介质型快中子探测器中子直照响应模拟研究

 介质型快中子探测器的中子直照响应对其设计和实际应用具有重要影响。利用Geant4编制Monte-Carlo模拟程序对此型探测器的中子直照响应进行了计算。模拟了探测器芯子常用材料在中子入射时带电重粒子的发射情况，发现电荷收集极、卡阈吸收片和后高压绝缘层材料的选择对中子直照响应特性有直接影响。在现有的以聚四氟乙烯为卡阈吸收片和后高压绝缘层材料的探测芯子中，直照响应给总的中子灵敏度带来约6%的贡献。提出了一种使用高电阻率石墨作为卡阈吸收片和后高压绝缘层材料的探测芯子的优化结构，可有效降低中子直照响应。

Neutron direct-radiation response of medium-type fast-neutron detector

The medium-type fast-neutron detector responds to direct neutron irradiation and it has an extreme effect on its design and practical applications. Monte-Carlo simulation programs based on Geant4 toolkit are developed to study the neutron direct radiation response sensitivity of the medium-type fast-neutron detector. The emission of the charged heavy particles of commonly used materials of detector’s sensitive unit due to neutron incidence is simulated. The result shows that the selection of the materials of the charge collector, the threshold absorber and the rear isolator directly affect on the response sensitivity of neutron direct radiation. The response sensitivity of neutron direct radiation contributes about 6% to the total neutron sensitivity in the present sensitive unit which us