Superconductive magnet having shim coils and quench protection circuits
A superconductive magnet is described comprising: a first persistent current loop comprising a first superconductor and a main coil connected to the first superconductor, the main coil being operative in response to superconduction therein to generate a primary magnetic field; a second persistent current loop comprising a second superconductor and a shim coil connected thereto, the shim coil being operative in response to superconduction therein to generate a corrective field for correcting aberrations in a predetermined gradient in the primary magnetic field, the shim coil having fewer turns than the main coil and being inductively coupled therewith whereby small changes in the current in the main coil cause much greater changes in the current in the shim coil. The magnet is characterized by an improvement which consists of: a first heater connected across the second persistent loop in parallel with the shim coil, the first heater being normally inoperative to carry current while the shim coil and the second superconductor are superconducting, the first heater being operative in response to current therein to heat the shim coil to a resistive state; and protective circuit means comprising a second heater connected to the main coil for carrying current from the main coil upon quenching of the main coil, the second heater being disposed in thermal contact with the second superconductor to heat the second superconductor to a resistive state in response to the current from the main coil to thereby divert current in the second persistent loop through the second heater causing it to heat the shim coil to a resistive state and resistively dissipate energy therein.
- Assignee:
- International Business Machines Corp., Armonk, NY
- Patent Number(s):
- US 4689707
- Application Number:
- TRN: 87-036935
- OSTI ID:
- 6084570
- Resource Relation:
- Patent File Date: Filed date 27 May 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
SUPERCONDUCTING MAGNETS
DESIGN
OPERATION
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRONIC CIRCUITS
HEATERS
MAGNETIC FIELDS
SUPERCONDUCTING COILS
CURRENTS
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELECTROMAGNETS
EQUIPMENT
MAGNETS
PHYSICAL PROPERTIES
SUPERCONDUCTING DEVICES
420201* - Engineering- Cryogenic Equipment & Devices