Recently, digital gamma-ray spectroscopy employing low-cost and publicly available (Commercial off the shelf) digitizers has been frequently used in different studies worldwide. In this paper, we considered the digital methods for gamma-ray spectroscopy in which the anode pulses of the photomultiplier tube (PMT) output in a NaI(Tl) scintillation detector were immediately digitized by a PC sound card. We introduced and developed the methods for gamma-ray spectroscopy of microCurie gamma-ray sources by a sampling rate of 96 kHz. First, at low count rates, the pulse arrival time was determined directly by the raw waveform, and the gamma-ray spectrum was obtained by summing the corresponding values in the samples per pulse. In addition, the gamma-ray spectrum was obtained by an enhanced sampling rate waveform and the pulse arrival time was determined by employing the digital constant fraction discrimination (DCFD) method, where each pulse area was achievable by summing the corresponding values of pulse samples. On the other hand, fitting the appropriate model function on the pulses and obtaining the fitted pulse area were undertaken for gamma-ray spectroscopy. To this end, a non-iterative algorithm to fast fit the Gaussian model function was improved. Moreover, the pile-up correction was performed at different count rates employing the Maximum Likelihood Estimation (MLE) method and Gaussian model function. Also, an approximate method for solving the high run time challenge was identified in the MLE method for long-time waveforms. To reject the pile-up events, a method was introduced based on the calculation of the full-width at half maximum pulses. By applying the proposed rejection method, we achieved an energy resolution of 6.2% at 663 keV gamma-rays and a count rate of 5.3 kcps.

最近，采用低成本和公开可用（现成商用）数字化仪的数字伽马射线光谱仪已在全球不同研究中频繁使用。在本文中，我们考虑了伽马射线光谱的数字方法，其中 NaI(Tl) 闪烁探测器中光电倍增管 (PMT) 输出的阳极脉冲立即由 PC 声卡数字化。我们介绍并开发了采样率为 96 kHz 的微居里伽马射线源的伽马射线光谱方法。首先，在低计数率下，脉冲到达时间直接由原始波形确定，伽马射线光谱是通过对每个脉冲样本中的相应值求和来获得的。此外，伽马射线谱是通过增强采样率波形获得的，脉冲到达时间是通过采用数字恒定分数鉴别（DCFD）方法确定的，其中每个脉冲区域通过对脉冲样本的相应值求和来实现。另一方面，对脉冲拟合适当的模型函数并获得拟合的脉冲面积用于伽马射线光谱。为此，改进了一种快速拟合高斯模型函数的非迭代算法。此外，使用最大似然估计 (MLE) 方法和高斯模型函数以不同的计数率执行堆积校正。此外，在长时间波形的 MLE 方法中确定了解决高运行时间挑战的近似方法。为了拒绝堆积事件，介绍了一种基于半峰全宽计算的方法。通过应用所提出的拒绝方法，我们在 663 keV 伽马射线和 5.3 kcps 的计数率下实现了 6.2% 的能量分辨率。