Airborne radon-222 measurement by active sampling with charcoal adsorptionand gamma-ray spectrometry

A simple method for measuring radon concentration in air is presented. Airb orne radon is adsorbed in a charcoal bed by an active air sampling. In time , the adsorbed radon comes to attain radioactive equilibrium with its short -lived progeny Pb-214. Utilizing this fact, radon concentration is derived from gamma-ray measurement of Pb-214. This method is estimated to be capabl e of detecting radon concentration in air down to 0.79 Bq.m(-3). The adsorp tion coefficient obtained with the method is compared with what is obtainab le with passive sampling. Applications of this method to indoor and outdoor radon measurements are described.