Cathode head with focal spot control
View Patent ↗A cathode head is provide that is suitable for use in an x-ray device that includes an anode having a target surface configured and arranged to receive electrons emitted by the cathode head. The cathode head may be constructed of magnetic or non-magnetic material and includes an emitter block carrying a filament that defines a longitudinal axis about which is disposed one or more magnetic coils. The filament is configured and arranged to emit an electron beam that defines a focal spot on the target surface of the anode. The magnetic coil, or coils, disposed about the longitudinal axis defined by the filament generate a magnetic field that enables control of the location of the focal spot on the target surface of the anode.
1. A cathode head suitable for use in an x-ray device and the cathode head comprising:
an emitter block;
an emitter attached to the emitter block and configured to generate electrons of an electron beam, at least a portion of the emitter being positioned within the emitter block, and
at least one magnetic element that defines an opening within which a portion of the emitter is positioned.
2. The cathode head as recited in claim 1 , wherein the at least one magnetic element comprises at least one electromagnet.
3. The cathode head as recited in claim 1 , wherein the at least one magnetic element comprises at least one permanent magnet.
4. The cathode head as recited in claim 1 , wherein the emitter block is substantially non-magnetic.
5. The cathode head as recited in claim 1 , wherein the emitter defines a longitudinal axis which extends through the opening defined by the at least one magnetic element.
6. The cathode head as recited in claim 1 , wherein the at least one magnetic element comprises a pair of electromagnets, each of which defines an opening within which a respective portion of the emitter is positioned.
7. The cathode head as recited in claim 1 , wherein the at least one magnetic element and the emitter block cooperate to create a magnetic field through which at least a portion of the electron beam passes.
8. The cathode head as recited in claim 1 , wherein the emitter comprises at least one filament.
9. The cathode head as recited in claim 1 , wherein the at least one magnetic element is arranged such that flux lines of a magnetic flux density B of a magnetic field associated with the at least one magnetic element are substantially perpendicular to a direction of travel of an electron beam generated by the emitter.
10. A cathode head suitable for use in an x-ray device and comprising:
a magnetic emitter block;
an emitter attached to the emitter block and configured to generate electrons for an electron beam that defines a focal spot; and
means for facilitating focal spot control, wherein the means generates a magnetic field with a magnetic flux density B having flux lines that are substantially perpendicular to a direction of travel of the electron beam.
11. The cathode head as recited in claim 10 , wherein the means for facilitating focal spot control serves to adjust a position of the focal spot.
12. The cathode head as recited in claim 10 , wherein the means for facilitating focal spot control enables at least lateral adjustments to a position of the focal spot.
13. The cathode head as recited in claim 10 , wherein the means for facilitating focal spot control implements an adjustable deflection of the electron beam.
14. The cathode head as recited in claim 10 , wherein the means for facilitating focal spot control acts on the electron beam in a location proximate the emitter.
15. The cathode head as recited in claim 10 , wherein the means for facilitating focal spot control cooperates with the emitter block to create a magnetic field through which at least a portion of the electron beam passes.
16. An x-ray device, comprising:
a vacuum enclosure;
an anode substantially disposed within the vacuum enclosure, the anode including a target surface; and
a cathode head comprising the following elements, each of which is substantially disposed within the vacuum enclosure:
an emitter block;
an emitter attached to the emitter block and configured to emit electrons of an electron beam that defines a focal spot on the target surface of the anode; and
at least one magnetic element that defines an opening within which a portion of the emitter is positioned.
17. The x-ray device as recited in claim 16 , wherein the at least one magnetic element comprises a pair of magnets, each of which defines an opening within which a respective portion of the emitter is positioned.
18. The x-ray device as recited in claim 16 , wherein the at least one magnetic element comprises a permanent magnet.
19. The x-ray device as recited in claim 16 , wherein the emitter block is substantially non-magnetic.
20. The x-ray device as recited in claim 16 , wherein the emitter block is magnetic.
21. The x-ray device as recited in claim 16 , wherein the emitter defines a longitudinal axis which extends through the opening defined by the at least one magnetic element.
22. The x-ray device as recited in claim 16 , wherein the at least one magnetic element and the emitter block cooperate to create a magnetic field through which at least a portion of the electron beam passes.
23. The x-ray device as recited in claim 16 , wherein the anode is a rotating anode.
24. The x-ray device as recited in claim 16 , wherein the anode is a stationary anode.
25. The x-ray device as recited in claim 16 , wherein the at least one magnetic element is arranged such that flux lines of a magnetic flux density B of a magnetic field associated with the at least one magnetic element are substantially perpendicular to a direction of travel of an electron beam generated by the emitter.
26. A cathode head suitable for use in an x-ray device and comprising:
an emitter block;
a filament attached to the emitter block and defining a longitudinal axis, the filament being configured to emit electrons of an electron beam; and
first and second magnetic elements that define respective openings within which the emitter block is positioned.
27. The cathode head as recited in claim 26 , wherein the emitter block is substantially non-magnetic.
28. The cathode head as recited in claim 26 , wherein the emitter block is magnetic.
29. The cathode head as recited in claim 26 , wherein at least one of the magnetic elements comprises an electromagnet.
30. The cathode head as recited in claim 26 , wherein a portion of the filament is positioned within one of the openings respectively defined by the magnetic elements.
31. The cathode head as recited in claim 26 , wherein flux lines of a magnetic flux density B of a magnetic field associated with at least one of the magnetic elements are substantially perpendicular to a direction of travel of the electron beam.
32. The cathode head as recited in claim 26 , wherein the emitter block substantially comprises ceramic.
33. The cathode head as recited in claim 26 , wherein at least one of the magnetic elements comprises a permanent magnet.
34. The cathode head as recited in claim 26 , wherein the first and second magnetic elements are disposed in a spaced apart arrangement with respect to each other.
35. A cathode head suitable for use in an x-ray, the cathode head comprising:
a magnetic emitter block;
an emitter attached to the magnetic emitter block; and
at least one magnetic element arranged such that flux lines of a magnetic flux density B of a magnetic field associated with the at least one magnetic element are substantially perpendicular to a direction of travel of the electron beam.