共面栅碲锌镉探测器读出电路设计及性能研究

为有效读出共面栅碲锌镉(CPG-CZT)探测器的核脉冲信号，本文结合CPG-CZT探测器工作原理及国内外研究，设计了可用于CPG-CZT探测器的读出电路，主要包括高压偏置电路、前置放大电路、增益调节及减法电路。为研究读出电路性能，本文测试了各单元电路的性能及探测系统能量分辨率随偏置电压、增益调节电路中两路信号的相对增益G的变化规律。结果表明：高压偏置电路两路输出偏压与输入偏置电压的相关系数R²均为0.998；前置放大电路输出噪声为5 mV；增益调节及减法电路输出信号噪声为10 mV；输入偏置电压、相对增益G的变化均会影响探测系统能量分辨率，当偏置电压为-1650 V、相对增益G为0.7时对¹³⁷Cs源产生的γ射线能量分辨率最佳，可达3.65%，且无明显拖尾现象。

Design and Performance Study of Readout Circuit for CPG-CZT Detector

In order to effectively read the nuclear pulse signal of coplanar-grid CdZnTe (CPG-CZT) detector, a readout circuit that can be used for CPG-CZT detector based on CPG-CZT detector measurement principle and domestic and foreign research was designed in this paper. The circuit mainly includes high voltage bias circuit, preamplifier circuit, gain adjustment and subtraction circuit. For studying the performance of the readout circuit, the performance of each unit circuit was test. Besides, the variation law of the energy resolution of detection system with the bias voltage and the relative gain G of the two signals in the gain adjustment circuit was test. The results show that the R² between the two-output bias voltage of the high voltage bias circuit and the input bias voltage is as high as 0.998, the output noise of the preamplifier circuit is 5 mV, and the output signal noise of gain adjustment and subtraction circuit is 10 mV. The changes of the input bias voltage and the relative gain G will affect the detection system energy resolution. When the bias voltage is -1 650 V and the relative gain G is 0.7, the detection system has the best energy resolution of 3.65% for γ-ray generated by ¹³⁷Cs source and there is no obvious tailing phenomenon.