The ionization chamber is defined by a removable block disposed in heat transfer relationship to a temperature controlled mounting block, preferably the removable block comprised of graphite, silicon carbide or aluminum. The ion source includes a mounting flange for joining the ion source to the housing of an ion implanter, the ionization chamber being located on the inside of the mounting flange and the vaporizer being removably mounted to the exterior of the mounting flange via at least one isolation valve which is separable from the mounting flange with the vaporizer, enabling the vaporizer charge volume to be isolated by the valve in closed position during handling, preferably there being two isolation valve in series, one unified with and transportable with a removed vaporizer unit, and one constructed to remain with and isolate the remainder of the ion source from the atmosphere. In certain preferred embodiments, two such vaporizers are provided, enabling one to be absent, while being charged or serviced, while the other operates, or enabling two different materials to be vaporized without maintenance of the ion source, or enabling additional quantities of the same materials to be present to enable a protracted implant run.