Elliptical ion beam distribution method and apparatus.

摘要

An ion source (10) for creating an ion beam. The source includes an ionization chamber (16) having one wall that defines a generally elliptical opening (50) for allowing ions to exit the ionization chamber. Use of an elliptical (in section) ion beam has advantages over a rectangular ion beam which allow the integrity of a relatively high current ion beam to be maintained as ions travel to a beam treatment workstation. A dual configuration extraction electrode assembly (20) also provies for a range of extraction energies from a single source.