A study of the longitudinal coupled bunch instability in the Fermilab Main Ring

Longitudinal synchrotron oscillations of proton bunches in the Fermilab Main Ring have been observed during various portions of the acceleration cycle. These oscillations have an effect upon the ability to coalesce 11 proton bunches into one bucket for subsequent transfer into the Tevatron. The oscillations appear to be caused by a longitudinal coupled bunch instability. We report measurements made to characterize the instability as well as design of a narrow-band feedback system.