一种无源效率刻度法与有源相对比较法相结合的γ谱分析方法的研究

Research on A Method of Gamma Spectrum Analysis Combing Laboratory Sourceless Calibration Software with Relative Comparison Method

为解决在γ谱核素分析中无源效率刻度法准确度不够、有源相对比较法需要制备相近标准源的弊端,选取可溯源且密度与标准源不一致的建材样品作为待测盲样,利用对标准源测量得到的效率和无源效率之间的比值作为修正因子,来修正利用效率刻度法测得的盲样比活度,并与证书值或中位值做比较。在对2个不同盲样3种核素采用3种不同的方法测量得到的6组数据中可以看出,5组数据中无源效率刻度法与有源相对比较法相结合的方法得到数据最接近证书值或中位值,1组数据中其为次优。该方法可提高γ谱核素定量分析的准确性。

There are two main methods in gamma spectrum analysis,one is Laboratory Sourceless Calibration Software（Lab SOCS）,and the other is relative comparison method,both of them have some disadvantages. Using the relative comparison method,the component of the sample and of the source should be roughly the same. But it is difficult to realize in most circumstances. And the other method-Lab SOCS cannot be accurate enough. So a new method is found to solve the problems above. Two different efficiencies were gotten by measuring the source with two methods,and a correction factor could be obtained by the ratio between the two efficiencies. Getting the activity of the traceable blind sample by the method of Lab SOCS,whose density was different with the source. Compare the activity of the traceable blind sample with the median value in the certificate after correcting the activity with the correction factor.6 sets of data were obtained by the measurement of three nuclides in 2 different blind samples with three different methods. And the results showed that the data obtained by the new method was closest to the certificate value or median value. The method of gamma spectrum analysis combing Lab SOCS with relative comparison method can improve the accuracy of gamma spectrum quantitative analysis.