NORMAL-MODE SUPPRESSION IN ALL METAL CANTILEVER VIBRATION ISOLATORS

An all metal multi-stage low frequency vibration isolator for a laser interferometer gravitational wave detector has been built and tested. Curved cantilever springs are used to form a low frequency compact for m of isolation element. The system has many modes with moderately high Q factors which require damping. We describe here the successful damp ing of normal modes in all relevant degrees of freedom in an isolator with cutoff frequency less than 10 Hz. Measurements show no added nois e above the control bandwidth.