Electron beam superimposition method and apparatus
AssigneeVarian Associates, Inc.
InventorsThomas Koller, Rajesh Bandari, Jeff Takenaka, Rick Smith
Life of this patent
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Abstract
A method and apparatus for superimposing a plurality of electron beams at a desired location after X-ray tube manufacturing processes are generally complete. The method is embodied in providing mechanical and electrical means which are internal to the X-ray tube which provide means for adjustment of a focal point of a plurality of electron beams being emitted from a cathode assembly to thereby provide precise control of where the plurality of electron beams achieve superimposition on a target anode.
Claims22
An X-ray tube capable of adjusting a focal point of electron beams to thereby superimpose said electron beams generated by a cathode assembly onto an anode assembly comprises:
- a vacuum envelope in which is disposed the anode assembly;
- a cathode port extending through a wall of the vacuum envelope;
- and
- a cathode assembly support structure coupled to the vacuum envelope and the cathode assembly, and including means for selectively adjusting a position of the cathode assembly relative to the anode assembly while partially extending the cathode assembly into the vacuum envelope through the cathode port.
A method for electron beam superimposition on a target anode, where an X-ray tube having a plurality of electron beams generated by a cathode assembly are directed at the anode assembly to thereby generate X-rays from a location where the plurality of electron beams strike the anode assembly, said method comprising the steps of:
- (1) suspending the cathode assembly over the anode assembly utilizing an adjustable cathode support structure which is capable of moving the cathode assembly generally along a cathode axis;
- and
- (2) adjusting a distance between the cathode assembly and the anode assembly utilizing the adjustable cathode support structure, thereby respectively moving a focal point of the plurality of electron beams further from or closer to the anode assembly along the cathode axis.
An X-ray tube capable of adjusting a focal point of electron beams to thereby superimpose said electron beams generated by a cathode assembly onto an anode assembly, wherein the X-ray tube comprises:
- a cathode face of the cathode assembly directed toward the anode assembly;
- a plurality of cathode cups disposed in the cathode face to thereby project a plurality of corresponding electron beams at the anode assembly;
- a plurality of insulators disposed on the cathode face, wherein each of the plurality of insulators is disposed adjacent to a corresponding cathode cup;
- a plurality of electrodes, wherein each of the plurality of electrodes is disposed on the plurality of insulators and electrically isolated from the cathode face, and capable of developing an electrical potential which can alter a path of each of the plurality of corresponding electron beams;
- and
- a plurality of means for delivering a different electrical potential to each of the plurality of electrodes.
An X-ray tube capable of adjusting a focal point of electron beams to thereby superimpose said electron beams generated by a cathode assembly onto an anode assembly, wherein the X-ray tube comprises:
- a cathode face directed toward the anode assembly;
- a first cathode cup disposed in the cathode face of the cathode assembly so as to project a first electron beam at the anode assembly;
- a second cathode cup disposed in the cathode face of the cathode assembly so as to project a second electron beam at the anode assembly;
- an insulator disposed adjacent to the first cathode cup and the second cathode cup, but so as not to electrically isolate the first and the second cathode cup from each other;
- an electrode disposed on the insulator and electrically isolated from the cathode assembly, wherein the electrode is capable of developing an electrical potential which can alter a path of the first electron beam and the second electron beam;
- and
- a means for delivering an electrical potential to the electrode.
Dependencies are inferred from the claim text.