Patent ID: 6147579
Filing Date: 2000-11-14
Classification: F17C,G01R,H01F,Y10S

Abstract:
A thermally insulating superconducting magnet having an axis and suitable for magnetic resonance imaging and including a cryogen pressure vessel concentric within and spaced from a vacuum vessel, and a thermal radiation shield interposed between the vessels and extending along the axis thereof, and a suspension system to maintain the positions of the vessels and the thermal radiation shield concentrically about said axis comprising:a support extending at an angle to said axis between said cryogen pressure vessel and said radiation shield around said thermal radiation shield and forming a space therebetween which increases along said axis defining a frustro-conical surface;a non-uniform thickness thermal insulation assembly interposed between said support and said thermal radiation shield including:a first multi-layer thermal insulating blanket of alternating layers of low thermal conductivity spacers and thermally reflective material;a second multi-layer insulating blanket overlying a portion of said first multi-layer insulating blanket forming a non-uniform stepped thickness;the number of layers in said multi-layer thermal insulating blanket being greater in the region of said space remote from said radiation shield and the apex of said angle forming a non-uniform thickness in said space; andat least one fastener passing through and securing the multi-layer thermal blankets within said space between said support and said thermal radiation shield.