Abstract: There is provided a method of forming an encapsulated coupled coil arrangement. The method comprises: coupling a first lead of a first coil to a second lead of an electrical circuit device, by soldering or infusion, using a superconductive jointing alloy; and encapsulating the first coil, the electrical circuit device and the jointed leads of the first coil and the electrical circuit device in an encapsulation material. The jointing alloy has a melting point higher than a highest temperature experienced by the encapsulation material during the encapsulation process.

Abstract: A current lead-through for providing an electrically conductive path between an interior of a vessel and the exterior of the vessel. The electrically conductive path is electrically isolated from the material of the vessel. The current lead-through comprises an electrically conductive pin surrounded by an electrically isolating sealing material, and retained within a tubular carrier body by the sealing material, the electrically conductive pin being exposed at each end of the tubular carrier body to enable electrical connection thereto.

Abstract: A method for controlling egress of gas from a cryogen vessel (12) housing a superconducting magnet (10). A controller (30) receives data indicative of gas pressure within the cryogen vessel; a controlled valve (40) controls the egress of cryogen gas from the cryogen vessel (12); and data is made available to the controller, indicating a state of the magnet. Egress of cryogen gas from the cryogen vessel is controlled by operation of the controlled valve (40) by the controller (30) in response to the available data indicating a state of the magnet.

Abstract: In a magnet system for MRI imaging comprising a superconducting magnet (10) mounted within a cryogen vessel (12), apparatus is provided for controlling egress of cryogen gas from the cryogen vessel. The apparatus comprises a controlled valve (42) linking the interior of the cryogen vessel to a gas exit path; and a controller (30) arranged to control the valve. The valve is arranged such that a gas pressure in the cryogen vessel exceeding a gas pressure in the gas exit path acts on the valve to open the valve and allow venting of cryogen gas. The valve is also arranged such that a gas pressure in the cryogen vessel inferior to a gas pressure in the gas exit path acts on the valve to urge it closed, so restricting flow of gas into the cryogen vessel.

Abstract: A resin-impregnated superconducting magnet coil comprising a number of turns of superconducting wire (14) embedded within a resin (16) having an outer filler layer (18) composed of the resin, filled with filler material (20). The coil further comprises a cooling layer (22) interposed between the superconducting wire (14) and the filler layer (18).

Abstract: An annular end piece for a cylindrical vacuum vessel, comprising a metal end piece (42); an outer decorative shell (44) spaced away from a surface of the metal end piece; and a layer of solid foam filling the space between the metal end piece and the outer decorative shell.

Abstract: A processor is provided in a MRI scanner which senses pressure within a cryogen vessel and the ambient environmental pressure outside of the scanner. It controls a pressure controller means in the cryogen to in turn control the pressure to ensure that it is set to provide as large a buffer as possible before a pressure relief valve is opened. This ensures that cryogen is not lost unnecessarily.

Abstract: Particle radiation therapy equipment arranged to apply a charged particle beam to a region of application in a predetermined direction, comprising a charged particle beam source arranged to direct a charged particle beam in the predetermined direction, further comprising magnetic field generation means for generating a magnetic field in an imaging volume which includes the region of application at the same time that the charged particle beam is applied, wherein the magnetic field generation means is arranged to provide access to the region of application for the charged particle beam, and to provide a homogeneous magnetic field in the region of application of the charged particle beam, said magnetic field being directed substantially in the predetermined direction.

Abstract: A burst disc replacement apparatus (100) comprises a magazine (122) that carries a first burst disc (232) and a second burst disc (234). A flow path (104) passes through the apparatus (100) for venting fluid. The first burst disc (232) is located in the flow path (104). A translation mechanism (112, 144, 146, 200, 214, 220, 222) is arranged to move the second burst disc (234) into the flow path (104) in place of the first burst disc (232) in response to an indication that fluid pressure at one side of the first burst disc (232) has exceeded a predetermined pressure corresponding to rupture of the first burst disc (232).

Abstract: A burst disc replacement apparatus (102) comprises a magazine (114) carrying a first burst disc (116) and a second burst disc (118). The apparatus also comprises a flow path (104) therethrough for venting fluid. The first burst disc (116) is located in the flow path (104) and the second burst disc (118) is located outside the flow path (104). A translation mechanism is also provided and coupled to the magazine (114) and arranged to permit manual translation of the magazine (114) so that the second burst disc (118) moves, when in use, into the flow path (104) in place of the first burst disc (116).

Abstract: In a method and apparatus for mounting and retention of ancillary equipment to cover panels of a magnetic field generator of a magnetic resonance imaging system having a cryogenic refrigerator and/or liquid cryogen housed within at least an outer vacuum container, ancillary equipment, cables and conduits are attached to the magnetic field generator, by integrating the electronic assemblies, cables and conduits into a set of modular covers which are connected to each other on installation. The covers may be mechanically mounted directly to the OVC, enabling them to be quickly fitted either in the factory or on the user's site.

Abstract: A cryostat comprises a cryogen vessel housed within an outer vacuum container (OVC), a thermal radiation shield being located between an external surface of the cryogen vessel and an internal surface of the OVC. A decouplable thermal link arrangement is provided between an external surface of the cryogen vessel and an internal surface of the thermal radiation shield, being decoupled by action of an applied magnetic field.

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 limiter is provided to limit the motion of components in a cryostat during transit. This permits the use of a support structure which minimises the disturbance to an insulating structure and thus reduces ingress of heat to the cryogen. Cryogen loss is reduced leading to lower operating costs.

Abstract: Pumping out of a vacuum vessel and housing of a scanner is facilitated by providing a hole through a radiation shield. To reduce radiation of heat via this hole to an inner coolant containing vessel a closure member is provided. This is held in spaced apart relationship during pump down by clips. The closure member is provided with a ferrous constituent or member which is then attracted inwards during initialization of the superconducting. This draws the closure member into engagement with the shield to close the hole and to prevent radiation thereby. The clips are profiled to maintain the abutment of the closure member over the hole.

Abstract: In a tomography system having a superconducting magnet and gradient coils, a cooling arrangement for cooling the gradient coils includes a cooling circuit which itself comprises an outward branch carrying cooling fluid to the gradient coils and a return branch carrying cooling fluid away from the gradient coils. At least part of each of the outward and return branches is formed of an electrically conductive conduit. The conduits provide electrical connections from a power supply to the superconducting magnet. In one embodiment, a first end of the bore of the first electrically conductive conduit is fluidly coupled to the bore of the outward branch; and a first end of the bore of the second electrically conductive conduit is fluidly coupled to the bore of the return branch. An electrically isolating bridging conduit is fluidly coupled between second ends of the first and second electrically conductive conduits.

Abstract: A cryogen tank in thermal and mechanical attachment with the equipment to be cooled. Direct thermal conduction between the cryogen and the equipment provides the required cooling. The tank is preferably arranged so as to lie within an existing profile of the cooled equipment, and to be relatively small as compared to known cryogen tanks.

Abstract: A compressor (1) including a compressor mechanism; an input line (12) for providing gas to the compressor; and an output line (14) for providing compressed gas from the compressor. The compressor may supply gas at a first pressure or at a second pressure, by variation of the charge pressure within a gas circuit. A buffer volume and arrangement of valves, contained within the compressor, facilitate the change in static charge pressure. The electrical power drawn by the compressor is reduced when the charge pressure is reduced. Changing the charge pressure in the compressor also varies the cooling power delivered by the refrigerator. Therefore, this variable charge compressor can be used to reduce the electrical power drawn by an MRI system when it is in standby, and the full refrigeration capability is not required. Also, this has the effect of reducing wear and increasing the life of certain components within the refrigerator and compressor.

Abstract: A reworkable pressure vessel for containing a superconducting magnet arrangement. At least first and second separate parts of the vessel are fabricated from fibre-reinforced thermoplastic material. Said first and second parts comprise facing end surfaces adapted for fusion bonding together to form a union closing said vessel such that said vessel can be opened by application of heat and a cutting tool, and re-closed by re-application of fusion bonding to said union.

Abstract: A magnet assembly comprising a former having an outer surface (20) with a cavity (12) formed therein, and a coil (14) wound into the cavity (12), said cavity being of greater depth than the coil, wherein the coil is overlain with a layer of filler material (18) of sufficient thickness that its outer surface at least aligns with the outer surface of the former (20); a clamp (22, 30) is provided, over at least part of the surface of the layer of filler material, and fastened to the outer surface of the former; and the filler material and the coil are impregnated with a solid material.