Synchrotron type accelerator and medical treatment system employing the same

• US 6,087,670 A
• Filed: 08/03/1999
• Issued: 07/11/2000
• Est. Priority Date: 12/03/1996
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Matsuda, Koji, Hiramoto, Kazuo, Umezawa, Masumi
• Primary Examiner(s): Anderson, Bruce C.
• Assistant Examiner(s): Wells, Nikita
• Application Number:
  US09/365,835
• Time in Patent Office: 343 Days
• Field of Search: 250/492.3, 250/398, 250/396 ML, 315/503
• US Class Current: 250/492.3
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: H05H 13/04 Synchrotrons
• CPC Class Codes: H05H 7/10 Arrangements for ejecting particles from orbits

Abstract

A synchrotron type accelerator including a deflecting electromagnet arranged on a circulating orbit of a charged particle beam, four-pole divergence electromagnets and four-pole convergence electromagnets arranged on said circulating orbit. A high frequency applying unit arranged on the circulating orbit for applying a high frequency electromagnetic field to the charged particle beam circulating and for increasing an amplitude of betatron oscillation of the particle beam to a level above a stability limit of resonance. A first deflector for beam ejection arranged on the circulating orbit for deflecting the charged particle beam excited above the stability limit of the resonance by the high frequency applying unit and a second deflector for beam ejection arranged on the circulating orbit used in pairs with the first deflector for beam ejection for introducing the charged particle beam deflected by the first deflector for beam ejection into an ejected beam transporting system. The deflecting electromagnet and the second deflector for beam ejection are arranged in this order at downstream with respect to the first deflector for beam ejection, and the four-pole divergence electromagnets are arranged at downstream with respect to the first deflector for beam ejection and upstream with respect to the deflecting electromagnet and at downstream with respect to the deflecting electromagnet and upstream with respect to the second deflector for beam ejection.

Claims

1. A synchrotron type accelerator including:

a deflecting electromagnet arranged on a circulating orbit of a charged particle beam;

four-pole divergence electromagnets and four-pole convergence electromagnets arranged on said circulating orbit;

a high frequency applying unit arranged on said circulating orbit for applying a high frequency electromagnetic field to said charged particle beam which circulates and for increasing an amplitude of betatron oscillation of said charged particle beam to a level above a stability limit of resonance;

a first deflector for beam ejection arranged on said circulating orbit for deflecting said charged particle beam excited above said stability limit of the resonance by said high frequency applying unit and a second deflector for beam ejection arranged on said circulating orbit used in pairs with said first deflector for beam ejection for introducing said charged particle beam deflected by said first deflector for beam ejection into an ejected beam transporting system;

wherein said deflecting electromagnet and said second deflector for beam ejection are arranged in this order downstream with respect to said first deflector for beam ejection, and said four-pole divergence electromagnets are arranged downstream with respect to said first deflector for beam ejection and upstream with respect to said deflecting electromagnet and downstream with respect to said deflecting electromagnet and upstream with respect to said second deflector for beam ejection.

2. A synchrotron type accelerator according to claim 1, further comprising:

a power source for supplying power to generate an electric field or a magnetic field in said deflecting electromagnet, said four-pole divergence electromagnets, said four-pole convergence electromagnets, said first deflector for beam ejection and said second deflector for beam ejection; and

control means for controlling said power source so that the strength of said electric field or said magnetic field is maintained at a substantially constant level, while said high frequency applying unit is applying said high frequency electromagnetic field to said charged particle beam.

3. A medical treatment system comprising:

a synchrotron type accelerating according to claim 1;

an ejected beam transporting system for transporting a charged particle ejected from said synchrotron type accelerator; and

an irradiation system connected to said ejected beam transporting system for irradiating said charged particle beam transported by said ejected beam transporting system to a patient.

4. A synchrotron type accelerator including:

a deflecting electromagnet arranged on a circulating orbit of a charged particle beam;

a high frequency applying unit arranged on said circulating orbit for applying a high frequency electromagnetic field to said charged particle beam which circulates and for increasing an amplitude of betatron oscillation of said charged particle beam to a level above a stability limit of resonance;

a first deflector for beam ejection arranged on said circulating orbit for deflecting said charged particle beam excited above said stability limit of the resonance by said high frequency applying unit and a second deflector for beam ejection arranged on said circulating orbit used in pairs with said first deflector for beam ejection for introducing said charged particle beam deflected by said first deflector for beam ejection into an ejected beam transporting system;

wherein said deflecting electromagnet and said second deflector for beam ejection are arranged in this order downstream with respect to said first deflector for beam ejection, and said deflecting electromagnet has a divergence function in a horizontal direction and deflects said charged particle beam deflected by said first deflector for beam ejection toward said second deflector for beam ejection.