Superconductive magnetic resonance magnet without cryogens

An open magnetic resonance imaging magnet comprising:

• a first and second resin impregnated circular coil of superconductor wire, said coils having the same diameter and number of turns;
• a first and second heat conductive means, each having a thermal conductivity greater than said resin, contacting said first and second impregnated coils, respectively, along the length of at least one of each of the impregnated coil surfaces;
• a plurality of thermally conductive support means, having a thermal conductivity greater than that of the resin, thermally coupling at discrete locations the heat conductive means on said first and second coil and spacing said coils apart parallel to one another with the geometric center of each coil lying on the same imaginary axial line;
• a thermal radiation shield spaced away from and individually enclosing said first coil and said second coil and individually surrounding each of said support means;
• an evacuable cryostat housing spaced away from and enclosing said radiation shield;
• a two stage cryocooler mounted in said housing, the warmer stage thermally coupled to said radiation shield, the colder stage thermally coupled to said heat conductive means;
• a plurality of bracket means;
• and
• a third and fourth circular coil of current conducting wire, said third and fourth coils each having the same diameter and number of turns their diameter being less than the diameter of said first and second coils said third and fourth coils supported by said plurality of bracket means to be approximately in the same plane as the first and second coil, respectively, the geometric centers of said third and fourth coils lying on the same imaging axial line as the centers of the first and second coils.

An open magnetic resonance imaging magnet comprising:

• a first and second resin impregnated circular coils of superconductor wire, said coils having the same diameter and number of turns;
• a third and fourth resin impregnated circular coils of superconductor wire, said coils having the same diameter and number of turns, said third and fourth coils having a smaller diameter than the first and second coils;
• first and second heat conductive means, having a thermal conductivity greater than that of the resin, said first heat conductive means contacting the first and third resin impregnated coils along the length of at least one of each of the impregnated coils surfaces, said second heat conductive means contacting the second and fourth resin impregnated coils along the length of at least one of each of the impregnated coil surfaces;
• a plurality of thermally conductive support means, having a thermal conductivity greater than that of the resin, thermally coupling at discrete locations the first and second heat conductive means and said plurality of support means spacing said first and second coils, as well as said third and fourth coils, apart and parallel to one another with the geometric centers of all the coils lying on the same imaginary axial line;
• a thermal radiation shield spaced away from and enclosing said first and third coils and said first conduction means together and separately enclosing said second and fourth coils and said second conduction means ,together, said plurality of support means each individually enclosed;
• an evacuable cryostat housing spaced away from and enclosing said radiation shield;
• and
• a multistage cryocooler mounted in said housing, having a stage thermally coupled to said radiation shield and a stage capable of achieving lower temperatures than the other stage coupled to said second heat conductive means.

A superconducting magnetic resonance magnet comprising;

• a hollow cylindrical fiber reinforced plastic coil form having circumferential slots on the outer surface and an axial slot joining said circumferential slots;
• copper bus bars adhesively bonded in said axial slots;
• superconductor wire wound in said circumferential slots soldered at the beginning to the bus bars at one side and at the end to the bus bar at the other side;
• overbanding enclosing the superconductor windings in the slots;
• a conductive shell enclosing the exterior surface of said coil form;
• resin impregnating the shield coil form interior, surrounding said windings with resin;
• a radiation shield surrounding said coil form;
• a vacuum housing enclosing said radiation shield;
• suspension means supporting said coil form and radiation shield from said housing;
• and
• a two stage cryocooler having a first stage thermally coupled to said shield and a second stage thermally coupled to said conductive shell.