基于NaI(Tl)谱仪的3种γ能谱解谱方法比较

Comparative Study of Three γ Spectrum Solution Methods Based on NaI(Tl) Spectrometer

摘要: 目的：NaI(Tl)谱仪相对分辨率较低，通过比较3种解谱方法并选出最优解谱方法，提高γ能谱测量值的准确性和可靠性。方法：先用相对比较、逆矩阵、最小二乘法3种分析方法对已知活度的混合标准源进行活度计算，再比较计算活度与标准源活度的相对偏差。结果：使用相对比较法、逆矩阵法、最小二乘法计算出3种核素相对偏差分别为：²²⁶Ra (13.62%、14.71%、9.12%)、²³²Th (14.43%、20.59%、13.17%)、⁴⁰K (2.18%、4.91%、4.84%)。结论：使用最小二乘法对²²⁶Ra和²³²Th 2种核素的计算活度相对偏差最小，优于相对比较法与逆矩阵法；40K核素的活度计算采用相对比较法更合适。

Abstract: Objective: The resolution of NaI(Tl) spectrometer is relatively low. By comparing the three spec-trum solution methods and selecting the best solution method, the accuracy and reliability of the measured values of the γ energy spectrum can be improved. Methods: First use relative compari-son, inverse matrix, and least square analysis methods to calculate the activity of the mixed standard source with known activity, and then compare the relative deviation between the calcu-lated activity and the standard source activity. Results: The relative deviations of the three nuclides calculated using the relative comparison method, the inverse matrix method, and the least square method: ²²⁶Ra (13.62%, 14.71%, 9.12%), ²³²Th (14.43%, 20.59%, 13.17%), ⁴⁰K (2.18%, 4.91%, 4.84%). Conclusions: Using the least square method to calculate the relative deviation of the activities of ²²⁶Ra and ²³²Th nuclides is the smallest, which is better than the relative comparison method and the inverse matrix method. The activity calculation of 40K nuclides is more suitable for the relative comparison method.