水中氚含量测定比对及其能力评定标准差确定

Inter-laboratory Comparison of Tritium Analysis in Water and Determination of Standard Deviation of Proficiency Test

放射性分析领域的能力验证活动较少,与之相关的一些经验值往往需要估计得出。通过对近年来水中氚含量测定的实验室间比对活动进行总结,统计了能力评定标准差,为今后类似活动提供了计算依据和经验参考。根据2015—2018年全国6个水中氚样品的比对数据,总结了每次比对的基本信息,绘制比对结果的分布图,并与2017年国际原子能机构组织的水中氚国际比对进行对比。使用经典统计方法,将剔除离群值后的参与结果标准偏差作为能力评定标准差,计算每次比对活动的z值。综合7轮次水中氚含量测定的实验室间比对结果,得到水中氚分析的能力评定标准差的相对值范围为5.38%~16.3%。水中氚活度浓度大于100 Bq/L时,能力评定标准差的相对值小于10%。采用相对偏差法进行准确度评价时,参与结果均可接受。采用z值进行评价时,出现有问题或不满意结果。不同评价方法得到的比对结论存在较大差异。

There are few activities of proficiency test in the field of radioactivity analysis,and some related empirical values often need to be estimated.By summarizing the analysis and inter-laboratory comparison of tritium in water in recent years,the standard deviation of proficiency test is given,which provides calculation basis and experience reference for similar activities in the future.According to the comparison data of 6 tritium samples in water from 2015 to 2018,the basic information of each comparison is summarized,and the distribution map of comparison results is drawn,which is compared with the international comparison of tritium in water organized by the International Atomic Energy Agency in 2017.Using the classical statistical method,the standard deviation of participants’results after outliers are removed is taken as the standard deviation of ability evaluation,and the z value of each comparison activity is calculated.According to the comparison results of seven rounds of tritium water samples,the relative value range of standard deviation of capability evaluation of tritium analysis in water is 5.38%~16.3%.When tritium activity concentration in water is greater than 100 Bq/L,the relative value of standard deviation of capability evaluation is less than 10%.When the relative deviation method is used to evaluate the accuracy,the participants’results are acceptable.When using z value to evaluate,there are problems or unsatisfactory results.The comparison conclusions obtained by different evaluation methods are quite different.