According to one embodiment, a magnetic resonance imaging apparatus includes processing circuitry. The processing circuitry is configured to calculate an allowable amount of heat input to a superconducting magnet, the allowable amount being allocated to each of a plurality of imagings scheduled during a target period. The processing circuitry is configured to determine an imaging condition based on the allowable amount in the each of the plurality of imagings.

According to one embodiment, a MRI apparatus determines a first time during which a subsidiary power supply is capable of supplying power to a cooling device based on a capacity of the subsidiary power supply when power outage of a main power supply occurs, and determines a second time needed to demagnetize a superconducting magnet based on an excitation current of the superconducting magnet and a temperature of the superconducting magnet. The MRI apparatus determines starts ramp-down of the superconducting magnet after a third time based on the first time and the second time has elapsed from initiation of power outage of the main power supply.

According to one embodiment, a MRI apparatus determines a first time during which a subsidiary power supply is capable of supplying power to a cooling device based on a capacity of the subsidiary power supply when power outage of a main power supply occurs, and determines a second time needed to demagnetize a superconducting magnet based on an excitation current of the superconducting magnet and a temperature of the superconducting magnet. The MRI apparatus determines starts ramp-down of the superconducting magnet after a third time based on the first time and the second time has elapsed from initiation of power outage of the main power supply.

According to one embodiment, a MRI apparatus determines a first time during which a subsidiary power supply is capable of supplying power to a cooling device based on a capacity of the subsidiary power supply when power outage of a main power supply occurs, and determines a second time needed to demagnetize a superconducting magnet based on an excitation current of the superconducting magnet and a temperature of the superconducting magnet. The MRI apparatus determines starts ramp-down of the superconducting magnet after a third time based on the first time and the second time has elapsed from initiation of power outage of the main power supply.

According to one embodiment, a MRI apparatus determines a first time during which a subsidiary power supply is capable of supplying power to a cooling device based on a capacity of the subsidiary power supply when power outage of a main power supply occurs, and determines a second time needed to demagnetize a superconducting magnet based on an excitation current of the superconducting magnet and a temperature of the superconducting magnet. The MRI apparatus determines starts ramp-down of the superconducting magnet after a third time based on the first time and the second time has elapsed from initiation of power outage of the main power supply.

A magnet includes a stack of a plurality of superconducting pancake wound coils having a stacking axis normal to a winding direction of the coils. The stack has axial ends and has a stack midplane relative to the stacking axis. A quench detector is provided for detecting a quench in the stack of superconducting pancake wound coils. A plurality of resistance quench heaters (RQH) are distributed symmetrically along the axis with respect to the stack midplane. Control circuitry is provided for controlling the operation of the RQH upon the detection of a quench by the quench detector. A method of quenching a magnet is also disclosed.

A magnet includes a stack of a plurality of superconducting pancake wound coils having a stacking axis normal to a winding direction of the coils. The stack has axial ends and has a stack midplane relative to the stacking axis. A quench detector is provided for detecting a quench in the stack of superconducting pancake wound coils. A plurality of resistance quench heaters (RQH) are distributed symmetrically along the axis with respect to the stack midplane. Control circuitry is provided for controlling the operation of the RQH upon the detection of a quench by the quench detector. A method of quenching a magnet is also disclosed.

A toroidal field coil comprising a central column, a plurality of return limbs, a quench protection system, and a cooling system. The central column comprises IITS material. Each return limb comprises a quenchable section, two IITS sections, and a quenching 5 system. The quenchable section comprises superconducting material, and is configured to contribute towards a magnetic field of the toroidal field coil. The IITS sections comprise IITS material. The IITS sections electrically connect the quenchable section to the central column and are in series with the central column and the quenchable section. The quenching system is associated with the quenchable section 10 and configured to quench the quenchable section. The quench protection system is configured to detect quenches in the toroidal field coil and, in response to detection of a quench, cause the quenching system to quench the superconducting material in one or more of the quenchable sections in order to dump energy from the toroidal field coil into the one or more quenchable sections. The cooling system is configured to cool each 15 quenchable section to a temperature at which the superconducting material is superconducting. Each quenchable section has a heat capacity sufficient to cause a temperature of the quenchable section to remain below a first predetermined temperature when energy is dumped from the toroidal field coil into the quenchable section, and a resistivity sufficient to cause decay of the magnet's current quickly 20 enough that the temperature of the quenched part of the HTS section remains below a second predetermined temperature.

A toroidal field coil comprising a central column, a plurality of return limbs, a quench protection system, and a cooling system. The central column comprises IITS material. Each return limb comprises a quenchable section, two IITS sections, and a quenching 5 system. The quenchable section comprises superconducting material, and is configured to contribute towards a magnetic field of the toroidal field coil. The IITS sections comprise IITS material. The IITS sections electrically connect the quenchable section to the central column and are in series with the central column and the quenchable section. The quenching system is associated with the quenchable section 10 and configured to quench the quenchable section. The quench protection system is configured to detect quenches in the toroidal field coil and, in response to detection of a quench, cause the quenching system to quench the superconducting material in one or more of the quenchable sections in order to dump energy from the toroidal field coil into the one or more quenchable sections. The cooling system is configured to cool each 15 quenchable section to a temperature at which the superconducting material is superconducting. Each quenchable section has a heat capacity sufficient to cause a temperature of the quenchable section to remain below a first predetermined temperature when energy is dumped from the toroidal field coil into the quenchable section, and a resistivity sufficient to cause decay of the magnet's current quickly 20 enough that the temperature of the quenched part of the HTS section remains below a second predetermined temperature.

An HTS magnet system comprising an HTS field coil and a power supply. The HTS field coil comprises a plurality of turns comprising HTS material and a metallic stabiliser; and an electrically conductive layer separating the turns, such that current can be shared between turns via the conductive layer. The power supply is configured to: during ramp-up of the HTS field coil, provide a first current to the HTS field coil; and during ramp-down of the HTS field coil, provide a second current to the HTS field coil opposite in direction to the first current.