Author/Authors :
Beccaria، نويسنده , , M. and Bernardini، نويسنده , , M. and Bougleux، نويسنده , , E. and Braccini، نويسنده , , S. and Bradaschia، نويسنده , , C. and Casciano، نويسنده , , C. and Cella، نويسنده , , G. and Cuoco، نويسنده , , E. and DʹAmbrosio، نويسنده , , E. and De Carolis، نويسنده , , G. and Del Fabbro، نويسنده , , R. and De Salvo، نويسنده , , R. and Di Virgilio، نويسنده , , Rocco A. and Ferrante، نويسنده , , I. and Fidecaro، نويسنده ,
Abstract :
The detection band of the interferometric gravitational wave detector VIRGO can be extended down to a few Hz by suspending each optical component of the interferometer from a chain of mechanical filters designed to suppress the transmission of seismic vibrations. Each mechanical filter supports the weight of the stages below it through a set of cantilevered blade springs. A system of permanent magnets, providing an “antispring” force, helps to reduce the highest vertical resonance of the chain from 7 Hz to about 2 Hz. This improvement allows VIRGO to reduce the frequency detection threshold from 10 Hz to about 4 Hz. A characterization of the mechanical filters is provided in this paper.
