The behaviors of three significantly different geometries of industrial ion sources are compared. The gas flow needed for a given discharge voltage can be significantly reduced by additional neutralizer filament current beyond that needed to eliminate arcing/sparking due to excess charge build-up from the positive ions from the source. This reduced gas flow also reduces the process pressure and thereby reduces the competition of that gas for a position in the matrix of a film being deposited with the ion assisted deposition intended to produce increased film density.