二元并行CdZnTe探测器读出电路及信号处理方法

Readout and signal processing system for two-element parallel CdZnTe detectors

本文为CdZnTe(CZT)二元并行探测器设计并制作了信号处理系统电路,包括前置放大电路,差分放大电路,极零相消电路,滤波成形电路,微调电路和基线恢复电路和加和电路。137Cs(662keV)辐射下的信号,经过差分放大,极零相消和滤波成形电路的输出,信号持续时间在10μs内,幅度为260mV,两路信号相加后信噪比大于15:1。能谱测试初步结果表明:采用这个信号处理系统,二元CZT并行探测器对137Cs(662keV)源的探测效率分别是单元器件的1.74和2.2倍,能量分辨率接近于单元器件。

In this paper, we describe the development of readout electronics for two channels CZT detectors, including the charge sensitive preamplifier and signal processing circuit. The latter includes the differential amplifier, pole -zero cancellation circuit, filter circuit, fine -tuning circuit, baseline restoration circuit and summing amplifier. After the signal from ^137 Cs （662keV） source being through differential amplification, pole - zero cancellation and filter circuit, the output signal is about 260mV and the signal duration is within 10μs. After the signals from the two channels being summed through the summing amplifier, the signal to noise ratio is greater than 15：1. The preliminary results show that for the ^137Cs source, the detection efficiency of the two parallel CZT detectors with this signal processing system is as many 1.74 and 2.2 times as the single ones, respectively, and the energy resolution （FWHM） is similar to that of the single one.