Bunch by bunch feedback systems for the KEKB rings

Transverse bunch-by-bunch feedback systems for damping coupled-bunch instabilities in the KEKB rings have been working since the early stages of the commissioning of the rings. Stabilization of the beams with the system has been successful, permitting tests of higher beam currents and various filling patterns. The performance of these systems has been demonstrated under the normal physics run pattern of an 8 ns bunch spacing over long-term operation, and also under special filling patterns with a minimum bunch spacing of 2 ns.