Abstract: A turret subassembly for use as part of a cryostat, the turret subassembly comprising a vent tube (32) housing an auxiliary vent (40); a refrigerator sock (34) for housing a refrigerator; a termination box (30) linking the vent tube and the refrigerator sock, and having an opening (52) in one wall (54); and means (38) for attachment of the turret subassembly to a cryogen vessel (12).

Abstract: The present invention relates to a cryostat having a service neck for access to a superconducting magnet. In many cryogenic applications components, e.g. superconducting coils for magnetic resonance imaging (MRI), superconducting transformers, generators, electronics, are cooled by keeping them in contact with a volume of liquefied, the whole cryogenic assembly being known as a cryostat. In order to operate a superconducting magnet, it must be kept at a temperature below its superconducting transition temperature. A cryostat must provide access to the vessel containing the liquefied helium for the initial cooling of the magnet to its low operating temperature, for periodic refilling of systems where there is a loss of helium, and provide sufficient access whereby to enable operation and maintenance of the magnet.

Abstract: In a method or joint for joining first and second semiconductor wires, each comprising a number of filaments which each comprise a superconductive core within a respective sheath, the filaments being embedded within a matrix and wherein the superconductive cores comprise magnesium diboride and the sheaths comprise niobium, over a certain length a matrix is removed to expose the filaments. The exposed filaments are immersed in molten tin such that the nobium of the sheaths is converted to niobium-tin throughout a thickness of the sheaths. A superconductive path is provided between the superconductive cores of filaments of the first wire through the niobium-tin sheaths of the filaments to the superconductive cores of the second wire.

Abstract: A cyclone has a cyclone body formed with a plurality of inlet ducts and an outlet. A first end of each of the inlet ducts is coupled to a downcomer and a second end of each of the inlet ducts is coupled to the cyclone body. The downcomer proximate the cyclone body is co-axial with and mounted to the cyclone body on a support. Each inlet duct exits the downcomer radially and enters the cyclone body tangentially.

Abstract: A feed roll and stripper assembly for a rolling mill includes at least one feed roll at each of an entry side and an exit side of a pair of work rolls and a stripper at each of the entry and exit side of the pair of work rolls. Each stripper has a stripper tip. At least one of the strippers or feed rolls are adapted to have an adjustable vertical separation from one of the work rolls, according to the direction of movement of material through the work rolls. The vertical separation of the at least one stripper or feed roll from the one work roll on the entry or exit side is different from the vertical separation of the other at least one stripper or the feed roll on the other of the entry or exit side. Each stripper tip is separated from one of the work rolls.

Abstract: In a superconducting electromagnet system or method, cryogenically cooled magnet coils are arranged to provide a static magnetic field in an imaging region. A gradient coil assembly is arranged to provide oscillating magnetic fields within the imaging region. An electrically conductive shield is positioned between the cryogenically cooled magnet coils and the gradient coil assembly. The cryogenically cooled magnet coils are located within an outer vacuum chamber, and the electrically conductive shield is positioned outside the outer vacuum chamber between a surface of the outer vacuum chamber and the gradient coil assembly and inside a bore tube of the outer vacuum chamber. The conductive shield is supported on resilient damping mounts between the conductive shield and the gradient coil assembly and between the conductive shield and the bore tube of the outer vacuum chamber.

Abstract: A cooled current lead for conducting electrical current into a cooled vessel. The current lead comprises an electrical conductor (22) comprising a region (29) which, in use, is heated by electrical current flowing through it; a cooled component (31) situated above a the region (29) and which is provided with a path for removal of heat; and a thermo-siphon comprising a cavity (35) in thermal contact with both the region of the electrical conductor and the cooled component, said cavity containing a fluid (35).

Abstract: An assembly includes a cylindrical magnet assembly, which includes comprises at least one coil mounted on a former. The assembly also includes a bore tube with a number of radially-directed retaining protrusions formed in a material of the bore tube, each of the number of radially-directed retaining protrusions configured to bear against a periphery of a corresponding cavity in the former.

Abstract: A quench propagation arrangement for a superconducting magnet comprising a plurality of series-connected superconducting coils, the arrangement comprising: a positive supply line connected to cathodes of first diodes, of which respective anodes are connected to each respective node of the series connection of superconducting coils; a negative supply line connected to anodes of second diodes, of which respective cathodes are connected to each respective node of the series connection of superconducting coils; a number of heaters, respectively thermally connected to each of the superconducting coils and electrically connected between the positive supply line and the negative supply line; and a voltage limiter connected between the positive supply line and the negative supply line, in parallel with the heaters.

Abstract: In an apparatus and a method for detecting deposition of solid frost caused by air ingress into a cryogen vessel, a quartz crystal microbalance, that includes a crystal sensor, is placed within the cryogen vessel, and an actuating circuit actuates resonance of the crystal sensor, and detection equipment detects a change in the resonant characteristics of the crystal sensor caused by frost deposition on the crystal sensor, and signaling equipment indicates the detected change.

Abstract: A superconducting joint that electrically joins superconducting wires has a block of thermally and electrically conductive material that is coated with an electrically isolated coating that covers at least a part of a surface of the block. Molded semiconducting joint material is provided in contact with the electrically isolating coating. Superconducting filaments of the superconducting wires are embedded within the molded superconducting joint material.

Abstract: A cryostat, comprising an outer vacuum vessel containing cryogenic equipment suspended from the outer vacuum vessel by a number of suspension rods. At least one of the suspension rods is provided with a tensioning and retaining mechanism for holding that suspension rod in tension braced against a suspension bracket). This tensioning and retaining mechanism includes a tubular rod carrier arranged, in use, to pass through a hole or slot in the suspension bracket, the rod carrier having an axial bore through which, in use, the rod may pass; a thread on its outer surface along at least part of its length; and a rod bearing surface for, in use, transmitting force to the rod. This tensioning and retaining mechanism also comprises a tensioning nut threaded onto the thread so as to, in use, brace against the suspension bracket to urge the tubular rod carrier in the direction of the rod bearing surface so as to apply tension to the rod.

Abstract: In an emergency run down unit for a superconductive magnet assembly, a quench in the magnet is induced by the release of stored mechanical energy or by direct manual actuation.

Abstract: A shim arrangement for increasing the homogeneity of a magnetic field within a homogeneous field region, comprising: shim channels extending within a volume between a magnetic field generator and the homogeneous field region; at least one piece of shim material located within each shim channel; an arrangement for moving each shim piece along the corresponding shim channel; and retaining means for retaining each shim piece in position. Shimming is performed by moving shim pieces within the shim channels, with the magnet at field. No shim pieces are added to, or removed from, the shim channels during the shimming step.

Abstract: A tool for assembling a cylindrical magnet assembly to a bore tube and a resulting assembly. The cylindrical magnet assembly includes at least one coil mounted on a former. A cavity is provided in the former at selected locations. At each of the selected locations, the material of the bore tube is deformed to form a radially-directed protrusion. Each protrusion is brought to bear against a periphery of each corresponding cavity.

Abstract: A support system comprising a number of racetrack-shaped tensile support bands held in tension between a supported article and a supporting article, respective curved end portions of each tensile support band being retained by respective mounting points mounted on respective surfaces of the supported article and the supporting article, respectively. At least one of the tensile support bands is arranged so that the curved end portions lie in a plane substantially parallel to the surface upon which the respective mounting point is mounted; and at least one mounting point is a monolithic mounting point having a curved surface which is complementary to an inner curved surface of an end of the tensile support band.

Abstract: An energy dissipation arrangement for a cryogenically cooled superconductive magnet comprising a plurality of superconductive coils (10) connected in series and housed within a cryostat (24), comprising a superconducting switch (25) having a superconductive current path (28) in series with the superconductive coils (10); and a resistor (38), external to the cryostat, electrically connected in parallel with the superconductive current path (28) of the superconducting switch (25). The superconductive switch is arranged (26, 32, 30) to open in response to an electric current applied to an associated heater (26; 40).

Abstract: The present invention provides a cryostat comprising a cryogen vessel (1), a thermal radiation shield (2), and a sleeve (5) for accommodating a cryogenic refrigerator. Also provided is a first thermal contact for thermally and mechanically connecting a first stage of a cryogenic refrigerator to the radiation shield for cooling thereof. A secondary recondensing chamber is provided (8) for accommodating a second stage of a cryogenic refrigerator, and means (10; 24) are provided for thermally connecting the secondary recondensing chamber to a recondensing surface (11a; 44) exposed to the interior of the cryogen vessel. The cryostat further comprises a pressure control arrangement (100) for controlling the pressure of a gas within the secondary recondensing chamber.

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: In a method for measuring the level of liquid cryogen in a cryogen vessel, a current pulse is applied to a cryogen level probe includes an ignition current pulse part of sufficient magnitude to ensure that a resistive front propagates down the probe to below the liquid cryogen surface; a recovery current pulse part allowing that part of the superconducting wire below the surface of the liquid cryogen to return to a superconducting state; and a measurement current pulse part of sufficient magnitude and duration to allow an accurate measurement of the superconducting wire's resistance to be measured.