Joint determination of the concentrations of the222Rn and220Rn decay products in air

Abstract

The authors describe a modification of the Kuznets and Markov methods normally employed for the determination of radon 220 and 222 daughter alpha product concentration in air in which an air sample is taken for 10 minutes on a filter at a flow rate of 10-40 liters per minute. After the conclusion of sampling the filter activity is measured for another 10 minutes. In order to then determine the latent energy of the radon 222 daughter products and to bring into account the radon 220 daughter products in the total activity measurements of the filter are taken for a second time for 30 minutes five hours after initial sampling. The level of latent energy of the combined daughter products are calculated by an equation which incorporates alpha particle detection efficiency, aerosol retention efficiency in the filter, and the Kuznets coefficients, and analyzes the separate and combined contributions of both daughter products from both sampling periods. A statistical analysis employing the Markov method is also depicted in modified form and is recommended when a more rapid analysis of air radioactivity is mandated.