X-ray micro-target source

• US 7,050,540 B2
• Filed: 06/22/2001
• Issued: 05/23/2006
• Est. Priority Date: 06/22/2000
• Status: Expired due to Fees

• Current Assignee: XRT Ltd.
• Original Assignee: XRT Ltd.
• Inventors: Wilkins, Stephen William, Miller, Peter Robert
• Primary Examiner(s): Church, Craig E.
• Assistant Examiner(s): Artman, Thomas R.
• Application Number:
  US10/312,294
• Publication Number:
  US 20030108155A1
• Time in Patent Office: 1,796 Days
• Field of Search: 378124-126, 378/143
• US Class Current: 378/124
• CPC Class Codes: G21K 2207/005 Methods and devices obtaining contrast from non-absorbing interaction of the radiation with matter, e.g. phase contrast
• CPC Class Codes: G21K 7/00 Gamma- or X-ray microscopes
• CPC Class Codes: H01J 2235/086 Target geometry
• CPC Class Codes: H01J 2235/088 Laminated targets, e.g. plurality of emitting layers of unique or differing materials
• CPC Class Codes: H01J 2235/1204 of the anode
• CPC Class Codes: H01J 35/12 Cooling non-rotary anodes
• CPC Class Codes: H05H 6/00 Targets for producing nuclear reactions supports for targets or objects to be irradiated G21K5/08 ; preparation of tritium C01B4/00; targets, e.g. pellets for fusion reactions by laser or charged particles beam injection H05H1/22

Abstract

X-ray generation apparatus including an elongated target body and a mount from which the body projects to a tip remote from the mount. The target body includes a substance that, on being irradiated by a beam of electrons of suitable energy directed onto the target body from laterally of the elongate target body, generates a source of x-ray radiation from a volume of interaction of the electron beam with the target body. The mount provides a heat sink for the target body.

Claims

1. X-ray generation apparatus including:

an elongated target body and a mount from which the body projects to a tip remote from the mount, said mount providing a heat sink for said target body, the target body including at least one layer, displaced from said tip along a longitudinal axis of the elongated target body, of a substance that, on being irradiated by a beam of electrons of suitable energy directed onto the target body from laterally of the elongate target body, generates a source of x-ray radiation from a volume of interaction of the electron beam with said at least one layer of the target body; and

an aperture spaced from said tip in the longitudinal direction of said target body, to define a beam or cone of said x-ray radiation emitted generally about said tip.

2. X-ray generation apparatus according to claim 1 wherein said mount is a sufficient heat sink for heat generated in said target body by said beam of electrons as to substantially prevent softening or melting of said target while it is being irradiated by said beam of electrons.

3. X-ray generation apparatus according to claim 1 wherein said body is structured whereby, on adjustment of the volume of interaction of the electron beam on the body or on adjustment of the excitation energy of the electron beam, or both, the energy profile of the generated x-ray radiation correspondingly alters.

4. X-ray generation apparatus according to claim 3 wherein there are a plurality of said substances arranged as respective layers extending a width dimension of the body and arranged successively in the longitudinal direction of said target body, and wherein the characteristic energies of the x-ray radiation generated by the respective layers differ for a given incident electron energy.

5. X-ray generation apparatus according to claim 4, wherein said beam or cone is a divergent beam.

6. X-ray generation apparatus according to claim 4, wherein said source is of effective source size less than or equal to 200 nm.

7. X-ray generation apparatus according to claim 3 wherein said target body is structured for providing said variable energy profile of the generated x-ray radiation in that the target body is formed in composite material which varies in its x-ray emission characteristics with change in position along the target body.

8. X-ray generation apparatus according to claim 1 wherein said elongated target body is an elongated cone.

9. X-ray generation apparatus according to claim 8 wherein said elongated cone has a taper comprising an included angle less than 10°

.

10. X-ray generation apparatus according to claim 9, wherein said taper comprises an included angle less than 4°

.

11. X-ray generation apparatus according to claim 8, wherein said tip of the elongated target body is rounded.

12. X-ray generation apparatus according to claim 8, wherein said beam or cone is a divergent beam.

13. X-ray generation apparatus according to claim 8, wherein said source is of effective source size less than or equal to 200 nm.

14. X-ray generation apparatus according to claim 1 wherein said tip of the elongated target body is rounded.

15. X-ray generation apparatus according to claim 1 wherein said tip of the elongated target body is a segment of a sphere.

16. X-ray generation apparatus according to claim 1 wherein said beam or cone is a divergent beam.

17. X-ray generation apparatus according to claim 16 when said divergent beam has a solid angle such that the beam is an expanded cone of radiation.

18. X-ray generation apparatus according to claim 1 further including means whereby said volume of interaction of the electron beam with the target body is adjustable.

19. X-ray generation apparatus according to claim 18 wherein said adjustment is by adjustment of the relative positions of the electron beam and the target body.

20. X-ray generation apparatus according to claim 1, wherein said target body is a good electrical conductor or semiconductor to minimize charging up of the target body.

21. X-ray generation apparatus according to claim 1, wherein said mount is integral with the target body.

22. X-ray generation apparatus according to claim 1, wherein said source is of effective source size less than or equal to 200 nm.

23. A method of generating x-ray radiation comprising:

directing a beam of electrons of suitable energy onto an elongated target body from laterally of the target body, wherein said target body projects from a mount for the body to a tip remote from the mount, and wherein the target body includes at least one layer, displaced from said tip along a longitudinal axis of the elongated target body, of a substance that, on being irradiated by said beam of electrons, generates a source of x-ray radiation, said mount providing a heat sink for said target body and defining a beam or cone of such x-ray radiation emitted generally about said tip by means of an aperture spaced from said tip in the longitudinal direction of said target body.

24. A method according to claim 23 wherein said mount is a sufficient heat sink for heat generated in said target body by said beam of electrons as to substantially prevent softening or melting of said target while it is being irradiated by said beam of electrons.

25. A method according to claim 23 including adjusting the volume of interaction of the electron beam on the body whereby to correspondingly alter the energy profile of the generated x-ray radiation.

26. A method according to claim 23 including adjusting the excitation energy of the electron beam whereby to correspondingly alter the energy profile of the generated x-ray radiation.

27. A method according to claim 26 including providing said target body structured for providing said variable energy profile of the generated x-ray radiation in that there are a plurality of said substances arranged as respective layers extending a width dimension of the body and arranged successively in the longitudinal direction of said target body, and wherein characteristic energies of the x-ray radiation generated by the respective layers differ for a given incident electron energy.

28. A method according to claim 27, wherein said beam or cone is a divergent beam.

29. A method according to claim 26 including providing said target body structured for providing said variable energy profile of the generated x-ray radiation in that the target body is formed in composite material which varies in its x-ray emission characteristics with change in position along the target body.

30. A method according to claim 23 wherein said elongated target body is an elongated cone.

31. A method according to claim 30 wherein said elongated cone has a taper comprising an included angle less than 10°

.

32. A method according to claim 31 wherein said taper comprises an included angle less than 4°

.

33. A method according to claim 30, wherein said beam or cone is a divergent beam.

34. A method according to claim 23 wherein said beam or cone is a divergent beam.

35. A method according to claim 34 when said beam or cone has a solid angle such that the beam is an expanding cone of radiation.

36. A method according to claim 23 including adjusting said volume of interaction of the electron beam with the target body.

37. A method according to claim 36 wherein said adjustment is by adjustment of the relative positions of the electron beam and the target body.

38. A method according to claim 23 wherein said mount is integral with the target body.

39. X-ray generation apparatus comprising:

an elongated target body, the target body being an elongated cone having a length and a width and formed of respective layers extending substantially wholly across the width of the body and arranged successively in the longitudinal direction of said target body, each layer comprising a substance that, on being irradiated by a beam of electrons of suitable energy directed onto the target body from laterally of the elongated target body, generates a source of x-ray radiation from a volume of interaction of the electron beam with the respective layer; and

a mount from which the body projects to a tip remote from the mount, said mount providing a heat sink for said target body; and

wherein the characteristic energies of the x-ray radiation generated by the respective layers differ for a given incident electron energy.

40. X-ray generation apparatus according to claim 39, wherein said mount is a sufficient heat sink for heat generated in said target body by said beam of electrons as to substantially prevent softening or melting of said target while it is being irradiated by said beam of electrons.

41. X-ray generation apparatus according to claim 39, wherein said elongated cone has a taper comprising an included angle less than 10°

.

42. X-ray generation apparatus according to claim 41, wherein said taper comprises an included angle less than 4°

.

43. X-ray generation apparatus according to claim 39, wherein said tip of the elongated target body is rounded.

44. X-ray generation apparatus according to claim 39, wherein said tip of the elongated target body is a segment of a sphere.

45. X-ray generation apparatus according to claim 39, wherein said x-ray radiation is a divergent beam.

46. X-ray generation apparatus according to claim 45, wherein said divergent beam is directed laterally with respect to said beam of electrons about said tip.

47. X-ray generation apparatus according to claim 45, wherein said divergent beam has a solid angle such that the beam is an expanding cone of radiation.

48. X-ray generation apparatus according to claim 39, further including means whereby said volume of interaction of the electron beam with the target body is adjustable.

49. X-ray generation apparatus according to claim 48, wherein said adjustment is by adjustment of the relative positions of the electron beam and the target body.

50. X-ray generation apparatus according to claim 39, wherein said target body is a good electrical conductor or semiconductor to minimize charging up of the target body.

51. X-ray generation apparatus according to claim 39, wherein said mount is integral with the target body.

52. X-ray generation apparatus according to claim 39, wherein said source is of effective source size less than or equal to 200 nm.

53. A method of generating x-ray radiation comprising directing a beam of electrons of suitable energy onto an elongate target body from laterally of the target body, wherein said target body projects from a mount for the body to a tip remote from the mount, and wherein the target body is an elongated cone having a length and a width and is formed of respective layers extending substantially across the width of the body and arranged successively in the longitudinal direction of said target body, each layer comprising a substance that, on being irradiated by said beam of electrons, generates a source of x-ray radiation, said mount providing a heat sink for said target body, wherein the characteristic energies of the x-ray radiation generated by the respective layers differ for a given incident electron energy.

54. A method according to claim 53 wherein said mount is a sufficient heat sink for heat generated in said target body by said beam of electrons as to substantially prevent softening or melting of said target while it is being irradiated by said beam of electrons.

55. A method according to claim 53 including adjusting the volume of interaction of the electron beam on the body whereby to correspondingly alter the energy profile of the generated x-ray radiation.

56. A method according to claim 53 wherein said elongated cone has a taper comprising an included angle less than 10°

.

57. A method according to claim 56 wherein said taper comprises an included angle less than 4°

.

58. A method according to claim 53 further including defining a divergent beam of said radiation emitted by said target body.

59. A method according to claim 58 wherein said divergent beam is directed laterally with respect to said beam of electrons about said tip.

60. A method according to claim 58 wherein said divergent beam has a solid angle such that the beam is an expanding cone of radiation.

61. A method according to claim 53 including adjusting said volume of interaction of the electron beam with the target body.

62. A method according to claim 61 wherein said adjustment is by adjustment of the relative positions of the electron beam and the target body.

63. A method according to claim 53 wherein said mount is integral with the target body.

64. X-ray generation apparatus including:

an elongated target body and a mount from which the body projects to a tip remote from the mount, the target body including a substance that, on being irradiated by a beam of electrons of suitable energy directed onto the target body from laterally of the elongate target body, generates a source of x-ray radiation from a volume of interaction of the electron beam with the target body, said mount providing a heat sink for said target body, and wherein said elongated target body is an elongated cone having a taper with an included angle less than 10°

.

65. X-ray generation apparatus according to claim 64, wherein said taper comprises an included angle less than 4°

.

66. A method of generating x-ray radiation, comprising:

directing a beam of electrons of suitable energy onto an elongated target body from laterally of the target body, wherein said target body projects from a mount for the body to a tip remote from the mount, and wherein the target body includes a substance that, on being irradiated by said beam of electrons, generates a source of x-ray radiation, said mount providing a heat sink for said target body, and wherein said elongated target body is an elongated cone having a taper with an included angle less than 10°

.

67. A method according to claim 66, wherein said taper comprises an included angle less than 4°

.

68. X-ray generation apparatus comprising:

an elongated target body, the target body having a length and a width and formed of respective layers extending substantially wholly across the width of the body and arranged successively in the longitudinal direction of said target body, each layer comprising a substance that, on being irradiated by a beam of electrons of suitable energy directed onto the target body from laterally of the elongated target body, generates a source of x-ray radiation from a volume of interaction of the electron beam with the respective layer; and

a mount from which the body projects to a tip remote from the mount, said mount providing a heat sink for said target body; and

wherein the characteristic energies of the x-ray radiation generated by the respective layers differ for a given incident electron energy, and said x-ray radiation is a divergent beam directed laterally with respect to said beam of electrons about said tip.

69. X-ray generation apparatus according to claim 68, wherein said mount is a sufficient heat sink for heat generated in said target body by said beam of electrons as to substantially prevent softening or melting of said target while it is being irradiated by said beam of electrons.

70. X-ray generation apparatus according to claim 68, wherein said elongated target body is an elongated cone.

71. X-ray generation apparatus according to claim 70, wherein said elongated cone has a taper comprising an included angle less than 10°

.

72. X-ray generation apparatus according to claim 68, wherein said tip of the elongated target body is rounded.

73. X-ray generation apparatus according to claim 68, wherein said divergent beam has a solid angle such that the beam is an expanding cone of radiation.

74. X-ray generation apparatus according to claim 68, further including means whereby said volume of interaction of the electron beam with the target body is adjustable.

75. X-ray generation apparatus according to claim 68, wherein said source is of effective source size less than or equal to 200 nm.

76. A method of generating x-ray radiation comprising directing a beam of electrons of suitable energy onto an elongate target body from laterally of the target body, wherein said target body projects from a mount for the body to a tip remote from the mount, and wherein the target body has a length and a width and is formed of respective layers extending substantially across the width of the body and arranged successively in the longitudinal direction of said target body, each layer comprising a substance that, on being irradiated by said beam of electrons, generates a source of x-ray radiation, said mount providing a heat sink for said target body, wherein the characteristic energies of the x-ray radiation generated by the respective layers differ for a given incident electron energy, and said x-ray radiation is a divergent beam directed laterally with respect to said beam of electrons about said tip.

77. A method according to claim 76 wherein said mount is a sufficient heat sink for heat generated in said target body by said beam of electrons as to substantially prevent softening or melting of said target while it is being irradiated by said beam of electrons.

78. A method according to claim 76 including adjusting the volume of interaction of the electron beam on the body whereby to correspondingly alter the energy profile of the generated x-ray radiation.

79. A method according to claim 76 wherein said elongated target body is an elongated cone.

80. A method according to claim 79 wherein said elongated cone has a taper comprising an included angle less than 10°

.