Fuzzy controller for beam stabilization in a heavy-ion synchrotron

In this paper a fuzzy controller is presented which guides a disturbed particle beam in a heavy-ion synchrotron back to the stable fixed point and thus prevents undesired longitudinal beam oscillations. The advantage over common control systems which only provide additional damping of the beam oscillations is the minimal increase of the rms beam emittance. The decision making of the controller depends on the position of the barycenter of the bunch in phase space which consists of the phase slip to the accelerating gap voltage and the energy deviation to the reference particle. As only the phase slip can be measured it is shown how the energy deviation can be obtained by differentiating the phase slip with a robust sliding mode differentiator as developed by Levant [8]. The performance of the proposed fuzzy controller is demonstrated by macro particle simulations.