Abstract: A hermetic electronic assembly incorporating cryogenically-cooled and air-cooled elements in an integrated assembly. A hermetic cryogenically-cooled enclosure is disposed in close physical proximity to one or more air-cooled circuit cards to minimize physical separation, thereby optimizing signal bandwidth and noise immunity. The air-cooled circuit cards, which generate substantial heat but do not require low operating temperatures, are thermally decoupled from the cryogenically-cooled elements to optimize cryo-cooler efficiency by reserving cooling capacity for the temperature-sensitive processor elements mounted within an evacuated hermetic enclosure. Thus, thermal isolation and physical/electrical proximity are preserved in the same package.

Abstract: A board containing plural superconducting power planes, one for each required potential level, is used to distribute power to one or more semiconductor logic chips which, together with the board, are immersed in liquid nitrogen. Each chip is coupled thermally to a heat exchanger and is coupled electrically to the board through leads that minimize heat transfer from the chip to the board.

Abstract: This invention provides a superconducting magnetic shield and a magnetic shielding apparatus including the same, thereby accurately measuring an extremely weak magnetic field such as magnetoencephalographic waves by reducing the influence of magnetic field of the earth or magnetic noises.

Abstract: An electrical conductor particularly suited for use as a downlead to low temperature devices includes a ceramic honeycomb body having longitudinal channels wherein films of substantially single crystals of a ceramic superconductor are grown. The maximum current carrying capacity of the ceramic superconductor may be oriented parallel to the channels. Square channels arranged in alternating rows of oppositely directed current provide desirable magnetic field cancellations and permit high current flows. A method for making the electrical conductor and a method of extruding the ceramic honeycomb body are also disclosed.

Abstract: A superconductive transmission line is formed of mixed metallic oxide ceramic material, particularly Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-x drawn epitaxially upon a substrate. The superconductive material has basal crystallographic planes in alignment with copper oxide of the ceramic material. The planes are parallel to the substrate. The transmission line is constructed of a plurality of electrically conductive elements, each of which is formed of the superconductive material. The conductive elements are arranged with the crystalline planes parallel to an axis of the transmission line, along which axis power is to flow. Thereby, magnetic fields induced by currents flowing in the conductive elements intersect the conductive elements perpendicularly to the basal crystallographic planes to maximize the current which can flow while retaining linearity between magnetization and applied magnetic field.

Abstract: Superconducting fluids are disclosed. The fluid is made by dispersing a superconducting oxide ceramic powder in a liquid nitrogen. A magnetic field shielding device is constructed by disposing the fluid in a suitable container which is adapted to have the superconducting fluid surrounding a space to be shielded from an external magnetic field.

Abstract: A contact maker-breaker is disclosed in which the power contacts are associated in series with a superconducting element which is controlled by a heating element and which is structured so as to have a very high resistance following its controlled transition from the superconducting state to the normal state in response to a closing or opening order or following its intrinsic transition from the superconducting state to the normal state in response to a fault current, so that closing and opening of the power contacts takes place on the same leak current of a very low value.

Abstract: A mounting arrangement for electronic circuit chips in which at least one chip is mounted upon an appropriately electrically insulating chip plate. A connector board is mounted on top of the chip plate to electrically connect the chip with a cable allowing signals to be passed to and from the chip. The chip plate is mounted for good thermal conductivity to a refrigerator cold head. A plate formed of a material with good heat conductitivity properties may be interposed between the chip plate and the cold head. This plate may include an element, such as a spring biased piston, which contacts the chip to allow heat transfer by conduction. The refrigerator cold head forms the upper surface of the expansion space in a Stirling-cycle cryogenic cooling engine. To reduce power requirements, the elements are insulated from contact with the atmosphere.

Abstract: An improved transmission system for electrical energy comprising a plurality of ball members interspersed by mating members enclosed within at least one protective outer wrapping, with the ball members and the mating members being in contact with adjacent members and being formed of material which is electrically conductive at superconductor temperatures and each having an axial opening extending therethrough to permits passage of a suitable coolant fluid, such as liquid helium.

Abstract: A cryocooled field-replaceable logic unit for use with a cryogenic cold head such as that of a cryocooler comprises a thermally conductive plate adapted to be disposed in thermal contact with the cold head, a thermally insulating enclosure portion cooperating with the conductive plate to form a sealed enclosure detachable from the cold head, and one or logic chips mounted in the enclosure in thermal contact with the conductive plate. Preferably the conductive plate is attached to the thermally insulating portion through a resilient mounting which forms a recess for receiving the cold head and which is tension-loaded when the logic unit is mounted on the cold head to urge the plate into intimate thermal contact with the cold head. In one embodiment the enclosure receives from an external source a supply of gaseous nitrogen which is liquified by contact with the conductive plate to form a pool of liquid nitrogen in which the logic chips are immersed.

Abstract: A superconductive conductor (1) is formed by at least three superconducting wires (3) comprising oxide superconductor members (4) and stabilizing members (5), which are point-symmetrically arranged in section. The superconducting wires (3) are so point-symmetrically arranged that electromagnetic force and magnetic fields provided by the respective superconducting wires (3) cancel each other, whereby it is possible to reduce distortion and influence by applied magnetic fields.

Abstract: The device is provided for detachably coupling a power source to a lead pin of the superconducting magnet, the magnet being located in a cryostat using helium and the lead pin being in the region of helium vapor. Device includes a split connector formed to engage the pin, an elongated rod joined to the connector in conductive relationship, and a torque tube positioned around the rod in rotatable relationship. The tube is rotated, a nut joined to the tube and positioned around split connector causes the connector to tightly grip the pin. The device is configured to direct a flow of helium vapor along a path which is proximate to the interface between the connector and pin, to remove heat from the interface and thereby reduce resistance to current flow across the interface.

Abstract: Four magnet cartridge axial supports are provided to prevent axial motion between the magnet cartridge and the surrounding vacuum vessel. Each axial support includes two high strength steel rods in parallel. The rods are brazed to a bar on one end which mounts to the magnet cartridge. The other end of the rods is brazed to a threaded stud which is secured by a bolt to a bracket secured to the vacuum vessel.

Abstract: A superconducting conductor comprises a first fraction of prior-tinned strands (1, 3, 5, 7, 9, etc. . . . ) and an additional fraction of non-prior-tinned strands (2, 4, 6, 8, 10, etc., . . . ). The strands of the first fraction and of the additional fraction alternate regularly and are maintained in a coherent assembly after being assembled with transposition by heating to melt the layer of tin on the prior-tinned strands, with the tin from said layer then solidifying, thus providing substantially point adherence between the previously tinned strands while leaving channels (11, 12, etc. . . . ) inside the superconducitng conductor for cooling liquid circulation. The invention is also to a method of manufacturing such a superconducting conductor.

Abstract: A mounting apparatus in which the vertical, lateral and torsional stiffness of the mounting apparatus are greater than the pivot stiffness. The greater stiffnesses are produced either by loading columns in tension or compression or by bending a rectangular column along its narrow, higher moment of inertia face.

Abstract: A lead interface for a superconducting device has a segment of normal conducting lead electrically connected to a segment of superconducting lead coiled within a dewar. The superconducting lead is adapted to be cooled to below the superconductor critical temperature by circulating a cooling fluid through an internal fluid chamber which runs the length of the superconducting coil and into an intermediate disk having an internal spiral fluid chamber. When the superconducting device is on standby, a superconducting switch is closed and the superconducting segment of the interface is left uncooled. To charge or discharge the superconducting device, the superconducting segment of the interface is cooled prior to opening the superconducting switch.

Abstract: An actively shielded refrigerated superconductive magnet is provided. The magnet includes a generally cylindrical vacuum vessel having an axially extending bore. A plurality of superconductive main coils are positioned in the vacuum vessel concentrically surrounding and spaced away from the bore. A pair of superconductive shield coils having a larger diameter than the superconductive main coils are situated in the vacuum vessel, concentric with the superconductive main coils. The superconductive shield coils are situated at either end of the superconductive main coils. The superconductive shield coils and the superconductive main coils are electrically connected to one another so that the superconductive shield coils and the superconductive main coils are capable of carrying current in opposite circumferential directions. A thermal shield encloses the superconductive main and shield coils, with the thermal shield spaced away from the vacuum vessel and superconductive main and shield coils.

Abstract: Apparatus for washing the disc portions of an electrical insulator includes first and second mating housing portions for positioning about the discs and fluid lines for delivering a cleansing fluid through the housing portions for cleaning the surface of the discs. The two mating housing portions preferably define a basin for collecting the cleansing fluid and facilitating removal of the cleansing fluid after use. A support assembly including a robotic arm positions the first and second mating housing portions about the discs of the electrical insulator for cleaning. A cleaning liquid such as water or freon or a cleaning gas such as air or steam is applied through the mating housing portions for cleaning the surface of the discs. Following the cleaning, a surface-enhancing material such as a silicone coating can be applied to the surface of the insulator for protection from future contamination and make the insulator more resistant to electrical or mechanical degradation.

Abstract: A refrigerated superconductive magnet is provided with six magnet cartridge radial struts supporting the magnet cartridge in the vertical and lateral directions. The struts are positioned such that two lateral struts on each end of the magnet cartridge react against the contact force of the cryocooler cold head and support half of the vertical (gravitational) load of the magnet cartridge. Two vertical struts support the other half of the vertical load. The vertical struts pivot to allow the cartridge axial centerline to shrink towards the cryocooler interface during cool down. The strut attachment points have been located near the horizontal midplane in order to minimize the sag of the magnet cartridge due to its own weight.

Abstract: Two pair of thermal shield axial supports are provided. Each support includes a strand of wire brazed on either end into threaded studs. One stud is threaded into a topped hole in the end of the magnet cartridge. The stud on the other end extends through a clearance hole on the end flange of the thermal shield. Belleville spring washers are compressed against the shield by a nut. Prior to cool down, the Belleville washers are compressed. As the shield and magnet cool down, the shield contracts axially with respect to the magnet cartridge, thus relaxing the washer stack compression. The wire tension relaxes from the maximum pretension to a nominal tension at operating temperature.

Abstract: A pulsed superconducting magnet system includes a vacuum vessel and a cryogenic containment vessel assembly disposed within the vacuum vessel. A superconducting coil is positioned within the cryogenic containment vessel assembly for providing a magnetic field. The vessel assembly includes a helium vessel including a relatively thin metallic inner tube for holding liquid helium and the coil. The helium vessel also includes a relatively thick outer tube encompassing the inner tube with a relatively rigid insulative spacer positioned between the inner and outer tubes so that the tubes are not in contact with each other. The outer tube is predominantly metallic and has at least one joint formed of insulative material to prevent the outer tube from forming a low electrical resistance loop. The inner tube provides a vacuum seal and the outer tube provides structural support for the inner tube so that eddy current losses resulting from ramping of the current to the coil are reduced.

Abstract: An electronic system having components operating at low temperature at various locations within the system, cryogenic fluid and electrical power are distributed by means of the same conduit. In one embodiment, the conduit consists of a supply section and a return section with each section comprising a channel for conveying cryogenic fluid having superconducing walls for conveying electrical power. In another embodiment of the invention, the conduit comprises a copper rod having channels formed therein for the transport of cryogenic fluid and a channel for supporting a rod of superconducing material therein. The superconducing rod conducts electrical current to a subsystem while being cooled by cryogenic fluid in nearby channels and the cryogenic fluid is used at its destination for cooling purposes.

Abstract: A fence clip assembly for securing strands of fencing wire and the like to wood and metal fence posts and including a pair of ears with holes therethrough and a main body with a wire holder that may comprise a pin to lock strands of wire to a clip by insertion through aligned holes in flanges and that is removable to allow the wire to be readily released and that further includes an insulator connector to insulate supported electrical wires at the fence poles.

Abstract: A self contained, self charging automatic hydraulic activation mechanism (AHAM) for a superconducting energy magnetic storage (SMES) system is disclosed. The AHAM is operatively coupled to arc activated switches disposed across a superconducting coil to automatically close the switches upon a coolant dump. The arc activated switches are also self actuating and close in response to arcing across the switch contacts or across spark gaps provided on the switches.

Abstract: A package for superconducting devices, enabling signal transmission at a small propagation delay between superconducting devices provided within a heat insulating vacuum vessel, and semiconductor devices provided outside the heat insulating vacuum vessel. The package comprises a heat insulating vacuum vessel capable of maintaining the interior thereof at a low temperature, a substrate having mounted thereon superconducting devices and disposed within the heat insulating vacuum vessel, another substrate having mounted thereon semiconductor devices and disposed outside the heat insulating vacuum vessel, and film cables electrically connecting the respective circuit patterns of these substrates. Since the thickness of the film cables are very small, the rate of influx of heat that flows into the heat insulating vacuum vessel can be limited to a low value.

Abstract: A coil-like conductor of superconducting material is made from a solid element of sintered superconducting oxide, having a high critical temperature, with the shape of said conductor being imparted thereto by machining the solid element, thus constituting a self-supporting structure.

Abstract: A current-carrying lead that may be connected between a source of current and a superconducting device and which comprises a ceramic superconductor and a support made of an insulator, a nonmagnetic metal or a good electrical conductor. The lead may be contructed to conduct currents having a single or dual polarities.

Abstract: A superconducting transmission line system for transferring electrical power over long distances. The system includes a superconducting transmission line extending from a first location where power is supplied to the line to a second location where electrical power is taken from the line. The line includes an inner tube, and a superconducting core positioned inside the tube and spaced from the inner surface of the tube. The core and the inner tube define a passageway for a cryogenic liquid, the boiling temperature of which is above the superconducting transition temperature of the core. The transmission line system also includes a number of spaced supports holding the transmission line with the portion of the transmission line extending between a pair of adjacent supports being lower than the parts of the line held by the pair of adjacent supports. A regenerator for the cryogenic liquid is mounted on each of the pair of supports.

Abstract: A precooler with a geometry that permits it to be mounted in a cryocooler interface and to use the same thermal connections at the heat stations is provided. The precooler has two stages each with its own heat exchanger, thermally isolated from the other. The latent heat of evaporation of cryogenic liquids is used to remove the sensible heat of superconductive magnet. The different stages can be cooled at a controlled rate resulting in reduced temperature gradients and therefore lower thermal stresses.

Abstract: A superconductive magnet coolable with a two stage cryocooler is provided. The superconductive magnet includes a cryostat containing a magnet winding, a thermal radiation shield surrounding the magnet winding and spaced away therefrom. The cryostat defines an aperture in which a cryocooler cold head interface receptacle is situated. The interface receptacle has a first and second heat station for connecting in a heat flow relationship with the first and second heat stations of the crycooler, respectively. A precooler has first and second stage heat exchangers connected in a heat flow relationship with the first and second heat stations of said interface, respectively. The interface has an inlet and outlet port for supplying and removing cryogens. Piping means fabricated from heat insulating material connect the first and second heat exchangers in a series flow relationship between the inlet and outlet ports.

Abstract: A superconductive magnet for magnetic resonance imaging not requiring consumable cryogens or requiring cryogen liquid or vapor cooling of superconducting coils is provided having a resin impregnated coil of superconductor wire. Heat conductive means having a thermal conductivity greater than the resin, contact the impregnated coil along the length of at least one of the impregnated coil surfaces. A thermal radiation shield is spaced away from and surrounds the resin impregnated coil and heat conductive means. An evacuable housing is spaced away from and surrounds the shield. The housing supports the shield, heat conductive means and the impregnated coil.

Abstract: In an installation including a superconducting solenoid coil in the form of an annulus having a vertical axis, a first vessel having an annular form and enclosing the coil for containing a primary cryogen at a temperature sufficient to maintain the coil superconductive, and at least one second vessel having an annular form and enclosing the first vessel for containing a secondary cryogen at a selected temperature, there are provided: cryogen storage containers spaced horizontally from the coil and the vessels for receiving the cryogens contained in the vessels; and conduit systems coupled between the vessels and the storage containers for permitting the flow of cryogens therebetween.

Abstract: A magnetic resonance magnet is provided having a cylindrical vacuum vessel and a cylindrical cartridge having superconductor windings, situated inside the vacuum vessel. The cartridge defines a pair of circumferential grooves in the outer surface of the cartridge near each end of the cartridge. Means are affixed to the vacuum housing for securing the ends of four cables to the housing. The securing means are situated in pairs circumferentially spaced on either side of where a first diametral line passing through said grooves on one end of the cartridge emerges radially on either side of the housing. The securing means are also situated in pairs circumferentially spaced on either side of where a second imaginary diametral line passing through said grooves on other end of the cartridge emerges radially on either side of the housing.

Abstract: The torodial ring magnet is cooled by a gaseous cooling medium which is conducted through a first cooling circuit through the channels of the magnet coils of the magnet. The gaseous cooling medium exiting the magnet is cooled by a second liquid cooling medium in a second cooling circuit within an auxiliary cooler. Temperature sensors are provided to sense the temperature of the exiting gaseous cooling medium from the magnet sections to permit the opening or closing of a valve in the auxiliary cooler to cause the gaseous coolant to be cooled or not by the liquid cooling medium.

Abstract: A thermally efficient electrically insulating joint operable at liquid nitrogen temperatures and below is provided for connecting a current lead to a cryocooler heat station. The joint includes clamping means, two indium sheets and a ceramic spacer. The ceramic spacer material can be either beryllia or alumina. The spacer has two faces situated opposite one another. Each of the indium sheets contacts a respective one of the faces. The ceramic spacer with the indium sheets on either side is situated between the current lead and the cryocooler heat station. The clamp means urge the cryocooler heat station and the lead together with sufficient force to cause the indium layers to conform to the surface with which they are in contact.

Abstract: In a superconducting coil refrigerating method and a superconducting apparatus, a flow of liquid helium is induced in a helium vessel only at a specified time upon change of a current of the superconducting coil, before the current change and/or after the current change. The induction of the helium flow before the current change provides a condition that the transfer of helium gas bubbles which may be generated upon subsequent current change is rapidly effected. The induction of the helium flow upon the current change or after the current change results in the rapid exhaustion of helium gas bubbles which continue to generate or have been generated. With such a construction, even if a superconducting pulse magnet is used, any influence of helium gas bubbles produced due to an AC loss upon change of a current can be eliminated, thereby providing a coil which is stable to a pulse-excited magnetization thereof.

Abstract: In a superconducting magnet apparatus comprising a liquid helium container accommodating a superconducting magnet in liquid helium and a vacuum insulating vessel surrounding the liquid helium container via a vacuum layer, the improvement wherein power supply leads inserted into a wiring tube fitted through the vacuum insulation vessel and the liquid helium container are formed of a superconductor having a critical temperature not lower than the temperature of liquid nitrogen.

Abstract: A superconductor of the cable-in-conduit type which employs forced flow of liquid helium, comprises a flat-sided housing having an essentially rectangular cross-section, within the housing a metal support bar cabled with multifilamentary superconducting subcables alternated with stainless steel cables or wires. The superconductor provides a large heat transfer surface owing to the multifilamentary superconducting subcables which have a void volume in the range of about 30-35%, as well as mechanical support owing to the stainless steel cables or wires.

Abstract: Conventional superconducting magnet systems supply coolant centrally from a refrigerating system and have a current input provided separately in each case or through special magnets at the beginning and end of a section formed from superconducting electromagnets. The superconducting magnet system of the invention, which is to be used in particular for accelerator units, provides a control cryostat between the refrigerating system and the magnet cryostats encompassing the magnet coils of the electromagnets. The control cryostat at the same time has a current supply lead from which the magnet cryostats associated with the respective control cryostat are supplied with the current necessary for excitation through superconducting cables.

Abstract: A superconducting electrical conductor comprises a porous substrate of bonded fibers which are coated by ceramic oxide superconducting material of the perovskite type so that its critical temperature of superconductivity is at or above the boiling point of liquid nitrogen. To form electrical cable, the conductor is encased within an inner tube. An outer tube surrounds the inner tube and defines an evacuated annular space therewith. This provides a thermal barrier between substrate, which will be bathed by liquid nitrogen, and the ambient. Electrical and heat insulation surrounds the outer tube.Joint connectors in the form of multiple rigid rods, each coated by superconducting material and held in a perforated frame, are used to connect facing ends of the substrate to form an electrical connection from one length of conductor to the next.

Abstract: A magnet system, having permanently installed power leads, for providing a magnetic field. The system includes a vacuum vessel and a cryogenic containment vessel supported within the vacuum vessel. The containment vessel holds a main coil formed of superconductive wire, along with a quantity of liquid helium to maintain the wire below its critical temperature. The power leads, which supply energy to the coil from a power supply outside the vacuum vessel, also take energy from the coil to a load resistor outside the vacuum vessel when the coil is discharged, each include an elongate metallic tube. The magnet system also includes a solenoid controlled valve which is responsive to the passage of electric current through the tubes of the power leads to cause helium gas resulting from the boiling of liquid helium in the containment vessel to be vented to atmosphere through the tube thereby cooling them.

Abstract: A monolithic chip is described which is suited for a superconductive device. The chip includes a substrate with high and low temperature region, a superconductive device formed on the low temperature region and various lines for transmitting signals between the device and the high temperature region. Various configurations are described for optional separation of the high and low temperature region as well as high and low bandwidth signal lines. Chips with various geometric substrates are also described.

Abstract: A cryogenic vessel for cooling electronic components, wherein the cryogenic vessel includes a pair of vessel portions, each vessel portion having an outer wall and an interior immersion chamber. A membrane member is located between the vessel portions for separating the mentioned immersion chambers. The membrane member includes openings for providing fluid transfer between the immersion chambers of the vessel portions and a portion extending from between the vessel portions to a point exterior of the vessel portions. Sealing members are located between the membrane member and each of the vessel portions for providing a fluid tight seal of the immersion chambers. An electronic component mounting socket is located on a portion of the membrane member within the immersion chambers for mounting an electronic component to be cooled. A supply conduit through the outer wall of one of the vessel portions introduces cryogenic fluid into the immersion chambers.

Abstract: A fence post and an insulator holder for an electric fence. A post has an insulator holder mount on its normally upper end portion. An insulator holder is mountable with the post in a depending relation. An insulator is mounted in the insulator holder and it in turn mounts a wire. The fence post and insulator holder is constructed and adapted to be used with other similar fence posts, insulator holders, insulators and a wire to form an electric fence. In the fence the posts are positioned in an alternating fashion on opposite sides of the wire. The insulator holders are positioned in an opposed relation on opposite sides of the line of the fence and insulators mount the wire.

Abstract: A separable connector module for connecting shielded electrical power cable and of the type including an insulating housing containing a bore contact assembly. The bore assembly includes a set of resilient receiving contact fingers attached to a rigid snuffer tube having on its inside wall a liner of ablative material. The improvement comprises that the portion of the snuffer liner adjacent the contacts is counterbored to have a greater inside diameter than the remaining portion of the snuffer liner. Such counterboring improves the performance of the connector for capacitive switching at relatively high voltages and in addition reduces the tendency for clear and restrike failures on typical distribution circuits.