生活饮用水中总α放射性的厚样法测量公式的实验验证

Experimental Verification of the Thick Sample Method for Measuring Total α-radioactivity in Drinking Water

在《生活饮用水标准检验方法放射性指标》(GB/T 5750.13-2006)中,总α放射性的厚样法测量公式中既将仪器计数效率从2π方向校正到4π方向,又对有效厚度层内逸出的α粒子数校正到了2π方向。两个校正有重复校正的嫌疑。本文用试验对标准中的厚样法测量公式进行了验证。试验结果表明,在对计数效率进行校正后,再次将有效厚度层内逸出的α粒子数校正到2π方向是不合适的,只将仪器计数效率从2π方向校正到4π方向即可。

In the ＂Radioactivity Standard Test Method for Drinking Water Standards＂（GB/T 5750.13-2006）, the measurement method of the thick-sample method of total alpha radioactivity not only calibrates the instrument counting efficiency from 2π direction to 4π direction, but also corrections the number of alpha particles escaping in the effective thickness to 2π direction. Two corrections are suspected of repeated correction. In this paper, the thickness measurement method formula in the standard was verified by experiments. The experimental results show that after correcting the counting efficiency, correcting the number of α particles in the effective thickness layer to the 2π direction is not appropriate. Only the instrument counting efficiency can be corrected from 2π direction to 4π direction.