Electron-bombardment ion source including alternating potential means for cyclically varying the focussing of ion beamlets
AssigneeIon Tech Limited
InventorsPaul D. Reader, Harold R. Kaufman
Life of this patent
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Abstract
An ion source includes apparatus that defines a region in which a supply of ions are produced. An apertured grid is disposed at one end of the region. A potential difference is impressed between the grid and the region so as to accelerate ions out of the region through the grid as a plurality of beamlets, the grid serving to focus those beamlets. To cyclically vary the degree of focus of the beamlets, the system as embodied further includes an arrangement for alternating a potential on the grid relative to a potential elsewhere in the ion source and to which the ions are subjected.
Claims19
An ion source comprising:
- means for producing a supply of ions within a defined region;
- an apertured grid disposed in the vicinity of one end of said region;
- means for impressing a potential difference between said grid and said region for accelerating ions out of said region through said grid as a plurality of beamlets, said grid serving to focus said beamlets;
- and means, including a source of alternating potential, for cyclically varying the degree of focus of said beamlets.
An ion source comprising:
- means for producing a supply of ions witin a defined region;
- an apertured screen disposed at one end of said region;
- an apertured grid spaced from said screen in a direction away from said region with the apertures in said grid being alined relative to the apertures in said screen so that said screen shields said grid from ionic bombardment;
- means for impressing a potential difference between said grid and said region for accelerating ions out of said region through said screen and said grid as a plurality of beamlets, said screen and said grid together serving to focus said beamlets;
- and means, including a source of alternating potential, for cyclically varying the degree of said focus of said beamlets.
Dependencies are inferred from the claim text.