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: 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 magnetic resonance apparatus comprises a magnet system for generating a magnetic field in a working volume. Magnetic gradient coils are used to generate one or more magnetic field gradients in the working volume so as to define regions from which magnetic resonance signals are obtained from a target material. A controller operates the gradient coils in use so as to apply one or more magnetic field gradients within each region. For each of the defined regions, the controller performs a method in which the one or more magnetic field gradients are controlled in accordance with the position of the said region with respect to the gradient coils, such that the one or more magnetic field gradients have a predetermined uniformity, thereby increasing the uniformity within regions at the periphery of the working volume.

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 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: A method of monitoring a surgical procedure, the method comprising exposing a region of interest to a static magnetic field with sufficient uniformity to carry out a magnetic resonance process; exposing the region of interest to a RF magnetic field having at least one gradient and detecting magnetic resonance signals emitted from the region of interest; and generating an image of at least one feature in the region of interest from the received signals.

Abstract: An apparatus for magnetic resonance imaging, comprises 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 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: A magnetic field generating system for use in steering a catheter has X (2,3), Y (8,9) and Z (10, 11) magnetic field generators arranged to generate corresponding magnetic fields in mutually orthogonal, X, Y and Z directions. Each of the X and Y magnetic field generators comprises a pair of magnets each magnet having a polarity defining a magnetic axis. The magnets within each pair are arranged such that their magnetic axes are oriented in the Z direction in a substantially antiparallel manner with respect to one another, and are laterally spaced apart with respect to their magnetic axes. The corresponding magnetic fields cooperate to generate a resultant magnetic field in a working region (50) separated in the Z direction from the magnetic field generators.

Abstract: A catheter steering assembly (1) is provided for attachment to a catheter (7) so as to enable the catheter to be steered within an applied magnetic field. The catheter steering assembly (1) comprises a magnetic element (3) formed from a material having a controllable magnetisation direction and at least one control element (4a, 4b, 4c) arranged to interact with the magnet element (3) so as to control the magnetisation direction of the magnetic element (3). The material of the magnetic element is arranged such that the magnetisation direction is maintained for a period after the interaction, whereby the catheter steering assembly (1) may be steered by the interaction between the magnetic field of the magnetic element (3) and the applied 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.