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US3577067A
Expired / Lapsed
US
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Persistent mode superconductive orthogonal gradient cancelling coils
Assignee: Varian Medical Systems Inc
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Filing: 1966-05-11
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Granted: 1971-05-04
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Expires: 1986-05-11
Abstract
Abstract A superconductive magnet is disclosed together with superconductive gradient cancelling coils for homogenizing the magnetic field produced by the magnet. A gyromagnetic spectrometer is also disclosed which employs the magnetic field produced by the superconductive magnet. The gradient cancelling coils include a plurality of turns of a superconductor arranged adjacent the region of the magnetic field to be corrected, such magnetic field having certain residual magnetic field gradients therein to be cancelled. Means are provided for energizing the gradient cancelling coils with electrical currents in such a configuration as to define orthogonal superconductive gradient cancelling coils. A superconductive connection is formed across the ends of the coil structure for closing the superconductive circuit across the ends of the coil to form a closed superconductive circuit, whereby the superconductive gradient cancelling coils may be operated in a persistent mode for enhanced stability and reduced power consumption. In one embodiment, a DC transformer is provided which has a primary winding coupled to the main magnetic field of the magnet and a secondary winding which serves to energize the gradient cancelling coils. In this manner, the gradient cancelling field components change their intensity in proportion to changes in intensity of the main magnetic field to maintain a corrected field.
Inventors
- 👤 Harry E Weaver Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:40
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/381; G01R33/3815; G01R33/387; G01R33/3875; H; H01; H01F; H01F6/00; H01F6/006; H01F6/008; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/879
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
219 words
A superconductive magnet system including, means forming a superconductive solenoid having a winding with a multitude of turns of superconductor for producing a main magnetic field region within said solenoid having certain residual magnetic field gradient components, said winding of said solenoid including a pair of end winding segments connected in series with an intermediate winding segment of more turns than each of said end winding segments, each of said winding segments comprising a multitude of turns of superconductor, means forming a superconductor shunt connected in shunt across each of said winding segments, means including nonsuperconductive current carrying leads connected to each end of each of said end winding segments for energizing said end winding segments from a current supply with current having an amplitude which is separately variable relative to the amplitude of the current in said intermediate winding segment of said solenoid to produce a gradient cancelling field component, means forming a switch connected in each of said superconductor shunts which shunt said end winding segments, whereby each of said end winding segments may be energized from the current supply to produce a certain gradient cancelling field component superimposed on the main field of said solenoid and then switched via said switch means into a persistent superconductive current mode to preserve the preestablished gradient cancelling field component.
Claim 2
Dependent Claim
219 words
A superconductive magnet system including, means forming a superconductive solenoid having a winding with a multitude of turns of superconductor for producing a main magnetic field region within said solenoid having certain residual magnetic field gradient components, said winding of said solenoid including a pair of end winding segments connected in series with an intermediate winding segment of more turns than each of said end winding segments, each of said winding segments comprising a multitude of turns of superconductor, means forming a superconductor shunt connected in shunt across each of said winding segments, means including nonsuperconductive current carrying leads connected to each end of each of said end winding segments for energizing said end winding segments from a current supply with current having an amplitude which is separately variable relative to the amplitude of the current in said intermediate winding segment of said solenoid to produce a gradient cancelling field component, means forming a switch connected in each of said superconductor shunts which shunt said end winding segments, whereby each of said end winding segments may be energized from the current supply to produce a certain gradient cancelling field component superimposed on the main field of said solenoid and then switched via said switch means into a persistent superconductive current mode to preserve the preestablished gradient cancelling field component.
Claim 3
Dependent Claim
51 words
The apparatus of claim 1 including, means forming a cryostat for containing said solenoid means and for cooling said solenoid to a superconductive state, means for immersing a gyromagnetic resonance sample of matter within the gradient cancelled region of magnetic field, means for exciting and detecting gyromagnetic resonance of the sample.
Claim 4
Dependent Claim
150 words
In a superconductive magnet apparatus, means forming a superconductive solenoid for producing a main magnetic field region to be corrected which has certain residual magnetic field gradient components therein, first and second gradient cancelling coil means for cancelling the residual magnetic field gradient components, each of said first and second gradient cancelling coil means having an orthogonal current path geometry relative to each other, a superconductive joint connected across the ends of each of said first and second coil means to form first and second closed superconductive circuits, and wherein said closed superconductive circuits are disposed inside said solenoid surrounding the field region to be corrected, whereby each of said coil means acts as the secondary winding of a DC transformer and the correct current amplitude will automatically flow through each of said orthogonal coil geometries to cancel the certain residual magnetic field components in the region to be corrected.
Claim 5
Dependent Claim
150 words
In a superconductive magnet apparatus, means forming a superconductive solenoid for producing a main magnetic field region to be corrected which has certain residual magnetic field gradient components therein, first and second gradient cancelling coil means for cancelling the residual magnetic field gradient components, each of said first and second gradient cancelling coil means having an orthogonal current path geometry relative to each other, a superconductive joint connected across the ends of each of said first and second coil means to form first and second closed superconductive circuits, and wherein said closed superconductive circuits are disposed inside said solenoid surrounding the field region to be corrected, whereby each of said coil means acts as the secondary winding of a DC transformer and the correct current amplitude will automatically flow through each of said orthogonal coil geometries to cancel the certain residual magnetic field components in the region to be corrected.
Claim 6
Dependent Claim
189 words
In a superconductive magnet apparatus, means forming a superconductive solenoid for producing a main magnetic field region to be corrected which has certain residual magnetic field gradient components therein, first and second gradient cancelling coil means for cancelling the residual magnetic field gradient components, each of said first and second coil means having an orthogonal current path geometry relative to each other, means forming a superconductive connection connecting across the ends of each of said first and second coil means to form first and second closed superconductive circuits, means forming a direct current transformer having a primary winding energized with current proportional to the current flowing in the windings of said superconductive solenoid, and said superconductive connection which connects across the ends of each of said first and second coils being wound to form first and second secondary windings of said direct current transformer means, whereby the gradient cancelling field components produced by said first and second gradient cancelling coil means have magnitudes which vary in proportion to the current flowing in said solenoid, thereby preserving the preestablished gradient cancelling effect when the main magnetic field intensity is scanned.
Claim 7
Dependent Claim
189 words
In a superconductive magnet apparatus, means forming a superconductive solenoid for producing a main magnetic field region to be corrected which has certain residual magnetic field gradient components therein, first and second gradient cancelling coil means for cancelling the residual magnetic field gradient components, each of said first and second coil means having an orthogonal current path geometry relative to each other, means forming a superconductive connection connecting across the ends of each of said first and second coil means to form first and second closed superconductive circuits, means forming a direct current transformer having a primary winding energized with current proportional to the current flowing in the windings of said superconductive solenoid, and said superconductive connection which connects across the ends of each of said first and second coils being wound to form first and second secondary windings of said direct current transformer means, whereby the gradient cancelling field components produced by said first and second gradient cancelling coil means have magnitudes which vary in proportion to the current flowing in said solenoid, thereby preserving the preestablished gradient cancelling effect when the main magnetic field intensity is scanned.
Claim 8
Dependent Claim
41 words
The apparatus of claim 4 including means for varying the amount of magnetic coupling between the primary and secondary windings of said transformer means for adjusting the amplitude of the gradient cancelling field component produced by said gradient cancelling coil means.
References Cited (Backward Citations)
US3287630A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |