Radon progeny deposition in track-detection diffusion chambers

The sensitivity dependence for cylindrical diffusion chambers that are used for radon track-detection measurements on the deposition fraction of radon progeny atoms has been theoretically studied (sensitivity is the ratio: ar ea track density/integrated Rn-222 activity concentration). Experimentally, the sensitivity values of both the metal- and plastic-made chambers were d etermined. Results indicate that the experimental sensitivity for metal cha mbers is in accordance with the theoretical model while a deviation of 15% is observed for plastic chambers. The uncertainty in the sensitivity values that is related to possible variations of the diffusion coefficient for Po -218 atoms was estimated to be less than 10%. (C) 1999 Elsevier Science B.V . All rights reserved.