总α放射性标准源的制备

Preparation of Total Alpha Standard Source

采用掺标法将放射性核素241Am标准溶液加入到碳酸钙中,经过物理混合得到总α放射性粉末标准源。利用液体闪烁计数法测量掺标物质241Am在碳酸钙基材中的放射性活度,并使用同一测量方法考查了均匀性和稳定性。统计结果显示均匀性F<Fα,表明组内与组间无明显差异;12个月长期试验稳定性t检验结果符合要求。标准源使用液体闪烁计数法进行绝对测量定值,获得标准源的标准值为9.45 Bq/g,相对扩展不确定度为5.6%(k=2),借助锗γ谱仪能谱分析法验证,偏差为3.0%。该α放射性标准源可用于水中总α放射性测定方法的验证。

Radionuclide ^241Am standard solution added to the calcium carbonate in the total alpha was obtained by physical mixing powder standard source, by using liquid scintillation counting method of measuring mixed standard material ^241Am activity in the calcium carbonate base material, and the same measurement method was used to solve the uniformity and stability, the uniformity results of F 〈 Fα showed that no significant differences between groups and within the group. 12 months long-term stability test accorded with a requirement by t test. Standard source using liquid scintillation counting method, the measurement of absolute value obtained the standard source standard value of 9.45 Bq/g with the relative expanded uncertainty of 5.6% （k=2）, with the aid of germanium gamma spectrometer spectral analysis method yalidation, deviation of 3.0%. The alpha standard soure can be used to verify the method to determine total alpha radioactivity in water.