Refrigerated MR magnet support system

Claim 1

A superconductive magnet cooled by a two stage cryocooler comprising: a vacuum vessel; a magnet cartridge having at least one superconductive coil situated in the vacuum vessel; a first stage heat station for removably thermally engaging the first stage of the cryocooler; removably thermally engaging the second stage of the cryocooler, said second stage heat station in thermal and supporting contact with said magnet cartridge; a thermal radiation shield surrounding said magnet cartridge, said shield spaced away from said vacuum vessel and the magnet cartridge said thermal radiation shield defining an aperture; three concentric cylindrical tubes including an outer tube, an intermediate tube and an inner tube, said outer tube substantially enclosing said intermediate tue, said intermediate tube substantially enclosing said inner tube, each of said tubes having a first and second ends, said first and second heat stations situated inside said inner tube, said outer tube secured to said vacuum vessel at its first end and to said thermal radiation shield and first end of said intermediate tube at its second end, the second end of said intermediate tube being secured to the first end of said inner tube, the second end of said inner tube extending through the aperture in said thermal radiation shield and secured to said magnet cartridge; spring bias means secured between second end of said intermediate tube and said first stage heat station for maintaining a constant pressure between the cryocooler first stage and the first stage heat station when the second stage of said cryocooler is forced in contact with the second stage heat station; and means for thermally connecting said thermal radiation shield to said first stage heat station.