暗物质粒子探测卫星中子探测器的GEANT4模拟  

GEANT4 Simulation of Neutron Detector for DAMPE

作　　者：何明[1,2,3] 马涛[1,2] 常进[1,2] 张岩[1,2] 黄永益[1,2] 藏京京 伍健[1,2] 董铁矿[1,2] 

机构地区：[1]中国科学院紫金山天文台,南京210008 [2]中国科学院暗物质与空间天文重点实验室,南京210008 [3]中国科学院大学,北京100049

出　　处：《天文学报》2016年第1期1-8,共8页Acta Astronomica Sinica

基　　金：国家自然科学基金项目(11303105;11303107;11203090)资助

摘　　要：近几十年暗物质研究已逐渐成为天文学研究的重要领域之一,相关理论研究和试验项目日新月异,中国的暗物质粒子探测卫星正是在此背景下提出的.由于暗物质粒子探测卫星的探测对象涉及高能电子,为了减少其他带电粒子(主要是质子)被误认为是电子的事件率,必须采用适当的方法区分质子和电子.实验表明高能质子在BGO(锗酸铋)量能器内发生的强子簇射与电子在BGO量能器内发生的电磁簇射有明显的区别,且强子簇射通常伴随着大量的次级中子产生,通过测量BGO量能器底部出射的次级中子信号和入射粒子在BGO量能器中簇射的形状可以有效区分入射到BGO量能器的粒子是质子还是电子.介绍了暗物质粒子探测卫星中子探测器的构成以及探测原理,利用GEANT4软件,模拟了特征能量的质子和电子在中子探测器中产生的信号,并且总结出了中子探测器在不同电子接收效率情况下的电子、质子区分能力.During recent tens of years dark matter has gradually become a hot topic in astronomical research field, and related theory researches and experiment projects change with each passing day. The Dark Matter Particle Explorer （DAMPE） of our country is proposed under this background. As the probing object involves high energy electrons, appropriate methods must be taken to distinguish them from protons in order to reduce the event probability of other charged particles （e.g. a proton） being mistaken as electrons. The experiments show that, the hadronic shower of high energy proton in BGO electromagnetic calorimeter, which is usually accompanied by the emitting of large number of secondary neutrons, is significantly different from the electromagnetic shower of high energy electron. Through the detection of secondary neutron signal emitting from the bottom of BGO electromagnetic calorimeter and the shower shape of incident particles in BGO electromagnetic calorimeter, we can effectively distinguish whether the incident particles are high energy protons or electrons. This paper introduces the structure and detecting principle of DAMPE neutron detector. We use Monte- Carlo method with GEANT4 software to simulate the signal emitting from protons and electrons at characteristic energy in the neutron detector, and finally summarize the neutron detector＇s ability to distinguish protons and electrons under different electron acception efficiencies.

关 键 词：宇宙学 暗物质 仪器 探测器 技术 光测量 

分 类 号：P171[天文地球—天文学]