Size selective performance of low pressure Andersen sampler and its application to activity size distribution of radon progeny

摘要

Size selective collection performance of a low pressure Andersen sampler with some collecting substrates was investigated using 5 kinds monochromatic latex particles labeled with ~(222)Rn progeny. The best performance was obtained in the case of a silicone oil coated stainless steel disk. The sampler was applied to the measurements of the size distribution of the aerosol-attached radon progeny in the nuclear facility of Kyoto University. The size distributions were in fairly well agreement to a log-normal distribution. The geometric mean diameter ranged from 0.20 to 0.27 μm and the geometric standard deviation ranged from 1.7 to 2.4, depending on the kinds of the ambient aerosols. On the other hand, large variances were observed between participants in the domestic intercomparisons on the activity size distribution which were held between Japanese researchers.