基于时间差法的位置灵敏3He正比计数管位置分辨性能研究  

Position resolution performance of a position-sensitive 3He proportional counter based on a time-difference method

作　　者：王欣悦 刘国荣[1] 李井怀[1] 梁庆雷[1] 周浩[1] 田园 WANG Xinyue;LIU Guorong;LI Jinghuai;LIANG Qinglei;ZHOU Hao;TIAN Yuan(China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《核技术》2024年第6期65-75,共11页Nuclear Techniques

摘　　要：中子定位技术可用于乏燃料后处理流程监测,以避免发生核临界安全事故。利用蒙特卡罗(Monte Carlo,MC)算法模拟了不同中子发射方式、^(3)He气压、管径、慢化体厚度等对位置灵敏^(3)He正比计数管位置分辨能力和探测效率的影响。对于管径为2.54 cm、灵敏区长80 cm、^(3)He气压为405300 Pa的位置灵敏^(3)He正比计数管,MC模拟结果表明:轴向各处位置分辨能力相同,对热中子点源的位置分辨极限为0.17 cm;慢化体厚5 cm且^(244)Cm源紧贴慢化体外壁时中子探测效率为3.0%,位置分辨为9.25 cm。用时间差法测试了^(244)Cm源在灵敏区不同位置、源管距、慢化体厚度等情况下此位置灵敏^(3)He正比计数管对^(244)Cm源的位置分辨能力与探测效率,测试结果表明:实验装置的理论位置分辨极限可达2.64 cm,当慢化体厚5 cm且^(244)Cm源紧贴慢化体外壁时位置分辨为18.50 cm,为理论值的一半。[Background]Neutron localization technology can be used for monitoring spent fuel reprocessing to prevent nuclear criticality accidents.[Purpose]This study aims to investigate the effects of different neutron emission modes,^(3)He pressure,tube diameter,and moderators on the position resolution and detection efficiency of a position-sensitive ^(3)He proportional counter.[Methods]Firstly,a ^(3)He proportional counter with a tube diameter,tube length,and ^(3)He pressure of 2.54 cm,80 cm,and 405300 Pa,respectively,was taken as object of study,and the Monte Carlo(MC)algorithm was employed to simulate the effects of neutrons with different energies,neutron emission modes,^(3)He pressures,tube diameters,and moderating bodies on the position resolution and detection efficiency of a position-sensitive ^(3)He proportional counter.Then,the effects of the time difference of arrival(TDOA)on the location of a source in an active zone,source to tube distances,thickness of moderating body,and position resolution of the ^(3)He proportional counter were investigated.Finally,a linear fitting analysis of the active region was performed,and the locations of inactive regions were estimated to determine the positioning ability of the ^(3)He tube.[Results]Simulation results show that the position resolution of this ^(3)He proportional counter is equal in all axial sections,and the position-resolution limit of thermal neutron source is 0.17 cm.When the thickness of the moderating body is 5 cm,and the ^(244)Cm source is close to the external wall of the moderating body,the neutron detection efficiency is 3.0%,and the theoretical position resolution is 9.25 cm whilst experimental result of position resolution is 18.50 cm,half of the theoretical value,and the location resolution limit is 2.64 cm after processed by the linear fitting curve of the active location and a time-difference crest.[Conclusions]MC simulation and experimental tests show that the position-sensitive ^(3)He proportional counter exhibits better position resolution and de

关 键 词：位置灵敏 3He正比计数管 中子定位 蒙特卡罗模拟 时间差法 位置分辨 

分 类 号：TL816.5[核科学技术—核技术及应用]