IPAC2017 - List of Authors (Ezura, E.)

Paper	Title	Page
THPAB115	Development of a Longitudinal Feedback System for Coupled Bunch Instabilities Caused by the Accelerating Mode at Superkekb	3989
	K. Hirosawa, K. Akai, E. Ezura, T. Kobayashi, K. Nakanishi, M. Nishiwaki, S.I. Yoshimoto KEK, Ibaraki, Japan
	SuperKEKB is an asymmetric energy electron-positron circular collider. Phase-I commissioning was operated from February to June in 2016. The purpose of this accelerator is to aim at the higher luminosity than KEKB, so a larger beam current is made for it. In the future plan, beam currents in the electron and positron rings will be increased to 2.6A and 3.6A, respectively. As we consider beam dynamics in the storage ring, higher mode instability associated with the accelerating mode will be caused by a large beam current. Especially the target instability of this study is called μ=-2 mode Coupled Bunch Instability. To suppress it, we developed new feedback components for longitudinal coupled bunch instability. We have same mechanism feedback components for KEKB, but it supports only μ=-1 mode instability. Since a large current makes μ=-1 mode instability big, there is a possibility that suppression is difficult only by using KEKB components. In order to deal with this problem, new components we developed support μ=-1, -2, and -3 mode instabilities, and we improved the performance and usability as compared to existing components. We schedule studies using a beam at Phase-II.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB115
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Paper

Title

Page

Development of a Longitudinal Feedback System for Coupled Bunch Instabilities Caused by the Accelerating Mode at Superkekb

3989

K. Hirosawa, K. Akai, E. Ezura, T. Kobayashi, K. Nakanishi, M. Nishiwaki, S.I. Yoshimoto
KEK, Ibaraki, Japan

SuperKEKB is an asymmetric energy electron-positron circular collider. Phase-I commissioning was operated from February to June in 2016. The purpose of this accelerator is to aim at the higher luminosity than KEKB, so a larger beam current is made for it. In the future plan, beam currents in the electron and positron rings will be increased to 2.6A and 3.6A, respectively. As we consider beam dynamics in the storage ring, higher mode instability associated with the accelerating mode will be caused by a large beam current. Especially the target instability of this study is called μ=-2 mode Coupled Bunch Instability. To suppress it, we developed new feedback components for longitudinal coupled bunch instability. We have same mechanism feedback components for KEKB, but it supports only μ=-1 mode instability. Since a large current makes μ=-1 mode instability big, there is a possibility that suppression is difficult only by using KEKB components. In order to deal with this problem, new components we developed support μ=-1, -2, and -3 mode instabilities, and we improved the performance and usability as compared to existing components. We schedule studies using a beam at Phase-II.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB115

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)