Determination of 222Rn in air by alpha liquid scintillation using solvent extraction

A dynamic sampling method is proposed for the determination of 222Rn in air samples by extraction of the gas with a liquid scintillator and measurement of the alpha-radiation by a liquid scintillation technique. A detailed study of the procedure is carried out in order to define the optimal sampling conditions: times longer than 5 min and flows of the order of 450 cm3/min are recommended using a xylene-based scintillator at room temperature to extract the radon from the air. Background reduction is also improved by separation of the alpha and beta pulses, such that the alpha-spectra used for the determination of 222Rn present sufficient sensitivity for environmental applications.