量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum and Radiological Science and Technology.
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A new type of beam chopper has been developed and installed at HIMAC (Heavy Ion Medical Accelerator in Chiba) in NIRS (National Institute of Radiological Sciences).The chopper has only 11.6 cm length and has been set between the ion sources and the RFQ.It is similar to a beam transformer, and modulates the beam kinetic energy by 10%.The beam is successfully chopped because the RFQ has a rather small energy acceptance. A chopped beam was injected into the synchrotron and a beam study has been performed.A very short bunch was formed and accelerated to the top
energy.The behavior of the short bunch shows that a dipole oscillation was excited because of an unexpected frequency error of the RF system.It was caused by noise in the B-clock (Gauss Clock)circuit. The dipole oscillation caused by the frequency error was signi ficantly reduced and the acceleration efficiency was improved by replacing the B-clock module.
雑誌名
Nuclear Instruments & Methods in Physics Research Section A
Beam diagnostics using a chopped beam
