@article{oai:repo.qst.go.jp:00043704,
 author = {Ohmori, Chihiro and Kanazawa, Mitsutaka and Noda, Kouji and Uesugi, Tomonori and Shirakabe, Yoshihisa and Sugiura, Akinori and Mori, Yoshiharu and Mutou, Suguru and 金澤 光隆 and 野田 耕司 and 上杉 智教 and 白壁 義久 and 杉浦 彰則 and 森 義治 and 武藤 豪},
 journal = {Nuclear Instruments & Methods in Physics Research Section A},
 month = {Jul},
 note = {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.},
 pages = {215--221},
 title = {Beam diagnostics using a chopped beam},
 volume = {526},
 year = {2004}
}