Abstract: A superconducting magnet device is configured to include: a refrigerant circulation flowpath in which a refrigerant (R) circulates; a refrigerator for cooling vapor of the refrigerant (R) in the refrigerant circulation flowpath; a superconducting coil cooled by the circulating refrigerant (R); a protective resistor thermally contacting the superconducting coil and having an internal space (S); a high-boiling-point refrigerant supply section for supplying a high-boiling-point refrigerant having a higher boiling point than the refrigerant (R) and frozen by the refrigerant (R) to the internal space (S) in the protective resistor; and a vacuum insulating container for at least accommodating the refrigerant circulation flowpath, the superconducting coil, and the protective resistor.

Abstract: A superconductor cooling system has: a first superconductor; a first cooling conductor used for cooling the first superconductor; a first cooling unit configured to cool the first cooling conductor to a first temperature; and a current lead configured to supply a current to the first superconductor. Here, a part of a path of the current is formed of a second superconductor. The superconductor cooling system further has: a second cooling conductor used for cooling the second superconductor; a second cooling unit configured to cool the second cooling conductor to a second temperature; and a first thermal conduction switch connected between the first cooling conductor and the second cooling conductor to ON and OFF heat transfer between the first cooling conductor and the second cooling conductor.

Abstract: A hollow cylindrical thermal shield for a tubular cryogenically cooled superconducting magnet, has a first axis, an inner cylindrical tube having an axis aligned with the first axis, an outer cylindrical tube of greater diameter than the diameter of the inner cylindrical tube, having an axis aligned with the first axis, and annular end pieces, joining the inner cylindrical tube and the outer cylindrical tube to form an enclosure. The hollow cylindrical thermal shield further has a cylindrical stiffener, extending axially at least part of the axial length of the inner cylindrical tube, the stiffener being joined at intervals to the inner cylindrical tube, thereby to improve the mechanical rigidity of the inner cylindrical tube.

Abstract: A system and method for protecting a superconductor. The system may comprise a current sensor operable to detect a current flowing through the superconductor. The system may comprise a coolant temperature sensor operable to detect the temperature of a cryogenic coolant used to cool the superconductor to a superconductive state. The control circuit is operable to estimate the superconductor temperature based on the current flow and the coolant temperature. The system may also be operable to compare the estimated superconductor temperature to at least one threshold temperature and to initiate a corrective action when the superconductor temperature exceeds the at least one threshold temperature.

Abstract: A magnet, such as an open or closed magnet, has a first assembly with at least one superconductive main coil and with a first vacuum enclosure enclosing the main coil(s). A first cryocooler coldhead has a rigid first housing and is generally vertically aligned. A first flexible bellows is vertically aligned, has a first end attached to the first housing of the first cryocooler coldhead and has a second end attached to the first vacuum enclosure of the first assembly.

Abstract: An MR magnet assembly includes a cylindrical vessel for housing a superconducting magnet and having a vacuum between its inner and outer walls. The vessel defines a magnet bore for receiving a patient to be imaged. A gradient coil assembly is mounted in the bore adjacent the inner wall of the magnet assembly. To reduce gradient coil noise, the inner wall is constructed of a non-conductive material which does not support eddy currents.

Abstract: A superconductive magnet has a superconductive coil surrounded by a thermal shield surrounded by a vacuum enclosure. The thermal shield has one and preferably several flexible layers of thermally conductive material. A first flexible blanket of multi-layer thermal insulation surrounds the thermal shield within the vacuum enclosure, and a second such flexible blanket surrounds the superconductive coil within the thermal shield. A cryocooler coldhead has a first stage in thermal contact with each of the flexible layers of the thermal shield. At least most of the weight of the thermal shield is supported by the flexible blankets.

Abstract: An open magnetic resonance imaging (MRI) magnet having longitudinally spaced-apart superconductive main coils surrounded by a dewar containing a cryogenic liquid (e.g., liquid helium) and boiled-off cryogenic gas (e.g., helium vapor). A condenser is in physical contact with the boiled-off vapor and is in thermal contact with a cold stage of a cryocooler coldhead so as to re-liquefy the vapor. This allows the coils to be surrounded by a single (not double) thermal shield which allows the coils structurally to be located closer to the magnet's open space which reduces magnet cost by reducing the amount of coil needed for the same-strength magnetic field.

Abstract: An open access MRI magnet includes a ferromagnetic frame open on at least two sides and having upper and lower end plates and at least two support columns. A superconducting coil assembly is mounted to each end plate for generating a magnetic flux field in a patient receiving area located between the end plates. Each superconducting coil assembly includes a toroidal vacuum tight vessel, insulation, and one or more temperature shields mounted within the vacuum tight vessel. One or more coils of superconducting wire is wound within the vacuum vessel, and is coupled to a power source and to a persistent switch for maintaining a constant flow of current with no power consumption. A return path for the flux is provided by the end plates and support posts of the frame.

Abstract: A superconducting magnet lead assembly for a cryocooler-cooled superconducting magnet having a design current of between generally 50 and 250 amperes. A DBCO (Dysprosium Barium Copper Oxide), YBCO (Yttrium Barium Copper Oxide), or BSCCO (Bismuth Strontium Calcium Copper Oxide) superconducting lead has its ends flexibly, dielectrically, and thermally connected, one end to the generally 30 to 50 Kelvin first stage and the other end to the generally 8 to 30 Kelvin second stage of the cryocooler coldhead. The superconducting lead has a generally constant cross-sectional area along its length. The design current, the lead's length, and the lead's cross-sectional area are chosen such that the design current times the lead's length divided by the lead's cross-sectional area is between generally 720 and 880 amperes per centimeter for a DBCO or YBCO lead and is between generally 180 and 220 amperes per centimeter for a BSCCO lead. The superconducting lead will not itself precipitate a magnet quench (i.e.