基于DDAA的SNM探测系统蒙特卡罗模拟优化设计  

Monte Carlo simulation optimization study of DDAA applied to SNM detection

作　　者：张连军 郑玉来[1,2] 唐梦娇 李永[1,2] 刘超[1,2] 王强[1,2] 王国宝[1,2,3] 张晨 ZHANG Lianjun;ZHENG Yulai;TANG Mengjiao;LI Yong;LIU Chao;WANG Qiang;WANG Guobao;ZHANG Chen(Department of Nuclear Technology and Application,China Institute of Atomic Energy,Beijing 102413,China;IAEA Collaborating Center for Nuclear Security Technologies,China Institute of Atomic Energy,Beijing 102413,China;Key Laboratory of Nuclear Detection Technology,China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院核技术综合研究所,北京102413 [2]中国原子能科学研究院IAEA核安保协作中心,北京102413 [3]中国原子能科学研究院核探测技术重点实验室,北京102413

出　　处：《核技术》2025年第2期124-132,共9页Nuclear Techniques

基　　金：国际原子能机构协调研究项目J02015(No.26191)资助。

摘　　要：差分衰减分析技术(Differential Die-away Analysis,DDAA)可用于特殊核材料(Special Nuclear Materials,SNM)主动探测分析,无论核材料是否置于屏蔽体内,它皆可通过外加脉冲中子诱发核材料发生裂变来揭示核材料的存在。通过Geant4蒙特卡罗模拟软件设计基于DDAA技术的SNM探测系统,优化探测系统关键参数以及系统不同几何布置,获得探测系统达到最优灵敏度时的几何结构参数。计算结果表明,当探测系统的几何参数选择压强为0.405 3 MPa、直径5.08 cm的3He管,3He管外包裹密度为1.10 g·cm^(-3)、厚度为4 cm的慢化体,样品周围采用厚度为7 cm、密度为0.85 g·cm^(-3)的慢化体时,可达到1 g的235U核材料高灵敏探测。计算结果对基于DDAA技术的SNM探测系统的参数设计具有重要意义。[Background]Differential die-away analysis(DDAA)is a technique utilized for the active detection and analysis of Special Nuclear Materials(SNM).This method can identify the presence of nuclear materials irrespective of shielding by inducing fission through external pulsed neutrons.[Purpose]This study aims to design and optimize a detection system based on DDAA technology by Monte Carlo simulation to achieve the highest sensitivity in detecting SNM.[Methods]The Geant4 Monte Carlo simulation software was employed to design the SNM detection system with optimization of its key parameters.The size,pressure,thickness,and density of the 3He detector,as well as the thickness and density of the moderator were calculated for obtaining the geometric parameters required to achieve optimal neutron detection efficiency.Then,different geometric arrangements of the system were tested to identify the configuration that delivers optimal sensitivity for SNM detection.Finally,based on the DDAA principal and simulation optimization results,the detection system was evaluated using a pulsed neutron with an energy of 14 MeV and a pulse width of 100μs.[Results]The simulation results indicate that the detection system achieves high sensitivity for detecting 1 g of 235U nuclear material when configured with the following geometric parameters:a pressure of 0.4053 MPa,a 5.08 cm diameter 3He tube,an outer wrapping density of 1.10 g·cm^(-3) for the 3He tube,a 4 cm thick moderator,and a 7 cm thick moderator with a density of 0.85 g·cm-3 surrounding the testing sample.[Conclusions]The optimized geometric configuration significantly enhances the sensitivity of SNM detection systems based on DDAA technology.These findings provide crucial insights for the parameter design of effective SNM detection systems,thereby contributing to improved nuclear material security and non-proliferation efforts.

关 键 词：差分衰减分析 特殊核材料 探测效率 优化计算 

分 类 号：TL99[核科学技术—核技术及应用]