2006 Fiscal Year Final Research Report Summary
Stabilization of high intensity beam by higher harmonic cavity in electron synchrotron
| Project/Area Number |
16560040
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied physics, general
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| Research Institution | Tohoku University |
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Principal Investigator |
HINODE Fujio Tohoku University, Graduate School of Science, Assistant Professor (60292207)
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| Co-Investigator(Kenkyū-buntansha) |
HAMA Hiroyuki Tohoku university, Graduate School of Science, Professor (70198795)
KAWAI Masayuki Tohoku university, Graduate School of Science, Associate Professor (60374899)
MUTO Toshiya Tohoku university, Graduate School of Science, Research Physicist (10431496)
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| Project Period (FY) |
2004 – 2006
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| Keywords | electron synchrotron / harmonic cavity / RF |
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| Research Abstract |
A 1.2 GeV Stretcher-Booster (STB) ring at Laboratory of Nuclear Science(LNS), Tohoku University, has been mainly operated for experiments of nuclear physics. The STB is not the light source ring but also has storage ring-like function. One of the many issues limiting performance of the STB ring is supposed to be strong longitudinal coupled-bunch instability. Actually very strong synchrotron oscillation signal have been observed around 3.6 GHz with a threshold current of about 10 mA. In order to suppress the instability, applicability of a third-harmonic Landau cavity has been studied.
For the full energy operation, analytic modeling and simulations were first performed. The results show that if three harmonic cavities are used, near-optimal bunch-lengthening may be obtained at the maximum ring current of 100 mA. For injection energy of 200 MeV, almost same analysis were performed and showed that increased energy spread from the instability or lost macro-particles occurred for nearly all currents and tuning angles. Although the simulation study indicates that more cavities are required to suppress the instability, one harmonic cavity was manufactured and tested in the STB as the first step of the study. The very strong synchrotron oscillation signal due to the coupled-bunch instability was drastically damped by the harmonic cavity at a specific tuning angle. However, it is not considered that this suppression is due to the usual Landau damping, since a significant voltage is never excited in the harmonic cavity because of the large tuning angle. A tracking simulation using rigid-bunch model was performed to understand this situation. The result showed that a higher order mode of harmonic cavity can suppress the instability. For the lower energy operation, the effect of harmonic cavity might be also interesting, but no obvious improvement has been seen yet. Toward the future development, a study of the harmonic cavity in acceleration process will be also progressed.
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Research Products
(8 results)
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[Journal Article] A Study on the Applicability of Landau Cavity to the 1. 2 GeV Booster Synchrotron at Tohoku University2007
Author(s)
F. Hinode, K. Akiyama, H. Kama, M. Kawai, K. Kasamsook, A. Kurihara, T. Muto, K. Nanbu, Y. Shibasaki, S. Takahashi, T. Tanaka, M. Yasuda
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Journal Title
Proceedings of APAC 2007, Indore, India
Pages: 375-377
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] OPERATION STATUS OF LNS ACCELERATOR AND DEVELOPMENT2006
Author(s)
M. Kawai, F. Hinode, A. Kurihara, S. Takahashi, Y. Shibasaki, K. Nanbu, T. Mutou, T. Tanaka, K. Kasamsook, K. Akiyama, M. Yasuda, H. Hama
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Journal Title
Proceedings annual meeting of Particle Accelerator Society of Japan No.3, Sendai
Pages: 284-286
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Current status of a 1. 2 GeV STB ring at Tohoku University2004
Author(s)
F. Hinode, H. Hama, M. Kawai, A. Kurihara, A.Miyamoto, M. Muto, M. Nanao, Y. Noguchi, Y. Shibasaki, K. Shinto, S. Takahashi, T. Tanaka
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Journal Title
Proceedings annual meeting of Particle Accelerator Society of Japan No.1, Funabashi
Pages: 206-208
Description
「研究成果報告書概要(欧文)」より
