NLC linac feedback with ground motion

Beam-based feedback systems play an essential role in the operation of high energy electron-positron linear colliders. Ground motion, vibration and other disturbances can significantly alter the beam trajectory or degrade the beam quality. Feedback systems are required for long term stability and for ease and efficiency of operation. Trajectory feedback for the Next Linear Collider (NLC) has been studied extensively to understand both the achievable orbit quality and the time response characteristics. More recently, these studies have been extended to evaluate performance in the presence of ground motion.