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Paper Title: Impedance Measurement at KEKB
Primary Author: T. Ieiri
Institution: KEK
Secondary Authors and Institutions: K. Akai, H. Fukuma, Y. Funakoshi and K. Ohmi
Working Groups RF & Feedback (including single beam instabilities)
The longitudinal and transverse impedance of KEKB has been evaluated by measuring bunch lengthening, a synchronous phase shift and a betatron tune shift in a single-bunch mode. The measured longitudinal impedance estimated from bunch lengthening was about five times larger than the design. This unexpected high impedance affected the transverse mode-coupling instability observed in the low-energy ring. We will also report multi-bunch effects of the measurement.