暗物质空间探测器量能器读出的地面及在轨标定方法的研究

空间观测高能电子、伽玛射线等高能粒子能谱对暗物质的探测有着重要的意义。由于受到探测器重量、功耗等因素的限制，对于几十MeV到几TeV这样宽能谱的粒子能量的空间探测给探测器设计带来了很大的挑战。本课题基于我国科学家提出的一种暗物质粒子空间探测器方案，针对其中的BGO量能器读出及相应的地面和在轨标定方法进行研究。暗物质探测器的BGO量能器利用光电倍增管的多打拿极读出来达到MeV至TeV的大动态范围能谱测量，但随之带来无法获得合适的射线源对探测器读出进行标定的问题。本课题将研究利用现有的LED等发光源、宇宙射线等信号源建立地面系统对探测器进行综合标定的方法，标定探测器读出的动态范围、线性、能量分辨和精确度等性能。另外，为了解决探测器在轨运行中由空间环境变化、探测器老化等造成的探测器性能变化给粒子能量探测带来的误差，如何利用空间高能粒子结合探测器自身的响应对探测器进行在轨标定也是本课题的研究重点。

High-energy electron and gamma-ray measurement by orbital satellite is a powerful method to study the dark matter in space. But the detection of these particles in the energy range from tens MeV to several TeV is still a great challenge because of the limitation of the satellite in the weight and the power. DAMPE (dark matter particle explorer), a proposed mission by Chinese scientists in Purple Mountain Observatory, is to detect electron and gamma ray in space from 5 GeV to 10 TeV with high-energy resolution. BGO calorimeter is a sub-detector in the DAMPE satellite to measure the major energy which the injected particles deposited. This proposal is for the methods research of the on-ground and on-orbit calibrations for the BGO calorimeter. .To measure particles in several TeV, the single BGO calorimeter element need to have a wide dynamic range about 10E6. For reaching this requirement, we have to use the signals from three dynodes in PMT (photo multiplier tube)to extend the dynamic range of single BGO calorimeter element.However, it is difficult to get so high energy particle in laboratory to calibrate the BGO calorimeter. .In this proposal, we plan to built an on-ground calibration system using LED source and low energy particles to scale the characteristics of the BGO calorimeter(e.g. linearity, energy resolution, energy precision). Since these parameters will vary while the satellite working in orbit because of the variation of the space environment.Therefore, these parameters have to be re-calibrated in space.So we also plan to develop a related technology to calibrate the detector with cosmic ray in space.