Passage of nitrogen and oxygen ions through carbon and celluloid films

Abstract

The approach to charge-state equilibrium in v = 8 × 10 8 cm/s nitrogen and oxygen beams in celluloid and carbon solid films and nitrogen gas targets has been studied experimentally and theoretically. A two-film target has been used to show that the charge exchange taking place at the exit surface is of crucial importance for charge states detected outside solid targets. Electron capture cross sections inside solid targets have been calculated to be an order-of-magnitude lower than in gas targets. It is concluded that only very low lying excited states of the ions are populated within a solid, and that most ions are unexcited at least for near-equilibrium target thicknesses.