Role ofK-shell vacancies in determining charge-state fractions for heavy ions emerging from solids

The development of projectile $K$ vacancies in heavy ions passing through solids has recently been studied using both target and projectile x-ray yields. The analysis of these results implies that the post-foil charge-state fractions will exhibit a target thickness dependence which is related to the vacancy production and quenching processes for the $K$ shell of the projectile as it moves in the solid. We report experimental results for the charge-state fractions of 54-MeV S ions on thin foils of C, Al, Ti, and Ni. We propose a model which accounts for both the target thickness and the target-atomic-number dependences of the individual charge-state fractions.