不同基质241Am标准物质粉末对水中总α放射性测量的影响
Effects of 241Am standard material powder with different matrices on the determination of gross alpha activity in water
孙亚茹 1范富有 2王欢 1姚美男 1白斌 1马永忠1
作者信息
- 1. 北京市疾病预防控制中心,北京 100013
- 2. 中国计量科学研究院,北京 100029
- 折叠
摘要
目的 了解不同基质241Am标准物质粉末对水中总α放射性测量的影响,为α标准源的选取和使用提供参考.方法 使用低本底α、β测量仪测量不同基质241Am标准物质的α计数效率,通过加标实验测定水中α放射性化学回收率和全程效率.结果 4种基质241Am标准物质粉末的α计数效率从高到低依次为碳酸钙、碳酸钙和二氧化硅混合基质、硫酸钙和二氧化硅.厚源法测量水中总α放射性时如果默认化学回收率为 1,采用碳酸钙基质的241Am标准物质,会导致总α放射性测量值偏低约 35%,采用二氧化硅或者碳酸钙和二氧化硅混合基质的241Am标准物质,结果偏差约 10%.加入241Am标准溶液、241Am标准物质粉末(碳酸钙、二氧化硅以及混合基质)的 4种加标水样测定的α放射性全程效率范围值为 6.34%～7.30%.结论 不同基质的标准物质对α粒子的自吸收程度不同,对α化学回收率的影响程度不同.实验室在购买和使用α标准物质粉末时,应尽可能了解基质的成分,必要时通过测定全程效率确定水中总α放射性水平.
Abstract
Objective To understand the effects of 241Am standard material powder with different matrices on the determ-ination of gross alpha activity in water,and to provide a reference for the selection and use of alpha standard sources.Methods The alpha counting efficiency of 241Am standard material powder with different matrices was measured by low-background alpha and beta measuring instrument.The radiochemical recovery rate and whole process efficiency of gross al-pha activity in water were determined by spike experiments.Results The alpha counting efficiency of the 241Am standard material powder with four matrices was in the descending order of calcium carbonate,calcium carbonate and silica mixed matrix,calcium sulfate,and silica.The default chemical recovery rate is 1 when gross alpha activity in water is measured by thick source method.The use of 241Am standard material with calcium carbonate as a matrix resulted in about 35%decrease in gross alpha activity,and about 10%deviation was observed using 241Am standard material with silica or calcium carbon-ate and silica mixed matrices.The whole process efficiency of alpha activity in four spiked water samples with 241Am stand-ard solution and 241Am standard material powder with calcium carbonate,silica,or mixed matrix was 6.34%-7.30%.Conclusion Standard materials with different matrices demonstrate different self-absorption of alpha particles and various influence on the chemical recovery.When purchasing and using standard material powders for alpha activity measurement in laboratories,the composition of the matrix should be clarified as much as possible,and the gross alpha activity in water should be determined by measuring the whole process efficiency if necessary.
关键词
总α放射性/241Am标准物质/化学回收率/全程效率Key words
Gross alpha activity/241Am standard material/Chemical recovery/Whole process efficiency引用本文复制引用
基金项目
高层次公共卫生技术人才建设项目培养计划(学科带头人-01-20)
北京市科技计划(Z211100007021010)
国家自然科学基金项目青年科学基金项目(22106158)
出版年
2024
NETL
NSTL
万方数据