Abstract: A superconducting magnet assembly is provided. The magnet assembly includes a magnet and a switch assembly coupled to the magnet. The switch assembly includes a thermosyphon tube configured to carry cryogen therethrough, a switch, a first pressure valve, and a second pressure valve. The switch is configured to switch between a resistive mode and a superconducting mode, wherein the switch is in thermal contact with the thermosyphon tube. The first pressure valve and the second pressure valve are positioned on the thermosyphon tube and configured to control flow of the cryogen in the thermosyphon tube, and the switch is positioned between the first pressure valve and the second pressure valve. The magnet is configured to generate a polarizing magnetic field based on switching of the switch between the resistive mode and the superconducting mode.

Abstract: A superconducting magnet assembly is provided. The magnet assembly includes a magnet configured to generate a polarizing magnetic field, a thermosyphon tube, a main tank, and a metering tank. The thermosyphon tube is in thermal contact with the magnet, the thermosyphon tube configured to carry cryogen therethrough and cool the magnet via the cryogen. The metering tank contains the cryogen and is coupled with the main tank, and the main tank has an interior volume greater than an interior volume of the metering tank, The thermosyphon tube is coupled with the main tank at a first end of the thermosyphon tube and coupled with the metering tank at a second end of the thermosyphon tube, the second end opposite the first end, and the thermosyphon tube and the metering tank define a path along which the cryogen flows.

Abstract: A method of manufacturing a lead assembly of a cryogenic system is provided. The method includes developing a three-dimensional (3D) model of a heat exchanger. The heat exchanger includes a plurality of channels extending longitudinally through the heat exchanger from the first end to the second end, the plurality of channels forming a plurality of thermal surfaces within the heat exchanger, the heat exchanger having a transverse cross section. The method further includes modifying the 3D model by at least one of reducing an area of the cross section and increasing the plurality of thermal surfaces. The method also includes additively manufacturing the heat exchanger using an electrically-conductive and thermally-conductive material according to the modified 3D model. Further, the method includes providing a high temperature superconductor (HTS) assembly that includes an HTS strip, and connecting the HTS assembly to the heat exchanger at the second end of the heat exchanger.

Abstract: A superconducting magnet system having two-stage quenching. A primary coil assembly includes a coil section configured to be superconducting when conducting current below a first critical current. An EMI shielding coil assembly includes a coil section configured to be superconducting when conducting current below a second critical current, which is electrically coupled to a variable resistor configured to be superconducting when conducting current below a third critical current and to be non-superconducting when conducting current at or above the third critical current that is less than both the first and second critical currents. Generating a magnetic flux within the EMI shielding coil assembly causes the current conducted through the variable resistor to exceed the third critical current, quenching the variable resistor and generating heat. The EMI shielding coil assembly is disposed such that the heat from the variable resistor quenches the primary coil assembly.

Abstract: A superconducting magnet system having two-stage quenching. A primary coil assembly includes a coil section configured to be superconducting when conducting current below a first critical current. An EMI shielding coil assembly includes a coil section configured to be superconducting when conducting current below a second critical current, which is electrically coupled to a variable resistor configured to be superconducting when conducting current below a third critical current and to be non-superconducting when conducting current at or above the third critical current that is less than both the first and second critical currents. Generating a magnetic flux within the EMI shielding coil assembly causes the current conducted through the variable resistor to exceed the third critical current, quenching the variable resistor and generating heat. The EMI shielding coil assembly is disposed such that the heat from the variable resistor quenches the primary coil assembly.

Abstract: A method of manufacturing a lead assembly of a cryogenic system is provided. The method includes developing a three-dimensional (3D) model of a heat exchanger. The heat exchanger includes a plurality of channels extending longitudinally through the heat exchanger from the first end to the second end, the plurality of channels forming a plurality of thermal surfaces within the heat exchanger, the heat exchanger having a transverse cross section. The method further includes modifying the 3D model by at least one of reducing an area of the cross section and increasing the plurality of thermal surfaces. The method also includes additively manufacturing the heat exchanger using an electrically-conductive and thermally-conductive material according to the modified 3D model. Further, the method includes providing a high temperature superconductor (HTS) assembly that includes an HTS strip, and connecting the HTS assembly to the heat exchanger at the second end of the heat exchanger.

Abstract: A thermal management system is provided that includes a cold-head cryocooler and a cooling jacket. The cold-head cryocooler is configured to be operably coupled to a helium vessel of an MRI system, and is configured to cool at least one of superconducting magnets or a thermal shield of the MRI system. The cooling jacket has an outer surface defining a sleeve exterior, and includes a pathway disposed radially internally of the sleeve exterior defined by the cooling jacket. The cooling jacket is configured to receive boil-off gas from the helium vessel to be circulated through the pathway to cool the cold-head cryocooler.

Abstract: A dual-purpose displacer for adjusting a liquid cryogen level in a cryostat, the dual-purpose displacer includes a displacer wall having an exterior displacer surface and an interior displacer surface. The interior displacer surface defines a displacing chamber configured to contain a first portion of liquid cryogen. The exterior displacer surface is configured to displace a second portion of liquid cryogen contained in a cryogenic chamber of the cryostat. The dual-purpose displacer is disposed within the cryogenic chamber of the cryostat and configured to transfer the first portion of liquid cryogen contained within the displacing chamber to the cryogenic chamber.

Abstract: A dual-purpose displacer for adjusting a liquid cryogen level in a cryostat, the dual-purpose displacer includes a displacer wall having an exterior displacer surface and an interior displacer surface. The interior displacer surface defines a displacing chamber configured to contain a first portion of liquid cryogen. The exterior displacer surface is configured to displace a second portion of liquid cryogen contained in a cryogenic chamber of the cryostat. The dual-purpose displacer is disposed within the cryogenic chamber of the cryostat and configured to transfer the first portion of liquid cryogen contained within the displacing chamber to the cryogenic chamber.

Abstract: A cooling system includes a first cooling loop having a first cooling fluid configured for circulation therethrough and a second cooling loop having a second cooling fluid configured for circulation therethrough. The first cooling loop is in thermal communication with the superconducting magnet and is configured to provide primary cooling for the magnet, and the second cooling loop is in thermal communication with the superconducting magnet and is configured to provide secondary cooling for the magnet.

Abstract: An apparatus for shimming the magnetic field generated by a magnet arrangement of a magnetic resonance imaging (MRI) system has a number of discrete shim units; at least some of the discrete shim units exhibiting differing ferromagnetic characteristics, a channel incorporated in the magnet arrangement and disposed to receive a predetermined distribution of the discrete shim units to provide a required distribution of the ferromagnetic characteristics in relation to the magnetic field; a presenting arrangement for automatically presenting the discrete shim units at an entrance to the channel, in a sequence conforming to the distribution, and a powered arrangement for inserting the discrete shim units into the receiving channel in the sequence as presented.

Abstract: An apparatus for shimming the magnetic field generated by a magnet arrangement of a magnetic resonance imaging (MRI) system, has a number of shim devices of substantially similar cross-sectional dimensions, at least some of the shim devices exhibiting differing ferromagnetic characteristics. A structure body has an elongate, tubular channel cross-sectionally dimensioned to serially receive the shim devices in a predetermined sequence to provide a required distribution of the ferromagnetic characteristics in relation to said magnetic field, the channel being of length sufficient to accommodate the shim devices serially in said predetermined sequence. The shim devices are presented at the entrance of the channel in the sequence, and are forced into the channel in the sequence by pressurized fluid directed toward the entrance.