合成成形法在数字核脉冲信号处理中的应用研究

Application Research of Synthetic Shaping Method in Digital Nuclear Pulse Signal Processing

数字核谱仪系统中核脉冲信号的处理通常采用数字成形法,传统的核信号数字成形常采用传递函数法来实现核脉冲信号的梯形、三角形与高斯成形。为解决不同数字成形方法需要改变相应的传递函数与实现过程的问题,引入了数字核信号合成成形处理方法,该方法采用统一的传递函数,通过简单地改变成形参数,可将数字核信号成形为具有一定曲率的凹成形与凸成形输出,然后通过叠加合成实现三种数字成形。具体推导了Z域中合成成形的传递函数,以梯形合成成形为例分析了成形参数对脉冲堆积的影响,通过SignalTapⅡ获取成形数据,研究结果表明该方法可简单有效实现核脉冲信号的三种数字成形。选用NaI(Tl)探测器测量^(137)Cs,对产生的核脉冲信号采用合成成形处理,通过对获取的能谱分析可知,合成成形法比传统成形法具有更好的能量分辨率与计数率性能。

The digital shaping method typically is used to process nuclear pulse signal in digital nuclear spectrometer system.The trapezoidal,triangular and gaussian shaping of nuclear pulse signal are realized by the transfer function in the traditional way.To address the issue of requiring changes to the corresponding transfer function and implementation process for different digital shaping methods,a digital nuclear signal synthetic shaping method is introduced.This method uses a unified transfer function to shape digital nuclear signals into concave and convex shapes with a certain curvature,with simple changes to the shaping parameters.Thereafter,the three types of digital shaping are achieved through superposition and synthesis.The transfer function for synthetic shaping in the Z-domain is derived,and the influence of shaping parameters on pulse pile-up is analyzed using the trapezoidal synthetic shaping as an example.Shaping data were obtained using SignalTap II,demonstrating that this method can easily and effectively achieve the three types of digital shaping for nuclear pulse signals.The NaI(Tl)detector was used to measure the^(137)Cs energy spectrum,and the synthetic shaping method was employed to process the nuclear pulse signal.Analyzing the obtained energy spectrum revealed that the synthetic shaping method exhibits better energy resolution and counting rate performance than traditional shaping methods.