摘要
快中子多重性测量技术能够快速、准确地检测出特殊核材料(Special Nuclear Materials,SNM)中^(240)Pu的有效质量,对防止核扩散具有重要意义。本文详细介绍了团队开发的一套被动快中子多重性测量装置,该装置主要由32个自主研发的EJ-309液体闪烁探测器组成,集成了自主设计开发的32通道的高压电源以及用户友好图形界面的应用软件。为提高探测效率的均匀性,这些探测器以球对称形式排布。数据分析采用双重(Doubles)参数拟合和快中子多重性分析两种方法。对该装置的测试结果表明:该装置能够准确计算出^(252)Cf中子源(等效^(240)Pu有效质量为5.37~209.62 g)的自发裂变率。此外,该装置还在不同的环境本底(总中子计数率Singles分别为111.42±0.46、73.97±0.28、47.27±0.29)下进行测试。测量结果与低本底下(Singles计数率为0.51±0.02)的测量结果基本一致,这表明该装置具有非常好的抗本底干扰能力。
[Background]Quick and accurate detection of the effective quality of^(240)Pu in special nuclear materials(SNM)is of great significance for preventing nuclear proliferation whilst traditional thermal/epithermal neutron multiplicity counting systems based on 3He tubes have relatively low measurement accuracy and high development costs.Fast neutron multiplicity counting(FNMC)technique based on liquid scintillation detectors has become a research hotspot.However,FNMC systems currently built are still in the experimental research stage.[Purpose]This study aims to develop a passive FNMC system that can be used for practical measurement.[Method]Firstly,a passive FNMC system was built using 32 self-developed EJ-309 liquid scintillation detectors.To improve the uniformity of neutron detection efficiency of the system,these detectors were arranged in a spherically symmetrical geometry.A self-designed and developed 32-channel high-voltage power supply and a user-friendly application software were integrated for the system.Then,the Doubles parameter fitting method and the three-parameter fast neutron multiplicity analytical method were employed to evaluate the spontaneous fission rates of the^(252)Cf neutron sources respectively.Finally,the performance of the system under different neutron radiation backgrounds(with Singles rates of 111.42±0.46,73.97±0.28,and 47.27±0.29,respectively)was also investigatted.[Results]The experimental results show that the Doubles parameter fitting method can accurately evaluate the spontaneous fission rates of^(252)Cf neutron sources.The relative differences of the spontaneous fission rates of the^(252)Cf neutron sources evaluated by using the fast neutron multiplicity analytical method are less than±4%.The measurement results under different neutron radiation backgrounds are basically consistent with those under natural environment background(the Singles rates were 0.51±0.02).[Conclusions]The FNMC system developed in this study can accurately determine the spontaneous fission rate of the^(252)Cf neutron source(with an equivalent^(240)Pueff mass range of 5.37~209.62 g),and has very good anti-background interference capabilities.
作者
刘月壮
张少东
尤园江
林旭润
周志波
李多宏
周星宇
李梦远
金宝亮
李猛
马麟
张琦
李达
武朝辉
张小东
LIU Yuezhuang;ZHANG Shaodong;YOU Yuanjiang;LIN Xurun;ZHOU Zhibo;LI Duohong;ZHOU Xingyu;LI Mengyuan;JIN Baoliang;LI Meng;MA Lin;ZHANG Qi;LI Da;WU Zhaohui;ZHANG Xiaodong(School of Nuclear Science and Engineering,North China Electric Power University,Beijing 102206,China;State Nuclear Security Technology Center,Beijing 102401,China;China Nuclear Power Technology Research Institute Co.,Ltd.,Shenzhen 518031,China;Shenzhen Key Laboratory of Nuclear and Radiation Safety,Institute for Advanced Study in Nuclear Energy&Safety,College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen 518060,China)
出处
《核技术》
北大核心
2025年第5期167-176,共10页
Nuclear Techniques
基金
国家核安保技术中心,深圳市高等学校新引进高精尖缺人才科研启动经费(No.868-000001020169)资助。
关键词
快中子多重性测量
液体闪烁体探测器
球对称
自发裂变
^(252)Cf中子源
Fast neutron multiplicity counting
Liquid scintillation detectors
Spherically symmetrical
Spontaneous fission
^(252)Cf neutron sources
