INTERCOMPARISON EXPERIMENT AND UNCERTAINTY ANALYSIS OF THREE MEASUREMENT METHODS FOR RADON PROGENY AT NIM

An intercomparison experiment of three radon progeny measurement methods, based on alpha spectrometry (Kerr method), alpha–beta spectrometry and liquid scintillation counter (LSC method), was carried out in the standard radon chamber at NIM. Both the consistency and the uncertainty analysis of three different methods were studied in detail. Results show that, at the EEC level of 4000 Bq/m3, the uncertainties of the alpha–beta spectrometry, LSC method and Kerr method were 3.78%, 6.41% and 9.46%, respectively, which are mainly contributed by detection efficiency uncertainty, measuring time uncertainty and counting statistical uncertainty in sequence. The comparison results at different concentration levels show that the measurement values of three methods are consistent within the error range of 3%. The alpha–beta spectrometry can be used as a reference standard method to achieve the simultaneous measurement of RaA, RaB, RaC concentrations and EEC in the radon chamber.