BUNCH-BY-BUNCH ONLINE DIAGNOSTICS AT HLS*

The design goal for the bunch-by-bunch analogue transverse feedback system at the Hefei Light Source (HLS) is to cure the transverse coupled bunch instabilities. The prototype implemented bunch-by-bunch feedback in 2006. Then we changed the circuit and replaced some components by ones of higher performance in order to get better effect. Diagnostic techniques are important tools to determine instabilities and to confirm the performance of the feedback systems. In addition to transverse feedback this system can provide online beam diagnostics and analysis in transverse and longitudinal directions. The diagnostic functions can record the response of every bunch while the feedback system manipulates the beam. The experimental results are presented