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MPPE005 |
Dynamic Aperture and Resonance Correction for JPARC-RCS
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979 |
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- A.Y. Molodojentsev, E. Forest, S. Machida
KEK, Ibaraki
- H. Hotchi, F. Noda, M.J. Shirakata, Y. Shobuda, H. Suzuki, K. Yamamoto
JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- Y. Ishi
Mitsubishi Electric Corp, Energy & Public Infrastructure Systems Center, Kobe
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Main intrinsic field nonlinearities, which are common for synchrotrons with large aperture, are the nonlinear field of the bending magnets, the fringing field of the magnets and the sextupole field nonlinearity, used for the chromaticity correction. The particle motion in the ring bending magnets has been analyzed by two methods: (1) by direct integration of the particle motion equations in the 3D magnetic field (Tosca output), based on the 4th order Runge-Kutta integrator and (2) by determination the transfer 8th order map of the bending magnet by using the Gaussian wavelet in the 3D space. The second technique allows us to use powerful tools such as the normal form analysis, to define the resonance driving terms, which can be used for the resonance correction. As the result of this study it was shown that the main limitation of the RCS dynamic aperture can be caused by the structure normal sextupole-order resonance and the normal octupole-order resonance. Other high-order resonances have smaller effects on the particles motion than the resonances mentioned above. The correction scheme to improve the dynamic aperture near the normal sextupole-order resonance has been analyzed.
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WPAT008 |
Recent Status of RF Source in J-PARC Linac
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1123 |
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- E. Chishiro, T. Hori, H. Suzuki, M. Yamazaki
JAERI, Ibaraki-ken
- S. Anami, S. Fukuda, Y. Fukui, M. Kawamura, S. Yamaguchi, M. Yoshida
KEK, Ibaraki
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The construction of the J-PARC (Japan Proton Accelerator Research Complex) linac is under going. RF sources for the low beta linac section use 324-MHz klystrons and after the evaluation of seven prototype tubes, mass production of 20 tubes are conducted. These will be installed in the linac building from April 2005. Performances of the 324-MHz klystrons are described in this paper. The prototype klystron of 972-MHz klystron, which is planed to be installed in high beta linac section, oscillated strongly without any drive rf power, and it had been investigated to solve it. Though it was doubted to be a diode oscillation at first, recent experiment showed the drift-tube oscillation and we succeeded in stopping oscillation by deforming the integrated cavity and detuning. After this experiment, we built a new tube and started to test it. This experiment is written in this paper. Other status of construction related to the rf sources is also shown in this paper.
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TPPT049 |
Design and Cold Model Test of 500MHz Damped Cavity for ASP Storage Ring RF System
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3076 |
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- J. Watanabe, K. Nakayama, K. S. Sato, H. Suzuki
Toshiba, Yokohama
- M. Izawa
KEK, Ibaraki
- A. Jackson, G. LeBlanc, K. Zingre
ASP, Clayton, Victoria
- T. Koseki
RIKEN/RARF/CC, Saitama
- N. Nakamura, H. Sakai, H. Takaki
ISSP/SRL, Chiba
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TOSHIBA is constructing the storage ring RF system for the Australian Synchrotron Project(ASP). Two pairs of the 500MHz Higher Order Mode(HOM) damped cavities will be applied for this system. The cavities are modified KEK-PF type with silicon-carbide(SiC) microwave absorber and added three HOM anttenas for damping the longitudinal HOM impedance less than 20kOhm/GHz to meet requirement of ASP specification. The shunt impedance has been improved more than 5% in comparison with the original design by reducing the beam bore diameter without degrading HOM damping capability. The design of the cavity and the test results of an Al cold model are described.
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