Projectile and target ionization in MeV u^-1collisions of Xe ions with N₂

Abstract

Experimental cross sections are presented for single and multiple electron stripping from Xe18+ projectiles in collisions with N2 at energies 2.0-9.3 MeV u-1. The data are compared to 2-30 MeV u-1 n-body classical trajectory Monte Carlo calculations that explicitly include electrons on both centres. Two-centre electron-electron (e-e) and electron-screened nuclear interactions contribute to the ionization reactions. The computations are in reasonable accord for the total stripping cross section but underestimate the higher stages of multiple electron loss. An energy deposition model gives improved agreement with experiment. The energy dependence of the total stripping cross section is close to E-0.5. Calculations are also presented for target ionization by Xe+, Xe8+ and Xe18+ at 10 and 20 MeV u-1. Projectile and target ionization cross sections are found to be comparable. Cross sections for projectile stripping by ionized targets are also calculated and found to be relatively insensitive to the ionization stage of the target. This latter observation is attributed to the compensating contributions between the two-centre e-e and electron-screened nuclear interactions.