title: Bunch-by-bunch position measurement and analysis at PLS-II.
abstract: A bunch-by-bunch measurement system has been developed at Pohang Light Source II. The system consists of a four-channel button pick-up, 20 GHz sampling oscilloscope and an 800 MHz low-pass digital filter. Upon measuring a bunch-by-bunch spatio-temporal beam motion matrix over many turns, singular-value decomposition analysis is used to reveal the dominant coupled-bunch modes. The system can diagnose injection oscillations due to kicker errors and the effect of resistive-wall impedance that gives rise to instability during operation.
authors.affiliation: Pohang Accelerator Laboratory, POSTECH, Pohang, Kyungbuk 37673, Republic of Korea.
authors.forename: Jaeyu
authors.initials: J
authors.lastname: Lee
authors.affiliation: Pohang Accelerator Laboratory, POSTECH, Pohang, Kyungbuk 37673, Republic of Korea.
authors.forename: M H
authors.initials: MH
authors.lastname: Chun
authors.affiliation: Pohang Accelerator Laboratory, POSTECH, Pohang, Kyungbuk 37673, Republic of Korea.
authors.forename: G J
authors.initials: GJ
authors.lastname: Kim
authors.affiliation: Pohang Accelerator Laboratory, POSTECH, Pohang, Kyungbuk 37673, Republic of Korea.
authors.forename: D C
authors.initials: DC
authors.lastname: Shin
authors.affiliation: Pohang Accelerator Laboratory, POSTECH, Pohang, Kyungbuk 37673, Republic of Korea.
authors.forename: D T
authors.initials: DT
authors.lastname: Kim
authors.affiliation: Pohang Accelerator Laboratory, POSTECH, Pohang, Kyungbuk 37673, Republic of Korea.
authors.forename: S
authors.initials: S
authors.lastname: Shin
keywords: bunch by bunch; instability; position