Coincidence measurements of electron capture and target ionization in multiply charged Auq++(He,Ne) collisions

Experimental studies of target ionization and electron capture have been carried out through measurements of charge-analyzed projectiles and target ions in coincidence for Auq+ projectiles at 100-keV/amu (q=5-21) colliding with either helium or neon targets. Information about partial cross sections, where the charge state of both collision partners is specified both before and after the collision, is presented. For the low-charge-state projectiles, pure single-electron capture and pure single-target ionization are found to be dominating and of equal magnitude. At the highest-charge states, single-electron capture is found to dominate, whereas single ionization is small. However, single-electron capture accompanied by ejection of a second electron is found to be of significant importance with a cross section as large as 10-15 cm2.