HPGe γ谱仪对主动式活性炭法中222Rn样品的探测效率研究

主动式活性炭吸附²²²Rn的方法中，吸附时间不同，²²²Rn在活性炭盒中的分布不均匀，这对HPGe γ谱仪测量分析中效率刻度产生影响。通过在标准氡室进行的主动式双滤膜活性炭吸附实验，分析得到不同吸附时间下HPGe γ谱仪对²²²Rn子体不同能量特征γ射线的探测效率和²²²Rn在双滤膜活性炭盒中进出口计数相对偏差，拟合得到两者之间的关系曲线，即不同能量特征γ射线下的探测效率与²²²Rn进出口计数相对偏差呈线性关系。通过实验得到双滤膜活性炭盒对氡吸附量的拟合曲线值与测氡仪实测值相对偏差绝对值小于5%，验证了该方法的正确性和可靠性。

Study of Detection Efficiency of 222Rn Samples Obtained by Active Activated Charcoal by HPGe γ Spectrometry

In active adsorption of activated charcoal, it is uneven distribution of ²²²Rn in the collector in different adsorption time, which makes impact on efficiency calibration by HPGe γ spectrometry. By the adsorption experiment of active double-membrane activated charcoal in the standard radon chamber, the relationship between detection efficiencies of different energy characteristics of the γ-ray and counting relative deviation of ²²²Rn from import and export side of the double-membrane activated charcoal collector by HPGe γ spectrometry in different adsorption time was obtained, which is linear. The absolute value of relative deviation of adsorption capacity for ²²²Rn is less than 5% between calculated and measured, which is to verify the correctness and reliability of the method of active double-membrane activated charcoal.