Accelerator and particle beam irradiation system

Patent metadata

Field	Value
Publication number	US-2017303384-A1
Application number	US-201415513584-A
Country	US
Kind code	A1
Filing date	Dec 8, 2014
Priority date	Dec 8, 2014
Publication date	Oct 19, 2017
Grant date	—

Abstract

The accelerator includes a circular vacuum container which contains a circular return yoke. With respect to the central axis of the vacuum container, an incidence electrode is arranged towards the entrance of a beam emission path inside of the return yoke. Inside of the return yoke, electrodes are arranged radially from the incidence electrode in the periphery of the incidence electrode. Recesses are arranged alternately with the electrodes in the circumferential direction of the return yoke. In the vacuum container, an orbit-concentric region is formed in which multiple beam orbits centered on the incidence electrode are present, and, in the periphery of said region, an orbit-eccentric area is formed in which multiple beam orbits eccentric to the incidence electrode are present. In the orbit-eccentric region, the beam orbits between the incidence electrode and the entrance to the beam emission path are denser.

First claim

1 . An accelerator comprising:
an annular main coil; multiple magnetic poles configured to form isochronous magnetic fields; and an acceleration electrode configured to accelerate ions, wherein an ion injection portion, into which the ions are injected, is disposed at a position that is different from the position of the center of gravity of the main coil in a radial direction.

2 . An accelerator comprising:
a pair of iron cores which are installed to face each other and between which isochronous magnetic fields are formed; and an acceleration electrode configured to accelerate injected ions, wherein an ion injection portion, into which the ions are injected, is disposed at a position that is different from the position of the center of the iron cores in a radial direction.

3 . An accelerator comprising:
an annular main coil; multiple magnetic poles configured to form isochronous magnetic fields; and multiple acceleration electrodes configured to accelerate ions, wherein the multiple acceleration electrodes are installed to extend from the position of an inner surface of the main coil toward the inside of the main coil, and wherein a tip end portion of a portion of each of the multiple acceleration electrodes, which extends away from the inner surface of the main coil from the position of the inner surface and is positioned inside the main coil, is disposed at a position that is different from the position of the center of gravity of the main coil in a radial direction.

4 . An accelerator comprising:
a pair of iron cores which are installed to face each other and between which magnetic fields are formed; and an acceleration electrode configured to accelerate ions, wherein the iron core forms multiple protrusions, and wherein the multiple protrusions are formed in the iron core in such a way as to extend from an outer circumference of the iron core toward a position that is different from the position of the center of gravity of the iron core in a radial direction.

5 . The accelerator according to claim 4 ,
wherein all of the multiple protrusions are disposed in reflection symmetry, and are not rotationally symmetrical with each other.

6 . The accelerator according to claim 4 ,
wherein the center of gravity of all of the multiple protrusions is present at a different position from that of the center of the iron core.

7 . The accelerator according to claim 1 , further comprising:
an extraction port through which an accelerated ion beam is extracted, wherein the ion injection portion into which the ions are injected, a tip of an inner circumferential end portion of the electrode, or a tip of the magnetic pole installed to extend is provided closer to the extraction port than the center of gravity of the annular main coil or the center of the iron core.

8 . The accelerator according to claim 1 , further comprising:
a pair of iron cores that are joined together in a state where a beam turning region, on which multiple beam turning trajectories are formed, is interposed therebetween, and a beam extraction path that passes through the iron core and is an extraction port of an ion beam, wherein the center of gravity of the main coil is positioned on a central axis of the main coil, wherein the different position, at which the ion injection portion is disposed, is a position that is closer to an inlet of the beam path than the central axis of the main coil, and the ion injection portion is disposed at the position close to the inlet of the beam path, wherein each of the pair of iron cores extends radially from the ion injection portion at the periphery of the ion injection portion, forms the multiple magnetic poles, a tip end of each of which faces the ion injection portion, and forms multiple recessions which extend radially from the ion injection portion at the periphery of the ion injection portion, wherein the magnetic poles and the recessions are alternately disposed at the periphery of the ion injection portion, and wherein the main coil surrounds the multiple magnetic poles and the multiple recessions which are disposed inside each of the iron core.

9 . The accelerator according to claim 2 , further comprising:
a beam extraction path that passes through the iron core and is an extraction port of an ion beam, wherein the pair of iron cores are joined together in a state where a beam turning region, on which multiple beam turning trajectories are formed, is interposed therebetween, wherein the different position, at which the ion injection portion is disposed, is a position that is closer to an inlet of the beam path than the center of the iron core, and the ion injection portion is disposed at the position close to the inlet of the beam path, wherein each of the pair of iron cores extends radially from the ion injection portion at the periphery of the ion injection portion, forms the multiple magnetic poles, a tip end of each of which faces the ion injection portion, and forms multiple recessions which extend radially from the ion injection portion at the periphery of the ion injection portion, wherein the magnetic poles and the recessions are alternately disposed at the periphery of the ion injection portion, and wherein the main coil surrounds the multiple magnetic poles and the multiple recessions which are disposed inside each of the iron core.

10 . The accelerator according to claim 3 , further comprising:
a pair of iron cores that are joined together in a state where a beam turning region, on which multiple beam turning trajectories are formed, is interposed therebetween, and a beam extraction path that passes through the iron core and is an extraction port of an ion beam, wherein the ion injection portion is formed in the beam turning region, and is disposed closer to an inlet of the beam path than the center of gravity of the main coil, wherein the center of gravity of the main coil is positioned on a central axis of the main coil, wherein the different position, at which the tip end portion of each of the multiple acceleration electrodes is disposed, is a position that is closer to the inlet of the beam path than the central axis of the main coil, and the tip end portion of each of the multiple acceleration electrodes is disposed at the position close to the inlet of the beam path, wherein each of the pair of iron cores extends radially from the position close to the inlet of the beam path at the periphery of the position close to the inlet of the beam path, forms the multiple magnetic poles, a tip end of each of which faces the position close to the inlet of the beam path, and forms multiple recessions which extend radially from the ion injection portion at the periphery of the position close to the inlet of the beam path, wherein the magnetic poles and the recessions are alternately disposed at the periphery of the position close to the inlet of the beam path, and wherein the main coil surrounds the multiple magnetic poles and the multiple recessions which are disposed inside each of the iron core.

11 . The accelerator according to claim 4 , further comprising:
a beam extraction path that passes through the iron core and is an extraction port of an ion beam, wherein the pair of iron cores are joined together in a state where a beam turning region, on which multiple beam turning trajectories are formed, is interposed therebetween, wherein the position, which is different from the center of gravity of the iron core in the radial direction, is a position that is closer to an inlet of the beam path than the center of gravity of the iron core, and the ion injection portion is disposed at the position close to the inlet of the beam

Assignees

• Hitachi Ltd

Inventors

• Aoki Takamichi
• Ebina Futaro
• Nishiuchi Hideaki
• Hara Shigemitsu
• Umezawa Masumi
• Seki Takayoshi

Classifications

• H05H13/04

  Synchrotrons · CPC title

• H05H2277/11

  Radiotherapy · CPC title

• A61N2005/1087

  Ions; Protons · CPC title

• H05H13/005 Primary

  Cyclotrons · CPC title

• H05H7/08

  Arrangements for injecting particles into orbits · CPC title