SVD-based filter design for the trajectory feedback of CLIC

The trajectory feedback of the Compact Linear Collider (CLIC) is an essential mitigation method for ground motion effects at CLIC. In this paper signicant improvements of the design of this feedback are presented. The new controller is based on a singular value decomposition (SVD) of the orbit response matrix to decouple the in- and outputs of the accelerator. For each decoupled channel one independent controller is designed by utilising ground motion and noise models. This new design allows a relaxation of the required resolution of the beam position monitor from 10 to 50 nm. At the same time the suppression of ground motion effects is improved. As a consequence, the tight tolerances for the allowable luminosity loss due to ground motion effects in CLIC can be met. The presented methods can be easily adapted to other accelerators in order to loosen sensor tolerances and to efciently suppress ground motion effects.