Long-term measurements of radon progeny concentrations with solid-state nuclear track detectors

Experimental irradiation of LR 115 detectors to known Rn222 concentrations as well as known equilibrium factors were carried out to verify the present method. The relationship between ρi and the removed layer was then derived for the V function specifically determined for the LR 115 detectors we were using for the experiments. The actual removed layers for individual detectors after etching were measured accurately using surface profilometry. A curve showing the relationship between the removed layer and the track diameter of normally incident 3 MeV α-particles is also provided for other researchers, who do not have access to surface profilometry, to use the present technique conveniently.