Tests on a low-frequency inverted pendulum system

The authors report the performance and mechanical properties of an inverted pendulum as a vibration isolator. The advantages of such a system for vibration isolation in an interferometric gravitational wave detector is demonstrated through modelling of the isolator's response. An experimental investigation using a prototype inverted pendulum was also performed where the behaviour of the stability, resonant frequency and Q factor with varying load mass was examined. The pendulum was also used as a seismometer to examine low-frequency seismic activity.