探讨串道现象对饮用水中的总放射性测量结果的影响

Influence of crosstalk phenomenon on the measurement of gross alpha and gross beta radioactivity in drinking water

目的 研究串道现象对饮用水中的总放射性测量结果的影响程度.方法 采用不同标准物质、不同的厚度、不同面积进行总放射性测量试验.结果 用241 Am粉测试的串道因子数随质量增加无明显变化,铀粉则随质量增加而增加.仪器测试通道不同,串道因子数也不同.总α对总β的串道影响很明显,反过来串道因子数很小,可忽略.串道因子数受样品盘面积的影响不明显.结论 做饮用水中总放射性检测使用α-β同时测量模式时,总β放射性活度受α串道影响,可以通过粉末标准物质进行修正,减小对测量结果的影响.

Objective To study the influence of crosstalk phenomenon on the measurement of gross radioactivity in drinking water.Methods The gross activity in different standard materials with different thickness and area was measured using national standard method.Results There was no obvious change in crosstalk factor with the increase of 241Am powder amount in the measurement,whereas the larger amount of uranium used might lead to larger crosstalk factor.The different measurement channels resulted in different crosstalk factors.The influence of beta radioactivity on alpha radioactivity measurement was significant.On the contrary,the alpha-to-beta crosstalk factor was negligible.The area of sample plate imposed no significant influence on crosstalk factor.Conclusions The gross beta activity can be corrected to decrease the influence of alpha radioactivity using powder standard samples,when simultaneous alpha and beta counting mode is applied in measurement grass radioactivity in drinking water.