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. |