Three-stage low-frequency seismic noise active damping system with a quasi-fixed reference system for gravitational wave detection

Abstract The performance of a three-stage seismic noise active damping system with a quasi-fixed reference system is described, and the experimental result of active damping of a single-stage isolation system showed that the vertical normal mode of the system was suppressed from 3×10 −8 m √ Hz down to 2×10 −9 m √ Hz without introducing the high-frequency ground vibrations.