CHARGED PARTICLE BEAM IRRADIATION SYSTEM, AND BEAM EMISSION METHOD FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a charged particle beam irradiation system capable of suppressing generation of current ripples in an emission beam caused by a high-frequency voltage applied to an emission high-frequency electrode for increasing a betatron vibration amplitude of an ion beam, and of improving a dose rate.SOLUTION: A high-frequency voltage Fext applied to an emission high-frequency electrode is configured to satisfy the equation Fext=Fs+Fe by a high-frequency voltage (a supply high-frequency voltage) Fs applied so as to increase a vibration amplitude within a range not exceeding a stability limit and so that a beam circling in a synchrotron is not emitted to the outside of synchrotron, and a high-frequency voltage (an emission high-frequency voltage) Fe applied to emit from the synchrotron the circling beam dispersed to the vicinity of the stability limit 15 by the supply high-frequency voltage Fs. In addition, intensities of the supply high-frequency voltage Fs and the emission high-frequency voltage Fe are controlled by being arbitrarily combined depending on a target value of an ion beam current emitted to the outside of the synchrotron and its time change.