Seminar at the accelerator – J. Graham (Missouri University)

Speaker: Joseph Graham (department of Nuclear Engineering and Radiation Sciences, Missouri University of Science and Technology)

Title: Electron Dynamics in the Ion-Matter Interaction at Short Time Scales

Abstract: The ion-matter interaction contains a fascinating variety of electronic processes that occur at high excitation densities and short time scales. Following the initial transfer of energy from a swift ion, delta electrons travel outward from the interaction core, triggering an avalanche of electronic excitation. Subsequent relaxation of the system can proceed through processes such as: radiative and non-radiative recombination, energy transfer to the lattice through electron-phonon coupling, formation of bound states that transfer energy away from the impact site, and defect-mediated recombination. This talk will present recent efforts made to help advance our understanding of some of these processes in insulators and semiconductors using ab initio modeling and ionoluminescence (IL) measurements. However, current experimental probes of the effects of electronic energy loss from ion irradiation are either indirect or time-average methods. The prospects for developing time-resolved, in situ characterization capabilities, including ion pump + laser probe techniques, will be discussed, as will the potential for using simultaneous ion and pulsed laser irradiation for the modification of materials.