A diffusion barrier charcoal adsorption collector for measuring Rn concentrations in indoor air

Development of a practical detector for collecting Rn by adsorption in charcoal with a time integration of 2 d or more, achieved by use of a diffusion barrier through which Rn enters, is described. The sensitivity is adequate for monitoring Rn levels in houses. It is easily sent and returned by mail, and instructions for use are simple enough for any householder to follow. The cost per measurement is apparently well below that for competitive techniques.