FERROMAGNETIC FRAME MAGNET WITH SUPERCONDUCTING COILS

摘要

A magnetic resonance imaging magnet includes a ferromagnetic frame (20). A pair of generally toroidal superconducting coil units (68, 70) overlie inner faces (36, 40) of side walls (22, 24) incorporated in the frame. Each coil unit may include a vessel having hollow support extensions (80) extending into recesses in the side walls. The coil units may further include elongated, low-thermal conductance supports (110) disposed within the support extensions. The frame may include pole stems (54, 56) projecting inwardly from the side walls, and the coils may be disposed in close proximity to the pole stems. Cryocoolers (208, 208') may be mounted to the frame so that the cryocoolers are substantially mechanically isolated from the coils of the coil units, but are in thermal communication therewith. The cryocooler mountings may be arranged for convenient servicing and installation of the cryocoolers.