中子符合计数器在设计与应用时应注意的几个问题  

Several problems in the design and application of neutron coincidence counter

作　　者：李多宏 李达 刘立坤 初泉丽 周志波 杨丽芳 武朝辉 谭西早 许振华 LI Duohong;LI Da;LIU Likun;CHU Quanli;ZHOU Zhibo;YANG Lifang;WU Zhaohui;TAN Xizao;XU Zhenhua(State Nuclear Security Technology Center,Beijing 102401,China)

机构地区：[1]国家核安保技术中心,北京102401

出　　处：《世界核地质科学》2021年第1期112-117,共6页World Nuclear Geoscience

基　　金：中国核动力院反应堆燃料及材料重点实验室基金项目(编号:6142A06180612)资助。

摘　　要：在核材料衡算中,对铀、钚的分析可以采用化学的方法,但需要对样品进行破坏,且操作复杂,测量周期较长。由于铀、钚都可以自发裂变产生中子,可以进行中子测量,中子测量不需要破坏样品,可以对大体积样品进行快速分析,且误差较小。就中子符合计数器进行了参数优化实验,更好地理解了中子探测器的设计原理,包括中子计数统计、屏蔽厚度、不同材料对中子的散射、高压影响、门宽设置、死时间的修正、衰减时间确定、探测效率验证和γ干扰影响等;同时进行了测量条件实验,包括偶然事件影响等。为更好地使用此技术,具有一定的借鉴意义。In nuclear material accounting,the analysis of uranium and plutonium can be carried out by chemical method,but it needs to destroy samples,which is complicated and takes a long time to measure.Because both uranium and plutonium can spontaneously fission to produce neutrons,neutron measurements can be carried out without destroying samples,and large volume samples can be rapidly analyzed with little error.In this paper,the parameters optimization experiment of neutron coincidence counter is carried out to better understand the design principle of neutron detector,including shielding thickness,neutron absorption,scattering,shielding effect,high pressure effect,gate width setting,attenuation time determination,A/T test,detection efficiency verification,gamma interference effect,axial and radial efficiency verification,etc.,including accidental events,external neutron and gamma sources.In order to better use this method,it has certain reference significance.

关 键 词：非破坏性分析 中子符合计数器 设计 散射 死时间修正 

分 类 号：TL81[核科学技术—核技术及应用]