Ion Track Technology

PhysicsConsult

Reimar Spohr

PostHeaderIcon Abstract

Track size and track structure in polymer irradiated by heavy ions. Apel, P.; Schulz, A.; Spohr, R.; Trautmann, C.; Vutsadakis, V.. Nuclear Inst. and Methods in Physics Research, B: Beam Interactions with Materials and Atoms (1998), 146(1-4), 468-474.

The structure of latent tracks in PET was studied using chem. etching combined with a conductometric technique. Polymer samples were irradiated with Ar, Kr, Xe, Au, and U ions with energies in the range of 1 to 11.6 MeV/u. The etching kinetics of the tracks were investigated in the radii range 0-100 nm. The highly damaged track core manifests itself on the etching curves as a zone where the etch rate changes dramatically and reaches its min. at a radius of a few nm. It was found that the track core radius is approx. proportional to (dE/dx)0.55. The track core is surrounded by a halo. In the track halo, the etching proceeds at a rate that slowly increases approaching a const. value. Crosslinking of macromols. causes redn. of the etch rate in the halo which extends up to distances exceeding 100 nm in the case of the heaviest ions. Measurable change of the etch rate at such large radii could not be predicted from the shape of the calcd. spatial distributions of energy dissipated in tracks. Obviously, formation of the extended track halo is influenced by the diffusion of active intermediates from the track core to the polymer bulk.