Single and double ionization of He by 0.5-8 MeV/q Liq+ (q=1,2,3) ions

Single and double ionization of He by Liq+ projectiles (q=1,2,3) have been investigated in the energy range 0.5-8 MeV/q. Target ionization associated with specific outgoing projectile charge states was identified using time-of-flight techniques. The primary goal of this work was to investigate the ionization of He by ''structured'' projectiles and to determine the effect of the projectile electrons on the ionization process. For all energies investigated, the double-to-single ionization ratios associated with electron capture and loss are significantly larger than those for direct ionization (no projectile charge change). The direct double-to-single ionization ratios are largely independent of the incoming projectile charge state, apparently depending only on the nuclear charge. For single-electron capture and single-electron loss, the ratios depend quite strongly on the incoming projectile charge state, however. (orig.)