基于氢氧化铁-碳酸钙载带的水中~(226)Ra的γ能谱分析方法

建立了一种基于氢氧化铁-碳酸钙载带水中~(226)Ra的γ能谱分析方法,适用于环境水中~(226)Ra分析。在计算公式中,采用样品粉末质量修正因子和方法回收率对测量结果进行修正。通过对20 L水样的加标验证,本方法加标样的回收率高于83.0%,各组加标样回收率的平均值高于90.9%,准确度范围为2.05%-12.7%,精确度范围为3.20%-5.38%。利用无源效率刻度软件计算探测效率来确定探测下限和样品使用量的关系,得出采样量为40-60 L时最佳,此时探测下限为2.0 mBq·L~(-1)左右。

The gamma-spectrometry method of analyzing 226Ra in water based on ferric hydroxide-calcium carbonate carrier

Background: It is difficult to measure226Ra in water accurately because of its low content. The existing three methods have the disadvantages such as complex sample processing, large measurement error and lower detection limit, and thus could not satisfy the measurement needs.Purpose: This study aims to build a new gamma-spectrometry method to analyze226Ra in water simply and accurately with reasonable lower limit.Methods: Ferric hydroxide calcium carbonate was used as carrier for226Ra in water.Results: Experimental results shows that the spiked sample recovery rate by this method is higher than 83.0%, the average recovery of each group is higher than 90.9%, the accuracy range is 2.05%?12.7%, and the precision range is 3.20%?5.38%. The relationship between the detection limit and the usage of the sample is calculated using the sourceless efficiency calibration software. The best sample sizes are 40?60 L, and at this point the lower detection limit is about 2.0mBq?L?1.Conclusion: The results show that the method is accurate and reliable, which can be used to analyze and determine the content of226Ra in water.