Integrated simulation of ground motion mitigation, techniques for the future compact linear collider (CLIC)

CLIC is a proposal of CERN for a future high-energy particle collider. CLIC will collide electron and positron beams at a centre of mass energy of 3 TeV with a desired peak luminosity of 2×1034 cm−2 s−1. The luminosity performance of CLIC is sensitive to ground motion. Ground motion misaligns accelerator components, most importantly quadrupole magnets, which leads to emittance growth and beam–beam offset at the interaction point. This paper discusses the beam based feedback strategies currently used together with mechanical stabilization systems to address the above mentioned issues. These strategies consist of an Interaction Point Feedback (IPFB) and an Orbit Feedback (OFB). The two feedbacks have been designed independently and the main objective of this paper is to show how they interact. A simulation program is used in order to simulate the whole collider, it includes the behaviour of the beams, magnets, supports, ground attenuators, sensors, and actuators. Beam-offset feedback optimization and integrated simulations have been performed and results show that despite a detrimental coupling of both feedbacks at high frequency, it is possible to decrease the beam–beam offset and maintain the desired luminosity.