The idea of using a device with thermo-luminescent detectors (TLD) for the simultaneous measurement of radon (Rn-222) and thoron (Rn-220) decay products' concentrations was invented and developed in the Silesian Centre for Environmental Radioactivity at the Central Mining Institute, Katowice, Poland. The results of a preliminary analysis of the technical applicability, the required minimum period of air sampling and the optimised time schedule proved that such measurements can provide information about the potential alpha energy concentrations (PAECs) of radon and thoron decay products (TnDP).Following the analysis, preliminary measurements were performed at several locations-in a thoron chamber, in dwellings and even outdoors. Surprisingly, the maximum PAEC of the TnDP in the basement of a twin house in the Upper Silesia region was as high as 0.68 ± 0.15µJ m-3. This paper presents the results of those measurements.
Keywords: PAEC; TLD; detection method; radon; thoron.
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