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 Li9+ projectiles (q = 1,2,3) hav e been investigated in the energy range 0.5-8 MeV/q. Target ionization associated with specific outgoing projectile charge states was identi fied using time-of-flight techniques. The primary goal of this work wa s to investigate the ionization of He by ''structured'' projectiles an d to determine the effect of the projectile electrons on the ionizatio n process. For all energies investigated, the double-to-single ionizat ion 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 independen t of the incoming projectile charge state, apparently depending only o n the nuclear charge. For single-electron capture and single-electron loss, the ratios depend quite strongly on the incoming projectile char ge state, however.