Abstract: A magnet assembly for a Magnetic Resonance Imaging (MRI) system includes a vacuum vessel including an inner cylinder, an outer cylinder and a pair of tapered flanges connecting the inner and outer cylinders. The inner cylinder is made of a composite material. The outer cylinder and flanges are composed of several magnetic segments that provide a magnetic flux return path with low eddy currents. The segments are bonded together and electrically insulated from each other. A container, a thermal shield and a superconducting magnet coil assembly are disposed within the vacuum vessel. The superconducting magnet coil assembly includes a non-conductive cylindrical structure and superconducting coils. A thermally conductive cable is wrapped around the cylindrical structure and coils to form a thermally conductive envelope.

Abstract: A low eddy current cryogen circuit for superconducting magnets including at least a first cooling coil made of an electrically conducting material and having at least one electrical isolator incorporated in the first cooling coil. The electrical isolator is located to inhibit induced eddy current loops due to inductive coupling of the first cooling coil with eddy current inducing field sources.

Abstract: A system and method for connecting superconducting magnet coils made up of coil segments to allow an integrated winding concept. The integrated winding concept can include serially connecting coil segments of coil pairs in an alternating pattern, which causes coil pairs to be electrically symmetric. Symmetric coil pairs can eliminate or significantly reduce the currents in magnet coils induced by gradient or other pulses, produce a homogenous field, and reduce the accumulated voltages in the coils due to gradient pulsing.

Abstract: A low eddy current cryogen circuit for superconducting magnets including at least a first cooling coil made of an electrically conducting material and having at least one electrical isolator incorporated in the first cooling coil. The electrical isolator is located to inhibit induced eddy current loops due to inductive coupling of the first cooling coil with eddy current inducing field sources.

Abstract: A system and method for a magnetic resonance (MR) imaging system includes a coil form, at least one magnet positioned about the coil form and configured to generate a magnetic field, at least one gradient coil for manipulating the magnetic field generated by the at least one magnet by way of a gradient field, and a heat pipe thermally connected to the coil form and having a cryogen therein. The MR imaging system also includes a cryocooler connected to the heat pipe to cool the heat pipe and the cryogen, wherein the coil form is comprised of a thermally conductive material in which eddy currents are substantially reduced during operation of the at least one gradient coil. The present invention has been described in terms of the preferred embodiment, and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.

Abstract: Method for joining wires using low resistivity joints is provided. More specifically, methods of joining one or more wires having superconductive filaments, such as magnesium diboride filaments, are provided. The wires are joined by a low resistivity joint to form wires of a desired length for applications, such in medical imaging applications.

Abstract: A permanent magnet assembly for an imaging apparatus having a permanent magnet body having a first surface and a stepped second surface which is adapted to face an imaging volume of the imaging apparatus, wherein the stepped second surface contains at least four steps.

Abstract: A method and apparatus for actively controlling quench protection of a superconducting magnet includes a magnetic resonance imaging (MRI) system and a computer readable storage medium having stored thereon a computer program comprising instructions which when executed by a computer cause the computer to detect a quench condition of the superconducting magnet. The instructions also cause the computer to actively control a quench protection system of the superconducting magnet in response to the detected quench condition.

Abstract: A vacuum vessel assembly includes an inner cylinder and an outer cylinder formed of a material in which eddy currents are substantially not produced. The inner cylinder includes a first and second half having an annular flange thereon. A plurality of metal interfaces are connected to the inner cylinder and the outer cylinder. The plurality of metal interfaces bond the first half and second half of the inner cylinder and also bond the inner cylinder to the outer cylinder.

Abstract: An electrical current lead assembly for ramping a superconducting magnet includes a vacuum vessel wall that has a first side exposed to an atmospheric pressure and a second side exposed to a vacuum pressure. A pool wall extends from the first side of the vacuum vessel wall and forms a dam region. A first conductor is affixed to and sealingly penetrates the vacuum vessel wall and has a first portion extending into the dam region. A second conductor is affixed to and sealingly penetrates the vacuum vessel wall and has a first portion extending into the dam region. A superconducting magnet on the second side of the vacuum vessel wall has a first low temperature superconducting (LTS) lead and a second LTS lead. A first superconductor electrically connects the first conductor to the first LTS lead, and a second superconductor electrically connecting the second conductor to the second LTS lead.

Abstract: An electrical current lead assembly for ramping a superconducting magnet includes a vacuum vessel wall that has a first side exposed to an atmospheric pressure and a second side exposed to a vacuum pressure. A pool wall extends from the first side of the vacuum vessel wall and forms a dam region. A first conductor is affixed to and sealingly penetrates the vacuum vessel wall and has a first portion extending into the dam region. A second conductor is affixed to and sealingly penetrates the vacuum vessel wall and has a first portion extending into the dam region. A superconducting magnet on the second side of the vacuum vessel wall has a first low temperature superconducting (LTS) lead and a second LTS lead. A first superconductor electrically connects the first conductor to the first LTS lead, and a second superconductor electrically connecting the second conductor to the second LTS lead.

Abstract: A method and apparatus for local grading shielding includes a gradient shield loop having a plurality of arcs positioned adjacent to a superconducting magnet coil. The plurality of arcs magnetically couple with a gradient magnetic field generated by a magnetic field gradient to locally shield the superconducting magnet coil.

Abstract: A system and method for protecting a superconductor from a quench condition. A quench protection system is provided to protect the superconductor from damage due to a quench condition. The quench protection system comprises a voltage detector operable to detect voltage across the superconductor. The system also comprises a frequency filter coupled to the voltage detector. The frequency filter is operable to couple voltage signals to a control circuit that are representative of a rise in superconductor voltage caused by a quench condition and to block voltage signals that are not. The system is operable to detect whether a quench condition exists in the superconductor based on the voltage signal received via the frequency filter and to initiate a protective action in response.

Abstract: A cold mass for a superconducting magnet system in one example comprises a superconducting magnet, a cryogenic cooling circuit, and a magnet and cooling circuit support. The magnet and cooling circuit support comprises a substantially conductive coupler in a discrete path that serves to couple the superconducting magnet and the cryogenic cooling circuit.

Abstract: A method and apparatus for local grading shielding includes a gradient shield loop having a plurality of arcs positioned adjacent to a superconducting magnet coil. The plurality of arcs magnetically couple with a gradient magnetic field generated by a magnetic field gradient to locally shield the superconducting magnet coil.

Abstract: A low AC loss electrical conductor includes a plurality of single-filament superconducting strands longitudinally wound about one another. An insulative housing surrounds the plurality of single-filament superconducting strands.

Abstract: A low AC loss electrical conductor includes an electrically conductive core surrounded by a first layer of superconductor filaments. A resistive shell surrounds the first layer and an insulation coating radially encloses the resistive shell.

Abstract: An open magnetic resonance imaging (MRI) device is provided with at least one main coil for generating a magnetic field for imaging a volume, and at least one shaping coil. The at least one shaping coil is positioned relative to the at least one main coil to shape the magnetic field in the volume.

Abstract: A cold mass for a superconducting magnet system in one example comprises a superconducting magnet, a cryogenic cooling circuit, and a magnet and cooling circuit support. The magnet and cooling circuit support comprises a substantially conductive coupler in a discrete path that serves to couple the superconducting magnet and the cryogenic cooling circuit.

Abstract: A cold mass for a superconducting magnet system in one example comprises a superconducting magnet, a cryogenic cooling circuit, and a magnet and cooling circuit support. The magnet and cooling circuit support comprises a substantially conductive coupler that serves to couple the superconducting magnet and the cryogenic cooling circuit. The cryogenic cooling circuit comprises an inlet path and a substantially upward outlet path. The inlet path avoids direct conductive thermal engagement with the substantially conductive coupler. The substantially upward outlet path comprises direct conductive thermal engagement with the substantially conductive coupler.