中子脉冲堆积信号处理方法研究

Research on Neutron Pulse Pile-up Signal Processing Method

  • 摘要: 在强辐射环境下探测中子时,探测器输出的脉冲信号时常会出现堆积的现象,从而导致脉冲波形和中子能谱的失真。本文针对脉冲堆积问题,提出了一种数字化的脉冲堆积判别与校正方法,首先通过计算脉冲信号一阶微分中的下冲过零点个数来判别脉冲堆积,然后基于构建的4种标准堆积脉冲模型(n+n、γ+γ、n+γ、γ+n)还原构成堆积的原始脉冲。实验结果表明,该方法能准确地判别脉冲堆积事件,在堆积脉冲时间间隔小至20 ns时仍能有效地还原原始脉冲,既提高了中子有效计数率又校正了畸变的中子能谱。

     

    Abstract: The issue of pulse pile-up is frequently encountered when the neutron is detected in intense radiation environment, which will distort the pulse shape and the neutron spectra. In this paper, a digital method of pulse pile-up identification and reconstruction was presented to solve the problem. The pulse pile-up was firstly identified by detecting the downward-going zero-crossings in the first-order derivative of the original signal, and then the constituent pulse was recovered based on four constructed models. The experiment results show that the method is capable of identifying pulse pile-up accurately, as well as disentangling two pulses with a minimum time interval of 20 ns, and it both improves neutrons’ effective counting rate and corrects the distorted neutron pulse spectrum due to pile-up event.

     

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