高辐射通量下CdZnTe探测器的脉冲处理技术研究

Research on Pulse Processing Technology of CdZnTe Detector Under High Irradiation Flux

针对高辐射通量条件下碲锌镉(CdZnTe)辐射探测器对模拟前端输出信号应具有快速上升时间及窄脉宽的要求,研究了CdZnTe探测器中电荷灵敏前置放大器(CSA)、准高斯脉冲滤波整形放大器的原理。采用Multisim,仿真分析了CSA输出脉冲信号上升时间、衰减时间和滤波整形放大器级联输入电阻、运放反馈电容等优化参数。基于仿核精密脉冲源搭建实验平台,完成了CSA和准高斯滤波整形放大器的实验验证工作。结果表明,CSA的输出信号上升时间为10 ns,下降时间为150μs,准高斯脉冲脉宽达200 ns。CSA和滤波整形放大电路的输出脉冲波形与仿真结果一致,满足了高分辨率半导体能谱测量系统的要求。

In high radiation flux conditions,CdZnTe material based semiconductor radiation detectors should have an analog front end that the output signals have fast rise time and small impulse width.The principles of the charge sensitive preamplifier(CSA)and the pseudo-Gaussian impulse shaping-filter amplifier were investigated.The optimal parameters such as the impulse output signal rise time and fall time in the CSA,the cascaded input resistance and opamp’s feedback capacitance in the shaping-filter amplifier,were analyzed by Multisim.Based on the pseudo-nuclear precision pulse sources,an experimental platform was built to complete the experimental verification procedures of the CSA and the pseudo-Gaussian shaping-filter amplifier.The results showed that the rise time of the CSA output signal was 10 ns,the fall time was 150μs,and the pulse width of the pseudo-Gaussian shaping-filter amplifier reached 200 ns.The output pulse waveforms of the CSA and the pseudo-Gaussian shaping-filter amplifier were consistent with the circuit simulation results,which had met the requirements of the high resolution semiconductor energy spectrum measurement systems.