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

Hirosawa, Kouki; Akai, Kazunori; Ezura, Eizi; Kobayashi, Tetsuya; Nakanishi, Kota; Nishiwaki, Michiru; Yoshimoto, Shin-ichi

doi:10.18429/JACoW-IPAC2017-THPAB115

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RIS citation export for THPAB115: Development of a Longitudinal Feedback System for Coupled Bunch Instabilities Caused by the Accelerating Mode at Superkekb

TY - CONF
AU - Hirosawa, K.
AU - Akai, K.
AU - Ezura, E.
AU - Kobayashi, T.
AU - Nakanishi, K.
AU - Nishiwaki, M.
AU - Yoshimoto, S.I.
ED - Schaa, Volker RW
ED - Arduini, Gianluigi
ED - Pranke, Juliana
ED - Seidel, Mike
ED - Lindroos, Mats
TI - Development of a Longitudinal Feedback System for Coupled Bunch Instabilities Caused by the Accelerating Mode at Superkekb
J2 - Proc. of IPAC2017, Copenhagen, Denmark, 14â19 May, 2017
C1 - Copenhagen, Denmark
T2 - International Particle Accelerator Conference
T3 - 8
LA - english
AB - 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.
PB - JACoW
CP - Geneva, Switzerland
SP - 3989
EP - 3991
KW - cavity
KW - impedance
KW - operation
KW - damping
KW - target
DA - 2017/05
PY - 2017
SN - 978-3-95450-182-3
DO - 10.18429/JACoW-IPAC2017-THPAB115
UR - http://jacow.org/ipac2017/papers/thpab115.pdf
ER -