Measurements of time-averaged radon-daughter concentrations with passive dosemeters

With standard dosemeters of the Karlsruhe type it is possible to measure simultaneously time-integrated radon and radon-daughter concentrations. For this purpose the dosemeters were equipped with a lid and a bottom foil. Pre-etching conditions for either type of foil were optimized; under these conditions no effects of plate-out were observed. The method seems to be sensitive to neutral radon daughters only. Possible improvements of the dosemeter geometry are indicated.