a higher dose.Monte Carlo codes combined with the MRCPs can be employed to estimate physical dose to individuals in concrete irradia tion scenarios.
