Abstract: A magnetic field source is provided comprising a support structure upon which is positioned a conducting surface path of superconductor material. The support structure has an at least partially radially overlapping layer of material arranged in a spiral. A corresponding conducting surface path of superconductor material is arranged on the surface of the support structure such that the conducting path has a first point for the introduction of current and a second point for the extraction of current.

Abstract: A magnetic field source is provided comprising a support structure upon which is positioned a conducting surface path of superconductor material. The support structure has an at least partially radially overlapping layer of material arranged in a spiral. A corresponding conducting surface path of superconductor material is arranged on the surface of the support structure such that the conducting path has a first point for the introduction of current and a second point for the extraction of current.

Abstract: A magnetic field generating assembly comprising a set (A1-A3;B1-B3;C1-C3) of, typically substantially coaxial, coils substantially symmetrically arranged about a plane orthogonal to the axis. At least some of the coils carry working currents in the opposite sense to the other coils The arrangement of turns and working currents carried by the coils is such that a first working volume (10) with a substantially homogeneous magnetic field is generated within the envelope defined by the assembly, and two second working volumes (11) each with a substantially homogeneous magnetic field are generated outside the envelope, the homogeneity of each of the first and second working volumes being sufficient to perform a NMR experiment on a sample in the working volume.

Abstract: Magnetic resonance apparatus is provided comprising a magnet having a first pair of coils arranged in a plane. The coils are operable in a counter-running manner when in use so as to generate a sensitive volume of magnetic field spaced apart from said plane. The magnetic field in the sensitive volume is arranged to have sufficient uniformity to enable magnetic resonance signals to be obtained from a target when located within the sensitive volume. The magnetic field direction Z is oriented to lie substantially parallel to the planes. The coils are arranged such that the sensitive volume is elongate in a direction X substantially parallel to the planes. A drive system is provided to cause relative movement between the magnet and the target so as to allow the sensitive volume to be moved with respect to the target.

Abstract: Magnetic resonance apparatus is provided comprising a magnet having a plurality of pairs of coils arranged in respective substantially parallel planes. The coils in each pair are operable in a counter-running manner when in use so as to generate a region of magnetic field spaced apart from said planes, having sufficient uniformity to enable magnetic resonance signals to be obtained from a target within the region. The magnetic field has a magnetic field direction Z lying substantially parallel to said planes and each of the coils is elongate in a direction X substantially parallel to said planes.

Abstract: A magnet assembly comprising first and second sets of coils (1, 2) for generating respective magnetic fields, wherein the coils are constructed and arranged such that under working conditions, a first homogeneous region (3) can be generated within the envelope defined by the magnet 10 assembly and a second homogeneous region (4) can be generated outside the envelope, the resultant magnetic field in each region being sufficiently homogeneous to enable a NMR process to be performed on an object in the region.

Abstract: An apparatus for magnetic resonance imaging includes a first magnet for generating a first magnetic field and a second magnet for generating a second magnetic field, dissimilar to the first magnetic field, the second magnet being spaced apart from the first magnet. The apparatus is arranged such that the first and second magnets cooperate to generate a substantially homogeneous magnetic field defining a working region wherein the first and second magnetic fields are arranged asymmetrically with respect to the working region, and wherein at least part of the working region is positioned within the first magnet or between the first and second magnets.

Abstract: A magnetic field generating assembly comprises a magnetic field generation system (7, 8) for generating, in a first mode, a first, relatively strong static magnetic field in a working volume (71) located outside the assembly, and for generating, in a second mode, a second, static magnetic field in the working volume in a second mode. In the second mode the magnetic field in the working volume (71) is weaker but more uniform than the first relatively strong magnetic field.

Abstract: A catheter guide assembly (3) is provided having a magnet support for mounting to a catheter; at least two permanent magnets (1A+1B, 2) mounted to the support; and a control system (4). The control system (4) is used to adjust the relative magnetisation directions of the permanent magnets between a first configuration in which their direction of magnetisation are such that the magnets generate a relatively large resultant magnetic field, and a second configuration in which their directions of magnetisation are such that the magnets generate a relatively small resultant magnetic field.

Abstract: The present invention relates to an electrical transformer which includes a primary winding coupled to first and second magnetic circuits. A magnetic flux is driven through the magnetic circuits by the primary winding. First and second secondary windings are also provided, each associated with a respective one of the magnetic circuits and being electrically connected together in series opposition. A closed superconducting fault current winding is also provided to link with the magnetic flux in the second magnetic circuit.

Abstract: The present invention relates to an electrical transformer which includes a primary winding coupled to first and second magnetic circuits. A magnetic flux is driven through the magnetic circuits by the primary winding. First and second secondary windings are also provided, each associated with a respective one of the magnetic circuits and being electrically connected together in series opposition. A closed superconducting fault current winding is also provided to link with the magnetic flux in the second magnetic circuit.

Abstract: The present invention relates to an electrical transformer which includes a primary winding coupled to first and second magnetic circuits. A magnetic flux is driven through the magnetic circuits by the primary winding. First and second secondary windings are also provided, each associated with a respective one of the magnetic circuits and being electrically connected together in series opposition. A closed superconducting fault current winding is also provided to link with the magnetic flux in the second magnetic circuit.

Abstract: An electrical current limiting device comprises an electrical superconductor for attachment in an electrical circuit. The superconductor achieves a superconducting condition at relatively high temperatures. A cooling system includes a motor for flowing a cooled gas past the superconductor so that heat can be removed from the superconductor by a heat transfer process with the cooled gas.

Abstract: A current limiting device comprises a first superconducting element for connection in an electrical circuit. The superconducting element has a critical current density. A second superconducting element detects the onset of a fault condition. A coil is responsive to the second superconducting element to vary the relationship between the critical current density and the current carried by the first superconducting element so that the element transforms into a resistive state.

Abstract: A current limiting device having an electrical superconductor for attachment in an electrical circuit, the superconductor being made of material having a critical current density which varies with applied magnetic field. A magnetic field generator generates a magnetic field to which the superconductor is exposed. Under normal working conditions a magnetic field applied causes the critical current density to be less than a maximum critical current density. A controller adjusts the critical current density such that after a current carried by the superconductor exceeds the critical current density so that the superconductor transforms to a resistive state, the controller can be activated to increase the critical current density causing the superconductor to return the superconducting condition without terminating the flow of current through the superconductor.

Abstract: A nuclear magnetic resonance apparatus having a magnetic assembly which generates a main static field in a working region which is external of the magnetic assembly. The main static magnetic field has a uniformity suitable for performing NMR experiments. An oscillating magnetic field generating assembly is provided with a set of axially aligned electrical coils connected to an oscillating electrical source. The axially aligned electrical coils generate an rf magnetic filed within the working region of the magnet assembly. Adjacent coils of the axially aligned electrical coils are wound in opposite senses and connected in series so as to generate opposing magnetic fields which superimpose to produce an oscillating magnetic field external of the magnet assembly. The oscillating magnetic field is sufficiently uniform within the working region to perform NMR experiments.

Abstract: A former for a magnetic coil, particularly a superconducting magnet of the filamentary intermetallic wire type in which the coil is wound green and reacted after winding, the former being typically of stainless steel having an alumina coating flame sprayed onto its surface.

Abstract: A mechanically strengthened intermetallic superconductor formed around filaments of one component of the superconductor in a matrix material. The selection of specified relative proportions for the components of the assembly leads to enhanced mechanical properties of the superconductor in the composite.