Influence of sampling air flow rate in the decay correction applied to the determination of 7Be and short-lived radionuclides in aerosol samples

An original decay correction procedure is proposed for the activity determination of short-lived radionuclides in airborne dust samples. To this end, the hypothesis of air flow rate attenuation during sampling is considered and tested. The other decay corrections: to the delay time, from the end of the sampling until the start of the counting; and to the counting time, were executed as standard. Differences from classic corrections, which consider a constant air flux rate in the sampling with a weekly sampling duration, are of the order of 1% for Be-7 and approximately 10% for I-131. Moreover, the procedure can be applied to estimate the air volume sampled in the last 24h before the end of the sampling. This volume can be used to calculate the activity concentration of a radionuclide (short-or long-lived radionuclide) if a major nuclear accident causes an instantaneous contamination immediately before the end of sampling. (c) 2006 Elsevier Ltd. All rights reserved.