Ion source with corner cathode
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsFederico A. Herrero, Patrick A. Roman
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Abstract
An ion source may include first, second, and third electrodes. The first electrode may be a repeller having a V-shaped groove. The second electrode may be an electron emitter filament disposed adjacent the base of the V-shaped groove. The third electrode may be an anode that defines an enclosed volume with an aperture formed therein adjacent the electron emitter filament. A potential of the first electrode may be less than a potential of the second electrode, and the potential of the second electrode may be less than a potential of the third electrode. A fourth electrode that is disposed between the electron emitter filament and the anode may be used to produce a more collimated electron beam.
Claims20
An ion source, comprising:
- a first electrode comprising a repeller having a V-shaped groove defined by a pair of planar surfaces symmetrically disposed at an angle to each other, the V-shaped groove including a base defined by a line of intersection of the pair of planar surfaces;
- a second electrode comprising an electron emitter filament disposed adjacent the base of the V-shaped groove midway between the pair of planar surfaces and in the angle between the pair of planar surfaces, the electron emitter filament having a longitudinal axis that is substantially parallel to the base of the V-shaped groove;
- and
- a third electrode comprising an anode, the anode defining an enclosed volume having an aperture formed therein adjacent the electron emitter filament, wherein a center of the aperture lies in a plane that contains the base of the V-shaped groove and the longitudinal axis of the electron emitter filament;
- wherein a potential of the first electrode is less than a potential of the second electrode and the potential of the second electrode less than a potential of the third electrode.
Dependencies are inferred from the claim text.