基于6Li+CdTe的新型中子探测器的优化设计研究  

Research on optimal design of new neutron detector based on 6Li + CdTe

作　　者：马龙[1] 田立朝 马燕云[1,2] 吕中良 韩鹏 彭猛 杨晓虎 张国博 李宵宵 单飞 MALong;TIAN Lichao;MAYanyun;LYU Zhongliang;HAN Peng;PENG Meng;YANG Xiaohu;ZHANG Guobo;LI Xiaoxiao;SHAN Fei(College of Art and Science,National University of Defense Technology,Changsha 410073,China;IFSA Collaborative Innovation Center,Shanghai Jiaotong University,Shanghai 200240,China)

机构地区：[1]国防科技大学文理学院,长沙410073 [2]上海交通大学IFSA协同创新中心,上海200240

出　　处：《核技术》2020年第8期74-79,共6页Nuclear Techniques

基　　金：国家自然科学基金(No.11505287、No.11975308)资助。

摘　　要：面对3He气体资源严重短缺的国际形势,2018年基于6Li+CdTe新型中子探测器方案被提了出来,其具备热中子探测效率高、γ灵敏度低及可与3He气体中子探测器相比拟的特点,有很好的应用前景。本文分析6Li+CdTe中子探测器的结构和工作原理,采用MCNP6软件对6Li+CdTe中子探测器进行物理建模并且对其物理性能、结构参数、中子慢化体设计等进行模拟计算,并就该探测器在特殊核材料监测系统中的应用开展了探索研究。结果显示:CdTe吸收层的最佳厚度为10μm;当6层6Li+CdTe的中子探测单元叠加时,6Li转化层的最佳厚度为60μm,此时热中子探测效率超过50%;探测系统的尺寸达到4 m×32 cm时,可以满足特殊核物质监测的要求。整个模拟研究获得了探测器最佳工作参数以及辐射监测系统设计方案,对特殊核材料在线中子监测装置的实验研究具有指导意义。[Background] Facing the internationally serious shortage of 3He gas, a novel neutron detector based on 6Li+CdTe was proposed in 2018, which has high neutron detection efficiency and low γ sensitivity, showing a good application prospect. [Purpose] This study aims to conduct an optimal design of the neutron detector based on 6Li+CdTe and explore its application to the special nuclear material monitoring system. [Methods] First, the structure and operating principle of a typical 6Li+CdTe unit was analyzed. Then the Monte Carlo simulation of MCNP6 was employed to optimize the key parameters of this detector. Finally, integrated analysis was performed using this model for the special nuclear material monitoring system. [Results] The optimal thickness of the CdTe absorption layer is 10 μm. When the number of 6Li+CdTe detection units reaches 6 layers with the optimal ~6Li layer of 60 μm, the detection efficiency is more than 50%. A detector system with an area of 4 m×32 cm, surrounded by polyethylene of 3 cm in the front and 10 cm in the side and back, can meet the requirements of the special nuclear material monitoring system. [Conclusions] The novel neutron detector with optimal design can be used as the alternative of 3He based neutron detector in the special nuclear material monitoring system.

关 键 词：中子探测 半导体探测器 6Li MCNP模拟 

分 类 号：TL816.3[核科学技术—核技术及应用] O571.53[理学—粒子物理与原子核物理]