Particle-beam control electromagnet and irradiation treatment apparatus equipped therewith

A particle-beam control electromagnet comprising:

• a first superconducting coil group configured to form a bending magnetic field and a focus/defocus magnetic field, the bending magnetic field is for bending a traveling direction of a particle beam passing through inside of a vacuum duct and the focus/defocus magnetic field is for controlling an outer diameter of the particle beam;
• a second superconducting coil group configured to be placed around a trajectory of the particle beam at an end portion of the first superconducting coil group and form a correction magnetic field for correcting the trajectory of the particle beam;
• and
• a vacuum vessel configured to hermetically house the first superconducting coil group, the second superconducting coil group and a cooling medium to insulate from outside air,
• wherein the first superconducting coil group includes a first focus/defocus coil group and a second focus/defocus coil group arranged side by side along the trajectory of the particle beam, each focus/defocus coil group forming the focus/defocus magnetic field and including an even number of excitation coils placed axially symmetrically with respect to the trajectory of the particle beam, current flow in the excitation coils of the second focus/defocus coil group being opposite to current flow in the excitation coils of the first focus/defocus coil group.