A broadband bunch-by-bunch feedback system has been developed for the longitudinal, the vertical and the horizontal plane to combat coupled bunch instabilities. Our initial motivation was to allow ramping of the stored current up to 300 mA. To achieve this goal, a longitudinal feedback (LFB) system is required to damp longitudinal oscillations caused by the interaction of the beam with the higher order modes (HOM) of the accelerating radio frequency (RF) cavities.

The transverse feedback system (TFB) uses similar processing and was therefore easily derived from the LFB. It will damp horizontal and vertical instabilities arising from the interaction of the beam with the resistive wall impedance of the vacuum chamber and with the ions remaining in the UHV system. This damping will allow operation at reduced chromaticity, i.e. with relaxed sextupole settings. It is expected to provide a larger dynamical aperture of the lattice and a corresponding longer lifetime.