Cryostat with external refrigerator for super-conducting NMR spectrometer
An improved cryostat for the superconducting magnet of an NMR spectrometer comprises a nested structure of isothermal shells surrounding a thermally conductive central reservoir of substantially spherical shape containing liquid helium in which the superconducting solenoid remains operational when only partially immersed. A radiation shield surrounding the central reservoir is cooled by the boil-off of escaping helium vapor. The radiation shield is enclosed within a isothermal shell maintained at the temperature of liquid nitrogen by thermal contact with a liquid nitrogen reservoir disposed above the region of the central reservoir and shielded therefrom by a wall of the isothermal shell. An outer radiation shield surrounds the liquid nitrogen reservoir and associated isothermal shell and the outer radiation shield is maintained at a temperatures of the order of 180* K. By an external refrigeration facility. A hermitica sealed containment vessel forms the outer wall of the cryostat and provides a port for evacuating to a very low common pressure all the interior spaces between adjacent nested structures. The spacing between adjacent nested surfaces is maintained by a novel internal mechanical bracing system of low thermal conductivity comprising polyester cords disposed under tension between adjacent shells.
- Assignee:
- Varian Associates Inc
- Patent Number(s):
- US 4291541
- Application Number:
- TRN: 82-005037
- OSTI ID:
- 5806113
- Resource Relation:
- Patent File Date: Filed date 30 Jun 1980
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
CRYOSTATS
DESIGN
NMR SPECTROMETERS
SUPERCONDUCTING MAGNETS
HELIUM
HELIUM DILUTION REFRIGERATORS
LIQUIDS
NITROGEN
RADIATION PROTECTION
SHELLS
SHIELDS
SOLENOIDS
THERMAL CONDUCTIVITY
CONTROL EQUIPMENT
ELECTRIC COILS
ELECTRICAL EQUIPMENT
ELECTROMAGNETS
ELEMENTS
EQUIPMENT
FLUIDS
GASES
MAGNETS
MEASURING INSTRUMENTS
NONMETALS
PHYSICAL PROPERTIES
RARE GASES
REFRIGERATORS
SPECTROMETERS
SUPERCONDUCTING DEVICES
THERMODYNAMIC PROPERTIES
THERMOSTATS
420201* - Engineering- Cryogenic Equipment & Devices