An apparatus that forms a source bushing, while comprehending the possible formation of electrically conductive films thereon, is disclosed. Such an apparatus may advantageously be used to isolate an ion source from other components within the ion implanter, as these components may be at different electrical potentials. In one embodiment, the source bushing is constructed from a material having a lower electrical resistance than is currently used. By constructing the bushing in this manner, the effects of the applied lower resistance films is reduced, as the change in effective resistance is reduced. In other embodiments, the source bushing is purposely lined with an electrically semiconducting material, so that the effects of the later applied lining are minimized. In either case, the electrical potential between the two devices that are being isolated by the bushing is more evenly applied across the bushing.