Determination of calibration coefficient for radon measurements using a track detector

The calibration coefficient for radon measurements using a LR-115-II detector in a diffusion chamber was determined. Deposition of radon decay products on the inner chamber walls influenced the track density distribution. It was assumed that 214Po was 100% deposited before decay; however, part of 218Po atoms decay before they can be deposited. The radial track density distribution depends on the partially deposited 218Po. This dependence was assumed in order to estimate the amount of deposited 218Po so that more realistic calibration coefficients for radon measurements could be determined.