天然放射性环境分析标准物质的研制

PREPARATION OF NATURAL RADIOACTIVE REFERENCE MATERIALS FOR ENVIRONMENT ANALYSIS

为满足国内天然放射性检测工作的需要，参照国家一级标准物质技术规范，研制了系列天然放射性环境分析标准物质，包括铀-镭，钍，钾及铀、镭、钍、钾混合标准物质共4种，已于2004年批准为国家二级标准物质GBW（E）040012-GBW（E）040015。标准物质的原料采白天然环境，钾标准物质的基质为钾长石，其它标准物质的基质为石英，天然放射性系列达到放射平衡，且氡气析出百分数低。样品均匀性良好，定值测试邀请了国内9家实验室，共采用5种分析方法。

Considering the need in environmental natural radioactivity measurement, a series of Secondary Certified Natural Radioactivity Environment Reference Materials GBW（E）040012 - GBW（E）040015 were prepared according to Technical Specification of Primary Reference Material. These reference materials are composites of natural materials. The matrix of K reference material is potash feldspar and that of other reference materials is quartz. The radioactive equilibrium of U series and Th series in raw materials proved to be attained. Having passed homogeneity test, collaborative analyses were carried out in nine laboratories with five reliable analytical methods based on different principles of measurement. For each reference material, the values of U, Ra, Th and K were certified. Farther study indicated that the emanation coefficient of Rn in these reference materials was low.