Ion beam diagnostics by Doppler shifted light emissions
Broad ion beams in the energy range of 0.2 to 1.5 keV originating from a filament source with argon as feed gas have been analyzed by high-resolution emission spectroscopy. The Doppler structure of Ar + emissions reveals the existence of different velocity classes. Besides slow ions and ions possessing the main beam energy, electronically axcited Ar + ions with twice the main beam energy are detected which are attributed to a single-electron capture process in Ar + + /Ar collisions. As a preliminary result from a reactive beam extracted from a microwave CF4 source plasma fast F atoms are detected which are attributed to charge exchange and dissociative collisions in the process chamber.