A control method for a superconducting magnet apparatus comprising steps of: causing a superconducting coil to transition to a superconductive state by causing a cooler to cool the superconducting coil to or below a critical temperature; supplying electric current to the superconducting coil, which has transitioned to the superconductive state, from an excitation power supply; starting a persistent current mode by stopping supply of the electric current; adjusting temperature of the superconducting coil to a specific temperature which is equal to or lower than the critical temperature and higher than a steady operation temperature; and starting a steady operation by cooling the superconducting coil to or below the steady operation temperature, after a specific condition for stabilizing a magnetic field of the superconducting coil is satisfied.

A superconducting magnet system and a cyclotron using the same. The superconducting magnet system includes a cryogenic device, a superconducting device and a protecting module. The cryogenic device includes a refrigerating machine and a cryogenic container assembly. The cryogenic container assembly includes a first container end, a connecting tube and a second container end. The first container end is communicated with the second container end through the connecting tube. The superconducting device includes a superconducting coil arranged in the first container end and immersed in a liquid or gaseous cooling medium. The protecting module is connected to the superconducting coil and is configured to protect the superconducting coil if the superconducting coil suffers a quench.

A superconducting magnet system and a cyclotron using the same. The superconducting magnet system includes a cryogenic device, a superconducting device and a protecting module. The cryogenic device includes a refrigerating machine and a cryogenic container assembly. The cryogenic container assembly includes a first container end, a connecting tube and a second container end. The first container end is communicated with the second container end through the connecting tube. The superconducting device includes a superconducting coil arranged in the first container end and immersed in a liquid or gaseous cooling medium. The protecting module is connected to the superconducting coil and is configured to protect the superconducting coil if the superconducting coil suffers a quench.

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.

Techniques are described for lowering strains applied to superconducting material in a superconducting magnet by arranging structural partitions between turns of the superconducting material that intercept and transfer strain to a mechanically stronger structure, such as the housing of the magnet. A structural partition may be formed with a feedthrough slit so that the superconducting aterial can easily pass through the partition. A number of structural partitions may be interspersed between groups of turns of super-conducting material in a magnet so that forces can be sufficiently distributed by the partitions throughout the magnet. At the same time, the number of structural partitions may be selected to minimize the amount of space within the magnet occupied by the partitions that could otherwise be occupied by current-carrying superconducting material.

Techniques are described for lowering strains applied to superconducting material in a superconducting magnet by arranging structural partitions between turns of the superconducting material that intercept and transfer strain to a mechanically stronger structure, such as the housing of the magnet. A structural partition may be formed with a feedthrough slit so that the superconducting aterial can easily pass through the partition. A number of structural partitions may be interspersed between groups of turns of super-conducting material in a magnet so that forces can be sufficiently distributed by the partitions throughout the magnet. At the same time, the number of structural partitions may be selected to minimize the amount of space within the magnet occupied by the partitions that could otherwise be occupied by current-carrying superconducting material.

To provide a superconducting magnet device enabling improved access to internal equipment. A superconducting magnet device includes: a superconducting coil; and a hollow tubular cryostat having an outer peripheral wall and an inner peripheral wall connected to each other so as to define a vacuum region where the superconducting coil is disposed. The cryostat has a tubular partition wall connecting the outer peripheral wall and the inner peripheral wall and a cavity partitioned from the vacuum region by the tubular partition wall is formed inside the tubular partition wall. The outer peripheral wall has an opening portion wide in the circumferential direction of the cryostat, and the opening portion communicates with the cryostat hollow portion radially inside the inner peripheral wall through the cavity.

To provide a superconducting magnet device enabling improved access to internal equipment. A superconducting magnet device includes: a superconducting coil; and a hollow tubular cryostat having an outer peripheral wall and an inner peripheral wall connected to each other so as to define a vacuum region where the superconducting coil is disposed. The cryostat has a tubular partition wall connecting the outer peripheral wall and the inner peripheral wall and a cavity partitioned from the vacuum region by the tubular partition wall is formed inside the tubular partition wall. The outer peripheral wall has an opening portion wide in the circumferential direction of the cryostat, and the opening portion communicates with the cryostat hollow portion radially inside the inner peripheral wall through the cavity.

A spool has a cylindrical outer shape extending in an axial direction intersecting an upward/downward direction, the spool having an outer circumferential surface in which a plurality of annular groove portions extending in a circumferential direction are formed with a space being interposed between the plurality of annular groove portions in the axial direction, a superconducting coil being wound and accommodated inside each of the plurality of annular groove portions. A cover portion is attached to the spool so as to cover each of the plurality of annular groove portions, the cover portion and the plurality of annular groove portions forming a plurality of annular flow paths for refrigerant to cool the superconducting coil. One or more communication paths extend in parallel with the axial direction to communicate adjacent annular flow paths of the plurality of annular flow paths with each other.