CHARGE-STATE ANALYSIS OF HEAVY-IONS AFTER PENETRATION OF UNCLEANED AND SPUTTER CLEANED CONDUCTING SURFACES

The evolution of the charge state distribution of fast ions inside a s olid is of basic interest in various research fields as stopping power measurements etc. The existing models for the charge state evolution differ in the treatment of the projectile-exit-surface interaction, wh ich has a strong influence on the final charge state distributions. We measured the charge state distributions for C+, N+, and O+ (30 less-t han-or-equal-to E/M less-than-or-equal-to 130 keV/u) impact on thin C, Cu, and Au foils, where the surface properties were modified by sputt er cleaning. The measurments show a pronounced change of the mean proj ectile charge state to lower values in the case of sputter cleaned sur faces. This result underlines the importance of the projectile-surface interaction for the generation of the outcoming charge state distribu tion.