瞬发裂变中子铀矿测井中超热中子探测器的优化研究  

Optimization study of epithermal neutron detector in prompt fission neutron uranium logging

作　　者：王新光[1] 刘丹[1] 王国保[1] 

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《核技术》2013年第6期33-37,共5页Nuclear Techniques

摘　　要：瞬发裂变中子铀矿测井是利用脉冲中子源和超热中子探测器,记录热中子和235U发生裂变反应产生的瞬发超热中子,得到地层含铀量信息的测井方法。为提高仪器中超热中子探测器的探测效率,利用蒙特卡罗数值计算程序MCNP5对中子铀矿测井仪的探测器进行了优化计算研究,得到最优的中子慢化体和中子探测器尺寸组合,并将计算结果用于仪器的改进,取得了满意的实验结果。Background： Prompt fission neutron uranium logging is a method for uranium exploration. Pulsed neutron source and epithermal neutron detector are used to detect the prompt epithermal neutron from the fission of thermal neutron and 235U. Purpose： The efficiency of epithermal neutron detector of the logging instrument need to be improved. Methods： The energy distribution of fission neutron detected by the epithermal neutron detector, as well as the detection efficiency of epitbermal neutron detector with different sizes of moderator are studied by Monte Carlo simulation. Results： Under the studied conditions, the optimal sizes of neutron moderating material and neutron detector are obtained, which is the combination of 0.5-mm thick cadmium, 1.1-cm thick polyethylene and 2.6-cm diameteraHe tube. Conclusions： In the space with outer diameter of 4.8 cm, the maximum of the epithermal neutron detection efficiency was achieved by combination of a 1.1-cm thick tube and a 2.6-cm diameter 3He moderator when using polyethylene or organic glass as the moderator material.

关 键 词：超热中子探测器 铀矿测井 瞬发裂变中子 蒙特卡罗模拟 探测效率 

分 类 号：TL816.3[核科学技术—核技术及应用]