Abstract: A superconducting magnet assembly may include a main magnet assembly having at least one annular coil arranged about an axis, and at least one shield coil, of greater diameter than the main magnet assembly, arranged about the axis. At least one support may be provided, attached to the shield coil and to the main magnet assembly.

Abstract: A device for filling a tank or tanks with pressurized gas comprising a circuit comprising a plurality of upstream ends connected respectively to separate pressurized gas sources, at least one compressor, at least one buffer storage, a set of controlled valves and at least one downstream end intended to be connected to the tank(s) to be filled, the device further comprising an electronic control member configured to control the valves and/or the compressor in order to ensure a transfer of gas into the tank from at least one source and/or at least one buffer storage and/or via the compressor, the device comprising a set of sensors for measuring the pressure in the sources and the buffer storages, the control member comprising member for receiving or generating signal representative of the filling demand from a relatively high demand to a relatively low demand, the control member being configured to ensure the transfer of gas into the tank according to at least a first transfer mode using the source having the h

Abstract: A valve is configured to control a flow of a gas disposed within a convective cooling loop. The valve can be actuated between an open position and a closed position via a magnetic field generated by at least one electrically conductive coil disposed within a cryostat.

Abstract: A method for maintaining a refrigeration unit includes a connecting step of connecting a refrigerator body to a vacuum case with a first cooling stage in thermal contact with a radiation shield, where in the connecting step, the fastening force of the fastening member is adjusted such that the temperature of the first cooling stage becomes a target temperature.

Abstract: In a method and an apparatus for magnetic resonance tomography, an eddy current field is compensated by taking into account its progression over time and its dependence on a sensed value, by having a sensor determine the sensed value and, on the basis of the sensed value, a current strength for a conductor in order to generate an opposing field to reduce the eddy current field is determined, and supplied to the conductor.

Abstract: A cryocooler is provided that includes: a regenerator piston; a drive coupler; and a link flexure having a proximal end coupled by a first pin to the drive coupler and having a distal end coupled by a second pin to the regenerator piston, where the link flexure forms a vane having flattened opposing faces that are orthogonal to a longitudinal axis for the first and second pin.

Abstract: A device includes a component operable at a temperature in a range of 3.5 to 6 Kelvin. The device further includes a thermal reflective sheet comprising a plurality of layers, wound around at least a portion of the component. The device also includes a coupling device for coupling the thermal reflective sheet to at least the portion of the component.

Abstract: A method is provided of operating a cryogenic cooling system, in which a target region for receiving a sample is cooled by a dilution refrigerator containing an operational fluid. Firstly any operational fluid is removed from the dilution refrigerator. Target apparatus comprising the sample is loaded from a high temperature location to the target region. The target apparatus is then pre-cooled in the target region to a first temperature using a mechanical refrigerator. The operational fluid is then supplied to the dilution refrigerator and the dilution refrigerator operated so as to cool the target apparatus in the target location to a second temperature that is lower than the first temperature. A suitable system for performing the method is also disclosed.

Abstract: A thermal interface between a removable cryogenic refrigerator (4) and an article (10) to be cooled by the cryogenic refrigerator. The thermal interface consists of a recondensing chamber filled with a gas (12), the recondensing chamber being in thermal contact with a cooling surface (9) of the refrigerator and the article (10) to be cooled.

Abstract: A conduit for the transfer of a cooling medium is provided that may include a tube that has a length and a through aperture that extends through the entire length. The tube may have an inner surface that defines a helical channel that may be continuous along a length of the tube such that the helical channel is continuous along a plurality of turns of the helical channel along the inner surface. The conduit may be incorporated into a cooling system of a magnetic resonance imaging device.

Abstract: Provided is a cryogen supply and return apparatus and a superconducting rotating electric machine, comprising stationary and rotatable members arranged out of contact with each other, preventing an increase of maintenance cost or a temperature increase of the cryogen which would be caused by contacts of the members. A cylinder 20 has on its outer peripheral surface ring-like recesses or grooves regularly or irregularly spaced in the longitudinal direction or spiral recesses or grooves continuously or discontinuously extending in the peripheral direction, to resist helium gas flowing through a cylindrical space between the cylinder 20 and the inner tube 14b of the second double tube member and, as a result, to control a leakage of the helium gas from the cylindrical space.

Abstract: The invention relates to a method of regulating the temperature of an element cooled by a cryorefrigerator with periodic operation, characterized in that it comprises the following steps: (a) measuring at least the periodic temporal evolution of the temperature T of the element, this evolution making it possible to obtain a temperature signal representative of the periodic operation of the cryorefrigerator; (b) constructing a periodic so-called equivalent thermal flux signal (Soeq), as a function of the temperature signal obtained in step (a); (c) constructing a thermal flux control signal, depending on the equivalent thermal flux signal constructed in step (b), said thermal flux control signal serving also, in return, for the construction of the equivalent thermal flux signal (ScDeq, S*oeq) during step (b); (d) injecting a thermal flux into the element, on the basis of the thermal flux signal constructed in step (c), so as to compensate for the measured periodic variations of the temperature T of the element

Abstract: A superconducting magnet coil support with cooling and a method for coil cooling are provided. One superconducting coil support arrangement includes a superconducting coil and at least one support beam supporting the superconducting coil and defining a tank for storing a cooling fluid therein. The superconducting coil support arrangement further includes a plurality of cooling tubes coupled to the superconducting coil and connected to the at least one support beam, wherein the plurality of cooling tubes are configured to transfer the cooling fluid therethrough.

Abstract: A cryostat (1) with a magnet coil system including superconductors for the production of a magnet field B0 in a measuring volume (3) has a plurality of radically nested solenoid-shaped coil sections (4, 5, 6) and which are electrically connected in series, at least one of which being an LTS section (5, 6) with a conventional low temperature superconductor (LTS) and at least one of which being an HTS section (4) including a high temperature superconductor (HTS), wherein the magnet coil system is located in a helium tank (9) of the cryostat (1) along with liquid helium at a helium temperature TL<4 K. The apparatus is characterized in that heating means are provided which always keep the HTS at an increased temperature TH>TL and TH>2.2 K. The cryostat in accordance with the invention can maintain the HTS section over a long period of time in a reliable manner.

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 superconducting coil is accommodated in a vacuum chamber. A radiation shield is arranged in the vacuum chamber with a prescribed space from the vacuum chamber to surround a periphery of the superconducting coil. A refrigerator cools the superconducting coil and the radiation shield by conduction. A provided member at least partly lies between the vacuum chamber and the radiation shield, through which heat is conducted from the vacuum chamber to the radiation shield. A cooling pipe has opposite end portions drawn out of the vacuum chamber and an intermediate portion in contact with the superconducting coil, the radiation shield, and the provided member. The provided member dissipates heat into a coolant flowing through the cooling pipe, to reduce the heat conducted to the radiation shield.

Abstract: A coil comprises a set of windings with a generally annular shape and formed by a plurality of series-connected partial windings made of a superconductor with a high critical temperature, in which these partial windings are arranged next to each other in stratified form, and at least one cooling sheet which is made of thermally conductive material and arranged in contact with this set of windings and which is designed to be connected in a thermally conductive manner to a cryogenic cooling system.

Abstract: A magnetic field generator comprises a superconducting bulk body, which generates a superconducting magnetic field, a refrigerant vessel for storing solid nitrogen, a vacuum container, which accommodates therein the superconducting bulk body and the refrigerant vessel, and a refrigerator having a cooling head for cooling the refrigerant vessel. The superconducting bulk body is arranged along a wall of the vacuum container. The cooling head of the refrigerator and the refrigerant vessel are in thermal contact with each other. The refrigerant vessel and the superconducting bulk body are in thermal contact with each other.

Abstract: A magnetic resonance imaging (MRI) system having an open superconducting magnet system (1) includes a number of horizontally oriented superconducting coils (3–10) in a cryogenic container (11). The cryogenic container contains a liquid cooling medium for cooling the superconducting coils which are located within the cryogenic container. At its top, the cryogenic container is provided with a recondensor (23) for continuously liquefying the cooling medium. The magnet system has a circuit for guiding the liquid cooling medium from the recondensor along at least part of the superconducting coils.

Abstract: A system capable of pumping or mixing fluids using a rotating magnetic element or bearing levitated by a cold superconducting element is disclosed.

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: Heater duty cycle (the active pressure control circuit) in recondensing superconducting magnet systems is monitored to determine total thermal system performance, to minimize non-zero boil-off operation, and to reduce maintenance costs. Undesirable conditions, such as a degrading cold head, plumbing leaks, and so forth, may be detected earlier by monitoring heater duty cycle. Appropriate service intervals may be determined and cryogen or helium losses may be reduced. The technique provides earliest possible identification of failures related to such variables, as well as, facilitates isolation of the root cause of the problem. Monitoring of heater duty cycle (energization time) offers advantages over the traditional approach of monitoring or alarming on low level in the cryogen (helium) vessel. The technique may provide for relying on observation of the effects of reduced cooling capacity, such as abnormal heater duty cycle, early enough in the failure cycle to prevent helium loss and equipment damage.

Abstract: A high temperature superconductor (HTSC) 5 is magnetized between drive coils 1,2 forming poles of a magnet connected by an iron yoke 9 by relative movement of a vacuum insulated cryostat 4 containing the HTSC and the magnetizing magnet, in order to magnetize a large area of HTSC using a magnet with a small region 3 of magnetizing flux. Alternatively, the HTSC 5may be contained in an evacuated region of a cryostat containing the magnetizing magnet. An interconnecting chamber allows the HTSC to be moved between an operative region and a magnetizing region without substantial loss of vacuum.

Abstract: A magnet, such as an open magnetic-resonance-imaging (MRI) magnet) has a first assembly including a superconductive main coil and a magnetizable pole piece which, during magnet operation, has a temperature equal to generally the temperature of the main coil. In one example, a cryogenic-fluid (e.g., liquid helium) dewar encloses the main coil, and the dewar has an interior surface defined in part by a surface portion of the pole piece. A method for providing a homogeneous imaging volume for a magnet includes steps to construct the above-described magnet.

Abstract: A superconducting magnet assembly having two individual magnetic coils contained in separate vacuum jackets with a radiation shield between each magnet and its respective vacuum jacket. Each magnet coil is cooled to superconducting temperature by direct coupling to the second stage of a separate two stage closed cycle refrigerator. A first stage of each refrigerator cools an associated radiation shield.

Abstract: A magnet, such as an open magnetic-resonance-imaging (MRI) magnet) has a first assembly including a superconductive main coil and a magnetizable pole piece which, during magnet operation, has a temperature equal to generally the temperature of the main coil. In one example, a cryogenic-fluid (e.g., liquid helium) dewar encloses the main coil, and the dewar has an interior surface defined in part by a surface portion of the pole piece. A method for providing a homogeneous imaging volume for a magnet includes steps to construct the above-described magnet.

Abstract: A coil for magnetizing an article. The coil includes a cooling coil component and an electric coil component. An elongate electric coil component is placed with its center along a bobbin, wherein one end is wound in one direction around the bobbin and the other end in the other direction. The cooling coil component includes a disk-like member in which a passage is formed for carrying a fluid coolant. The disk-like member is "C" shaped to substantially prevent the flow of eddy currents. Electric coil components disposed at the ends of the coil are provided with a greater number of windings to make the magnetic field in the coil more uniform.

Abstract: A magnet cartridge for an open architecture superconducting magnet including an iron ring sandwiched between two coil forms, and including radial and axial positioning and securing apparatus to position, secure and maintain the relative positions of the coils on the coil forms and the iron ring in the presence of the strong superconducting magnet field generated by superconducting operation of said magnet.

Abstract: A non-uniform multi-layer thermally insulating blanket assembly for use in a superconducting magnet in the tapered space between the thermal radiation shield and a conical support assembly includes three steps at different thicknesses provided by multiple blankets with layer staking and blanket positioning.

Abstract: A superconducting system having a coil or cable in the form of strands at superconducting temperature is connected to a power supply at room temperature. The connection is by means of a stranded current lead substantially under regular conducting conditions. Each current lead strand is insulated and connected to a corresponding superconducting strand so as to supply current and to contribute an individual series resistance. The temperature-sensitive resistance provides an important current self-limiting mechanism to forestall current imbalance or channeling among the superconducting strands and therefore forestall premature quenching. Various embodiments are directed to regulating the current in the individual superconducting strands, including regulating the resistance in the individual current lead strands with careful temperature control as well as improving the overall superconducting system with optimized cooling.

Abstract: A superconducting magnet apparatus including a superconducting coil for generating a magnetic field, a radiation shield surrounding the superconducting coil, a refrigerator for cooling the superconducting coil, and a cryostat provided inside the radiation shield to store a coolant cooled by the refrigerator, wherein the cryostat is thermally connected to the superconducting coil.

Abstract: An improved apparatus for removing magnetic material from a flowing fluid such as water by magnetic separation has a single set of electromagnets which are used with a plurality of magnetic filters for continuous magnetic separation operation alternately without obstructing the flow of the fluid being processed. A high-gradient magnetic filter arrangement which passes through a magnetic field generated by the magnets is made up of at least two magnetic filters separated by a watertight partition. When the fluid being processed is flowing through one of the magnetic filters, the other filter is removed from the flow of the fluid into a magnetic filter housing which is separated from the fluid flow through the magnetic filter by means of partitions. Backwashing of this other magnetic filter is carried out while purification of the fluid being processed by the former magnetic filter continues uninterrupted.

Abstract: A structure of a superconducting coil capable of improving cooling efficiency is provided. The superconducting coil is formed by stacking a plurality of double pancake coils with each other. The double pancake coils are stacked in the direction of a coil axis. A cooling plate is arranged between the double pancake coils.

Abstract: A superconducting magnet utilizing a pair of donut-shaped annular magnet assemblies including in each a cryogen pressure vessel with a non-magnetic cylindrical divider forming pairs of concentric chambers. Pairs of axial non-magnetic strut members spaced about the interior of the pressure vessel extend at an angle within the concentric chambers between the end flanges of each assembly to resist forces generated within and between the pair of magnet assemblies.

Abstract: A thermally insulating joint for multilayer insulating blankets for a superconducting magnet with layers of low thermal emissivity material separated by low conductivity spacers staked together with adjacent joints and vents offset from each other and with low emissivity adhesive strips overlying the remote ends of adjacent layers of the joined blankets.

Abstract: An open architecture recondensing superconducting magnet utilizing an upper and lower cryogen vessel connected by a passageway which extends above the bottom of upper cryogen vessel to discontinue the flow of liquid cryogen through the passageway to reserve liquid cryogen in the upper cryogen vessel when the cryogen level falls to provide an increased ride-through period in the event of a depleting liquid cryogen supply due to failure of the cryogen gas recondenser. A signal is provided to indicate the need to correct the failure.

Abstract: A superconducting magnet is accessible for ramping within a cryostat by inserting flexible current leads through openings in the cryostat and pushing and twisting these leads inward until connections are made with electrical contacts provided on the superconducting magnet. For each current lead, a permanently installed channel guides the lead as it is pushed through the external opening and extends to make contact with the magnet terminal. The guide channel extends outside of the cryostat and includes an internal or external bend, whereby the overhead space required for the cryostat/magnet assembly may be reduced. After ramping, the leads are withdrawn.

Abstract: A pressure control system for the cryogen pressure vessel of a helium cooled superconducting magnet assembly including a helium gas recondenser to return liquid helium to the helium supply including a temperature sensor proximate to the recondenser to provide a control signal for maintaining a preselected temperature of said recondenser in order to maintain a preselected pressure within said helium vessel above the pressure outside the vessel and further including an indication of the thermal conductance across the interface between the recondenser and the cryocooler which cools the recondenser.

Abstract: An improved apparatus for removing magnetic material from a flowing fluid such as water by magnetic separation has a single set of electromagnets which are used with a plurality of magnetic filters for continuous magnetic separation operation alternately without obstructing the flow of the fluid being processed. A high-gradient magnetic filter arrangement which passes through a magnetic field generated by the magnets is made up of at least two magnetic filters separated by a watertight partition. When the fluid being processed is flowing through one of the magnetic filters, the other filter is removed from the flow of the fluid into a magnetic filter housing which is separated from the fluid flow through the magnetic filter by means of partitions. Backwashing of this other magnetic filter is carried out while purification of the fluid being processed by the former magnetic filter continues uninterrupted.

Abstract: An NMR measuring device contains an NMR probe head (10a) having an NMR receiver coil (11), and the probe head can be supplied via a cryogenically insulated transfer conduit (9) with coolant from a cooling device (1a). The cooling device comprises a cryo-cooler (2) having a first cooling stage (4) with a first stage exchanger (12) and a second cooling stage (3) having a second stage exchanger (8). A pump (6) transports coolant in the cooling circuit. The NMR probe head (10a), in addition to the NMR receiver coils (11), has preamplifiers (21) for amplifying the received NMR signals and an additional cryogenically insulated transfer conduit (20) is inserted between the cooling device (1a) and the NMR probe head (10a) by means of which, the preamplifiers (21) and/or the components in contact with the preamplifiers (21) can be supplied with a flow of coolant at a higher temperature than that used for cooling the NMR receiver coils (11).

Abstract: Vibration and noise isolation for a magnetic resonance imager (MRI) superconducting magnet cryocooler includes a bellows between the cryocooler and its vacuum sleeve in the magnet, a mass suspended along the axis of, but at a distance from, the cryocooler, elastomeric blocks parallel to the axis, and braided copper wires connecting the vacuum sleeve and the heat shields of the MRI. Motion limiters and bellows flexures are provided for dynamic loads which might be encountered during transport of the magnet.

Abstract: An apparatus for mounting a superconducting element includes a first chamber which accommodates a first coolant and maintains the superconducting element at a very low temperature, a second chamber which accommodates a second coolant and is thermally connected to the first chamber via a barrier member, the second coolant being liquidized at a temperature lower than that of the first coolant, and a cooling device which is connected to the second chamber and liquidizes the first coolant.

Abstract: A temperature controlled cryogenic package system for efficiently and precisely monitoring and controlling the operating temperature of a high temperature superconductor circuit placed on a substrate. The cryogenic package system comprises a heating element formed on the same substrate as the high temperature superconductor circuit, a control circuit capable of activating and deactivating the heating element, and a temperature sensor placed in thermal proximity to the high temperature superconductor circuit. The temperature sensor monitors the operating temperature of the high temperature superconductor circuit, and conveys temperature information to the control circuit. The control circuit activates or deactivates the heating element according to the warming or cooling effect that is necessary in order to maintain the high temperature superconductor circuit within a predetermined temperature range, where the range of temperature fluctuation is within plus or minus 0.1 K of a predetermined temperature.

Abstract: A super conducting magnet system for magnetic resonance systems comprising at least one radiation shield. Temperature sensors, an external refrigeration system and a controller are provided for maintaining said at least one shield at a constant temperature by heating the shield and reducing the heat provided as the refrigerator system wears or by increasing the frequency of the refrigeration cycle as the system wears or both.

Abstract: Lead-in module for the supply of a low critical temperature superconducting electric loadThe module (3) is located inside a cryostat (1), it is fixed to its sealing cover (2) and it comprises a pair of metal conductors (6, 7) which pass through the cover (2) and whose lower ends are connected to the upper end of a high critical temperature superconducting module (8) comprising two conductors (9, 10) electrically connected to said pair of metal conductors (6, 7) and separated by an insulating core (11) making up a mechanical reinforcement, with an insulating structure (14) whose upper end (15) is fixed to the bottom of said cover (2) of the cryostat (1), surrounding the pair of metal conductors (6, 7) in a sealed manner until its junction (16) with the superconducting module (8), the structure (14) extending in an unsealed manner until at least the lower end of the superconducting module (8), the structure (14) comprising at its lower end fastening means (20) to support the electric load (4).

Abstract: Apparatus and methods for cooling a superconducting magnet by circulating a pressurized helium gas through a convective cooling loop by natural convection, and apparatus and methods have been provided for quickly and effectively cooling a warm superconducting magnet down to operating temperature.

Abstract: A cooling system for a superconductive magnet. A dewar, located outside the magnet, includes a vacuum jacket hermetically connected to the magnet's vacuum enclosure and includes liquid helium located within the vacuum jacket. A thermal busbar is located within and spaced apart from the hermetically connected vacuum jacket and vacuum enclosure. The thermal busbar has a first end located within the vacuum jacket and a second end located within the vacuum enclosure and in thermal contact with the magnet's superconductive coil. A cryocooler coldhead, located outside the vacuum enclosure, has a housing located outside the vacuum jacket and has a cold stage extending from the housing to inside the vacuum jacket to re-liquefy any helium boiled-off in cooling the magnet 10.

Abstract: A Cryogenic Cooling System generally comprises a portable Dewar and a charging station for the Dewar. In the preferred embodiment, a HTSC device, such as a MRI coil, is contained in the Dewar which uses liquid nitrogen as a cryogenic coolant. The Dewar includes a reservoir for holding cryogenic fluid, an optional wicking material, a transfer tube between the reservoir and the HTSC device (or wick), and a vacuum space. Preferably a vent channel is adjacent the reservoir and provides an escape path for evaporating gas from the wick and/or HTSC device. The vent channel preferably provides a feed-back system: as more cryogenic coolant is transferred via the transfer tube, more cool gas is vented through the channel which cools the reservoir and thereby reduces the transfer. A charging system may also be provided as a source of cryogenic coolant. In the preferred embodiment, the charging system comprises a relatively large reservoir for liquid nitrogen.

Abstract: A superconducting magnet which is capable of improving the refrigerating and the assembling characteristics and of composing in small size. A helium vessel 2 contains a cylindrical superconducting coil for cryogenically refrigerating it by liquid helium. A second and a first heat-shields 5 and 6 and a vacuum vessel 4 are coaxially provided so as to surround the helium vessel 2. Over the helium vessel 2, a L-letter shaped duct 50 is provided to be exposed to helium gas atmosphere being evaporated in the helium vessel 2. A refrigerator-mounting cylinder 51 has an end coupled to the L-letter shaped duct 50 through the bellows 52 and is mounted on an end surface of the vacuum vessel 4 substantially in parallel to the axial direction of the superconducting coil. A three-stage cold heat accumulation refrigerator 30 is inserted into and fixed to the refrigerator-mounting cylinder 51 for reliquefying the helium gas having been drawn into the L-letter shaped duct 50 by a third heat state 43.