Charge Equilibration Time of Slow, Highly Charged Ions in Solids

We report observations of nonequilibrium charge state distributions of slow, highly charged (33+{le} q{le}75+) ions after transmission of thin carbon foils. Charge equilibration times are determined directly from the dependencies of exit charge states on projectile velocity (0.5{times}10{sup 6}{lt}v{lt}10{sup 6} m/s) and foil thickness (5{endash}10thinspthinspnm). Ions like Xe{sup 44+} and Au{sup 68+} are found to equilibrate inside of solid matter in a time of only 7thinspthinspfs. {copyright} {ital 1999} {ital The American Physical Society}