Measurement of radon progeny concentration in air by α-particle spectrometric counting during and after air sampling

A procedure is presented for calculating air concentrations of the short-lived progeny of radon-222 by the use of α-particle spectrometry. The procedure allows the determination of the concentrations of RaA, RaB and RaC from one integral α-count of RaA and two integral α-counts of RaC' with counting intervals during and/or after air sampling. A computer program is presented which calculates the concentrations of RaA, RaB and RaC in air and the accuracies in these calculated concentrations, for overlapping or non-overlapping counting and sampling intervals. The advantages of counting during sampling are discussed and the counts compared with those taken after the termination of sample collection. (author)