Interaction cross sections needed for simulation of secondary electron emission spectra from thin metal foils after fast proton impact

Abstract

Monte Carlo simulations of secondary electron emission from thin metal foils after fast proton impact require reliable interaction cross sections with the target under consideration. Total and energy differential inelastic cross sections have been derived for aluminum, copper, and gold thin-metal foils within the plane-wave first Born approximation (PWFBA) that factorizes the double cross section into the generalized oscillator strength and kinematic factors. The generalized oscillator strength or Bethe surface of the medium is obtained by using a semi-empirical optical oscillator strength distribution published in the literature and an extension algorithm based on the delta-oscillator model. Energy differential, total, and stopping cross sections are then obtained by simple integrations. Comparisons with other calculations and experimental values from the literature show that our model offers a good agreement in the energy range considered. As a final step, the cross sections and a transport model for copper have been implemented into the Monte Carlo track structure code PARTRAC where simulations of secondary electron emission spectra from copper foil have been performed.