Structural analysis of simulated swift heavy ion tracks in quartz

Swift heavy ions (SHI), of specific kinetic energies in the excess of 1 MeV/u, can create cylindrical regions of structural transformation in SiO2 targets, also known as SHI tracks. Recent measurements of the track cross-sections in α-quartz show significant and consistent discrepancies across different experimental techniques used. In particular, the track radii obtained from channelling experiments based on the Rutherford Backscattering Spectrometry (RBS-c) method increase monotonically with the electronic stopping power, whereas the track radii obtained from the Small Angle X-ray scattering (SAXS) saturate past a certain stopping power threshold. We perform a systematic study of the structure of the α-quartz tracks obtained from the molecular dynamics (MD) simulations incorporating a time-dependent energy deposition based on the inelastic thermal spike model, which allows us to discuss the possible origins of these experimental discrepancies.