Thermal effects on CR-39 detector response and permeability of some membranes used in radon measurements

Passive technique based on a diffusion chamber fitted with permeable membrane and CR-39 detector is applied in the present study. The detector response and the filter permeability for radon were measured as a function of exposure temperature. The combined effects on the detector and membrane are studied in the temperature range from 27 to 58 °C. Two membrane categories, the paper-type and the polymer-type, are used. The obtained results show advantages of paper-type membranes over polymer-type, where the permeability of paper filter is temperature independent. As a result, the detector response is increased with temperature by a higher rate in case of polymer membrane. Consequently, the using polymer type in radon measurement at unusual temperature needs corrections. The measurements were taking into consideration the effect of temperature on the radon source emanation power which increased from 0.518 to 0.724 in the studied temperature range. The combined uncertainty for all measured parameters is calculated and discussed.