Coplanar RF probe coil arrangement for multifrequency excitation

• US 6,201,392 B1
• Filed: 11/07/1997
• Issued: 03/13/2001
• Est. Priority Date: 11/07/1997
• Status: Expired due to Term

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Varian Incorporated (Agilent Technologies, Inc.), Bruker Instruments Incoporated
• Inventors: Wong, Wai Ha, Delin, Kevin A., Fuks, Luis Felipe, Withers, Richard S., Anderson, Weston
• Primary Examiner(s): ARANA, LOUIS M
• Application Number:
  US08/965,735
• Time in Patent Office: 1,222 Days
• Field of Search: 324/300, 324/307, 324/309, 324/312, 324/315, 324/318, 324/321, 324/322
• US Class Current: 324/300
• CPC Class Codes: G01R 33/34023 Superconducting RF coils
• CPC Class Codes: G01R 33/34061 Helmholtz coils
• CPC Class Codes: G01R 33/34092 RF coils specially adapted for NMR spectrometers
• CPC Class Codes: G01R 33/3635 Multi-frequency operation

Abstract

The present invention provides apparatus for utilizing planar HTS probe coils in substantially coplanar coil sets, each set comprised of a plurality of coils, two such similar sets being positioned on opposite sides of the sample to form a plurality of coil pairs. The coil pairs may be used for excitation of the sample, for receiving the NMR response signal or for both. A feature of the invention is the ability afforded to adjust the coupling between coil pairs to a minimum value to thereby prevent interaction between coil pairs having simultaneously applied high power signals and weak NMR response signals.

Claims

1. In a nuclear magnetic resonance (NMR) probe having a plurality of coil pairs for exciting multiple resonances and detecting NMR responses, the improvement comprising,

each of said coil pairs having a first planar coil and a second planar coil, all of said first planar coils being disposed substantially parallel to one another, and all of said second planar coils being disposed substantially parallel to one another, at least on of said coil pairs being made from an HTS material and said first and second planar coils having no point of direct electrical contact.

2. A nuclear magnetic resonance probe comprising,

a holder for holding an NMR sample and for positioning said sample in a sample space in a static magnetic field, said sample space having first and second opposing sides and a center;

two coil pairs, each said coil pair being affixed to said probe, each said coil pair having a first planar coil and a second planar coil, each said first planar coil being positioned proximate to said first side of said sample space, each said second planar coil being positioned proximate to said second side of said sample space, each said planar coil having a center of symmetry;

said first planar coils of said two coil pairs being a substantially coplanar first coil set and said second planar coils of said two coil pairs being a substantially coplanar second coil set;

said coplanar first coil set and said coplanar second coil set being substantially parallel and defining a sample axis therebetween, said sample axis parallel in common with both said coplanar coil sets;

said first planar coil and said second planar coil of each of said two coil pairs defining a magnetic field therefrom when excited, each of said coil pairs defining an axis of symmetry, said coils being positioned so that each of said axes of symmetry passes through said center of said sample space and the major component of each said magnetic field is orthogonal to said sample axis and parallel to one another.

3. The NMR probe of claim 2, wherein one or more Faraday shields are affixed to said probe.

4. The NMR probe of claim 3, wherein two Faraday shields are affixed to said probe, one of said shields being positioned between said planar coils proximate to said first side of said sample space, the other said shield being positioned between said planar coils proximate to said second side of said sample space.

5. The NMR probe of claim 2, wherein at least one of said coil pairs is an HTS coil pair.

6. The NMR probe of claim 5, wherein said axis of symmetry of each of said magnetic fields defined by said first coil pair and said second coil pair are common collinear axes.

7. The NMR probe of claim 6, wherein said first coil pair and said second coil pair are nested HTS coil pairs.

8. The NMR probe of claim 7, wherein said first planar coils of said first coil pair and said second coil pair are made from a single thin film deposited on one side of a first substrate, and said second planar coils of said first coil pair and said second coil pair are made from a thin film deposited on one side of a second substrate.

9. The NMR probe of claim 8, wherein one of said coil pairs is a proton (¹H) coil pair and the other said coil pair is tuned for a different NMR nucleus.

10. The NMR probe of claim 9, wherein said different NMR nucleus is chosen from a group consisting of ²H, ³¹P, ¹³C, ¹⁴N, ¹⁵N, ¹⁹F and ³⁵Cl.

11. The NMR probe of claim 10, wherein the other said coil pair is a field-frequency lock coil pair and said different NMR nucleus is deuterium (²H).

12. The NMR probe of claim 11, wherein the deuterium field-frequency lock coil pair includes an LC trap.

13. The NMR probe of claim 12, wherein said HTS films are YBa₂Cu₃O_7-δ

and said first and second substrate materials are selected from the group consisting of sapphire, lanthanum aluminate and magnesium oxide.

14. The NMR probe of claim 6, wherein said first coil pair and said second coil pair are overlapping HTS coil pairs.

15. The NMR probe of claim 14, wherein said first planar coils of said first coil pair and said second coil pair are made from thin films deposited on opposite sides of a first substrate, and said second planar coils of said first coil pair and said second coil pair are made from thin films deposited on opposite sides of a second substrate.

16. The NMR probe of claim 15, wherein one of said coil pairs is a proton (¹H)coil pair and the other said coil pair is tuned for a different NMR nucleus.

17. The NMR probe of claim 16, wherein said different NMR nucleus is chosen from a group consisting of ²H, ³¹P, ¹³C, ¹⁴N, ¹⁵N, ¹⁹F and ³⁵Cl.

18. The NMR probe of claim 17, wherein the other said coil pair is a field-frequency lock coil pair and said different NMR nucleus is deuterium (²H).

19. The NM probe of claim 18, wherein the deuterium field-frequency) lock coil pair includes an LC trap.

20. The NMR probe of claim 19, wherein said HTS films are YBa₂Cu₃O_7-δ

and said first and second substrate materials are selected from the group consisting of sapphire, lanthanum aluminate and magnesium oxide.

21. The NMR probe of claim 14, wherein said first planar coil of said first coil pair is a thin film deposited on a first substrate, and said first planar coil of said second coil pair is a thin film deposited on a second substrate, and said second planar coil of said first coil pair is a thin film deposited on a third substrate, and said second planar coil of said second coil pair is a thin film deposited on a fourth substrate.

22. The NMR probe of claim 21, wherein one of said coil pairs is a proton (¹H) coil pair and the other said coil pair is tuned for a different NMR nucleus.

23. The NMR probe of claim 22, wherein said different NMR nucleus is chosen from a group consisting of ²H, ³¹P, ¹³C, ¹⁴N, ¹⁵N, ¹⁹F and ³⁵Cl.

24. The NMR probe of claim 23, wherein the other said coil pair is a field-frequency lock coil pair and said different NMR nucleus is deuterium (²H).

25. The NMR probe of claim 24, wherein the deuterium field-frequency lock coil pair includes an LC trap.

26. The NMR probe of claim 25, wherein said HTS films are YBa₂Cu₃O_7-δ

and said first, second, third, and fourth substrate materials are selected from the group consisting of sapphire, lanthanum aluminate and magnesium oxide.

27. The NMR probe of claim 21, wherein a first Faraday shield is positioned between said first planar coil of said first coil pair and said first planar coil of said second coil pair, and wherein a second Faraday shield is positioned between said second planar coil of said first coil pair and said second planar coil of said second coil pair.

28. The NMR probe of claim 27, wherein one of said coil pairs is a portion (¹H) coil pair and the other said coil pair is tuned for a different NMR nucleus.

29. The NMR probe of claim 28, wherein said different NMR nucleus is chosen from a group consisting of ²H, ³¹P, ¹³C, ¹⁴N, ¹⁵N, ¹⁹F and ³⁵Cl.

30. The NMR probe of claim 29, wherein the other said coil pair is a field-frequency lock coil pair and said different NMR nucleus is deuterium (²H).

31. The NMR probe of claim 30, wherein the deuterium field-frequency lock coil pair includes an LC trap.

32. The NMR probe of claim 31, wherein said HTS films are YBa₂Cu₃O_7-δ

and said first, second, third, and fourth substrate materials are selected from the group consisting of sapphire, lanthanum aluminate and magnesium oxide.

33. The NMR probe of claim 5, wherein said axis of symmetry of said magnetic field defined by said first planar coil pair is angularly displaced from said axis of symmetry of said magnetic field defined by said second coil pair.

34. The NMR probe of claim 33, wherein said first coil pair and said second coil pair are non-overlapping HTS coil pairs.

35. The NMR probe of claim 34, wherein said first planar coils of said first coil pair and said second coil pair are made from a single thin film deposited on one side of a first substrate, and said second planar coils of said first coil pair and said second coil pair are made from a thin film deposited on one side of a second substrate.

36. The NMR probe of claim 35, wherein one of said coil pairs is a proton (¹H) coil pair and the other said coil pair is tuned for a different NMR nucleus.

37. The NMR probe of claim 36, wherein said different NMR nucleus is chosen from a group consisting of ²H, ³¹P, ¹³C, ¹⁴N, ¹⁵N, ¹⁹F and ³⁵Cl.

38. The NMR probe of claim 37, wherein the other said coil pair is a field-frequency lock coil pair and said different NMR nucleus is deuterium (²H).

39. The NMR probe of claim 38, wherein the deuterium field-frequency lock coil pair includes an LC trap.

40. The NMR probe of claim 39, wherein said HTS films are YBa₂Cu₃O_7-δ

and said first and second substrate materials are selected from the group consisting of sapphire, lanthanum aluminate and magnesium oxide.

41. The NMR probe of claim 33, wherein said first coil pair and said second coil pair are overlapping HTS coil pairs.

42. The NMR probe of claim 41, wherein said first planar coils of said first coil pair and said second coil pair are made from thin films deposited on opposite sides of a first substrate, and said second planar coils of said first coil pair and said second coil pair are made from thin films deposited on opposite sides of a second substrate.

43. The NMR probe of claim 42, wherein one of said coil pairs is a proton (¹H) coil pair and the other said coil pair is tuned for a different NMR nucleus.

44. The NMR probe of claim 43, wherein said different NMR nucleus is chosen from a group consisting of ²H, ³¹P, ¹³C, ¹⁴N, ¹⁵N, ¹⁹F and ³⁵Cl.

45. The NMR probe of claim 44, wherein the other said coil pair is a field-frequency lock coil pair and said different NMR nucleus is deuterium (²H).

46. The NMR probe of claim 45, wherein the deuterium field-frequency lock coil pair includes an LC trap.

47. The NMR probe of claim 46, wherein said HTS films are YBa₂Cu₃O_7-δ

and said first and second substrate materials are selected from the group consisting of sapphire, lanthanum aluminate and magnesium oxide.

48. The NMR probe of claim 41, wherein said first planar coil of said first coil pair is a thin film deposited on a first substrate, and said first planar coil of said second coil pair is a thin film deposited on a second substrate, and said second planar coil of said first coil pair is a thin film deposited on a third substrate, and said second planar coil of said second coil pair is a thin film deposited on a fourth substrate.

49. The NMR probe of claim 48, wherein one of said coil pairs is a proton (¹H) coil pair and the other said coil pair is tuned for a different NMR nucleus.

50. The NMR probe of claim 49, wherein said different NMR nucleus is chosen from a group consisting of ²H, ³¹P, ¹³C, ¹⁴N, ¹⁵N, ¹⁹F and ³⁵Cl.

51. The NMR probe of claim 50, wherein the other said coil pair is a field-frequency lock coil pair and said different NMR nucleus is deuterium (²H).

52. The NMR probe of claim 51, wherein the deuterium field-frequency lock coil pair includes an LC trap.

53. The NMR probe of claim 52, wherein said HTS films are YBa₂Cu₃O_7-δ

and said first, second, third, and fourth substrate materials are selected from the group consisting of sapphire, lanthanum aluminate and magnesium oxide.

54. The NMR probe of claim 48, wherein a first Faraday shield is positioned between said first planar coil of said first coil pair and said first planar coil of said second coil pair, and wherein a second Faraday shield is positioned between said second planar coil of said first coil pair and said second planar coil of said second coil pair.

55. The NMR probe of claim 54, wherein one of said coil pairs is a proton (¹H) coil pair and the other said coil pair is tuned for a different NMR nucleus.

56. The NMR probe of claim 55, wherein said different NMR nucleus is chosen from a group consisting off ²H, ³¹P, ¹³C, ¹⁴N, ¹⁵N, ¹⁹F and ³⁵Cl.

57. The NMR probe of claim 56, wherein the other said coil pair is a field-frequency lock coil pair and said different NMR nucleus is deuterium (²H).

58. The NMR probe of claim 57, wherein the deuterium field-frequency, lock coil pair includes an LC trap.

59. The NMR probe of claim 58, wherein said HTS films are YBa₂CU₃O_7-δ

and said first, second, third, and fourth substrate materials are selected from the group consisting of sapphire, lanthanum aluminate and magnesium oxide.

60. A nuclear magnetic resonance probe comprising,

a holder for holding an NMR sample and for positioning said sample in a sample space in a static magnetic field, said sample space having first and second opposing sides and a center;

a plurality of coil pairs, each said coil pair being affixed to said probe, each said coil pair having a first planar coil and a second planar coil, each said first planar coil being positioned proximate to said first side of said sample space, each said second planar coil being positioned proximate to said second side of said sample space;

said first planar coils of each of said plurality of coil pairs being a substantially parallel first coil set and said second planar coils of each of said plurality of coil pairs being a substantially parallel second coil set, said parallel first coil set being substantially parallel to said parallel second coil set;

a magnetic field therefrom each of said magnetic fields defining a axis of symmetry said coils being a first axis extending from the center of said first planar coil of said first pair to the center of said second planar coil of said first pair, and a second axis and said first and second axes pass through extending from the center of said first planar coil of said second pair to the center of said second planar coil of said second pair, passes through said center of said sample space.

61. The NMR probe of claim 60, wherein said plurality of coil pairs is comprised of at least a first coil pair, a second coil pair and a third coil pair.

62. The NMR probe of claim 61, having three coil pairs wherein said second coil pair is an HTS coil pair.

63. The NMR probe of claim 62, wherein said first planar coil of said second coil pair is on a first plane and said first planar coils of said first coil pair and said third coil pair are on a second plane, said second plane being displaced from said first plane in a direction perpendicular to said first plane, and wherein said second planar coil of said second coil pair is on a third plane and said second planar coils of said first coil pair and said third coil pair are on a fourth plane, said fourth plane being displaced from said third plane in it direction perpendicular to said third plane.

64. The NMR probe of claim 63, wherein Faraday shields are interposed between said first plane and said second plane, and between said third plane and said fourth plane.

65. The NMR probe of claim 64, wherein said Faraday shields are made of HTS material.

66. The NMR probe of claim 60 wherein no coils comprising said first coplanar coils are directly electrically connected therebetween and no coils comprising said second coplanar coils are directly electrically connected therebetween.

67. The NMR probe of claim 60 wherein said first and second axes intersect at the center of said sample space.