The radial structures of etched tracks induced by randomly incidenting
alpha-particles from radon and its progeny in the bare and 50 mu m po
lyethylene covered samples, made of the CR-39 plastics, were studied b
y means of the confocal imaging technique. The electrochemically etche
d tracks were sequentially sectioned into (1-2) mu m optical sections
and reconstructed in three-dimensional images. The morphometric parame
ters of their radial cross-sections were measured.