Measurement system for alpha and beta emitters with continuous air sampling under different exposure situations

In the present study, a continuous radioactive aerosol measurement system (CRAMS) was developed for measurements of radioactive plume (e.g. ¹³¹I, ¹³⁴Cs and ¹³⁷Cs) under the emergency situation, and measurements of radon/thoron progeny under the existing situation. As a result, it is suggested that the CRAMS could follow the variation of radon concentration, and the detection limit of the CRAMS under ambient dose equivalent rate of 20 µSv h⁻¹, where the temporary evacuation is required within one week in the Japanese regulation, was evaluated to be 129 Bq m⁻³ in the manner of ISO11929. - Highlights: • Continuous radioactive aerosol measurement system (CRAMS) developed for radioactive plume. • CRAMS tested under existing situation for radon progeny. • CRAMS tested at evacuation zone in Fukushima Prefecture. • Detection limits were calculated for several dose rates according to ISO11929 and Kaiser.