密闭空间内氡浓度水平分布规律的实验研究

Experimental study on horizontal distribution of Rn concentration in confined chamber

氡气运移研究成果表明,氡气的运移具有方向性。为了进一步研究密闭空间内长时间积累条件下水平方向氡浓度分布规律,根据相似理论,设计出一种基于CR-39型固体径迹探测器的测量方法,对水平方向上氡浓度分布进行了测量。采用最小二乘法拟合方法对不同测量距离影响氡及其子体分布的反扩散系数进行了拟合,实验研究结果表明,水平方向反扩散系数与测量距离呈负幂函数相关关系,随着测量距离的增加反扩散效应对氡浓度分布的影响逐渐减弱。通过实验可得在扩散源氡浓度为45 Bq·m-3,水平测量距离为0–4 cm时,反扩散系数急剧,之后该系数则趋于稳定。

The radon migration research result shows that the migration of Rn is directional. Purpose： We aim to research further the concentration distribution of accumulated Rn in the horizontal direction and within the confined space in a long time. Methods： A measuring device was designed based on the CR-39 type solid track detector to measure Rn concentration distribution in the horizontal direction. The method of least squares fitting was applied to fit anti-diffusion coefficient that affects the distribution of Rn and its daughters within different horizontal distances. Results： The anti-diffusion coefficient and the measured distance in horizontal direction were related with a negative power function, with the increase of horizontal distance, the anti-proliferation effect on Rn concentration distribution were gradually weakened. Conclusion： With the Rn concentration of 45 Bq.m-3, the anti-diffusion coefficient decreases sharply within the distance of 0-4 cm and then tends to be steady.