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https://doi.org/10.18429/JACoW-IPAC2017-THPAB115
Title Development of a Longitudinal Feedback System for Coupled Bunch Instabilities Caused by the Accelerating Mode at Superkekb
Authors
  • K. Hirosawa, K. Akai, E. Ezura, T. Kobayashi, K. Nakanishi, M. Nishiwakipresenter, S.I. Yoshimoto
    KEK, Ibaraki, Japan
Abstract 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.
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Conference IPAC2017, Copenhagen, Denmark
Series International Particle Accelerator Conference (8th)
Proceedings Link to full IPAC2017 Proccedings
Session Posters Thursday 1
Date 18-May-17   16:00–18:00
Main Classification 06 Beam Instrumentation, Controls, Feedback and Operational Aspects
Sub Classification T27 Low Level RF
Keywords cavity, impedance, operation, damping, target
Publisher JACoW, Geneva, Switzerland
Editors Volker RW Schaa (GSI, Darmstadt, Germany); Gianluigi Arduini (CERN, Geneva, Switzerland); Juliana Pranke (ESS, Lund, Sweden); Mike Seidel (PSI, Villigen, Switzerland); Mats Lindroos (ESS, Lund, Sweden)
ISBN 978-3-95450-182-3
Published May 2017
Copyright
Copyright © 2017 by JACoW, Geneva, Switzerland     CC-BY Creative Commons License
cc Creative Commons Attribution 3.0