基于EJ-301液闪的快中子多重性测量装置对Pu样品质量的测量研究  

Measurement Study of Pu Sample Mass Using a Fast Neutron Multiplicity Counting System Based on EJ-301 Liquid Scintillator

作　　者：张岩 程伟[1,2] 李多宏 程璨[2,3] 贾文宝 ZHANG Yan;CHENG Wei;LI Duo-hong;CHENG Can;JIA Wen-bao(College of Materials Science and Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 211106,China;Institute of Nuclear Analytical Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 211106,China;College of Electrical Engineering and Control Science,Nanjing Tech University,Nanjing 211816,China;State Nuclear Security Technology Center,Beijing 102401,China)

机构地区：[1]南京航空航天大学材料科学与技术学院,江苏南京211106 [2]南京航空航天大学核分析技术研究所,江苏南京211106 [3]南京工业大学电气工程与控制科学学院,江苏南京211816 [4]国家核安保技术中心,北京102401

出　　处：《分析测试学报》2024年第10期1658-1663,共6页Journal of Instrumental Analysis

基　　金：国家自然科学基金(12105143);江苏省市场监督管理局科技计划项目(KJ2024009,KJ2024044);前瞻布局科研专项(1006-ILB23003)。

摘　　要：快中子多重性测量技术(FNMC)可以对保密封装或者非固定状态的核裂变材料的质量进行无损检测,且不需要标准样品刻度,在核保障领域,特别是核材料衡算方面具有重要的意义。该文研究了EJ-301液体闪烁体探测器组成的快中子多重性测量装置对Pu样品质量测量的准确性。利用Geant4模拟软件搭建了1×6 EJ-301液体闪烁体探测器组成的快中子多重性测量系统,并对Pu-240自发裂变中子源的方向、能量、时间分布进行了模拟。通过对不同质量的Pu-240源进行多重性质量计算,得到其相对质量偏差均在10%以下,但随着裂变材料质量的增加,相对质量偏差也相应增加。对钚金属进行多重性测量,得到其平均相对质量偏差为15.5%左右,偏差相对于模拟结果较大的原因可能由n/γ甄别误差导致。该结果比中子多重性测量装置的相对质量偏差降低了16%。结果表明,基于EJ-301液闪的快中子多重性测量装置能够较好地实现对钚金属的质量测量。Fast neutron multiplicity counting(FNMC)is a non-destructive technique for assessing the mass of fissile materials in sealed or unconsolidated states,without standard sample calibration.It holds significant importance in nuclear safeguards,particularly in nuclear material accountancy.This study focuses on the accuracy of Pu sample mass measurements using a fast neutron multiplicity measurement system composed of EJ-301 liquid scintillator detectors.A measurement system consist⁃ing of 1×6 EJ-301 detectors was constructed using Geant4 simulation software to simulate the direc⁃tion,energy,and timing distributions of neutrons from spontaneous fission of Pu-240 sources.Mul⁃tiplicity mass calculations were performed on different masses of Pu-240 sources,revealing relative mass deviations consistently below 10%.However,deviations increase proportionally with the mass of fissile material.Experimental measurements of plutonium metal yielded a average relative mass de⁃viation of approximately 15.5%,potentially attributed to n/γdiscrimination errors compared to simu⁃lation results.A 16%reduction in relative mass deviation was observed when comparing the results of the neutron multiplicity measurement device.Overall,the results demonstrate that the fast neutron multiplicity measurement system based on EJ-301 liquid scintillators effectively achieves mass mea⁃surements of plutonium metal.

关 键 词：快中子多重性测量技术 液体闪烁体 Geant4模拟 核材料质量 

分 类 号：O571.53[理学—粒子物理与原子核物理] TL817.3[理学—物理]