The present invention is a system that produces zero noise magnetic field, which consists of: a coil made of superconducting wire, a precision current source, a Normally Closed Reed (NC) Relay, a Normally Opened (NO) Reed Relay, a cooling mechanism to maintain the superconductor temperature below the critical temperature. The precision current source generates the necessary initial current to act as source for the superconducting coil. The NO reed relay connects the precision current source to the superconductive coil. When this current start to flow, the NC Relay is used to close a superconductive path of the superconductive coil on to itself. Once the system becomes stabilized, the NO reed relay is made open, cutting off the precision source while the Normally Closed relay is closed, thereby a steady value current keeps flowing inside the superconducting coil with zero resistance and zero magnetic noise.

Static magnetic field inhomogeneity is reduced by measuring inhomogeneity of a static magnetic field distribution in an imaging space, evaluating a distribution of a correction magnetic field that should be generated by a correction magnetic field generating unit disposed in the vicinity of the imaging space based on the measured static magnetic field distribution, reducing the electric current value of the superconducting coil to a predetermined (greater than zero) low current value smaller than a rated current value, notifying an operator to set a correction magnetic field of the correction magnetic field generating unit to the correction magnetic field evaluated by calculation in a state where an electric current at the low current value is flowing in the superconducting coil and a low static magnetic field B_low is being generated, and repeating the above operations.

An object of the present invention is to provide a persistent current switch with high heating efficiency by simplifying the configuration of the persistent current switch and reducing the heat capacity. To achieve the object, a superconducting magnet in accordance with the present invention includes a superconducting coil, a persistent current switch, and one of an alternating-current power supply, a pulsed power supply, or a charge/discharge circuit. The one of the alternating-current power supply, the pulsed power supply, or the charge/discharge circuit is connected to a loop circuit of the superconducting coil and the persistent current switch such that it is in parallel with the persistent current switch.

A superconducting magnet device includes a plurality of superconducting coil excitation circuits which each include a superconducting coil and an exciting power supply thereof and are operable independently of each other, a plurality of quenching detectors each of which detects quenching of the superconducting coil of a corresponding superconducting coil excitation circuit, and a controller that, when at least one of the plurality of quenching detectors detects the quenching, controls the exciting power supply of a superconducting coil excitation circuit in which the quenching is not detected among the plurality of superconducting coil excitation circuits to demagnetize the superconducting coil of that superconducting coil excitation circuit.

A superconducting magnet apparatus includes a plurality of superconducting magnet coil sections connected in series and housed within a cryogenically cooled, vacuum container. A power source generates a current. A first lead is electrically connected to the superconducting magnet coil sections. A second lead is enclosed entirely within the vacuum container. The second lead has a first section and a second section, and the first section is electrically connected to the power source. The second section is electrically connected to the first lead, and rigidly connected to a linear displacement device enclosed entirely within the vacuum container. The linear displacement device linearly displaces the second section relative to the first section, so that the first section contacts the second section thereby electrically connecting the first and second sections, or by creating a gap between the first section and second section thereby electrically disconnecting the first section from the second section.

Systems and methods for rapidly ramping the magnetic field of a superconducting magnet, such as a superconducting magnet adapted for use in a magnetic resonance imaging system, are provided. The magnetic field can be rapidly ramped up or down by changing the current density in the superconducting magnet while monitoring and controlling the superconducting magnet's temperature to remain below a transition temperature. A superconducting switch is used to connect the superconducting magnet and a power supply in a connected circuit. The current generated by the power supply is then adjusted to increase or decrease the current density in the superconducting magnet to respectively ramp up or ramp down the magnetic field strength in a controlled manner. The ramp rate at which the magnetic field strength is changed is determined and optimized based on the operating parameters of the superconducting magnet and the current being generated by the power supply.

The superconducting magnet device reduces the number of connections within and/or the number of wires leading out of a superconducting coil winding and promptly starts expending the magnetic energy in a superconducting coil operating in a persistent-current mode when the superconducting coil increases in temperature or transitions to normal conductivity. This invention provides a superconducting magnet device that has the following: a superconducting coil connected to an excitation power supply; a persistent-current switch connected to the superconducting coil; a heater that controls the temperature of the persistent-current switch; a current source that is connected in parallel with the persistent-current switch and has a different polarity from the excitation power supply; a driving circuit connected to the heater and the current source; and a signal-inputting means for inputting a signal to the driving circuit. The driving circuit operates the heater and the current source when the signal is inputted thereto.

A high-temperature superconducting flux pump system comprises a flux pump body, a superconducting load, and a stator group. A double-pancake coil group comprises at least one double-pancake coil. The stator group comprises at least one stator. The flux pump body has an air gap for receiving the stator group. The superconducting load and the stator group are connected to form a closed circuit. The high-temperature superconducting flux pump system has a simpler structure, solves the problem of low charging rate of magnets, and greatly reduces the power cost without changing the magnet structure and winding cost.

A superconducting current pump arranged to cause a DC electrical current to flow through a superconducting circuit accommodated within a cryogenic enclosure of a cryostat comprises a rotor external to the cryogenic enclosure and a stator within the cryogenic enclosure, the rotor and stator separated by a gap through which passes a thermally insulating wall of the cryogenic enclosure, the rotor and the stator comprising at least in part a ferromagnetic material to concentrate magnetic flux in a magnetic circuit across the gap between the rotor and the stator and through the wall, so that movement of the rotor external to the cryogenic enclosure relative to the stator within the cryogenic enclosure induces a DC transport current to flow around the superconducting circuit within the cryogenic enclosure. There is no coupling between a drive motor external to the cryogenic enclosure and an internal rotor which may introduce a path for heat leakage into the cryostat, in turn increasing the heat load and thus increasing the cooling power required to maintain the cold components within the cryogenic enclosure at the low operating temperature required.

Provided is a DC magnetic field superconducting coil power supply device using a superconducting coil at low cost. A DC magnetic field superconducting coil power supply device 1 comprises: a superconducting coil 17; a power supply device 11 configured to supply a DC voltage; a plurality of chopper circuits 13 connected in parallel between one end of the power supply device 11 and one end of the superconducting coil 17; and a controller 18 configured to control the plurality of chopper circuits 13, wherein the 10 controller 18 is configured to operate the plurality of chopper circuits 13 in a time-division manner when charging the superconducting coil 17.