空间太阳硬X射线成像仪量能器读出电子学设计

Design of the Readout Electronics for Solar Hard X-ray Imager

先进天基太阳天文台(ASO-S)是中国科学院空间科学先导专项2期规划的太阳观测卫星,其针对第25个太阳活动峰年,同时观测太阳磁场、日冕物质抛射和太阳耀斑爆发.硬X射线成像仪(HXI)作为该卫星3个科学载荷之一,实现了高时间分辨率和空间分辨率的太阳硬X射线成像观测,其量能器由99套溴化镧闪烁晶体-光电倍增管探测单元和读出电子学板构成,实现了30–200 keV的硬X射线光子能谱测量.针对HXI量能器的观测需求,设计了一套空间高事例率读出电子学系统,并通过实验室测试,证明了该系统单事例读出死时间小于2μs,同时验证了该系统电子学噪声小于120 fC,积分非线性小于2%,满足HXI仪器要求.

The Advanced Space-based Solar Observatory(ASO-S)is the first Chinese solar mission of Chinese Academy of Science,aimed at the 25th solar maximum.ASO-S is expected to observe solar magnetic field,coronal mass ejections(CMEs),and solarflares at the same time.Hard X-ray Imager(HXI)is one of the 3 payloads on board of ASO-S,providing solar X-ray image with high resolution in both time and position.The calorimeter in HXI consists of 99 LaBr3 scintillators with Photon Multiplier Tubes(PMTs),and their readout electronics measures spectrum of solar X-ray photons in energy range 30–200 keV.A readout electronics for high event rate has been designed to fulfill the requirements of HXI in this paper.The preliminary test results show that the deadtime of readout electronics is smaller than 2μs,the noise of readout system is lower than 2 fC,and integral non-linearity is less than 2%,meeting the requirements of HXI instrument.