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.COPYRIGHT: (C)2016,JPO&INPIT【課題】イオンビームのベータトロン振動振幅を増大させる出射用高周波電極に印加する高周波電圧に起因する出射ビームの電流リップルの発生を抑制し、線量率を向上させることができる荷電粒子ビーム照射システムを提供する。【解決手段】出射用高周波電極に印加する高周波電圧Fextとして、シンクロトロン内を周回するビームをシンクロトロン外に出射されないように、安定限界を超えない範囲で振動振幅を増大するように印加する高周波電圧(供給用高周波電圧)Fsと、供給用高周波電圧Fsにより安定限界15近傍まで拡散された周回ビームをシンクロトロンからビームを出射するために印加する高周波電圧(出射用高周波電圧)FeとでFext=Fs+Feを構成する。また、供給用高周波電圧Fsと、出射用高周波電圧Feの強度を、シンクロトロン外に出射されるイオンビーム電流の目標値およびその時間変化に応じて適宜組み合わせて制御する。【選択図】図2
