support system

A simple simulation shows that a support tube is enough to stabilize relative positions of the final focus magnets at both sides of electron and positron beams with an input ground motion measured at TRISTAN-Fuji experimental hall[4]. For NLC, additional "optical anchor" is considered, which is based on laser interferometer grounded on bed rock. SLD vibration was measured to be 30-50nm at f>1Hz. The laser interferometer can measure 1nm vertical oscillation of quadrupole magnets.