探测器信号波形离散序列的多项式与双指数曲线拟合及其在数字化核能谱中的应用

Polynomial and Bi-exponential Curve Fitting for Discrete-time Sequences of Detector Signals and Its Application in Digitized Nuclear Spectrum

对NaI(Tl)探测器输出的信号进行波形采样,获得信号幅度随时间变化的离散时间序列。基于非线性最小二乘原理,采用多项式和双指数拟合方法,对信号波形离散时间序列进行拟合,根据拟合曲线提取信号幅度。获得了137Csγ射线的数字化γ能谱。分别对多项式拟合和双指数拟合方法获得的数字化能谱与传统模拟多道系统的能谱进行了比较,结果表明,在50 MHzAD采样率下,数字化能谱的能量分辨与传统多道系统能量分辨相当甚至更优。

The discrete-time sequences of signals of NaI（T1） were gotten by ADC at 50 MHz sampling frequency. Polynomial and bi-exponential curve fitting methods were used to fit the discrete-time sequences of signals. The magnitudes of the signals were obtained by calculating the maximums of fitted curves. The digitized γ energy spectrum of ^137Cs were acquired by this methods for NaI（Tl） detector. The energy resolution of digitized energy spectrum was equivalent to or even better than that of traditional muhichannel spectrum.