# US 12,114,415 B2 · Circular accelerator

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- Number: US 12,114,415 B2
- Document ID: US12114415B2
- Status: Granted
- Kind: B2
- Application number: 17/892,311
- Filed: 2022-08-22
- Published: 2022-12-22
- Granted: 2024-10-08
- Earliest claimed: 2022-08-22
- Assignees: Hitachi High-Tech Corporation
- Applicants: Hitachi High-Tech Corporation
- Inventors: Takamichi Aoki
- Web page: https://patentgrep.com/patent/US12114415B2

## CPC

- H05H 7/04: Magnet systems {, e.g. undulators, wigglers (free-electron laser H01S3/0903)}; Energisation thereof
- A61N 5/103: {Treatment planning systems}
- A61N 5/1077: {Beam delivery systems}
- H01F 7/202: {Electromagnets for high magnetic field strength (for superconducting electromagnets H01F6/00; for transformers or inductances without a magnetic core H01F30/08)}
- H05H 7/08: Arrangements for injecting particles into orbits
- H05H 13/00: Magnetic resonance accelerators; Cyclotrons {(strophotrons, turbine tubes H01J25/62)}
- H05H 13/005: {Cyclotrons}
- H05H 13/02: Synchrocyclotrons, i.e. frequency modulated cyclotrons
- H05H 15/00: Methods or devices for acceleration of charged particles not otherwise provided for {, e.g. wakefield accelerators}
- A61N 2005/1087: {Ions; Protons}
- A61N 2005/1097: {Means for immobilizing the patient}
- H05H 2277/11: Radiotherapy
- H05H: PLASMA TECHNIQUE (apparatus or processes specially adapted for producing X-rays H05G2/00); PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES

## Abstract

Provided is a variable energy and miniaturized accelerator. It is impossible to change the energy of the extraction beam in the related cyclotron or to miniaturize an accelerator in the related synchrotron. The accelerator includes a pair of magnets which form a magnetic field therebetween; an ion source which injects ions between the magnets; an acceleration electrode which accelerates the ions; and a beam extraction path which extracts the ions to the outside. A plurality of ring-shaped beam closed orbits formed by the pair of magnets, in which the ions of different energies respectively circulate, are aggregated on one side. The frequency of the radiofrequency electric field fed to the ions by the acceleration electrode is modulated by the beam closed orbits.

## Claims

### Claim 1

An accelerator, comprising:
a pair of magnets forming a magnetic field therebetween;
an ion source which injects ions between the pair of magnets;
an acceleration electrode which accelerates the ions; and
a beam extraction path which extracts the ions to an outside, wherein
a plurality of ring-shaped beam closed orbits formed by the pair of magnets, in which ions of different energies respectively circulate, are aggregated on one side; and
the magnetic field formed by the pair of magnets is uniform along the plurality of ring-shaped beam closed orbits and decreases as energy increases.

### Claim 2 (depends on 1)

The accelerator according to claim 1, wherein
a distance between magnetic poles formed respectively in the pair of magnets is smallest in a vicinity of an injection point and increases toward an outer periphery.

### Claim 3 (depends on 1)

The accelerator according to claim 1, wherein
the plurality of ring-shaped beam closed orbits aggregate on one side in a predetermined energy range.

### Claim 4 (depends on 1)

The accelerator according to claim 1, wherein
the beam closed orbit is formed such that the plurality of ring-shaped beam closed orbits aggregate on one side in a predetermined outer peripheral region and do not aggregate in a predetermined inner peripheral region; and
the pair of magnets form the magnetic field such that a magnetic field gradient is substantially linear in the predetermined outer peripheral region where the plurality of ring-shaped beam closed orbits are aggregated on one side.

### Claim 5 (depends on 1)

A particle therapy system, comprising:
the accelerator according to claim 1;
a transfer which transfers ions accelerated by the accelerator;
an irradiation system which irradiates a target with the ions transferred by the transfer;
a positioning system which supports the target; and
a treatment planning creation system which creates a plan of performing the irradiation.