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CN-115812340-B - Particle accelerator and particle beam therapy device

CN115812340BCN 115812340 BCN115812340 BCN 115812340BCN-115812340-B

Abstract

A particle accelerator for accelerating a charged particle beam while rotating the charged particle beam as a rotating beam and emitting a part of the rotating beam as an emitting beam, the particle accelerator comprising a first deflection unit and a second deflection unit having deflection electromagnets, the first, second and third straight units having no deflection electromagnets, and a control unit for deflecting a part of the rotating beam toward the inside of a rotating track of the rotating beam and separating the part into the emitting beam, wherein the deflector of the rear section of the third straight unit deflects an emitting beam separated from the rotating beam by the deflector of the front section toward the other side of the rotating track of the rotating beam, and the control unit controls at least four-pole electromagnets so that the phase progress of vibration of the electron induction accelerator of the emitting beam becomes 270 DEG + -45 DEG in a section from the deflector of the front section to the deflector of the rear section.

Inventors

  • Mizuki Kota
  • SHIRAI TOSHIYUKI

Assignees

  • 国立研究开发法人量子科学技术研究开发机构

Dates

Publication Date
20260508
Application Date
20210129
Priority Date
20200623

Claims (13)

  1. 1. A particle accelerator for accelerating a charged particle beam while rotating the charged particle beam as a rotating beam and emitting a part of the rotating beam as an emitting beam, wherein, The particle accelerator includes: A plurality of deflection units each having a deflection electromagnet; A plurality of straight portions without the deflection electromagnet, and The control part is used for controlling the control part to control the control part, The plurality of straight portions include: A first straight line portion having a front-stage injection deflector; A second linear portion disposed downstream of the first linear portion in the traveling direction of the rotating beam and having a quadrupole electromagnet, and A third linear portion disposed downstream of the second linear portion in the traveling direction of the rotating beam, the third linear portion having a rear-stage deflector for emission, The plurality of deflection portions include: A first deflection portion connecting the first straight portion and the second straight portion, and A second deflection portion connecting the second straight portion and the third straight portion, The front-stage deflector deflects a part of the rotating beam toward one of an inner side and an outer side of a rotating track of the rotating beam to separate the rotating beam into the output beam, The rear-stage emission deflector deflects the emission beam separated from the rotating beam by the front-stage emission deflector toward the other of the inner side and the outer side of the rotating track of the rotating beam, The control unit controls at least the quadrupole electromagnet so that the phase progression of the vibration of the electron cyclotron of the emitted beam becomes 270±45 degrees in a section from the front-stage emission deflector to the rear-stage emission deflector.
  2. 2. The particle accelerator of claim 1, wherein the particle accelerator comprises a particle accelerator, The control unit controls at least the quadrupole electromagnet so that a phase progression of vibration of the electron cyclotron for the emitted beam becomes 270 + -45 degrees in a section from the front-stage emission deflector to the rear-stage emission deflector, The control unit controls the front-stage exit deflector so that the exit beam passes near the passing area of the turning beam in the first deflecting unit and the exit beam passes through the passing area of the turning beam in the second deflecting unit, or near the passing area of the turning beam in the second deflecting unit and the exit beam passes through a position apart from the passing area of the turning beam in the third linear unit.
  3. 3. The particle accelerator of claim 1, wherein the particle accelerator comprises a particle accelerator, The first straight line portion and the third straight line portion are disposed at positions opposed to each other on a revolving track of the revolving beam.
  4. 4. The particle accelerator of claim 3, wherein, The first straight line portion and the third straight line portion extend parallel to each other.
  5. 5. The particle accelerator of claim 1, wherein the particle accelerator comprises a particle accelerator, Each of the plurality of deflection units has the deflection electromagnet and a quadrupole electromagnet for the deflection unit, or has a quadrupole magnetic field generating mechanism for the deflection unit which is formed by integrating the deflection electromagnet and a quadrupole magnetic field coil, Each of the plurality of straight sections has the quadrupole electromagnet, The control unit adjusts the excitation amount of the quadrupole electromagnet for the deflection unit or the excitation amount of the quadrupole magnetic field generating mechanism for the deflection unit, and the excitation amount of the quadrupole electromagnet for the straight line unit, so that the phase progression of the electron induced accelerator vibration of the outgoing beam becomes 270±45 degrees in a section from the outgoing deflector at the front stage to the outgoing deflector at the rear stage.
  6. 6. The particle accelerator of claim 5, wherein, The control unit adjusts the excitation amount of the quadrupole electromagnet for the deflection unit or the excitation amount of the quadrupole magnetic field generating mechanism for the deflection unit, and the excitation amount of the quadrupole electromagnet for the straight line unit, so that the phase progression of the electron induced accelerator vibration of the outgoing beam becomes 270 + -45 degrees in a section from the outgoing deflector at the front stage to the outgoing deflector at the rear stage, The control unit adjusts the electric field intensity of the front-stage exit deflector so that the exit beam passes near the passing area of the turning beam in the first deflecting unit and the exit beam passes through the passing area of the turning beam in the second deflecting unit, or near the passing area of the turning beam in the second deflecting unit and the exit beam passes through a position apart from the passing area of the turning beam in the third straight line unit.
  7. 7. The particle accelerator of claim 1, wherein the particle accelerator comprises a particle accelerator, Each of the plurality of straight sections has the quadrupole electromagnet, The control unit adjusts the quadrupole electromagnets of each of the plurality of straight portions so that a phase progression of vibration of the electron accelerator of the emitted beam becomes 270±45 degrees in a section from the front-stage emission deflector to the rear-stage emission deflector.
  8. 8. The particle accelerator of claim 7, wherein the particle accelerator comprises a particle accelerator, The control unit adjusts the quadrupole electromagnets of each of the plurality of straight portions so that a phase progression of vibration of the electron accelerator of the emitted beam becomes 270 + -45 degrees in a section from the front-stage deflector for emission to the rear-stage deflector for emission, The control unit adjusts the electric field intensity of the front-stage exit deflector so that the exit beam passes near the passing area of the turning beam in the first deflecting unit and the exit beam passes through the passing area of the turning beam in the second deflecting unit, or near the passing area of the turning beam in the second deflecting unit and the exit beam passes through a position apart from the passing area of the turning beam in the third straight line unit.
  9. 9. The particle accelerator of claim 1, wherein the particle accelerator comprises a particle accelerator, The deflection angle of the charged particle beam based on the first deflection unit is 60 degrees or more.
  10. 10. The particle accelerator of claim 1, wherein the particle accelerator comprises a particle accelerator, The deflection angle of the charged particle beam based on the total of the first deflection unit and the second deflection unit is 180 degrees.
  11. 11. The particle accelerator of claim 1, wherein the particle accelerator comprises a particle accelerator, The first straight line portion and the third straight line portion each have the quadrupole electromagnet, The front-stage injection deflector is disposed downstream of the quadrupole electromagnet of the first linear portion in the traveling direction of the rotating beam, The rear-stage emission deflector is disposed downstream of the quadrupole electromagnet of the third linear portion in the traveling direction of the rotating beam.
  12. 12. The particle accelerator of claim 1, wherein the particle accelerator comprises a particle accelerator, The quadrupole electromagnet of the first linear portion is disposed at a substantially center of the first linear portion in a traveling direction of the rotating beam, The quadrupole electromagnet of the third linear portion is disposed substantially in the center of the third linear portion in the traveling direction of the rotating beam.
  13. 13. A particle beam therapy system, wherein, The particle beam therapy system comprising the particle accelerator according to claim 1, and And an irradiation device that irradiates an irradiation object by transporting the charged particle beam extracted from the particle accelerator as the emission beam.

Description

Particle accelerator and particle beam therapy device Technical Field The present invention relates to a particle accelerator and a particle beam therapy system. The present application is based on claims 2020-108088, which are entitled to priority in Japanese patent application No. 2020, 6-23, and the contents of which are incorporated herein by reference. Background Particle accelerators are widely used in various fields such as science, industry, and medical science as devices for generating high-energy charged particles. In the field of particle beam therapy, circular accelerators are currently used because of the ability to accelerate charged particles to high energies in a limited space. In addition, in order to reduce the cost of introducing a particle beam therapy facility, there is an increasing number of examples of miniaturization of particle beam therapy apparatuses using superconducting technology. When a superconducting magnet with a high magnetic field is used, charged particles with high energy can deflect with a short radius of curvature, and thus the circular accelerator can be miniaturized. In a particle beam therapy system, a circular accelerator occupies a large area, and in order to miniaturize the particle beam therapy system, it is very effective to use a superconducting electromagnet for the circular accelerator. The synchrotron, which is one of the circular accelerators, can accelerate the charged particle beam to various energies while maintaining a stable rotation orbit of the charged particle beam by applying acceleration energy to the high-frequency acceleration cavity while deflecting the charged particle beam by a magnetic field generated by the electromagnet and increasing the magnetic field generated by the electromagnet in accordance with the energy change of the charged particle beam, and can be taken out (ejected) from the synchrotron by the deflector for ejection. Since the charged particle beam rotated in the synchrotron accelerator passes through the same orbit even when the energy is changed by acceleration, individual constituent devices such as electromagnets are relatively small, and therefore, the charged particle beam is suitable for generating high-energy charged particles with good efficiency. Hitherto, in order to achieve downsizing of synchrotrons, synchrotrons having a substantially square shape as a whole, which are constituted by a short straight line portion and a curved line portion having a large curvature, have been proposed. In such a synchrotron accelerator, since each linear portion is short, an emission deflector for separating the front stage of the emission beam from the rotating beam is provided in the linear portion on the upstream side of the curved portion, and an emission deflector for extracting the emission beam separated from the rotating beam to the outside is provided in the linear portion on the downstream side of the curved portion. On the other hand, a deflection electromagnet such as a superconducting electromagnet that requires a cooling unit is provided at a curved portion having a large curvature. Fig. 9 is a diagram showing such a conventional particle accelerator and a particle beam therapy system to which such a conventional particle accelerator is applied. Fig. 10 is a diagram showing a relationship between a passing area (hatched portion in fig. 10) of the rotating beam 131 and a trajectory of the outgoing beam 132 in the conventional example shown in fig. 9. In fig. 10, the S-axis direction indicates the traveling direction of the rotating beam 131. The X axis included in the plane orthogonal to the S axis corresponds to the deflection direction of the deflection electromagnet 102. The Y axis included in the plane orthogonal to the S axis is orthogonal to the X axis. In the case of downsizing the synchrotron (particle accelerator) 100, it is a major problem to extract (eject) the accelerated high-energy beam without loss. In order to achieve effective miniaturization, it is necessary to shorten the deflection section 121 by increasing the magnetic field of the deflection electromagnet 102, and to shorten the straight sections 111 and 112 at the same time. However, in order to take out the emission beam 132 out of the synchrotron (particle accelerator) 100 without loss, the emission beam 132 and the rotating beam 131 need to be separated by the front-stage emission deflector 108, and the emission beam 132 needs to be greatly bent out of the synchrotron (particle accelerator) 100 by the rear-stage emission deflector 109, but these operations require a long space for disposing each of the front-stage emission deflector 108 and the rear-stage emission deflector 109, which is contrary to the need for shortening the straight portions 111 and 112. Therefore, in the conventional synchrotron (particle accelerator) 100 shown in fig. 9, which is aimed at downsizing, a structure is adopted in which the front-stage injection deflector