A model of ion track structure based on classical collision dynamics.

The energy deposition in ion tracks as a function of radial distance is calculated on the basis of classical collision dynamics and using empirical range-energy relationships for electrons. The calculations show that the energy density (i.e. energy deposited per unit mass) varies according to an inverse-square function with distance from the track centre. The maximum extension, the 'penumbra radius', is a power function of the ion's kinetic energy divided by its mass. Comparison with experimental data demonstrates the applicability of the model for ion specific energies greater than 1 MeVu-1.