Patent Number: 
Section: claims

1. A synchrotron that accelerates and decelerates a charged particle beam that circulates in the synchrotron, comprising:a first extraction deflector and a second extraction deflector that are used to extract the accelerated or decelerated beam from the synchrotron;a plurality of deflection magnets and a first single quadrupole magnet that are arranged between the first and second extraction deflectors, the first single quadrupole magnet being arranged between any deflection magnets among the plurality of deflection magnets;a second quadrupole magnet that is arranged on the upstream side of the first extraction deflector in a traveling direction of the charged particle beam on a path of the circulating charged particle beam; anda third quadrupole magnet that is arranged on the downstream side of the second extraction deflector in the traveling direction of the charged particle beam on the path of the circulating charged particle beam. 2. The synchrotron according to claim 1,wherein the first quadrupole magnet is a defocusing quadrupole magnet, and the second quadrupole magnet and the third quadrupole magnet are focusing quadrupole magnets. 3. The synchrotron according to claim 1,wherein the plurality of deflection magnets arranged between the first and second extraction deflectors are a first deflection magnet and a second deflection magnet, andthe first deflection magnet, the first quadrupole magnet and the second deflection magnet are arranged in this order from the upstream side in the traveling direction of the charged particle beam. 4. The synchrotron according to claim 1,wherein the plurality of deflection magnets arranged between the first and second extraction deflectors are a first deflection magnet, a second deflection magnet and a third deflection magnet, andthe first deflection magnet, the first quadrupole magnet, the second deflection magnet and the third deflection magnet are arranged in this order from the upstream side in the traveling direction of the charged particle beam. 5. The synchrotron according to claim 1,wherein the plurality of deflection magnets arranged between the first and second extraction deflectors are a first deflection magnet, a second deflection magnet and a third deflection magnet, andthe first deflection magnet, the second deflection magnet, the first quadrupole magnet and the third deflection magnet are arranged in this order from the upstream side in the traveling direction of the charged particle beam. 6. The synchrotron according to claim 1,wherein a combined function magnet is used instead of the deflection magnet and the first quadrupole magnet that are arranged between the first and second extraction deflectors. 7. The synchrotron according to claim 6,wherein the second quadrupole magnet and the third quadrupole magnet are focusing quadrupole magnets. 8. A particle therapy system comprising:the synchrotron according to claim 1, anda beam transport/irradiation system that transports the charged particle beam extracted from the synchrotron to a target and irradiates the target with the charged particle beam. 9. A particle therapy system comprising:the synchrotron according to claim 2, anda beam transport/irradiation system that transports the charged particle beam extracted from the synchrotron to a target and irradiates the target with the charged particle beam. 10. A particle therapy system comprising:the synchrotron according to claim 3, anda beam transport/irradiation system that transports the charged particle beam extracted from the synchrotron to a target and irradiates the target with the charged particle beam. 11. A particle therapy system comprising:the synchrotron according to claim 4, anda beam transport/irradiation system that transports the charged particle beam extracted from the synchrotron to a target and irradiates the target with the charged particle beam. 12. A particle therapy system comprising:the synchrotron according to claim 5, anda beam transport/irradiation system that transports the charged particle beam extracted from the synchrotron to a target and irradiates the target with the charged particle beam. 13. A particle therapy system comprising:the synchrotron according to claim 6, anda beam transport/irradiation system that transports the charged particle beam extracted from the synchrotron to a target and irradiates the target with the charged particle beam. 14. A particle therapy system comprising:the synchrotron according to claim 7, anda beam transport/irradiation system that transports the charged particle beam extracted from the synchrotron to a target and irradiates the target with the charged particle beam.