远紫外光子计数成像探测器的感应电荷读出方法

为了满足空间远紫外波段成像高空间分辨率和高计数率的探测需求,阐述了光子计数成像探测器的感应电荷读出方法,用于对地球电离层进行远紫外波段遥感探测的成像光谱仪.研究了具有成形网路的电荷灵敏放大器各参数间的关系,从理论上分析了电荷灵敏放大器的上升时间及成形网络的成形时间常数对电荷读出噪声和探测系统计数率的影响,并建立了它们之间的定量关系.提出了电荷读出网络参数的设计和选取原则,并采用适合空间环境的分立电子元件研制出基于楔条形阳极光子计数式成像探测器的电荷读出电路.实验结果表明,所设计的感应电荷读取链路在成形时间为500 ns时链路等效输入噪声电荷约为230 e,电荷灵敏放大器上升时间小于8 ns,与建立的模型计算值有较好的一致性.在入射光强计数率86.2 kcps条件下,所测图像的空间分辨率达到7.13 lp/mm,满足空间远紫外波段成像光谱仪的使用要求.

Inductive Charge Readout for Far Ultraviolet Photon Count Imaging Detector

In order to meet the need of high spatial resolution and high count rate in the imaging of far ultraviolet band,the method of acquiring the induced charge of the photon count imaging detector is described,which can be used in the imaging spectrometer for remote sensing of far ultraviolet band in the ionosphere of the earth. The relation between the parameters of the charge sensitive amplifier with pulse shaper is studied. The influence of the rise time of the charge sensitive amplifier and the time constant of the pulse shaper on the noise and counting rate is analyzed by numerical model. The selection principle of network parameters is proposed,and a front-end readout circuitry for photon count imaging detector based on wedge and strip anode is developed with discrete electronic components suitable for space applications.The experiment results show that when the shaping time is 500 ns,the equivalent input noise charge of readout circuits is about 230 e,and the rise time of the charge sensitive amplifier is better than 8 ns,which have better consistency with the calculated values. The spatial resolution of the measured images is up to7.13 lp/mm,and the highest counting rate is 86.2 kcps,which meets the requirements of the far-ultraviolet band imaging spectrometer on-orbit mission operations.