X-ray tube having planar emitter and magnetic focusing and steering components

Abstract

An X-ray tube can include: 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; a second magnetic quadrupole between the first magnetic quadrupole and the anode; a magnetic dipole between the cathode and anode; and a power supply system operably coupled with the first magnetic quadrupole, second magnetic quadrupole, and magnetic dipole, the power supply system being configured to: produce a first focusing magnetic quadrupole field at the first magnetic quadrupole; produce a second focusing magnetic quadrupole field at the second magnetic quadrupole; and produce a steering magnetic dipole field at the magnetic dipole configured to deflect the electron beam in order to shift a focal spot of the electron beam on the anode.

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;   a second magnetic quadrupole between the first magnetic quadrupole and the anode;   a magnetic dipole between the cathode and anode; and   a power supply system operably coupled with the first magnetic quadrupole, second magnetic quadrupole, and magnetic dipole, the power supply system being configured to:
 produce a first focusing magnetic quadrupole field at the first magnetic quadrupole; 
 produce a second focusing magnetic quadrupole field at the second magnetic quadrupole; and 
 produce a steering magnetic dipole field at the magnetic dipole configured to deflect the electron beam in order to shift a focal spot of the electron beam on the anode. 
   
     
     
         2 . The X-ray tube of  claim 1 , wherein the first magnetic quadrupole includes a first magnetic yoke, the second magnetic quadrupole includes a second magnetic yoke, and the magnetic dipole includes the first magnetic yoke or the second magnetic yoke. 
     
     
         3 . The X-ray tube of  claim 1 , further 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; and   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,   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.   
     
     
         4 . The X-ray tube of  claim 1 , further 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.   
     
     
         5 . The X-ray tube of  claim 1 , further 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   the magnetic dipole including four dipole electro magnets, each electromagnet of the magnetic dipole being operably coupled with a different steering power supply.   
     
     
         6 . The X-ray tube of  claim 1 , the magnetic dipole 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 the focal spot of the electron beam on the anode. 
     
     
         7 . The X-ray tube of  claim 1 , the magnetic dipole comprising a pair of magnetic dipoles being configured together to deflect the electron beam in an first axis and/or second axis orthogonal with the first axis in order to shift a focal spot of the electron beam on the anode. 
     
     
         8 . The X-ray tube of  claim 1 , further comprising:
 the first magnetic quadrupole 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; and   the second magnetic quadrupole 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.   
     
     
         9 . The X-ray tube of  claim 8 , further comprising:
 the magnetic dipole having a dipole yoke with four dipole pole projections and four dipole electromagnetic coils, wherein the first quadrupole yoke, second quadrupole yoke, and dipole yoke are separate yokes.   
     
     
         10 . The X-ray tube of  claim 9 , further comprising:
 the four dipole electromagnetic coils being wrapped around the dipole yoke in an even distribution; or   each dipole pole projection has a dipole electromagnetic coil wrapped there around.   
     
     
         11 . The X-ray tube of  claim 9 , 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 four dipole electromagnetic coils being at:
 0, 90, 180, and 270 degrees; or 
 at 45, 135, 225, and 315 degrees. 
   
     
     
         12 . The X-ray tube of  claim 9 , wherein the power supply system comprises:
 a first focusing power supply operably coupled with the four first quadrupole electromagnetic coils to produce the first focusing magnetic quadrupole field;   a second focusing power supply operably coupled with the four second quadrupole electromagnetic coils to produce the second focusing magnetic quadrupole field;   a first steering power supply operably coupled with at least one first dipole coil and configured for steering the electron beam in a first direction; and   a second steering power supply operably coupled with at least one second dipole coil and configured for steering the electron beam in a second direction that is orthogonal with the first direction,   wherein the at least one first dipole coil is different from the at least one second dipole coil.   
     
     
         13 . The X-ray tube of  claim 12 , comprising two opposing first dipole coils coupled in series to the first steering power supply or to the second steering power supply of the power supply system that provides an alternating current offset to the two opposing dipole coils. 
     
     
         14 . The X-ray tube of  claim 12 , comprising two pairs of opposing dipole coils coupled to the power supply system that provides an alternating current offset to the two pairs of opposing dipole coils, a first pair of the two pairs of opposing dipole coils being coupled with the first steering power supply and a second pair of the two pairs of opposing dipole coils being coupled with the second steering power supply. 
     
     
         15 . The X-ray tube of  claim 12 , wherein the power supply system further comprises:
 a command input controller; and   a command processor operably coupled with the command input controller to receive command inputs therefrom, and operably coupled with the first focusing power supply, second focusing power supply, first steering power supply and second steering power supply to provide the inputs thereto in order to control focusing and steering of the electron beam.   
     
     
         16 . The X-ray tube of  claim 15 , wherein:
 the command input controller is configured for command inputs of: current, large focal spot, small focal spot, voltage, and steering toggle pattern; or   the command processor is configured to determine:   a first current for focusing in a first axis,   a second current for focusing in a second axis that is orthogonal with the first axis,   a first wave form and amplitude for steering in a first direction, and   a second wave form and amplitude for steering in a second direction orthogonal with the first direction.   
     
     
         17 . The X-ray tube of  claim 12 , wherein:
 the first focusing power supply is operably coupled with the four first quadrupole electromagnetic coils in series;   the second focusing power supply is operably coupled with the four second quadrupole electromagnetic coils in series;   the first steering power supply is operably coupled with two first dipole coils in series; and   the second steering power supply is operably coupled with two second dipole coils in series.   
     
     
         18 . 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 axis;   operating the second magnetic quadrupole to focus the electron beam in a second axis orthogonal with the first axis; and   operating the magnetic dipole with alternating current offset to steer the electron beam away from the electron beam axis.   
     
     
         19 . The method of  claim 18 , further comprising inputting command inputs into a command input controller in order to control focusing in the first axis, focusing in the second axis, and/or steering away from the electron beam in a first direction and/or second direction, wherein a command processor is operably coupled with the command input controller to receive the command inputs therefrom, and operably coupled with the first focusing power supply, second focusing power supply, first steering power supply and second steering power supply to provide the inputs thereto in order to control focusing and steering of the electron beam. 
     
     
         20 . The method of  claim 19 , comprising, in response to the command inputs, the command processor determining:
 a first current for focusing in a first axis;   a second current for focusing in a second axis that is orthogonal with the first axis;   a first wave form and amplitude for steering in a first direction; and   a second wave form and amplitude for steering in a second direction orthogonal with the first direction.   
     
     
         21 . 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;   a second magnetic quadrupole between the first magnetic quadrupole and the anode;   a magnetic dipole between the cathode and anode, wherein the first magnetic quadrupole, second magnetic quadrupole, and magnetic dipole are separate; and   a power supply system operably coupled with the first magnetic quadrupole, second magnetic quadrupole, and magnetic dipole, the power supply system being configured to:
 produce a first focusing magnetic quadrupole field at the first magnetic quadrupole; 
 produce a second focusing magnetic quadrupole field at the second magnetic quadrupole; and 
 produce a steering magnetic dipole field at the magnetic dipole configured to deflect the electron beam in order to shift a focal spot of the electron beam on the anode. 
   
     
     
         22 . The X-ray tube of  claim 21 , wherein the X-ray tube has:
 the following order along the emitted electrons: cathode, first magnetic quadrupole, second magnetic quadrupole, magnetic dipole, and anode; or   the magnetic dipole includes a dipole yoke with four dipole electromagnetic coils.