NMR solenoidal coil for RF field homogeneity

Abstract

An NMR signal acquisition device that can increase the magnetic field homogeneity in a high frequency magnetic field by one of the following. (a) Current paths each having a different inductance are provided to adjust the diversion ratio of the current, (b) A current path branch point is provided in an intermediate part of the winding of a solenoidal coil so that there are more current paths in the intermediate part of the winding than in the current paths connected to the feeding points at both ends, (c) The radiuses of current paths are adjusted, (d) Winding pitches in the axis direction are adjusted, (e) Current path widths are adjusted, and (f) The solenoidal coil has both positive direction current paths and negative direction current paths.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the overview of an NMR signal acquisition device.

FIG. 2 is a cross section diagram showing the inside of a static magnetic field generator.

FIG. 3 is a current path diagram when a solenoidal coil in a comparison example is developed.

FIG. 4 is a current path layout diagram and a current path cross section diagram of a solenoidal coil in the comparison example.

FIG. 5 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil in a first embodiment.

FIG. 6 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil in a second embodiment.

FIG. 7 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil in a third embodiment.

FIG. 8 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil in a fourth embodiment.

FIG. 9 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil that has the characteristics of the first and fourth embodiments.

FIG. 10 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil that has the characteristics of the second and fourth embodiments.

FIG. 11 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil that has the characteristics of the third and fourth embodiments.

FIG. 12 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil in a sixth embodiment.

FIG. 13 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil that has the characteristics of the first, fourth, and sixth embodiments.

FIG. 14 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil that has the characteristics of the second, fourth, and sixth embodiments.

FIG. 15 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil that has the characteristics of the third, fourth, and sixth embodiments.

FIG. 16 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil that has the characteristics of the fourth and sixth embodiments.

FIG. 17 is a current path development diagram, a current path layout diagram, and a current path cross section diagram of a solenoidal coil in an eighth embodiment.

FIG. 18 is a diagram showing the high frequency magnetic field distribution in a sample space calculated in the first, second, and third embodiments.

FIG. 19 is a diagram showing the high frequency magnetic field distribution in a sample space calculated in the fourth, sixth, and eighth embodiments.

FIG. 20 is a diagram showing the simulation result of an rf homogeneity (810/90) pulse calculated in the first, second, and third embodiments.

FIG. 21 is a diagram showing the simulation result of an rf homogeneity (810/90) pulse calculated in the fourth, sixth, and eighth embodiments.

FIG. 22 is a cross section diagram showing a wire material in a ninth embodiment.

FIG. 23 is a cross section diagram showing the part layout in an eleventh embodiment.

FIG. 24 is a cross sectional diagram showing the part layout in a twelfth embodiment.

Claims

1. A solenoidal coil for an NMR (Nuclear Magnetic Resonance) signal, said solenoidal coil being used for NMR measurement, wherein there are a plurality of current paths connecting feeding points at both ends, a current path collection point is provided in a center of a winding, and the current paths are geometrically symmetric with respect to the center of the winding.

2. A solenoidal coil for an NMR signal, said solenoidal coil being used for NMR measurement, wherein a current path branch point and a current path collection point are provided in an intermediate part of a winding to provide more current paths in the intermediate part than in a part of the winding connected to feeding points at both ends.

3. A solenoidal coil for an NMR signal, said solenoidal coil being used for NMR measurement, wherein radiuses of current paths are made different according to a predetermined ratio.

4. A solenoidal coil for an NMR signal, said solenoidal coil being used for NMR measurement, wherein winding pitches in a coil axis direction have predetermined distributions from a center of the coil toward coil ends and the distributions are symmetric with respect to the center of the coil.

5. The solenoidal coil according to claim 1, wherein winding pitches in a coil axis direction have predetermined distributions from a center of the coil toward coil ends and the distributions are symmetric with respect to the center of the coil.

6. The solenoidal coil according to claim 2, wherein winding pitches in a coil axis direction have predetermined distributions from a center of the coil toward coil ends and the distributions are symmetric with respect to the center of the coil.

7. The solenoidal coil according to claim 3, wherein winding pitches in a coil axis direction have predetermined distributions from a center of the coil toward coil ends and the distributions are symmetric with respect to the center of the coil.

8. A solenoidal coil for an NMR signal, said solenoidal coil being used for NMR measurement, wherein current path widths in a coil axis direction have predetermined distributions from a center of the coil toward coil ends and the distributions are symmetric with respect to the center of the coil.

9. The solenoidal coil for an NMR signal according to claim 1, wherein current path widths in a coil axis direction have predetermined distributions from a center of the coil toward coil ends and the distributions are symmetric with respect to the center of the coil.

10. The solenoidal coil for an NMR signal according to claim 2, wherein current path widths in a coil axis direction have predetermined distributions from a center of the coil toward coil ends and the distributions are symmetric with respect to the center of the coil.

11. The solenoidal coil for an NMR signal according to claim 3, wherein current path widths in a coil axis direction have predetermined distributions from a center of the coil toward coil ends and the distributions are symmetric with respect to the center of the coil.

12. The solenoidal coil for an NMR signal according to claim 4, wherein current path widths in the coil axis direction have predetermined distributions from the center of the coil toward the coil ends and the distributions are symmetric with respect to the center of the coil.

13. The solenoidal coil for an NMR signal according to claim 5, wherein current path widths in the coil axis direction have predetermined distributions from the center of the coil toward the coil ends and the distributions are symmetric with respect to the center of the coil.

14. The solenoidal coil for an NMR signal according to claim 6, wherein current path widths in the coil axis direction have predetermined distributions from the center of the coil toward the coil ends and the distributions are symmetric with respect to the center of the coil.

15. The solenoidal coil for an NMR signal according to claim 7, wherein current path widths in the coil axis direction have predetermined distributions from the center of the coil toward the coil ends and the distributions are symmetric with respect to the center of the coil.

16. A solenoidal coil for an NMR signal, said solenoidal coil being used for NMR measurement, wherein said solenoidal coil has both a current path for generating a positive magnetic field and a current path for generating a negative magnetic field in a coil axis direction.

17. The solenoidal coil for an NMR signal according to claim 3, wherein said solenoidal coil has both a current path for generating a positive magnetic field and a current path for generating a negative magnetic field in a coil axis direction.

18. The solenoidal coil for an NMR signal according to claim 4, wherein said solenoidal coil has both a current path for generating a positive magnetic field and a current path for generating a negative magnetic field in a coil axis direction.

19. A NMR signal acquisition device comprising: a static magnetic field generator;a static magnetic field homogeneity compensation unit;a gradient field generator;a probe on which a solenoidal coil for an NMR signal is mounted; anda control unit that sends a high frequency current to said solenoidal coil for a NMR signal for acquiring the NMR signal, wherein said solenoidal coil has a plurality of current paths connecting feeding points at both ends, a current path collection point is provided in a center of a winding, and the current paths are geometrically symmetric with respect to the center of the winding.