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US 2011/0006678 A1Published application
Hollow beam electron gun for use in a klystron
OwnerPatrick Fergusoninventor
Life of this patent
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Abstract
A klystron has a hollow beam electron gun that has a circular planar electron emitting surface. A hollow electron beam is directed from the electron gun through a plurality of drift tubes, resonant chambers and magnetic fields to a collector. The hollow electron beam does not experience significant radial movement and can operate at a lower beam voltage which reduces the required length of the RF interaction circuit and lowers the risks of RF arcing.
Claims19
A hollow beam electron gun having a center axis comprising:
- an annular cathode having an annular electron emitting surface that is perpendicular to the center axis and defined by an inner radius and an outer radius about the center axis;
- a first focusing electrode mounted within the inner radius of the circular electron emitting surface;
- a second focusing electrode mounted outside the outer radius of the circular electron emitting surface;
- an annular anode that has an inner surface that is defined by an inner radius about the center axis;
- wherein the electron emitting surface is substantially planar, the length of the inner radius of the inner surface of the anode is larger than the length of the outer radius of the circular electron emitting surface and the anode is mounted distally of the cathode.
2 more elements
A hollow beam klystron having a center axis comprising:
- a hollow beam electron gun coupled to a proximal portion of the klystron comprising:
- (i) an annular cathode having an annular electron emitting surface that is perpendicular to the center axis and defined by an inner radius and an outer radius about the center axis, (ii) an anode, (iii) a first focusing electrode mounted within the inner radius of the circular electron emitting surface, and (iv) a second focusing electrode mounted outside the outer radius of the circular electron emitting surface;
- a plurality of drift tubes that have inner surfaces that are defined by an inner radius about the center axis and extend from the proximal portion to a distal portion of the klystron;
- a solenoid providing a magnetic field for focusing the electron beam;
- an RF input coupled to the proximal portion of the klystron;
- and
- an RF output coupled to the distal portion of the klystron.
4 more elements
A method for operating a klystron comprising:
- providing:
- (i) a hollow beam electron gun having:
- a cathode having an annular electron emitting surface that is perpendicular to a center axis of the electron gun and an anode;
- (ii) a plurality of aligned drift tubes that extend from the electron gun to a distal portion of the klystron;
- (iii) a plurality of solenoids that surround the drift tubes and generate magnetic fields within the drift tubes, and (iv) an RF input and an RF output;
- applying a voltage (V) and a current (I) to the hollow beam electron gun;
- and
- emitting a hollow electron beam from the circular electron emitting surface of the cathode through the drift tubes towards a distal portion of the klystron;
- wherein the perveance=31.62×I/V3/2>2.0.
6 more elements
Dependencies are inferred from the claim text.