Abstract: A disturbance magnetic field region provided in an outer peripheral portion of a main magnetic field region of an accelerator has a peeler region in which a strength of a magnetic field decreases toward an outside, a regenerator region in which the strength of the magnetic field increases toward the outside, and a substantially flat region in which the strength of the magnetic field is larger than the strength of the magnetic field of the peeler region and smaller than the strength of the magnetic field of the regenerator region.

Abstract: Conventional cyclotrons have been incapable of changing energy of a beam to be extracted. Conventional synchrotrons have been difficult to output beams in a continuous manner. An accelerator has a dense region dense region in which orbits of different energies densely gather as a result of using a radiofrequency electric field to accelerate an ion orbiting in an isochronous magnetic field in order to cause a beam orbit to be displaced in a specific direction with increasing acceleration, and a sparse region in which orbits of different energies are sparsely discrete from each other. The accelerator has a feature that a magnetic field has a magnetic field gradient in a radial direction of a beam orbit in the dense region, and a product of a gradient of magnetic field gradient and a beam size passing through the dense region becomes smaller than the magnetic field gradient.

Abstract: Ion beams are efficiently extracted with an accelerator that includes a circular vacuum container including a pair of circular return yokes facing each other. Six magnetic poles are radially disposed from the injection electrode at the periphery thereof in the return yoke. Six recessions are disposed alternately with the respective magnetic poles in the circumferential direction of the return yoke. In the vacuum container, a concentric trajectory region, in which multiple beam turning trajectories centered around the injection electrode are present, is formed, and an eccentric trajectory region, in which multiple beam turning trajectories eccentric from the injection electrode are present, is formed around the region. In the eccentric trajectory region, the beam turning trajectories are dense between the injection electrode and the inlet of the beam extraction path. Gaps between the beam turning trajectories are wide in a direction 180° opposite to the inlet of the beam extraction path.

Abstract: A particle therapy system capable of reducing the installation area and also suppressing a variation in the irradiation beam position is provided. A synchrotron generates a charged particle beam, and a beam delivery system irradiates an irradiation target with a charged particle beam extracted from the synchrotron thereby forming a radiation field. A rotating gantry is provided with the beam delivery system and is rotatable around the irradiation target. Dispersion measuring devices, each of which measures the dispersion of the charged particle beam at the position of the irradiation target at a plurality of rotation angles of the rotating gantry, are also provided. The orbit center of the charged particle beam extracted from the synchrotron and the rotation axis of the rotating gantry are located on substantially the same straight line.

Abstract: Conventional cyclotrons have been incapable of changing energy of a beam to be extracted. Conventional synchrotrons have been difficult to output beams in a continuous manner. An accelerator has a dense region dense region in which orbits of different energies densely gather as a result of using a radiofrequency electric field to accelerate an ion orbiting in an isochronous magnetic field in order to cause a beam orbit to be displaced in a specific direction with increasing acceleration, and a sparse region in which orbits of different energies are sparsely discrete from each other. The accelerator has a feature that a magnetic field has a magnetic field gradient in a radial direction of a beam orbit in the dense region, and a product of a gradient of magnetic field gradient and a beam size passing through the dense region becomes smaller than the magnetic field gradient.

Abstract: An accelerator 4 includes a circular vacuum container including circular return yokes 5A, 5B. An injection electrode 18 is disposed closer to an inlet of a beam extraction path 20 in the return yoke 5B than a central axis C of the vacuum container. Magnetic poles 7A to 7F are radially disposed from the injection electrode 18 at the periphery of the injection electrode 18 in the return yoke 5B. Recessions 29A to 29F are disposed alternately with the magnetic poles 7A to 7F in the circumferential direction of the return yoke 5B. In the vacuum container, a concentric trajectory region, in which multiple beam turning trajectories centered around the injection electrode 18 are present, is formed, and an eccentric trajectory region, in which multiple beam turning trajectories eccentric from the injection electrode 18 are present, is formed around the region.

Abstract: [Problem] A particle therapy system capable of reducing the installation area and also suppressing a variation in the irradiation beam position is provided. A synchrotron generates a charged particle beam, and a beam delivery system irradiates an irradiation target with a charged particle beam extracted from the synchrotron thereby forming a radiation field. A rotating gantry is provided with the beam delivery system and is rotatable around the irradiation target. Dispersion measuring devices, each of which measures the dispersion of the charged particle beam at the position of the irradiation target at a plurality of rotation angles of the rotating gantry, are also provided. The orbit center of the charged particle beam extracted from the synchrotron and the rotation axis of the rotating gantry are located on substantially the same straight line.

Abstract: Ion beams are efficiently extracted with an accelerator that includes a circular vacuum container including a pair of circular return yokes facing each other. Six magnetic poles are radially disposed from the injection electrode at the periphery thereof in the return yoke. Six recessions are disposed alternately with the respective magnetic poles in the circumferential direction of the return yoke. In the vacuum container, a concentric trajectory region, in which multiple beam turning trajectories centered around the injection electrode are present, is formed, and an eccentric trajectory region, in which multiple beam turning trajectories eccentric from the injection electrode are present, is formed around the region. In the eccentric trajectory region, the beam turning trajectories are dense between the injection electrode and the inlet of the beam extraction path. Gaps between the beam turning trajectories are wide in a direction 180° opposite to the inlet of the beam extraction path.

Abstract: An accelerator 4 includes a circular vacuum container including circular return yokes 5A, 5B. An injection electrode 18 is disposed closer to an inlet of a beam extraction path 20 in the return yoke 5B than a central axis C of the vacuum container. Magnetic poles 7A to 7F are radially disposed from the injection electrode 18 at the periphery of the injection electrode 18 in the return yoke 5B. Recessions 29A to 29F are disposed alternately with the magnetic poles 7A to 7F in the circumferential direction of the return yoke 5B. In the vacuum container, a concentric trajectory region, in which multiple beam turning trajectories centered around the injection electrode 18 are present, is formed, and an eccentric trajectory region, in which multiple beam turning trajectories eccentric from the injection electrode 18 are present, is formed around the region.