Ion source having fluid-cooled supply conductors

摘要

Two current supply conductors connected to an emissive filament located within a vacuum enclosure are each constituted by a leak-tight tube formed of material other than a heavy metal which traverses the enclosure wall through a leak-tight bushing, and by a conductor of electrically conductive heavy metal such as copper which is placed inside the leak-tight tube and completely isolated from the vacuum enclosure. This arrangement permits the continued use of heavy metals such as copper for current supply to ion sources without any attendant danger of heavy metal ion formation in the emitted beam.