Abstract
A method is described for the simultaneous collection of radon and its daughters from environmental air samples by a two-stage sampling device. The radon daughter products are separated from the air stream by means of a membrane filter and radon itself is then adsorbed on activated charcoal in the sampler's second stage. Subsequent to collection, radon daughter activity is measured by alpha scintillation techniques, and gaseous radon concentration is determined by gamma spectrometry of the charcoal adsorption bed. Samples were taken under varying external environmental conditions, as well as indoors. Results are presented comparing atmospheric radon concentrations determined by direct and filter paper techniques.