基于α能谱法^(220)Rn子体连续测量方法研究

Study on Continuous Measurement Method of ^(220)Rn Progeny Concentration Based onαSpectroscopy

本文基于α能谱法建立了无需频繁更换滤膜的220Rn子体连续测量方法,并在南华大学氡实验室开展了与标准220Rn子体参考水平定值方法的220Rn子体水平测量的对比研究。结果表明:在高220Rn子体水平测量环境中,ThB和ThC 8个测量周期的测量结果与参考方法的测量结果相差5.0%与7.0%左右。在低220Rn子体水平测量环境中,ThB 4个测量周期的测量结果与参考方法的测量结果相差控制在4.5%以内,ThC的控制在10.0%左右。在220Rn子体水平为100Bq/m3左右的测量环境中,ThB和ThC的总不确定度均控制在5%左右;采样过程中沉积在滤膜上的气溶胶对滤膜自吸收的影响可忽略。该方法的建立将为222 Rn/220Rn子体的准确、快速、连续测量提供技术手段。

A new method of continuous measurement of the concentration of 220Rn progeny without replacing membrane frequently was established based onαspectroscopy.A comparison study between the new method and the standard method for determination^220Rn progeny reference levels was carried out in the radon laboratory of the University of South China.The results show that under the high level measurement environment of ^220Rn progeny,the relative difference of the two method is 5.0%for ThB and 7.0%for ThC during eight measurement periods.Under the low level measurement environment of 220Rn progeny,ThB relative difference of the two methods is controlled within 4.5%and that of ThC is controlled at about 10.0% during four measurement periods.The total uncertainty of ThB and ThC is controlled at about 5% for measurement ^220Rn progeny＇s level of 100Bq/m3 in the environment,respectively.The effect of aerosolsdeposited on the membrane surface on membrane self-absorption can be ignored in the process of sampling.The new method provides accuracy,quick and continuous measurement for ^222 Rn/220Rn progeny.