Rutherford backscattering of laterally heterogeneous structures: The determination of radial density distributions in ion tracks in collodium

Energy loss spectrometry of ions transmitted through matter is hitherto known as a tool to probe the geometrical dimensions and/or density distributions within a given small sample in one, two, or even three dimensions. We show here that energy loss spectrometry can also be applied to determine the radial density distributions of latent ion tracks in polymers. First test experiments in Rutherford Backscattering (RBS) geometry are reported, where 2 MeV protons and α particles are used to probe the radial density distribution of self-created latent ion tracks in collodium films. Track overlapping leads to a rough surface structure which smoothens out with increasing irradiation dose.