Vibration Isolation System for Mirrors

Abstract

  Interferometer gravitational wave detectors consist of high quality mirrors, which should be isolated from ground vibration strongly. The vibration isolation system needs not only attenuation more than 10⁹ at 100 Hz but also reduction of root mean square motion of the mirrors. Many kinds of mechanisms for isolation at low frequencies have been suggested for gravitational wave detectors. We employed an inverted pendulum and geometric anti-spring filters as the isolator in Large-scale Cryogenic Gravitational wave Telescope (LCGT).