Abstract: A gas distributor for an ion source includes a plate having a recess and a series of apertures spaced radially outward from the recess. The apertures define paths for the flow of a gas through the plate, and the gas distributor further includes a sacrificial element that is separate from the plate and that is receivable and seats within the recess. The sacrificial element forms an area of the gas distributor that is subjected to erosive forces during normal operations of the ion source, and therefore, prevents erosion of the surface of the plate. The sacrificial element is removable from the plate and replaceable with another sacrificial element during a procedure which neither requires the plate to be removed from the ion source nor the ion source to be disassembled.