Determination of deposition behaviour of Po-218 from track density distribution on SSNTD in diffusion chamber

The radial distribution of track density on an LR115 detector inside a diff usion chamber used for radon measurements was found to be a function of the deposition fraction f(1) of Po-218 before decay. Therefore, the track dens ity distribution could be used to determine f(1). Examples of sensitivity d istributions were shown for different chamber dimensions in this work, and large chambers were found to be the best for the study of f(1). Furthermore , the radial track density distribution and the detector sensitivity were a lso found to be variable for different detector sizes The uncertainty in ra don measurements due to unknown f(1) was estimated for cylindrical chambers with different dimensions. It was found that smaller chambers possessed in ternal stability against f(1) while larger chambers had uncertainties depen ding on f(1) and could have uncertainties reaching as high as 30%. (C) 1999 Elsevier Science B.V. All rights reserved.