Radial variation of track damage in polycarbonate

Abstract

Several authors reported data showing a differentiated structure of ion tracks in some polymers, when analysed at submicroscopic level. Four zones can be distinguished: core, halo, cross-linking and bulk, at least in tracks produced by ions with specific energies higher than 0.2 MeV/n. Nevertheless there is a lack of experimental data for tracks produced by low specific energy ions, where thermal spike mechanisms prevails. In the present work, data of the track diameter evolution as a function of etching time are reported for ions with 2.6, 0.09 and 0.02 MeV/n specific energies. The four typical track zones can be identified in tracks produced by 2.6 MeV/n ions. Conversely, for 0.09 and 0.02 MeV/n ion tracks, the variations are smooth and the transitions between zones are not clear. This effect could be related to the thermal spike process.