Based on the track-etching technique, a convenient, low-cost, time-integrating monitor was developed for measuring the deposition rate of attached thoron (
220Rn) progeny indoors. Measurements of the deposition rates and concentrations of
220Rn progeny were simultaneously carried out in 13 dwellings throughout a year. Quite different deposition rates and concentrations of
220Rn progeny were found among those dwellings. However, seasonal variations of the deposition rates and concentrations were not significant in each dwelling. An average of (0.53±0.11)×10
-2cm·s
-1 was estimated for the deposition velocity of attached
220Rn progeny indoors, in fair agreement with most of the values for attached
222Rn progeny in dwellings in the literature. Significant correlation (
r=0.981) was found between the deposition rates and concentrations of
220Rn progeny, and the deposition velocity for attached
220Rn progeny was relatively constant among the typical dwellings. It suggests that it is possible to estimate indoor
220Rn progeny concentrations using their deposition rates with the proposed simple measurement technique.
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