基于波形采样的PPAC数据处理

Data Analysis of PPAC Based on Waveform Sampling

数字化波形采样技术在实验核物理中得到了广泛的应用,选取合适的采样频率非常重要。本文使用脉冲幅度甄别定时方法和恒比定时方法对采样频率为100MHz^5GHz的平行板雪崩计数器(PPAC)信号进行了模拟分析,采样频率为250~500MHz时,使用脉冲幅度甄别定时方法可得到比较精确的位置信息,与传统获取系统定位的位置分辨的差别Sigma小于0.15mm,采样频率低于100MHz时信号定位误差较大。使用高速采样数字化仪可对信号幅度小于20mV的信号进行定时分析,与传统的PPAC获取系统相比,探测效率提升了4.3%。

The digital waveform sampling technology is widely used in nuclear physics experiment.It is very important to choose an appropriate sampling frequency.The pulse amplitude discrimination timing method and the constant fraction discrimination timing method were utilized to simulate and analyze the parallel-plate avalanche counter(PPAC)signal with the sampling frequency from 100 MHz to 5 GHz.As the sampling frequency reaches 250-500 MHz,a more accurate position information can be obtained by using the pulse amplitude discrimination timing method.The position distribution Sigma between the pulse amplitude discrimination timing method and the traditional acquisition system is less than 0.15 mm.The position distribution error becomes larger as the sampling frequency is lower than 100 MHz.The high-speed sampling digitizer can be utilized to analyze small signals with signal amplitude less than 20 mV,and the detection efficiency is 4.3%higher than that of traditional PPAC acquisition system.