Indoor radon daughter contamination monitoring: the absolute efficiency of CR-39 taking into account the plateout effect and environmental conditions

In this work it is shown that CR-39 (Supergrade PM355, Pershore Mouldings Ltd, England) can be used as an absolute detector in 222Rn and radon daughters (RD) monitoring by employing it as an α spectrometer. By adopting the technique described here, one can measure separately: (a) the 222Rn activity, (b) the RD α activity in the air, and (c) the RD α activity plated out on the detector surface. The calibration factors measured for these three items were found to be weakly dependent on environmental conditions. The relationship between the track density and the radon and daughters α activity taking into account the influence of the plateout phenomenon and environmental conditions is discussed. Possible applications of the experimental results on subjects related to dose calculation, like the mean RD deposition rates indoors, are also discussed. (Author)