X-ray micro-target source

• US 20030108155A1
• Filed: 12/20/2002
• Published: 06/12/2003
• Est. Priority Date: 06/22/2000
• Status: Active Grant

• Current Assignee: XRT Ltd.
• Original Assignee: XRT Ltd.
• Inventors: Wilkins, Stephen William, Miller, Peter Robert
• Granted Patent: US 7,050,540 B2
• Time in Patent Office: Days
• US Class Current: 378/119
• 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, 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.

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 or 2 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 said target body is structured for providing said variable energy profile of the generated x-ray radiation in that the target body comprises respective layers for which the characteristic energies of the generated x-ray radiation differ for a given incident electron energy.

5. 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.

6. X-ray generation apparatus according to any preceding claim wherein said elongated target body is an elongated cone.

7. X-ray generation apparatus according to claim 6 wherein said taper comprises an included angle less than 10°

.

8. X-ray generation apparatus according to claim 6 wherein said taper comprises an included angle less than 4°

.

9. X-ray generation apparatus according to any preceding claim wherein said tip of the elongated target body is rounded.

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

11. X-ray generation apparatus according to any preceding claim further including means defining a divergent beam of said radiation emitted by said target body.

12. X-ray generation apparatus according to claim 11 wherein said divergent beam is directed laterally with respect to said beam of electrons about said tip.

13. X-ray generation apparatus according to claim 11 wherein said divergent beam is generally aligned with OR parallel to said beam of electrons.

14. X-ray generation apparatus according to claim 11, 12 or 13 when said divergent beam has a solid angle such that the beam is an expanding cone of radiation.

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

16. X-ray generation apparatus according to claim 15, wherein said adjustment is by adjustment of the relative positions of the electron beam and the target body.

17. X-ray generation apparatus according to any preceding claim, wherein said target body is a good electrical conductor or semiconductor to minimise charging up of the target body.

18. X-ray generation apparatus according to any preceding claim, wherein said mount is integral with the target body.

19. X-ray generation apparatus according to any preceding claim, wherein said source IS of effective source size less than or equal to 200nm.

20. (cancelled)

21. (cancelled)

22. (cancelled)

23. (cancelled)

24. (cancelled)

25. 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 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.

26. (Amended) A method according to claim 25, further including defining a divergent beam of said x-ray radiation emitted by said target body.

27. (Amended) A method according to claim 26 wherein said divergent beam is directed laterally with respect to said beam of electrons, about said tip.

28. A method according to claim 25, 26 or 27 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.

29. A method according to any one of claims 25 to 28 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.

30. A method according to any one of claims 25 to 29, including adjusting the excitation energy of the electron beam whereby to correspondingly alter the energy profile of the generated x-ray radiation.

31. A method according to claim 30 including providing said target body structured for providing said variable energy profile of the generated x-ray radiation in that the target body comprises respective layers for which the characteristic energies of the generated x-ray radiation differ for a given incident electron energy.

32. A method according to claim 30 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.

33. A method according to any one of claims 25 to 32 wherein said elongated target body is an elongated cone.

34. A method according to claim 33 wherein said taper comprises an included angle less than 10°

.

35. A method according to claim 33 wherein said taper comprises an included angle less than 4°

.

36. A method according to any one of claims 25 to 35 further including defining a divergent beam of said radiation emitted by said target body.

37. A method according to claim 36 wherein said divergent beam is directed laterally with respect to said beam of electrons about said tip.

38. A method according to claim 36 or 37 when said divergent beam has a solid angle such that the beam is an expanding cone of radiation.

39. A method according to any one of claims 25 to 38 including adjusting said volume of interaction of the electron beam with the target body.

40. A method according to claim 39, wherein said adjustment is by adjustment of the relative positions of the electron beam and the target body.

41. A method according to any one of claims 25 to 40 wherein said mount is integral with the target body.