IMPACT OF SIMPLIFIED STATIONARY CAVITY BEAM LOADING ON THE LONGITUDINAL FEEDBACK SYSTEM FOR SIS100 *

Abstract The main synchrotron SIS100 of the Facility for Antiproton and Ion Research (FAIR) will be equipped with a bunchby-bunch feedback system to damp longitudinal beam oscillations. In the basic layout, one three-tap finite impulse response (FIR) filter will be used for each single bunch and oscillation mode. The detected oscillations are used to generate a correction voltage in dedicated broadband radio frequency (RF) cavities. The digital filter is completely described by two parameters, the feedback gain and the passband center frequency, which have to be defined depending on the longitudinal beam dynamics. In earlier works BEAM LOADING were chosen in quadrature with the first harmonic of the beam current as sketched i