Abstract: Novel structures and methods for forming useful high temperature superconducting devices, most particularly resonators, are provided. Structures resulting in reduced peak current densities relative to known structures achieve numerous desirable benefits, especially including the reduced intermodulation effects of earlier resonators. In one aspect of this invention, a spiral in, spiral out resonator is provided, characterized in that it has an odd number of long runs, at least equal to five long runs, where the long runs are connected by turns, and wherein there are at least two sequential turns of the same handedness, followed by at least two turns of the opposite handedness. In yet another aspect of this invention, it has been discovered that reducing the size of the input and output pads of HTS resonators increases the relative inductance compared to the capacitance. Yet another resonator structure is a spiral snake resonator having a terminal end disposed within the resonator.

Abstract: In a superconducting short circuit current limiter for an AC power supply net including an iron core, a primary coil and a secondary short-circuited superconductive coil, both being magnetically coupled with the iron core but being arranged at a distance from each other, the iron core has gaps at opposite sides of the secondary coil for thermically uncoupling the secondary coil from the rest of the magnetic core and a tertiary coil is arranged closely adjacent the primary coil in a magnetically strongly coupled relationship therewith, and has a heat capacity sufficient to accommodate the joulean heat generated when a fault or short circuit occurs in the power supply net, and the iron core has an area of reduced cross-section which is so selected that it becomes magnetic flux saturated when the current in the primary coil exceeds a predetermined reaction current level.

Abstract: In order to make it possible to produce superconducting coils with small overall height, they are made from a plurality of coil subunits, optionally with a plurality of layers for each coil subunit, in particular in the case of the low-voltage coil of a transformer. The coil subunits contain as electrical conductor a high-temperature superconductor, around which a fibrous glass is spun and which is embedded in a glass-fiber reinforced epoxy resin or in a plastic. The coil subunits are placed around a transformer core in a cryostat.

Abstract: Lumped element electrical components, such as inductors and capacitors, are formed to include high temperature superconducting materials. In the preferred embodiment, thin film epitaxial high temperature superconductors are patterned to form capacitors and inductors on low loss substrates. Preferably, a ground plane is formed on the back side of the substrate, most preferably being formed of high temperature superconducting material, or other highly conductive materials such as gold or copper. Various advantageous structures include a planar spiral structure, a zig-zag serpentine structure, a single coil structure and a double coil structure. Single layer and multilayer structures are included. Improved narrow bandpass filters and high Q resonator structures are formed.

Abstract: A superconducting magnet coil, an insulating layer, and a superconducting magnet which do not generate quenching under cooled and operational conditions are provided by using a fixing resin capable of suppressing microcrack generation in a resin layer which causes quenching.A superconducting magnet coil manufactured by winding a superconducting wire and fixing the wire with resin and a method for manufacturing thereof, wherein said resin is a low cooling restricted thermal stress and high toughness fixing resin having a release rate of elastic energy G.sub.IC at 4.2 K. of at least 250 J.multidot.m.sup.-2, and/or a stress intensity factor K.sub.IC of at least 1.5 MPa.multidot..sqroot.m, and/or a stress safety factor at 4.2 K. of at least 3, and an allowable defect size at least of 0.3 mm.The superconducting magnet coil manufactured in accordance with the present invention does not cause quenching because microcracks are not generated in said resin when the coil is cooled to the liquid helium temperature, i.e.

Abstract: A winding support body (6, 10) for transformers/reactors with a winding of a tape-formed superconductor (8), wherein the support body consists of a substantially straight, circular-cylindrical tubular body which, on the side where the winding is to be placed and out towards the two ends, is provided with a helical slot with a plane surface with a width equal to the width of the tape. In this way, each turn of the slot around the support body forms a surface which practically constitutes the envelope surface of a straight frustum of a cone. The angle (v) between a generatrix (9) of the envelope surface and the axial center line of the support body increases for each turn out towards the ends of the support body in such a way that the envelope surface at all points coincides with the direction of the magnetic field (FIG. 4 ).

Abstract: A device for producing a uniform, parallel, intensity-variable magnetic field includes at least one coil and/or permanent magnet for producing a magnetic field, and a cylinder which contains a superconductor and which has a slit extending parallel to its axial direction. The axis of the coil and/or the permanent magnet and the axis of the cylinder are parallel to each other. The superconductor is a type II superconductor which has a critical current density not equal to zero under a magnetic field higher than its lower critical magnetic field. Furthermore, the cylinder may comprise several superconductor sheets joined together into a cylindrical shape or a superconductor-containing sheet which is wound spirally about itself or is rolled up several times about itself in the form of a hollow cylinder.

Abstract: A modular superconducting energy storage device includes a plurality of superconducting magnet modules joined in series in axial alignment. Each module comprises a core member having a superconducting coil member wound around it and a tensioning member that retains tension in the superconductor. The ends of the superconducting magnet are adapted for connection to a current source or to the free ends of the superconducting cable of an adjacent module as required. Each module is adapted for attachment to an adjacent module for retension in axial alignment. The attachment of additional modules increases energy storage capacity accordingly.

Abstract: A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

Abstract: An energy storage device comprising an array of electrical coils formed from relatively high temperature superconducting material, the coils being arranged around a common axis and carrying working currents in the same sense.

Abstract: A high temperature superconducting coil includes an oxide superconducting wire 2 wound in a coil, a container 3 for accommodating the superconducting wire 2, and a filling resin portion 4 for fixing the superconducting wire 2 in the container 3 by being injected into the container 3 and then cured.

Abstract: A superconducting energy storage inductor having two D-shaped coils with their flat sides being adjacent and facing one another. The coils are restrained from moving relative to one another and are immersed in a cryogenic fluid. The coils are connected in series and when provided with current, the resulting magnetic fields of the coils oppose one another.

Abstract: A pick-up coil assembly for a multi-channel SQUID magnetometer. The assembly includes a base plate, a plurality of support bars fixedly mounted on the base plate so as to form a matrix, and a plurality of pick-up coil units fixedly mounted on the support bars, each pick-up coil unit having a first and second pick-up coil block. Each of the pick-up coil blocks has a support body, a pair of pick-up coils, connection pads and connection lines. The pair of pick-up coils, the connection pads and the connection lines are formed by a lithography technique on the support body.

Abstract: The present invention provides a connection for feeding electricity to a transposed superconductive coil, the coil being placed in a cryostat and comprising a plurality of identical superconductive conductors, the free ends of which are distributed uniformly with cylindrical symmetry, the connection being constituted by two current leads each composed of a plurality of identical lead conductors each comprising a first end and a second end, the connection being characterized in that the number of the conductors is identical in each lead and equal to the number of the superconductive conductors in the coil, in that the conductors of the leads are disposed regularly and in parallel with the cylindrical symmetry about the axis of said coil, in that the leads are disposed coaxially and in that the first end of each lead conductor is connected to a respective superconductive conductor.

Abstract: A superconducting magnet module comprises an alternate series of abutting and coaxially aligned first and second superconductive magnet modules. The first magnet module includes a first substrate having opposed first and second faces and a bore filled with a superconductive material extending between the first and second faces. The first face is formed of an electrically conductive material and the second face is formed of an electrically insulating material. A first spiral track of the superconductive material is formed on the first face in electrical and thermal contact with the electrically conductive material. The first spiral track is melt fused to the superconductive material in the bore. The second magnet module includes a second substrate having opposed third and fourth faces. The third face is formed of an electrically conductive material and the fourth face is formed of the electrically insulating material.

Abstract: A beam member which is installed at diametral portion in a ring shape superconducting coil container for supporting hoop stress of the coil, or a portion of radiant heat shield covering the beam member, is partly or entirely composed of electrical insulators or high resistivity materials. In accordance with the above composition, eddy current which is generated in the coil container when the superconducting coil container crosses magnetic field caused by eddy current which is generated in the radiant heat shield when the radiant heat shield crosses strong magnetic field caused by the superconducting coils with relative vibration of the radiant heat shield to the superconducting coil by a dynamic cause can be suppressed. Accordingly, heat generation in the superconducting coil container can be reduced, and consequently, generation of quenching can be prevented.

Abstract: A tetrahedral junction waveguide switch having a first length of hollow rangular waveguide and a second length of hollow rectangular waveguide adjacent each other with a ferrite rod longitudinally disposed therebetween. A magnetic field is created by a superconducting switching coil placed around the junction of the two lengths of waveguide. The normally magnetically biased ferrite rod permits electromagnetic wave energy to be transmitted through the first and second lengths of waveguide. An open circuit control means selectively and controllably interrupts the current flowing around the superconducting switching coil causing the longitudinal magnetic field to be removed from the normally magnetically biased ferrite rod. The waveguide switch is thereby placed in a cut off, nontransmission, or reflective mode preventing transmission of electromagnetic wave energy.

Abstract: A tightly wound superconducting coil device includes a cooling medium vessel, a coil winding disposed in the cooling medium vessel, the coil winding including an unspliced superconducting wire and having a configuration such that a cooling medium disposed in the cooling medium vessel does not contact the unspliced superconducting wire, and an insulating member disposed between the coil winding and the cooling medium vessel, wherein a portion of the unspliced superconducting wire forming outer portions of the coil winding on two opposite sides of the coil winding has a composition which causes a stability margin of the outer portions of the coil winding to be greater than a stability margin of a remaining portion of the coil winding.

Abstract: A stable superconducting switch suitable for use in a conduction-cooled superconducting magnet includes a tape wound in a coil with the tape including an Nb.sub.3 Sn conductor sandwiched between stabilizing layers of copper, bronze or brass and wound in layers, with groups of layers separated by a partial layer of electrically conductive material.

Abstract: The present invention relates to a superconductive coil assembly which may be used particularly for a current limiter, the coil assembly comprising a plurality of coaxial cylindrical coils electrically connected in series, each coil comprising two windings of superconductive material electrically connected in parallel, arranged coaxially and wound in opposite directions, wherein in each coil, the windings are separated by a material which has a surface resistance in the radial direction lying in the range 10.sup.-5 .OMEGA..m.sup.2 to 10.sup.-2 .OMEGA..m.sup.2 at the temperature of the cryostat, and in which the strands which constitute the superconductive wires may themselves be covered with a layer of the same material.

Abstract: A coil configuration includes at least one superconducting coil having an associated coil surface and a conductor containing superconducting filaments and being wound substantially on the coil surface. The conductor has a longitudinal axis and has a respective transversal axis oriented approximately perpendicular to the coil surface at each point along the longitudinal axis. The conductor has a cross section being extended along the transversal axis at each of the points along the longitudinal axis. The conductor has two ends protruding from the at least one coil. At least one of the ends has a twist in the vicinity of the at least one coil. The transversal axis is approximately parallel to the coil surface downstream of the twist.

Abstract: In the case of high-temperature superconductors (6) which are used as inductive current limiters, unless any special precautionary measure is taken, there is a risk that short-circuit currents can lead to local stress centers and hot spots, and to local destruction of the high-temperature superconductor. In order to avoid this, a hollow cylinder (SL) of the high-temperature superconductor (6) is coated with a 1 .mu.m thick conductive-silver layer (E1). A second 10 .mu.m thick metal layer of foil made of silver or aluminum can be deposited thereon. In order to reduce or to avoid tensile stresses in the ceramic of the hollow cylinder (SL) made of a high-temperature superconductor, and in order to reduce the electrical contact resistance of the metal layers, this hollow cylinder (SL) has a mechanical reinforcing element (7), made of an elastic steel wire, wound around it, at room temperature, under tensile stress.

Abstract: A variable impedance device comprises a coil (10) and an associated magnetic circuit (16) having a gap receiving a plate (20) of superconducting material which acts as a shield or barrier so that, while the plate (20) is in its superconducting state, magnetic flux is caused to traverse the gap via pathways substantially greater in length than the width of the gap. If a large current is passed through the coil (10), the plate (20) becomes resistive thereby presenting a substantially increased impedance to the current. The device may be used in current limiting applications, or other applications where a variable impedance is required.

Abstract: There is disclosed a coil structure which can be rapidly energized or excited, and which reduces the generation of heat in a coil container by an eddy current due to a dynamic disturbance such as vibration and a magnetic field fluctuation, thereby suppressing the occurrence a quench. The coil container is constituted by a low-resistivity material, and a high-resistivity portion is provided at at least one portion of the coil container in the direction of the periphery of the coil container. The high-resistivity portion is provided at a position where a vibration displacement is small or a magnetic field fluctuation is small. When the coil structure is to be energized or excited, the eddy current produced in the direction of the periphery of the superconducting-coil container can be reduced at the high-resistivity portion, and when the dynamic disturbance develops, the generation of heat by the eddy current is suppressed by the low-resistivity material.

Abstract: Electrical energy is transferred or switched by selectively holding off the coupling of a magnetic field to a secondary inductive element (a coil) through a path which contains a high temperature superconductive element (HTS) which is capable of holding off the field when in its superconductive state notwithstanding that it is a high energy magnetic field. The HTS operates to hold off the magnetic field in accordance with the flux exclusion effect. When the HTS element is driven normal by heating with a laser pulse, the flux passes through the element and couples the field to the secondary, which may be connected to a load. A primary coil of superconducting material around the secondary coil can provide superconducting magnetic energy storage. The primary field is held off by HTS elements in the flux path to opposite ends of the secondary coil. These elements may be driven normal by laser pulses to transfer the stored magnetic energy to a load.

Abstract: A device having cores of metal oxide ceramic (for example, Y-Ba-Cu-O) for limiting a short circuit current in power supply systems. The concept provides that a choke core, when operated at a rated current, is superconductive and its shielding currents keep the resulting inductance in the choke at a low level. In the event of an overload, the winding of the choke generates a correspondingly high magnetic field in the core which puts the core into the normally conducting state. This causes the shielding currents to disappear in connection with a rise in the resulting inductance, thus limiting the current. In order to realize a particularly high inductance in the normally conductive case, the superconductive choke core may be made hollow and may be filled at least in part with a ferromagnetic material.

Abstract: A superconducting coil is mounted on a permanent non-magnetic coil form by first winding an unreacted wire onto a temporary coil form made of refractory materials which can be assembled and disassembled, reacting the wound unreacted wire at high temperatures to form a superconducting coil. The temporary coil form is disassembled and the superconducting coil is transferred to a permanent coil form made of a non-magnetic material. The temporary coil form includes a bore tube and an end flange made of a refractory material and a terminal flange made of a non-magnetic refractory material. The terminal flange is removably secured to the bore tube. The end flange is positioned next to the other end of the bore tube and held in position against the tube by means of an end plate. A terminal plate is removably positioned adjacent to the bore tube. The assembly is held together by means of an axial force on the terminal and end plates.

Abstract: An inductor uses high temperature superconductors in order to obtain high Q for high frequency operation. The superconductors are applied as thin films to substrates. In some embodiments, superconductor thin films are applied to opposite sides of the same substrate. Superconductive thin films are applied outside the magnetic field establishing superconductive thin films in order to shield against leakage of the magnetic field beyond the inductor. The inductor is connected to a capacitor to realize a resonant circuit used in a power conversion system.

Abstract: High-field magnets fabricated from high-critical-temperature superconducting ceramic (HTSC) thin films which can generate fields greater than 4 Tesla. The high-field magnets are made of stackable disk-shaped substrates coated with HTSC thin films, and involves maximizing the critical current density, superconducting film thickness, number of superconducting layers per substrate, substrate diameter, and number of substrates while minimizing substrate thickness. The HTSC thin films are deposited on one or both sides of the substrates in a spiral configuration with variable line widths to increase the field.

Abstract: An electrical switch structure which employs superconductive material. A magnetizable core is encompassed by a body of superconductive material. The body of superconductive material has a superconductive state and a normal resistive state and can be placed in either state. The magnetizable core is also encompassed by at least one electrically conductive winding through which electrical current flows to create a magnetic flux within the magnetizable core. When the body of superconductive material is in its superconductive state current is induced therein by the magnetic flux in the magnetizable core. Current flow in the body of superconductive creates a magnetic flux in the magnetizable core which cancels the magnetic flux which is created by current flow in the electrically conductive winding.

Abstract: A superconducting coil is disclosed. A plurality of coils made of oxide superconducting materials are formed on the respective surfaces of substrates, and the adjacent coils mounted on the substrates are connected by conductors to form one coil. Since the coil consists mainly of oxide superconductor, liquid nitrogen can be used to cool at a temperature less than Tc the coil which is energized in order to generate a magnetic field. Therefore it costs less to generate a magnetic field by the coil than by the conventional coils made of metallic superconductors. In addition, the coil is mechanically strong.

Abstract: A device for inductive current limiting of an alternating current consisting of an induction coil (2), which includes at least one winding and through which current flows, a body (3) made of a ceramic high-temperature superconductor arranged concentrically to the latter and having a centrosymmetrical form which is hollow in the interior, and having located in the interior of said body (3) a concentrically arranged core (4) made of a soft magnetic material of high permeability. In normal operation (rated current), the superconductivity of the body (3) is effective and impedance of the induction coil (2) is very low. With overcurrent (mains short-circuit) the superconductivity disappears and the impedance of the induction coil (2) reaches its maximum, current-limiting value.

Abstract: A novel construction of a superconductive coil system, having sufficient coupling strength and stiffness and being easy to assemble, is disclosed. A coil retainer of a stiffened cylindrical shell is divided into two parts for receiving coils and spacers. The inner circumference sides of the adjoining portions of the two parts form a dividing surface consisting of a plane extending longitudinally and are coupled with bolts having their axes directed in the circumferential direction. The outer circumference sides of the same adjoining portions form comb teeth meshed with each other and keyways extending longitudinally along the outer surface of the same comb teeth, and are coupled by keys inserted into the keyways and having their axes directed in the longitudinal direction.

Abstract: In a superconductive coil assembly, superconductive wires are extended in a sheath tube which also defines a passage for allowing a liquid helium to pass therethrough. Sheath tube is housed in reinforcing vessel which comprises a pair of vessel segments and welded to each other. Reinforcing vessel is enclosed by a turn insulation and a earth insulation.

Abstract: A superconducting transformer comprises primary and secondary superconducting coils which are coaxial and made of superconducting wires, and a cryostat for maintaining the superconducting coils in a superconducting state. The cryostat includes a vessel for containing refrigerant and which is formed of a ferromagnetic material. The coils are immersed in the refrigerant. Rod formed of ferromagnetic materials is inserted in the primary and secondary superconducting coils, and is magnetically coupled with the vessel. The cryostat also includes a heat insulating tank for thermally insulating the rod and the vessel from the refrigerant. The rod and the vessel together form a closed magnetic circuit, and function as a core for the superconducting coils.

Abstract: Thin-film transformer, for example suitable for use in a thin-film magnetic head, comprising a magnetic yoke composed of two magnetically permeable thin layers 3 and 5 and a primary turn constituted by an electrically conducting thin layer 13 and a secondary turn constituted by an electrically conducting thin layer 15. A thin layer 21 of a superconducting material is provided between the layer 3 and the said turns, or the turns are closely fitted together and made of a superconducting material themselves.

Abstract: A toroidal hybrid transformer includes a primary winding (2), which is superconducting in operation and a secondary winding (10) which is non-superconducting, separated by thermal and electrical insulation. A strength member (1) withstanding the centripetal forces exerted on the primary winding supports the primary winding (2) and is disposed inside the conductor turns (20, 21; 26, 27, 28) constituting the primary winding. Anchoring wedges (3, 12) mechanically couple the strength member to at least that portion of each of said conductor turns which is adjacent to the axis of symmetry (14) of the toroidal transformer, thereby transmitting the centripetal forces exerted on the primary winding to the strength member.

Abstract: A superconducting gradiometer for measuring weak magnetic fields for a measuring device comprising a SQUID (Superconductive Quantum Interference Devices), a gradiometer coil, a coupling coil, a cryosystem and a signal processing device, in which the well-defined gradient of a magnetic field to be measured is detected by means of the gradiometer. A coil of the gradiometer is made of superconducting wire, arranged about a carrier body in axial and circumferential grooves cut in the carrier body, the grooves being coated with a superconducting thin film. The thin film in the circumferential grooves is interrupted by slots. The wire in the respective circumferential grooves comprises loops wound in opposing directions connected by a twisted pair of connecting leads secured in the axial groove.

Abstract: A system, based on superconducting wires and elements, is used to rapidly generate magnetic field intensities at designated points. The apparatus consists of primary and secondary magnet windings, especially arranged so as to produce rapidly increasing magnetic fields. The primary magnet, located at a distance from the operating area, is charged prior to operation, thus producing a low magnetic field at the said area. Energy transfer to the secondary winding is initiated by induction from the primary winding, thus causing transfer to current to produce a high magnetic field in the said area. This system has many applications, including uses as reconnection-guns and electromagnetic launchers.

Abstract: A process for supplying a current consumer with current from an accumulator for electrical energy, in which electrical energy pulses of very short duration each are supplied to the current consumer from a superconducting accumulator (2) made with superconductors (8) of very small diameter or very small layer thickness. The superconductors (8) are preferably high-temperature superconductors.

Abstract: Disclosed is an apparatus for storing electrical energy in a superconducting coil. The secondary phenomenon of magnetic induction which limits the size of existing superconducting energy storage coils is overcome by utilizing two superconductor material coils coupled by mutual induction through a high permeability magnetic material. This eliminates induction in the superconductor material thus eliminating the difficulty of the destruction of superconducting capability because of secondary induction. This construction permits high current storage capability in a small volume.

Abstract: An actively shielded, superconducting magnet of a nuclear magnetic resonance tomography apparatus has an inner coil system and an outer coil system connected in series to avoid an increase in the external field upon the quench of one of the coil systems. To avoid losing the protection of the shielding effect from external magnetic field disturbances, a superconducting current limiter having a low critical current-carrying capability is connected in the coil system to guide a difference current between the inner coil system and the outer coil system. To avoid an unwanted increase in the external field in the event of a quench of one of the coil systems, the current limiter becomes normally conductive in the presence of a current difference larger than a prescribed value.

Abstract: A superconducting energy storage device for storing electric power in superconducting magnets in the form of magnetic energy. The superconducting magnets are include a superconducting toroidal magnet and a superconducting solenoid magnet arranged to be inscribed in the inside of the superconducting toroidal magnet, the magnets being connected electrically in series to each other. Further, the superconducting magnets include a plurality of units, each of which is formed as a combination of the aforementioned toroidal and solenoid superconducting magnets, the units being piled up in the axial direction of the superconducting solenoid magnet. In the thus arranged device, electromagnetic force generated in the superconducting magnets can be supported without the necessity of firm bed rock, thereby eliminating the limitation in conditions of location of the energy storage device. Further, the plurality of energy storage units can be arranged effectively so that space can be saved.

Abstract: A cryogenically coolable inductive coil including: a multicomponent conductor comprising a plurality of components, each component including a cable of conductive material having a longitudinal axis about which the cable is twisted, the cable being wrapped helically and being compacted, after wrapping, to minimize voids in the cable and to give the component a polygonal profile, the components being disposed parallel, and adjacent, to one another with mutually facing sides of adjacent components being in contact with one another; and an electrical insulating and support structure at least partially surrounding the conductor for supporting stresses induced in the conductor due to magnetic fields created by the flow of current through the conductor, the conductor and the structure being wound to form the coil.

Abstract: A pulsed transformer utilizing the transition of the primary winding from a superconducting state to a normal state to increase the efficiency of energy transfer to the secondary winding thereof and hence to a load across the secondary winding. The primary winding is constructed as a composite which has minimal resistance when in a superconductive state and significantly higher resistance when in a normal or critical state.

Abstract: Metallic insulation for superconducting magnets to provide coil to coil and pancake insulation. Exemplary metal alloys and an anodization coating for such insulation are identified and may be selectively removed to provide shunt current paths. The coating for such insulation may be selectively removed to provide shunt current paths when the coil experiences a quench condition to preclude coil damage. Various applications of metallic insulation to superconducting coils are discussed.

Abstract: The gradiometers are arranged with their associated SQUIDs in a double-wall Dewar vessel which is equipped with a narrow neck. A gradiometer array is provided with a multiplicity of individually mountable gradiometers, the detector coils of which are arranged side-by-side. The radiometers are connected via a superconducting plug connection to a SQUID array of DC-SQUIDs which is designed with a measuring head and a multiple connector as a plug-in module. The multiple connector can be inserted with the SQUID array through the neck of the Dewar vessel and can be plugged into a mating plug-in device which is associated with the gradiometer array and is fastened by a mounting device to the bottom of the Dewar vessel. In this embodiment of the apparatus, for instance, a plane gradiometer array for magnetocardiography can be exchanged for a curved gradiometer array for magnetoencephalography.

Abstract: An AC current limiter for a power transport line including an overload circuit-breaker member (6), the limiter comprising a transformer having a primary winding (6A) connected in series between the power supply circuit (R) and the load circuit (U) and one or more secondary windings (9) of superconductor material contained in a cryogenic enclosure (11) and short-circuited on themselves, the leakage reactance of the transformer as seen from the primary winding being low, and the resistance of the, or each, secondary winding when in the non-superconducting state and as seen from the primary being much greater than the nominal impedance of the transformer.

Abstract: A current sensor for measuring the DC component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop.

Abstract: An unimpregnated winding for use in a cryostat of a superconducting magnet is provided comprising a form including a shell having the shape of two truncated cones attached to one another at their respective bases. Superconducting wire is wrapped around the form under tension so that during superconducting magnet operation, the form remains under compression.