Some physical problems of very low 222Rn concentration measurements with the proportional counter

Abstract Deposition of radon atoms on the detector walls has been shown to occur during measurements by means of a proportional counter filled with a 222 RnCO 2 mixture. This paper describes studies of the phenomenon in a range of temperatures. A quantitative model based on the assumption of condensation of radon atoms on the CO 2 film adsorbed on the detector walls is considered. Further experiments to verify this hypothesis are proposed.