Continuous radon gas measurement along with intermittent radon- and thoron-progeny measurement for one year

摘要

Continuous indoor radon gas measurement along with intermittent outdoor and indoor radon-and thoron-progeny measurement in the afternoon were made for one year around the authors' office that is located in the northeastern part of Japan. Indoor radon-progeny concentrations were smaller than outdoor ones, and quite small equilibrium factors (F-value, mean value was 0.2) were observed. A definite seasonal variation was observed for continuous radon data and intermittent radon-progeny data (higher concentrations in autumn), while no significant seasonal variation was observed for indoor thoron-progeny. Statistical and time series analyses indicated several interesting results such as several-day periods of variation that was similar to wind velocity, 20- to 30-day periodicity that concerns the rotation of the sun, etc.