Multiple grooved x-ray generator

• US 7,012,989 B2
• Filed: 09/03/2003
• Issued: 03/14/2006
• Est. Priority Date: 09/03/2002
• Status: Active Grant

• Current Assignee: Parker Medical, Inc.
• Original Assignee: Parker Medical, Inc.
• Inventors: Holland, Timothy, Holland, William P., Suffredini, Joseph
• Primary Examiner(s): Glick, Edward J.
• Assistant Examiner(s): Kao, Chih-Cheng Glen
• Application Number:
  US10/655,485
• Publication Number:
  US 20040136499A1
• Time in Patent Office: 923 Days
• Field of Search: 378/119, 378/121, 378/122, 378/124, 378/125, 378/126, 378/130, 378/131, 378/132, 378/134, 378/136, 378/138, 378/143, 378/144
• US Class Current: 378/144
• CPC Class Codes: H01J 2235/086 Target geometry
• CPC Class Codes: H01J 35/10 Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes
• CPC Class Codes: H01J 35/147 Spot size control
• CPC Class Codes: H01J 35/153 Spot position control
• CPC Class Codes: H01J 35/26 by rotation of the anode or anticathode

Abstract

An X-ray tube has a metal-ceramic envelope having rotatably mounted therein an anode disk, which may be axially translatable and provided with a peripheral rim surface wherein a focal track spiral groove (or multiple annular grooves) is disposed. The groove(s) include a focal spot(s) area spaced from an electron emitting cathode(s), which is associated with a beam-forming structure and an X-ray transparent window mounted within an insulating structure aligned with the focal spot area. The insulating structure incorporates a multiplicity of imbedded annular electrodes which control an accelerating electric field, and which are structurally and operationally integrated into a power-control assembly that provides the electrical power and control signals necessary for the functioning of the X-ray tube.

Claims

1. An x-ray tube comprising:

an envelope;

a cathode mounted within the envelope; and

an anode target rotatably mounted about an axis of rotation within the envelope and spaced relative to the cathode, wherein the target includes an axially-extending peripheral portion defining first and second approximately v-shaped groove portions axially spaced adjacent to each other in an axial direction along the axis of rotation, the first and second groove portions are each defined by a base and first and second opposing side walls, respectively, that diverge outwardly relative to each other in an approximately v-shaped configuration and substantially radially relative to the axis of rotation, the first side walls intersect a common plane extending substantially parallel to the axis of rotation, the second side walls intersect said common plane, and at least one of the approximately v-shaped groove portions of the target cooperates with the cathode to define thereon at least one x-ray focal track.

2. An x-ray tube as defined in claim 1, wherein the anode target is disc-shaped and the first and second approximately v-shaped groove portions are formed in a peripheral rim of the disc-shaped target.

3. An x-ray tube as defined in claim 1, wherein surfaces of a the first and second approximately v-shaped groove portions are formed of at least one predetermined x-ray generating material.

4. An x-ray tube as defined in claim 3, wherein the surface of the first groove portion is formed of a first x-ray generating material, and the surface of the second groove portion is formed of a second x-ray generating material that is different than the first x-ray generating material.

5. An x-ray tube as defined in claim 4, wherein the first and second groove portions are located within the same groove and are angularly spaced relative to each other.

6. An x-ray tube as defined in claim 1, wherein each of the first and second approximately v-shaped groove portions defines a groove angle, and the groove angle of each groove portion is approximately equal to the groove angle of the other groove portion.

7. An x-ray tube as defined in claim 1, wherein each of the approximately v-shaped groove portions defines a groove angle, and the groove angle of the first groove portion is different than the groove angle of the second groove portion.

8. An x-ray tube as defined in claim 1, wherein the first and second groove portions form a helical groove.

9. An x-ray tube as defined in claim 1, further comprising a plurality of approximately v-shaped groove portions forming a plurality of helical grooves.

10. An x-ray tube as defined in claim 1,wherein the cathode includes a plurality of electron beam sources, and each electron beam source transmits a beam onto a focal spot of the anode target.

11. An x-ray tube as defined in claim 10, wherein the focal spots of a plurality of electron beam sources are superimposed on one another.

12. An x-ray tube as defined in claim 10, wherein a plurality of electron beam sources transmit respective beams onto different focal spots.

13. An x-ray tube as defined in claim 12, wherein a plurality of focal spots are located in a plurality of different approximately v-shaped groove portions axially spaced relative to each other.

14. An x-ray tube as defined in claim 12, wherein a plurality of focal spots are located in the same approximately v-shaped groove portion.

15. An x-ray tube as defined in claim 10, wherein a plurality of electron beam sources transmit respective beams onto different focal spots substantially simultaneously.

16. An x-ray tube as defined in claim 10, wherein the plurality of electron beam sources are at least one of (a) operable simultaneously and (b) operable serially.

17. An x-ray tube as defined in claim 1, wherein the anode target is rotatably mounted on at least one shaft, and the at least one shaft defines a fluid conduit coupled in fluid communication with a cooling fluid for allowing the cooling fluid to flow through the conduit and transfer heat away from the target and shaft.

18. An x-ray tube as defined in claim 17, further comprising a cooling fluid including a thermally-conductive material dispersed therein for at least one of facilitating the transfer of heat away from the target and shaft and inducing a turbulent flow of fluid within the conduit.

19. An x-ray tube as defined in claim 1, further comprising at least one target shaft rotatably supporting the anode target, wherein a first shaft portion is located on one side of the target and a second shaft portion is located on an opposite side of the target relative to the first shaft portion.

20. An x-ray tube as defined in claim 19, further comprising a first bearing rotatably supporting the first shaft portion on one side of the target, and a second bearing rotatably supporting the second shaft portion on an opposite side of the target relative to the first shaft portion.

21. An x-ray tube as defined in claim 20, further comprising a first induction rotor rotatably mounted on the first shaft portion on one side of the target, and a second induction rotor rotatably mounted on the second shaft portion on an opposite side of the target relative to the first shaft portion.

22. An x-ray tube as defined in claim 21, further comprising an x-ray tube housing receiving therein the envelope, and including a first stator coil electro-magnetically coupled to the first induction rotor, and a second stator coil electro-magnetically coupled to the second induction rotor.

23. An x-ray tube as defined in claim 21, wherein at least one of the first and second induction rotors defines an axially-elongated, substantially cylindrical rotor body rotatably mounted on the respective shaft portion.

24. An x-ray tube as defined in claim 23, further comprising at least one approximately annular stator coil defining an aperture therethrough, and wherein the axially-elongated, substantially cylindrical rotor body is received within the aperture of the stator and is electro-magnetically coupled thereto for rotatably driving the rotor body.

25. An x-ray tube as defined in claim 21, wherein at least one of the first and second induction rotors is substantially disc shaped, and a substantial portion of the disc-shaped rotor lies in a plane substantially perpendicular to an axis of the respective shaft portion.

26. An x-ray tube as defined in claim 25, further comprising at least one stator axially spaced adjacent to the disc-shaped rotor on an opposite side of the disc-shaped rotor relative to the anode target, and wherein the stator is electro-magnetically coupled to the disc-shaped rotor for rotatably driving the disc-shaped rotor.

27. An x-ray tube as defined in claim 25, further comprising at least one thermally-conductive fin extending angularly along an interior wall of the envelope, and projecting radially inwardly between the anode target and disc-shaped rotor for conducting heat away from the target and into the fin and envelope.

28. An x-ray tube as defined in claim 27, further comprising at least one cooling coil mounted on the envelope and coupled in thermal communication with the envelope and fin for conducting heat therefrom.

29. An x-ray tube as defined in claim 20, further comprising a sensor coupled to at least one of a rotor rotatably mounted on the at least one target shaft, and target and generating signals indicative of an angular position of at least one of the rotor and target.

30. An x-ray tube as defined in claim 29, wherein the sensor is optically coupled to at least one of the rotor and target.

31. An x-ray tube as defined in claim 29, further comprising at least one electron beam source on the cathode for transmitting an electron beam onto a focal spot, and a control unit coupled to the electron beam source and the sensor for controlling actuation of the electron beam based on the angular positional signals generated by the sensor.

32. An x-ray tube as defined in claim 19, further comprising at least one bearing rotatably supporting the target on the at least one shaft and permitting both rotational and axial translational movement of the target.

33. An x-ray tube as defined in claim 32, further comprising a sensor coupled to at least one of a rotatably mounted on the at least one target shaft and target and generating signals indicative of the axial translational position of the target.

34. An x-ray tube as defined in claim 33, wherein the sensor is optically coupled to at least one of the rotor and target.

35. An x-ray tube as defined in claim 33, further comprising a drive unit drivingly connected to the anode target for driving the anode target in at least one of the rotational and axial translational directions, and wherein the drive unit is coupled to the sensor for controlling at least one of the rotational and axial translational movements of the anode target based on the signals transmitted by the sensor.

36. An x-ray tube as defined in claim 32, wherein the at least one shaft includes a plurality of bearings received within at least one axially-extending groove, and wherein the bearings are permitted to move axially relative to the shaft and are restrained from rotating about the shaft.

37. An x-ray tube as defined in claim 36, further comprising at least one solenoid drivingly coupled to the target for driving the target in the axial direction.

38. An x-ray tube as defined in claim 1, wherein each groove portion further defines a crest formed on each side wall opposite the base, and wherein at least one focal spot is located on a side, crest, or base of one or more of the groove portions.

39. An x-ray tube as defined in claim 1, wherein the first and second groove portions are defined by a plurality of substantially circumferentially-extending groove portions.

40. An x-ray tube as defined in claim 1, wherein the anode target includes a body made of a first material, and a peripheral target extending about the body and made of a second material, wherein the first material is at least one of (i) a lower density than the second material, and (ii) thermally insulative in comparison to the second material.

41. An x-ray tube as defined in claim 1, further comprising at least one thermally-conductive fin extending angularly along an interior wall of the envelope, projecting radially into a respective groove of the anode target, and spaced axially adjacent to opposing walls of the groove and coupled in thermal communication therewith for conducting heat away from the target grooves and into the fin and envelope.

42. An x-ray tube as defined in claim 1, wherein the anode target is defined by a plurality of discs fixedly secured together and forming a plurality of approximately v-shaped grooves therebetween.

43. An x-ray tube as defined in claim 1, wherein the cathode includes an electrically insulative base defining an x-ray transmissive window therethrough, a recess formed within the electrically insulative base adjacent to a peripheral portion of the x-ray transmissive window, a filamentary electrode received within the recess, a first metalized conductive surface formed on a surface of the recess on one side of the filamentary electrode, a second metalized conductive surface formed on a surface of the recess on an opposite side of the filamentary electrode relative to the first metalized conductive surface and substantially electrically isolated relative to the first metalized conductive surface, a first terminal electrically connected to the first metalized conductive surface, and a second terminal electrically connected to the second metalized conductive surface, and wherein at least one of an electron beam size, shape, and direction emitted by the filamentary electrode is controllable by controlling a voltage differential between the first and second metalized surfaces.

44. An x-ray tube as defined in claim 43, wherein the recess is defined by an approximately annular groove extending about the periphery of the x-ray transmissive window.

45. An x-ray tube as defined in claim 43, wherein the electrically insulative base is formed of ceramic.

46. An x-ray tube as defined in claim 43, further comprising a plurality of filamentary electrodes angularly spaced relative to each other about the periphery of the x-ray transmissive window, and a plurality of pairs of first and second metalized surfaces and first and second terminals, wherein each pair of first and second metalized surfaces and first and second terminals is associated with a respective filamentary electrode.

47. An x-ray tube as defined in claim 46, wherein each filamentary electrode transmits a respective electron beam onto a respective focal spot on the anode target.

48. An x-ray tube comprising:

an envelope;

a cathode mounted within the envelope and including first means for transmitting at least one electron beam onto at least one focal spot; and

an anode target rotatably mounted about an axis of rotation within the envelope and spaced relative to the cathode, and defining an annular, axially-extending peripheral portion, and second means extending annularly about the peripheral portion for defining at least one focal track corresponding to the at least one focal spot and emitting x-rays therefrom upon impingement of the at least one electron beam thereon, wherein the second means includes first and second base portions axially spaced adjacent to each other in an axial direction along the axis of rotation, and first and second pairs of opposing side wall portions wherein each of the first and second pairs of opposing side wall portions diverge outwardly relative to each other in an approximately v-shaped configuration and substantially radially relative to the axis of rotation, the first side wall portions intersect a common plane extending substantially parallel to the axis of rotation, and the second side wall portions intersect said common plane.

49. An x-ray tube as defined in claim 48, wherein the second means is first and second approximately v-shaped groove portions axially spaced adjacent to each other on the peripheral portion of the anode target.

50. An x-ray tube as defined in claim 49, wherein the first and second v-shaped groove portions are defined by one of (i) a helical groove, and (ii) a plurality of annular grooves axially spaced relative to each other.

51. An x-ray tube as defined in claim 48, further comprising at least one target shaft rotatably supporting the anode target, wherein a first shaft portion is located on one side of the target and a second shaft portion is located on an opposite side of the target relative to the first shaft portion.

52. An x-ray tube as defined in claim 51, further comprising a first bearing rotatably supporting the first shaft portion on one side of the target, and a second bearing rotatably supporting the second shaft portion on an opposite side of the target relative to the first shaft portion.

53. An x-ray tube as defined in claim 51, further comprising a first induction rotor rotatably mounted on the first shaft portion on one side of the target, and a second induction rotor rotatably mounted on the second shaft portion on an opposite side of the target relative to the first shaft portion.

54. An x-ray rube as defined in claim 53, further comprising means coupled to at least one of (i) one of the first and second rotors, and (ii) the target, for generating signals indicative of an angular position of at least one of a respective rotor and target.

55. An x-ray tube as defined in claim 54, wherein the means for generating signals is an optical sensor.

56. An x-ray tube as defined in claim 48, further comprising means for permitting both rotational and axial translational movement of the anode target relative to the cathode.

57. An x-ray tube as defined in claim 56, wherein said means for permitting is a bearing assembly coupled between the anode target and at least one shaft that permits both rotational and axial translational movement of the anode target relative to the at least one shaft.

58. An x-ray tube as defined in claim 57, further comprising means coupled to at least one of a rotor rotatably mounted on the at least one target shaft and target for generating signals indicative of the axial translational position of the target.

59. An x-ray tube as defined in claim 58, wherein said means for generating signals is an optical sensor optically coupled to at least one of the rotor and target.

60. An x-ray tube as defined in claim 56, further comprising means for controlling actuation of the electron beam based on the rotational and axial translational position of the anode target.

61. An x-ray tube as defined in claim 48, further comprising means for rotatably driving the anode target, and means for axially driving the anode target.

62. An x-ray tube as defined in claim 61, wherein the means for rotatably driving the anode target is a stator and an induction rotor, and the means for axially driving the anode target is a solenoid.

63. An x-ray tube as defined in claim 48, wherein the first means is a filament for emitting an electron beam onto a respective focal spot, and the x-ray tube further includes third means formed on at least one surface adjacent to the filament for creating a voltage differential across the filament and, in turn, controlling at least one of the electron beam size, shape, and direction.

64. An x-ray tube as defined in claim 63, wherein the third means is defined by first and second metalized conductive surfaces formed on opposite sides of the filament relative to each other.

65. A method comprising the following steps:

providing an x-ray tube including a cathode, a rotatably mounted anode target spaced relative to the cathode and including an annular, axially-extending peripheral portion defining first and second approximately v-shaped groove portions, wherein the anode defines an axis of rotation, the first and second groove portions are axially spaced adjacent to each other along the axis of rotation, each of the first and second groove portions is defined by a base and a pair of opposing side walls that diverge outwardly relative to each other in an approximately v-shaped configuration and substantially radially relative to the axis of rotation., the first side walls intersect a common plane extending substantially parallel to the axis of rotation, and the second side walls intersect said common plane; and

further comprising at least one of the following steps;

(i) transmitting an electron beam from the cathode onto a focal spot defined within at least one of the first and second v-shaped groove portions and emitting x-rays therefrom upon impingement of the electron beam thereon, and simultaneously both rotatably and axially moving the anode target while transmitting the electron beam thereon; and

(ii) transmitting a first electron beam from the cathode onto a first focal spot defined within the first v-shaped groove portion and emitting a first x-ray beam therefrom upon impingement of the first electron beam thereon, and transmitting a second electron beam from the cathode onto a second focal spot defined within the second v-shaped groove portion and emitting a second x-ray beam therefrom upon impingement of the second electron beam thereon.

66. A method as defined in claim 65, comprising the step of transmitting the first and second electron beams substantially simultaneously.

67. A method as defined in claim 65, comprising the step of transmitting the first electron beam onto a first focal spot, and the second electron beam onto a second focal spot axially spaced relative to the first focal spot.

68. A method as defined in claim 65, further comprising the step of generating signals indicative of the rotational and axial translational position of the target, and controlling actuation of an electron beam emitted by the cathode based on the signals.

69. A method as defined in claim 65, further comprising the step of providing a cathode with at least one filament for emitting an electron beam therefrom, providing first and second metalized conductive surfaces on opposite sides of the filament relative to each other, controlling a voltage differential between the first and second metalized conductive surfaces and, in turn, controlling at least one of the electron beam size, shape, and direction based thereon.