Abstract: A high current ion source for generating ion beams from gases and non-volatile materials which comprises a furnace-cathode unit for generating vapor to be ionized, a major source unit for ionizing the vapor generated in the furnace-cathode chamber and an extraction unit for removing the ions from the major source unit. The three units are removably sealed to each other by vacuum-tight seals. The furnace-cathode unit includes a furnace chamber, the major source unit includes a discharge chamber and the extraction unit a source outlet electrode. Connecting means couple the furnace chamber to the discharge chamber, and suspension means are provided for suspending the components from surrounding flanges.