Superconducting resonators for NMR applications

• US 20020190715A1
• Filed: 04/10/2002
• Published: 12/19/2002
• Est. Priority Date: 04/17/2001
• Status: Active Grant

• Current Assignee: Bruker Switzerland AG (Bruker Corporation)
• Original Assignee: Bruker Invest AG (Bruker Corporation)
• Inventors: Marek, Daniel
• Granted Patent: US 6,727,700 B2
• Time in Patent Office: Days
• US Class Current: 324/318
• CPC Class Codes: G01R 33/34007 Manufacture of RF coils, e.g. using printed circuit board technology; additional hardware for providing mechanical support to the RF coil assembly or to part thereof, e.g. a support for moving the coil assembly relative to the remainder of the MR system
• CPC Class Codes: G01R 33/34023 Superconducting RF coils
• CPC Class Codes: G01R 33/34046 Volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly polarised coils
• CPC Class Codes: G01R 33/34061 Helmholtz coils
• CPC Class Codes: G01R 33/34076 Birdcage coils
• CPC Class Codes: G01R 33/34092 RF coils specially adapted for NMR spectrometers
• CPC Class Codes: G01R 33/3815 with superconducting coils, e.g. power supply therefor

Abstract

An RF receiver coil arrangement for the reception of measuring signals from a measuring sample in the measuring volume of an NMR spectrometer comprising an RF resonator having superconducting, inductively and capacitively acting conducting structures, which form resonant circuits, on planar substrate elements and which are disposed about the measuring sample, is characterized in that each individual current-carrying resonant circuit on the planar substrate element produces a magnetic field in the center of the measuring volume, which is parallel to the plane of the planar substrate element, on which the individual resonant circuit is located, wherein the deviation from parallelism, does not exceed 40 degrees. This introduces a new class of superconducting NMR resonators which better meet the technical requirements than those of prior art.

Claims

1. An RF(=radio frequency) receiver coil arrangement for the reception of measurement signals from a measuring sample disposed in a measuring volume of an NMR (nuclear magnetic resonance) spectrometer, the receiver coil comprising:

at least one planer substrate element disposed proximate the measuring sample;

superconducting, inductively, and capacitively acting conducting structures disposed on said at least one planar substrate element; and

means for connecting and arranging said conducting structures to form at least one individual current-carrying resonant circuit, wherein each individual current-carrying resonant circuit generates a magnet field in a center of the measuring volume which is substantially parallel to a plane of the planar substrate element on which said resonant circuit is located, wherein a deviation from parallelism does not exceed 40 degrees.

2. The RF receiver coil arrangement of claim 1, wherein the measuring volume has a longer extension in one spatial dimension than in two other spatial dimensions, with at least one of said conductor structures being disposed on said planar substrate element parallel to a longitudinal axis of the measuring volume.

3. The RF receiver coil arrangement of claim 1, wherein each superconducting resonant circuit on said planar substrate element is tuned to approximately a same resonance frequency.

4. The RF receiver coil arrangement of claim 1, wherein said resonant circuit on said planar substrate element is exclusively formed of both inductively and capacitively acting conducting structures.

5. The RF receiver coil arrangement of claim 4, wherein at least part of said superconducting conducting structures on said planar substrate element is disposed at a smallest possible separation from the measuring sample.

6. The RF receiver coil arrangement of claim 1, wherein said resonant circuit on said planar substrate element is formed by substantially purely inductively acting conducting structures and inductively and capacitively acting conducting structures.

7. The RF receiver coil arrangement of claim 6, wherein at least part of said purely inductively acting conducting structures is disposed at a smallest possible separation from the measuring sample.

8. The RF receiver coil arrangement of claim 6, wherein both inductively and capacitively acting conducting structures are disposed on regions of said planar substrate element facing away from the measuring volume.

9. The RF receiver coil arrangement of claim 6, wherein superconducting conducting paths in parts of said resonant circuit facing away from the measuring volume are branched into two or more conducting paths.

10. The RF receiver coil arrangement of claim 9, wherein said inductively and capacitively acting conducting structures of said resonant circuit comprise groups of branched conducting paths which engage each other like fingers.

11. The RF receiver coil arrangement of claim 9, wherein said inductively and capacitively acting conducting structures of said resonant circuit comprise branched conducting paths engaging each other individually like fingers.

12. The RF receiver coil arrangement of claim 9, wherein one part of said branched conducting paths in said inductively and capacitively acting conducting structures of said resonant circuit engage each other in groups and like fingers and a remaining part engages each other individually and like fingers.

13. The RF receiver coil arrangement of claim 1, wherein said superconducting conducting structures are disposed on a side of said planar substrate element facing the measuring volume.

14. The RF receiver coil arrangement of claim 1, wherein one single planar substrate element is disposed to extend tangentially outwards from the measuring volume, and said resonant circuit is provided on said substrate element having said conducting structures extending at least partially parallel to an axis of the measuring sample and being disposed as close as possible thereto.

15. The RF receiver coil arrangement of claim 14, further comprising a second identical planar substrate element which is rotated, with respect to said one single planar substrate element, through 180 degrees about a longitudinal axis of the measuring volume.

16. The RF receiver coil arrangement of claim 14, further comprising three further identical planar substrate elements which are rotated, with respect to said one single planar substrate element, through 90, 180 and 270 degrees about a longitudinal axis of the measuring volume.

17. The RF receiver coil arrangement of claim 14, further comprising n-1 further identical planar substrate elements which are rotated, with respect to said one single planar substrate element, through 360/n, 2·

360/n, 3·

360/n, . . . , (n-1)·

360/n degrees about a longitudinal axis of the measuring volume, thereby producing a symmetrical rosette-like structure, wherein n is a positive integer.

18. The RF receiver coil arrangement of claim 1, wherein two parallel planar substrate elements are disposed on opposing sides of the measuring volume, symmetrically to the measuring volume, and two superconducting resonant circuits are provided on each of said two substrate elements which are disposed symmetrically to the measuring volume, whose said conducting structures are at least partially parallel to an axis of the measuring sample and are disposed as closely as possible thereto.

19. The RF receiver coil arrangement of claim 1, wherein two pairs of planar substrate elements, disposed in a V-shape, are positioned with an open side of said V-shape close to the measuring volume and diametrally and symmetrically thereto, wherein one of said superconducting resonant circuit is provided on each individual substrate element whose said conducting structures are at least partly parallel to an axis of the measuring sample and as close as possible thereto.

20. The RF receiver coil arrangement of claim 18, further comprising a Helmholtz coil arrangement disposed externally about said planar substrate element to produce a B2 field in a center of the measuring volume which is perpendicular to a B1 field of said resonant circuits.

21. The RF receiver coil arrangement of claim 1, wherein said planar substrate element has line-shaped conducting paths.

22. The RF receiver coil arrangement of claim 1, wherein at least a part of said conducting structures which belong to said superconducting resonant circuit of a corresponding said substrate element and which are not disposed directly proximate the measuring volume has widening, conducting paths.

23. The RF receiver coil arrangement of claim 1, further comprising means for coupling to at least one further superconducting or normally conducting RF coil.

24. The RF receiver coil arrangement of claim 23, wherein at least one of said further coils comprises the RF receiver coil arrangement.