Uncertainty in radon measurements with CR39 detector due to unknown deposition of 218Po

Uncertainty in radon measurements using the CR39 solid-state nuclear track detector in chambers is introduced by the unknown fraction f1 of 218Po that deposited onto the inner chamber walls. This uncertainty was estimated for cylindrical chambers with different size in the present study. It was found that the uncertainty increased with the chamber height and radius. For short chambers with a height H=2 cm the uncertainty was less than 5%, while in tall chambers with H=7 cm it could be up to 17%. The radial track density on the CR39 detector inside the diffusion chamber was also found to be dependent on the fraction f1. In this work, some examples of this dependence are shown.