Dependence of convoy electron production on projectile charge state for 3.6 and 6.0 MeV carbon on Si(100)

Charge state distribution measurements of carbon ions exiting a grazing collision with a silicon (100) surface have been made, as well as coincidence measurements between these ions and collisionally produced convoy electrons for 3.6 and 6.0 MeV C{sup q+}, q=1, 2, and 3, incident at {approximately} 0.15{degrees} to the surface plane. Although the exit charge state distributions are at equilibrium, i.e. independent of incident charge state, at each energy, the yield and spectrum of convoy electrons in coincidence with specularly reflected projectiles exhibit a dependence on the incident charge state at the higher collision energy, suggesting that charge state equilibration was not achieved at the time of convoy electron production in that case. In addition, the equilibrium charge state distributions observed with surface targets at both energies are shifted to higher charge states than corresponding distributions observed with the same apparatus and with thick carbon foil targets.