Conductor Assembly Including A Flared Aperture Region

• US 20090085709A1
• Filed: 06/05/2008
• Published: 04/02/2009
• Est. Priority Date: 10/02/2007
• Status: Active Grant

• Current Assignee: Advanced Magnet Lab Incorporated
• Original Assignee: Advanced Magnet Lab Incorporated
• Inventors: Meinke, Rainer
• Granted Patent: US 7,880,578 B2
• Time in Patent Office: Days
• US Class Current: 336/225
• 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 33/34046 Volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly polarised coils
• CPC Class Codes: G01R 33/34053 Solenoid coils; Toroidal coils
• CPC Class Codes: G01R 33/34084 implantable coils or coils being geometrically adaptable to the sample, e.g. flexible coils or coils comprising mutually movable parts
• CPC Class Codes: H01F 2027/2833 using coaxial cable as wire
• CPC Class Codes: H01F 27/323 Insulation between winding turns, between winding layers
• CPC Class Codes: H01F 41/048 Superconductive coils
• CPC Class Codes: H01F 41/064 Winding non-flat conductive wires, e.g. rods, cables or cords
• CPC Class Codes: H01F 41/071 Winding coils of special form winding conductors onto closed formers or cores H01F41/08
• CPC Class Codes: H01F 41/086 in a special configuration on the former, e.g. orthocyclic coils or open mesh coils
• CPC Class Codes: H01F 41/098 Mandrels; Formers
• CPC Class Codes: H01F 5/00 Coils superconducting coils H01F6/06; fixed inductances of the signal type H01F17/00
• CPC Class Codes: H01F 5/02 wound on non-magnetic supports, e.g. formers
• CPC Class Codes: H01F 6/02 Quenching; Protection arrangements during quenching protection circuits H02H7/001
• CPC Class Codes: H01F 6/06 Coils, e.g. winding, insulating, terminating or casing arrangements therefor
• CPC Class Codes: H01F 7/202 Electromagnets for high magnetic field strength for superconducting electromagnets H01F6/00; for transformers or inductances without a magnetic core H01F30/08
• CPC Class Codes: H05H 7/04 Magnet systems , e.g. undulators, wigglers free-electron laser H01S3/0903; Energisation thereof
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49071 by winding or coiling
• CPC Class Codes: Y10T 29/49073 : by assembling coil and core

Abstract

A conductor assembly of the type which, when conducting current, generates a magnetic field or in which, in the presence of a changing magnetic field, a voltage is induced. A helical wiring pattern is positioned along an axis a radial distance R from the axis. The wiring pattern is formed about an aperture region extending from the axis toward the wiring pattern, the distance R varying along a portion of the axis.

Claims

1. A conductor assembly of the type which, when conducting current, generates a magnetic field or in which, in the presence of a changing magnetic field, a voltage is induced, comprising:

a helical wiring pattern positioned along an axis and a radial distance R from the axis, the wiring pattern formed about an aperture region extending from the axis toward the wiring pattern, the distance R varying along a portion of the axis.

2. The conductor assembly of claim 1 wherein along the portion of the axis that the distance R varies, the aperture extends from the axis portion a variable distance.

3. The conductor assembly of claim 1 wherein the wiring pattern includes a curved contour extending symmetrically along a direction of the axis as the aperture extends a variable distance.

4. The conductor assembly of claim 1 including first and second opposing ends and a center region between the ends, wherein the portion of the axis along which the distance R varies extends from one of the ends toward the other end.

5. The conductor assembly of claim 1 including first and second opposing ends and a center region between the ends, wherein the portion of the axis along which the distance R varies extends from one of the ends toward the center region.

6. The conductor assembly of claim 1 including first and second opposing ends and a center region between the ends, wherein the wiring pattern includes two flared end regions each extending to a different one of the opposing ends.

7. The conductor assembly of claim 1 including a second helical wiring pattern wherein:

the two wiring patterns are of opposing tilt angles with respect to the axis, corresponding to a double helix design,

the assembly includes first and second opposing ends, and

along one of the ends both of the wiring patterns include a flared end region.

8. The conductor assembly of claim 1 wherein the axis is a straight axis.

9. The conductor assembly of claim 8 wherein the wiring pattern includes a curved contour extending symmetrically along a direction of the axis as the aperture extends a variable distance.

10. The conductor assembly of claim 9 wherein the curved contour is a flared region along the axis.

11. The conductor assembly of claim 8 including first and second opposing ends and a center region, wherein the wiring pattern includes a flared section along the center region and between the ends, the flared section being of variable radius and formed between sections of constant coil row radius.

12. A conductor assembly of the type which, when conducting current, generates a magnetic field or in which, in the presence of a changing magnetic field, a voltage is induced, comprising:

a helical wiring pattern positioned along an axis and formed about an aperture region extending a radial distance R from the axis and toward the wiring pattern, the aperture region including flared section of variable distance R from the axis.

13. The conductor assembly of claim 12 wherein the flared section is formed between first and second aperture sections each of a constant radius corresponding to a constant distance R from the axis.

14. The conductor assembly of claim 12 wherein the wiring pattern includes first and second opposing ends and a center region between the ends along which the aperture region is of fixed radial distance R from the axis, wherein the flared section extends along the axis from one of the ends to the center region.

15. The conductor assembly of claim 14 wherein the radial distance R of the flared aperture section from the axis, monotonically increases from the fixed radial distance along the center region to said one of the ends.

16. The conductor assembly of claim 12 wherein:

the wiring pattern comprises multiple coil rows configured to generate a main multipole field of order n between first and second ends of the assembly;

the aperture region includes a first section along the axis of fixed radial distance R₁ from the axis and the flared section increases in radial distance from the axis to a distance R₂; and

as a result of increasing the radial distance to R₂, field quality along portions of the aperture region where R increases toward R₂ is improved relative to calculable field quality over the same aperture portions for a geometry wherein R remains the fixed radial distance R₁ from the axis instead of increasing to R₂.

17. The conductor assembly of claim 16 wherein the main multipole field is a dipole field and the field quality is determined based on relative magnitude of a sextupole field component measurable along a circle in a plane transverse to the axis, the circle having a radius extending 0.8 R₁ from the axis.

18. The conductor assembly of claim 16 wherein the multiple coil rows are constructed in accord with a tilted double helix configuration.