基于α能谱法220Rn子体连续测量方法研究

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100 Bq/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²²²Rn/²²⁰Rn子体的准确、快速、连续测量提供技术手段。

Study on Continuous Measurement Method of 220Rn Progeny Concentration Based on α Spectroscopy

A new method of continuous measurement of the concentration of ²²⁰Rn progeny without replacing membrane frequently was established based on α spectroscopy. 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 100 Bq/m³ in the environment, respectively. The effect of aerosols deposited 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 ²²²Rn/²²⁰Rn progeny.