Improved Source/Absorber Preparation for Radionuclide Spectrometry Based on Low-Temperature Calorimetric Detectors

High-resolution beta spectrometry based on low-temperature calorimetric detectors requires high-quality source/absorber combinations in order to avoid spectrum artifacts and to achieve optimal detection efficiency. In this work, preparation techniques and quality control methods to fabricate reliable source/absorber assemblies with the radionuclide under investigation embedded into them are discussed.

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.

NEW DEVELOPMENT OF RADON PROGENY MEASUREMENT METHOD BASED ON ALPHA–BETA SPECTROMETRY

Accurate measurement of radon progeny concentration is important for the dose assessment of radon exposure and the study of radon progeny behaviours. For measuring 218Po, 214Pb and 214Bi concentration as well as EEC with high sensitivity, an alpha–beta spectrometry method was developed and applied in a step-advanced filter radon progeny monitor. The derivation details of this method is given in this paper and the uncertainty is discussed. The comparison experiments are carried out in radon chamber and in field. Results show that the alpha–beta spectrometry method can give 218Po, 214Pb and 214Bi concentration as well as EEC with high sensitivity either for 60 min or for 30 min cycle, which leads to low uncertainty. This method can be used as a reference method for radon chamber and is suitable for portable radon progeny monitor.