An ion source for an ion implantation system includes a vaporizer for producing a process gas; an electron source for generating an electron beam to ionize the process gas within a ionization chamber. The ionization chamber includes an extraction aperture for extracting an ion beam. The ion source, in accordance with the preset invention, is configured to be able to be retrofit into the design space of existing ion sources in, for example, Bernas source-based ion implanters.