A Monte Carlo based software for the computation of the sensitivity of etch
ed radon track detectors was developed. It can be applied to the measuremen
t of radon and radon daughters in free air or inside of a measurement chamb
er. LR 115 and CR-39 detectors, with or without an attenuator, are specific
ally addressed. Various etching conditions and observation criteria for cou
nting the track density may be specified. The latent track formation and th
e etching process are realistically modelled. The dependence of the etch-ra
te ratio on the energy is taken into account. The plate-out phenomenon is i
ncluded in the model. An inhomogeneous source distribution in the detector
cup can be considered. (C) 2001 Elsevier Science Ltd. All rights reserved.