A joint of superconducting wires having at least two superconducting wires, each with a sheath and with a core of reacted superconducting MgB.sub.2. At least one first superconducting wire has a first flattened end and at least one second superconducting wire has a second flattened end. The joint further has a tubular metal connector having a centre filled with MgB.sub.2 material. The first flattened end of the first superconducting wire is inserted at one side of the connector until it is in contact with the MgB.sub.2 material, the second flattened end of the second superconducting wire is inserted at the other side of the connector until it is in contact with the MgB.sub.2 material, the connector is pressed at both sides to fix the superconducting wires, and the centre of the connector is pressed to compact the MgB.sub.2 material.

The present invention addresses a problem of providing an MgB2 wire material having a small reversible bending radius, a superconducting coil using the same, and an MRI without lowering a critical current value and a critical current density of the MgB2 wire material to an extreme. To solve the problem, provided are a superconducting wire having a plurality of MgB2 strands and a first base metal, a superconducting coil using the same, and an MRI, the superconducting wire being characterized in that in a cross section orthogonal to a wire longitudinal direction, a center point of an area surrounded by the plurality of MgB2 strands and a center axis of a cross section of the superconducting wire are disposed in separated positions.

A method for forming superconducting connection structure between at least two superconducting wires is disclosed, where each wire includes at least one superconducting filament. An end piece of each superconducting wire may be positioned inside a cavity of a pressing tool. A contacting material including MgB2 and/or a precursor material for MgB2 may also be positioned inside the cavity. Pressure may be applied to the contacting material through the pressing tool, and the contacting material may be heated inside the cavity. Pressure and heat may be applied simultaneously, at least during part of the process. A superconducting connection structure including at least two superconducting wires, each wire including at least one superconducting filament, and a superconducting connection between the end pieces of the two wires is also disclosed. The connection may be formed of heated and compressed contacting material including MgB2.

A brazing system (1) for manufacturing an armored superconductor wire (10, 10a) comprises: a first feeder (5) of a superconductor wire (11), a second feeder (6) of a conductor wire (12), a layer (13) of brazing alloy being applied to a first face (12a) of the conductor wire (12), an aligning device (8) for approaching the superconductor wire (11) to said first face (12a), a furnace for melting the brazing alloy layer (13), a collimator (15), comprising: at least one first plurality of rolls (17) rotatable about respective first rotation axes (Y) orthogonal to said axial direction (X) to compress said assembly in direction orthogonal to said first face (12a), at least one second plurality of rolls (18) rotatable about respective second rotation axes (Z) orthogonal to the axial direction (X) and to the first rotation axes (Y) to compress the sides of the assembly, cooling means (25) downstream of the rolls (17, 18) to solidify the brazing alloy layer (13).

A method and system for manufacturing a superconducting material is described. In one embodiment, a layer of refractory cushion is placed over a spool. A first layer of superconducting cable is wound over the first layer of refractory cloth. The superconducting cable is reaction heat-treated on the spool. A first layer of refractory fabric can be placed over the layer of refractory cushion. One or more adjustment mechanisms can be disposed between the first layer of the superconducting cable and the spool.

A method of manufacturing an MgB2 thin film wire having an optimum average grain size is done by providing an optimum average grain size range to increase a pinning force and improve Jc with respect to the MgB2 thin film wire. In this method, the MgB2 thin film wire is made of an aggregate of MgB2 grains having a columnar structure which alignment is controlled to be in a direction perpendicular to a surface, a ratio of MgB2 to a total volume of the thin film wire is 90% or more, an average grain size of the grains is 30 nm or more and 200 nm or less by forming the MgB2 thin film having a film thickness of 1000 nm or more and 10000 nm or less in the lateral direction, and the average grain size of the grains is 40 nm or more and 100 nm or less.

A system and method for fabricating accelerator cavities comprises forming at least two half cavities and joining the half cavities with a longitudinal seal. The half cavities can comprise at least one of aluminum, copper, tin, and copper alloys. The half cavities can be coated with a superconductor or combination of materials configured to form a superconductor coating.

A method for forming superconducting connection structure between at least two superconducting wires is disclosed, where each wire includes at least one superconducting filament. An end piece of each superconducting wire may be positioned inside a cavity of a pressing tool. A contacting material including MgB2 and/or a precursor material for MgB2 may also be positioned inside the cavity. Pressure may be applied to the contacting material through the pressing tool, and the contacting material may be heated inside the cavity. Pressure and heat may be applied simultaneously, at least during part of the process. A superconducting connection structure including at least two superconducting wires, each wire including at least one superconducting filament, and a superconducting connection between the end pieces of the two wires is also disclosed. The connection may be formed of heated and compressed contacting material including MgB2.

Operational characteristics of an extremely low resistance (ELR) film comprised of an ELR material may be improved by depositing a modifying material onto appropriate surfaces of the ELR film to create a modified ELR film. In some implementations of the invention, the ELR film may be in the form of a c-film. In some implementations of the invention, the ELR film may be in the form of an a-b film, an a-film or a b-film. The modified ELR film has improved operational characteristics over the ELR film alone or without the modifying material. Such operational characteristics may include operating in an ELR state at increased temperatures, carrying additional electrical charge, operating with improved magnetic properties, operating with improved mechanic properties or other improved operational characteristics. In some implementations of the invention, the ELR material is a mixed-valence copper-oxide perovskite, such as, but not limited to YBCO. In some implementations of the invention, the modifying material is a conductive material that bonds easily to oxygen, such as, but not limited to, chromium.

A superconducting wire comprises a MgB.sub.2 filament, a base material, a high-thermal expansion metal, and a stabilizing material. The high-thermal expansion metal is a metal (for example, stainless steel) having a higher thermal expansion coefficient at room temperature than the MgB.sub.2 and the base material (for example, iron or niobium). The manufacturing method includes a step of packing a mixed powder in a first metal pipe, a step of performing wire-drawing on the first metal pipe formed of the metal to be the base material, a step of producing a composite wire by accommodating the first metal pipe in a second metal pipe formed of the high-thermal expansion metal and the stabilizing material, a step of performing wire-drawing on the composite wire, and a step of performing heat treatment.