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Yoshimura, Nobuyuki*; Toyama, Takeshi*; Shobuda, Yoshihiro; Nakamura, Takeshi*; Omi, Kazuhito*; Kobayashi, Aine*; Okada, Masashi*; Sato, Yoichi*; Nakaya, Tsuyoshi*
Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.260 - 264, 2023/11
The J-PARC main ring (MR) will be increased to 1.3 MW. To cope with the increase in beam intensity, the intra-bunch feedback system (IBFB) needs to be upgraded to handle higher frequencies up to about 200 MHz. To evaluate the performance and understand the optimal parameters after this upgrade, we are developing a particle tracking simulation that includes the necessary components. The recoherence period induced by chromaticity between tracking simulations and experiments are compared and it cannot be discribed by the simple simulations, and we investigate what mechanisms explain this result. The shift of synchrotron tune caused by longitudinal wakes using tracking simulations are calculated and it find that introducing the effect of longitudinal wakes only does not explain the recoherence period in the experimental results.
Shobuda, Yoshihiro; Chin, Y. H.*; Omi, Kazuhito*; Toyama, Takeshi*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.1898 - 1900, 2005/00
At 3GeV RCS(Rapid Cycle Synchrotron) in J-PARC, the ceramic chamber is adopted to aviod the excess eddy current. This ceramic chamber is surrounded by Cu-stripes to supress the leak field caused by the beam. The inner surface of the chamber is coated with TiN to suppress the secondary electron emission. In order to discuss the beam instability, we have to calculate the impedance for this chamber. Previously, the impedance was calculated by replacing the Cu-stripes to the conducting beam pipe. In this paper we deal with Cu-stripes realistically, and compare the results with the previous results. The resistivity of Cu-stripes and the TiN are also considered.
