Equilibrium charge states of swift F ions after passage through thin foils: Projectile-velocity dependence and target-atomic-number dependence

Equilibrium charge-state distributions of F ions have been measured in the collisions of (1) (29-108)-MeV F+C and (2) 30- and 60-MeV $F+{}_{Z_2}{}^{}{}_{}{}^{}X$ foils. Measurement (1) is done to investigate the projectile-velocity dependence of the mean charge state, distribution width, and charge-distribution function. Measurement (2) is done to investigate the $Z_2$ (target atomic number) dependence of F-ion charge states using 20 kinds of foils with different $Z_2$. Contrary to the $Z_2$ oscillation of mean charge states of swift Si and Cl ions, obvious $Z_2$ oscillatory behavior has not been observed in 30- and 60-MeV F ions. Generally, higher-charge states are observed after passage through lower-$Z_2$ foils, which follows a trend similar to the $Z_2$ dependence of effective charges estimated from stopping powers.