Rf-driven ion source with a back-streaming electron dump
AssigneeThe Regents of the University of California
InventorsJoe Kwan, Qing Ji
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Abstract
A novel ion source is described having an improved lifetime. The ion source, in one embodiment, is a proton source, including an external RF antenna mounted to an RF window. To prevent backstreaming electrons formed in the beam column from striking the RF window, a back streaming electron dump is provided, which in one embodiment is formed of a cylindrical tube, open at one end to the ion source chamber and capped at its other end by a metal plug. The plug, maintained at the same electrical potential as the source, captures these backstreaming electrons, and thus prevents localized heating of the window, which due to said heating, might otherwise cause window damage.
Claims14
An RF driven ion source including an ion source chamber, an RF antenna disposed external to said chamber, an RF window interposed between said RF antenna and said ion source chamber, and a faceplate proximate the ion source chamber and opposite said RF window, said faceplate defining an extraction opening, the improvement comprising the affixing an electron beam dump to said RF window, wherein the ion source chamber is open to said beam dump.
Dependencies are inferred from the claim text.