Measurement of the VIRGO superattenuator performance for seismic noise suppression

Below a few tens of hertz interferometric detection of gravitational waves is masked by seismic vibrations of the optical components. In order to isol ate the mirrors of the VIRGO interferometer, a sophisticated suspension sys tem, called superattenuator, has been developed. Its working principle is b ased on a multistage pendulum acting on seismic vibrations as a chain of se cond order mechanical low-pass filters. A complete superattenuator has been built and tested. This apparatus allows extending the VIRGO detection band down to a few Hz. A detailed description of the attenuation system and its performance are presented in this article. (C) 2001 American Institute of Physics.