A Longitudinal Feedback System for SIS100

High intensity operation as planned for the synchrotron SIS100 is expected to lead to ion bunch oscillations in longitudinal phase space that must actively be damped [1]. Therefore a longitudinal feedback system has to be designed that is faster than Landau damping and copes with the expected growth rates of instabilities. One task of this feedback system is the damping of quadrupole oscillation modes. A more detailed description about the damping of these modes can be found in [2, 3]. Simulations [2, 4] with ESME [5] and a machine development experiment at SIS12/18 [6] have shown that quadrupole oscillations which are detectable by beam current amplitude measurements in time domain can be excited and damped by RF voltage amplitude modulations. Based on these specific results, a general closedloop control system was designed. The principle layout can be seen in Figure 1.