| 摘要 |
PCT No. PCT/GB93/00806 Sec. 371 Date Oct. 14, 1994 Sec. 102(e) Date Oct. 14, 1994 PCT Filed Apr. 16, 1993 PCT Pub. No. WO93/21539 PCT Pub. Date Oct. 28, 1993A super-conducting magnet, particularly suitable for use with an MRI system is provided. The super-conducting magnet includes a closed loop former, a coil winding around the former of a material which is super-conducting at low temperatures, a vacuum vessel containing the former and also of closed loop shape to define a passage through the magnet for receipt of objects to be investigated by nuclear magnetic resonance, electrical connection for the coil winding, a thermal shield within the vacuum vessel and around the former, characterized in that the former is non-electrically conductive and in that refrigeration is provided, operatively connected to the coil winding and the thermal shield, the refrigeration being such that no liquid reservoir for liquid helium or liquid nitrogen is required.
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