X-ray tube having magnetic quadrupoles for focusing and magnetic dipoles for steering

Patent metadata

Field	Value
Publication number	US-10008359-B2
Application number	US-201514642283-A
Country	US
Kind code	B2
Filing date	Mar 9, 2015
Priority date	Mar 9, 2015
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

An X-ray tube can include: a cathode including an electron emitter; an anode configured to receive the emitted electrons; a first magnetic quadrupole between the cathode and the anode and having a first quadrupole yoke with four first quadrupole pole projections extending from the first quadrupole yoke and oriented toward a central axis of the first quadrupole yoke and each of the four first quadrupole pole projections having a first quadrupole electromagnetic coil; a second magnetic quadrupole between the first magnetic quadruple and the anode and having a second quadrupole yoke with four second quadrupole pole projections extending from the second quadrupole yoke and oriented toward a central axis of the second quadrupole yoke and each of the four second quadrupole pole projections having a second quadrupole electromagnetic coil; and a magnetic dipole between the cathode and anode and having a dipole yoke with four dipole electromagnetic coils.

First claim

The invention claimed is:

1. An X-ray tube comprising:
a cathode including an electron emitter that emits an electron beam;
an anode configured to receive the emitted electrons of the electron beam;
a first magnetic quadrupole between the cathode and the anode and having a first quadrupole yoke with four first quadrupole pole projections extending from the first quadrupole yoke and oriented toward a central axis of the first quadrupole yoke and each of the four first quadrupole pole projections having a first quadrupole electromagnetic coil;
a second magnetic quadrupole between the first magnetic quadrupole and the anode and having a second quadrupole yoke with four second quadrupole pole projections extending from the second quadrupole yoke and oriented toward a central axis of the second quadrupole yoke and each of the four second quadrupole pole projections having a second quadrupole electromagnetic coil; and
a magnetic dipole between the cathode and anode and having a dipole yoke with four dipole pole projections and four dipole electromagnetic coils, wherein each dipole pole projection has a dipole electromagnetic coil, wherein the first quadrupole yoke, second quadrupole yoke, and dipole yoke are separate yokes.

2. The X-ray tube of claim 1 , comprising:
the first magnetic quadrupole being configured for providing a first magnetic quadrupole gradient for focusing the electron beam in a first direction and defocusing the electron beam in a second direction orthogonal to the first direction;
the second magnetic quadrupole being configured for providing a second magnetic quadrupole gradient for focusing the electron beam in the second direction and defocusing the electron beam in the first direction; and
wherein a combination of the first and second magnetic quadrupoles provides a net focusing effect in both first and second directions of a focal spot of the electron beam.

3. The X-ray tube of claim 1 , comprising the magnetic dipole being configured to deflect the electron beam in order to shift a focal spot of the electron beam on a target.

4. The X-ray tube of claim 1 , comprising the magnetic dipole having the dipole yoke with four dipole pole projections extending from the dipole yoke and oriented toward a central axis of the dipole yoke and each of the four dipole pole projections having one of the dipole electromagnetic coils.

5. The X-ray tube of claim 1 , comprising the four dipole electromagnetic coils are wrapped around the dipole yoke in an even distribution.

6. The X-ray tube of claim 5 , comprising the magnetic dipole having the dipole yoke with four dipole pole projections extending from the dipole yoke and oriented toward a central axis of the dipole yoke, and the four dipole electromagnetic coils are between the four dipole pole projections.

7. The X-ray tube of claim 1 , comprising:
the four first quadrupole pole projections having the first quadrupole electromagnetic coils being at 45, 135, 225, and 315 degrees;
the four second quadrupole pole projections having the second quadrupole electromagnetic coils being at 45, 135, 225, and 315 degrees; and
the four dipole electromagnetic coils being at 0, 90, 180, and 270 degrees.

8. The X-ray tube of claim 1 , comprising:
the four first quadrupole pole projections having the first quadrupole electromagnetic coils being at 45, 135, 225, and 315 degrees;
the four second quadrupole pole projections having the second quadrupole electromagnetic coils being at 45, 135, 225, and 315 degrees; and
the four dipole pole projections having the four dipole electromagnetic coils thereon being at 0, 90, 180, and 270 degrees.

9. The X-ray tube of claim 1 , comprising:
the four first quadrupole pole projections having the first quadrupole electromagnetic coils being at 45, 135, 225, and 315 degrees;
the four second quadrupole pole projections having the second quadrupole electromagnetic coils being at 45, 135, 225, and 315 degrees; and
the four dipole pole projections being at 0, 90, 180, and 270 degrees.

10. The X-ray tube of claim 9 , the cathode having a cathode head surface with one or more focusing elements located adjacent to the electron emitter.

11. The X-ray tube of claim 1 , comprising:
the four first quadrupole pole projections having the first quadrupole electromagnetic coils being at 45, 135, 225, and 315 degrees;
the four second quadrupole pole projections having the second quadrupole electromagnetic coils being at 45, 135, 225, and 315 degrees; and
the four dipole pole projections and/or the four dipole electromagnetic coils being at 45, 135, 225, and 315 degrees.

12. The X-ray tube of claim 1 , wherein the X-ray tube has the following order along the emitted electrons: cathode; first magnetic quadrupole; second magnetic quadrupole, magnetic dipole; and anode.

13. The X-ray tube of claim 1 , comprising the electron emitter having a substantially planar surface configured to emit electrons in an electron beam in a non-homogenous manner.

14. The X-ray tube of claim 1 , comprising:
the first magnetic quadrupole being operably coupled with a first focus power supply;
the second magnetic quadrupole being operably coupled with a second focus power supply;
a first dipole pair of the magnetic dipole being operably coupled with a first steering power supply; and
a second dipole pair of the magnetic dipole being operably coupled with a second steering power supply.

15. The X-ray tube of claim 1 , comprising:
the first magnetic quadrupole being operably coupled with a first focus power supply;
the second magnetic quadrupole being operably coupled with a second focus power supply; and
each electromagnet of the magnetic dipole being operably coupled with a different steering power supply.

16. The X-ray tube of claim 1 , comprising:
two magnetic dipoles that are orthogonal with respect to each other, each of the two magnetic dipoles being configured to deflect the electron beam in order to shift a focal spot of the electron beam on a target, the two magnetic dipoles configured on a dipole yoke.

17. The X-ray tube of claim 1 , comprising:
a pair of magnetic dipoles between the cathode and anode and having a dipole yoke with four dipole electromagnetic coils.

18. The X-ray tube of claim 1 , comprising a pair of magnetic dipoles being configured together to deflect the electron beam in an X axis and/or Y axis in order to shift a focal spot of the electron beam on a target.

19. A method of focusing and steering an electron beam in an X-ray tube, the method comprising:
providing the X-ray tube of claim 1 ;
operating the electron emitter so as to emit the electron beam from the cathode to the anode along an electron beam axis;
operating the first magnetic quadrupole to focus the electron beam in a first direction;
operating the second magnetic quadrupole to focus the electron beam in a second direction orthogonal with the first direction; and
operating the magnetic dipole to steer the electron beam away from the electron beam axis.

20. An X-ray tube comprising:
a cathode including an emitter that emits an electron beam;
an anode configured to receive the emitted electrons;
a first magnetic quadrupole formed on a first yoke and having a magnetic quadrupole gradient for focusing the electron beam in a first direction and defocusing the electron beam in a second direction perpendicular to the first direction;
a second magnetic quadrupole formed on a second yoke and having a magnetic quadrupole gradient for focusing the

Assignees

• Varex Imaging Corp

Inventors

• Canfield Bradley D
• Woodman Colton B

Classifications

• H01J35/06

  Cathodes · CPC title

• H01J35/305 Primary

  by using a rotating X-ray tube in conjunction therewith · CPC title

• H01J35/26

  by rotation of the anode or anticathode · CPC title

• H01J35/14 Primary

  Arrangements for concentrating, focusing, or directing the cathode ray · CPC title

• H01J35/153

  Spot position control · CPC title