Gas–solid effect in mean charge and slowing down of uranium ions at 60.2 and 200 MeV/u

Charge-state distributions and energy-loss measurements of uranium ions in gases and solids at incident energies of 60.2 and 200 MeV/u were performed with the magnetic spectrometer FRS at GSI Darmstadt. The charge distribution was investigated in various gases and solids. We observed a gas–solid effect in ionization and mean charge. This effect arises from the shorter collision time in solids comparable with the lifetimes of the excited states of the projectile. Simultaneously, the stopping force was measured for the same targets.