2005 Volume 40 Issue 2 Pages 177-182
A new method was developed for measuring particle size distribution of radon decay products. Aerosols of radon decay products were collected on the filters set on stages at a low pressure cascade impactor, and then alpha particles from those were detected by an imaging plate (IP) which has a high spatial resolution and a high sensitivity. Incident alpha particles were observed as a graphic image on the IP. The activity of radon decay products was estimated using the newly developed alpha spot counting program. The size distributions of aerosols of radon decay products were measured with this method in Kyoto University Research Reactor Institute (KURRI) and National Institute of Radiological Sciences (NIRS). The validity of the measuring technique using an IP was confirmed by comparing with the result using ZnS (Ag) scintillation counters.
