土壤样品中^(137)Cs和^(210)Pb活度分析比对研究

ASSESSMENT OF THE PROFICIENCY TEST ON THE DETERMINATION OF ^(137)Cs AND ^(210)Pb IN SPIKED SOIL

本文介绍了国际原子能机构(IAEA)组织的5个土壤样品中137Cs和210Pb活度分析的国际比对结果。本实验室比对用HPGe低本底γ谱仪对土壤样品进行测量,用LabSOCS(Laboratory Sourceless Calibration Software)进行系统无源效率刻度。通过IAEA的评价指标对结果进行评价表明,所测定的5个土壤样品中137Cs和210Pb活度结果都满足达标的要求,成功通过了IAEA的比对。IAEA公布的所有参加的18个实验室的比对结果显示,137Cs活度测定结果有82%的实验室属可接受,而210Pb活度测定结果只有33%的实验室属可接受。对这次国际比对总结分析经验和不足:137Cs与210Pb相比,其分析不确定性相对小,分析误差容易控制;210Pb是土壤中本身存在的放射性核素,其穿透能力较低,受土壤母质和本底的影响,其分析误差不容易控制。

This article summarized the results on the IAEA-CU-2006-02 proficiency test on the determination of ^137 Cs and ^210pb in spiked soil. LabSOCS（Laboratory Sourceless Calibration Software）was used to perform mathematical efficiency calibration of HPGe low-background gamma-spectrometry. The analytical data evaluation of this proficiency test according to the performance criteria of IAEA indicated that 100 % of the laboratory of the Institute of Agricultural Environment and Sustainable Development reported ＂acceptable＂ results for the ^137 Cs and ^210pb. And the analytical data evaluation of this proficiency test in IAEA＇ s report indicated that 82 % of the eighteen laboratories reported ＂acceptable＂ results for ^137 Cs and 33 % for ^210 Pb. Through this proficiency test, we could know the successful experiences and existed shortcomings. The uncertainty of 137 Cs measurement was lower than ^210Pb, the analytical error was easy to control. ^210Pb was the inherent radionuclides existed in the soil, the penetrating power was low, influenced by the soil parent material and the background, the analytical error was difficult to control.