tracks in SiO 2

Monte-Carlo simulations were applied for investigat ion of the initial electronic kinetics ( ≤ 10 -14 s) in tracks of Ca +19 (11.4 MeV/u) in SiO 2. The spatial and temporal distributions of the volume and excess energy densities of free e lectrons, electronic vacancies in different atomic shells and the lattice were obtained. It was demonstrated that at 10 -14 s an essential part (~ 55 %) of the energy deposited by the ion is trapped in electronic vacancies. The energy transferred to the lattice at times shorter than th e characteristic time of electron-phonon coupling was determined. It was found that only ~ 6 % of the excess energy of delocalized electrons near the projectile trajectory (~ 6 nm) may be thermaliz ed on the time 10 -14 s from the projectile passage. Ballistic spatial propagation of excess en ergy cannot be described by thermal diffusion.