Summary of coupling and tune feedback results during RHIC run 6, and possible implications for LHC commissioning

Early efforts to implement tune feedback during the acceleration ramp in RHIC were hampered by large betatron coupling, as well as the requirement for large dynamic range. Both problems have been addressed, the first by implementation of continuous measurement of coupling, and the second by the development of an improved analog front end. With these improvements, simultaneous coupling and tune feedback were successfully implemented for acceleration ramp development during RHIC Run 6. During the course of this work it became clear that direct excitation of the betatron resonances by high harmonics of the 60Hz power frequency was an obstacle to making the system fully operational. We report here on these results from RHIC Run 6, and implications for LHC commissioning