Comparison of Methods to Determine Radon in Soil Gas

Various methods to determine 222Rn concentration in soil gas were tested at two sites with different soil types in a depth of 1 m. They include instantaneous (spot), continuous (real time) and timeaveraging procedures with advective ('active' procedures) or diffusive ('passive' procedures) gas transport from soil to detector: a) active grab-sampling of soil gas from different thin soil gas probes via drying tube and particle filter into evacuated scintillation cells and subsequent analysis of radon activity, b) active sampling by pumping soil gas through continuously operating radon monitors with ionisation chamber or silicon detector and alpha analyser, c) exposition of etch track detectors mounted in small diffusion chambers and, d) diffusion of soil gas into continuously operating, electronic soil probes with silicon detector and alpha analyser.