HEADTAIL Feedback Module: Implementation and Results

A feedback module has been implemented in the HEADTAIL simulation code in order to investigate the feasibility of a transverse feedback system to damp the electron cloud instability. This instability provokes vertical oscillations within a bunch in the SPS when operated at and above nominal LHC beam current and 25 ns bunch spacing. In the present report the feedback module is described and applied to the case of the SPS at 55 GeV/c, previously identified as worst case energy for the LHC type beams in the SPS in terms of electron cloud instability. The numerical simulations show that a feedback system operating up to 500 MHz with a normalized gain of 0.16 can damp the instability. In contrast, a feedback system only acting on the rigid dipole bunch oscillation cannot cure the high frequency content of the motion.