220Rn activity concentration levels in large U/Th subterranean enclosures

Concurrent measurements of 220Rn and 220Rn progeny were conducted in an underground uranium mine. The 220Rn measurements represent the first accurate source of data for Canadian mines. Furthermore, a study of the ratio between 220Rn and its progeny under varying airflow conditions was conducted in order to determine its usefulness in deriving 220Rn activity concentration levels from experimentally simpler 220Rn progeny measurements. The data obtained suggest that the relationship between these two variables, although approximate, can be used for practical applications when no great accuracy is required. (author)