The monolithic suspension for the Virgo interferometer

Abstract fused silica suspensions are needed to reduce the suspension thermal noise level in future, ground-based gravitational waves interferometric detectors. We present the status of the monolithic suspension system which will be employed for the test masses of the Virgo+ detector. Two fully monolithic suspensions have been realized using a spare Virgo mirror, so the assembling pipeline was checked ; moreover, a very reliable recovery procedure was developed, to allow an efficient and fast (about a week) suspension repairing in case of wires failure. The performances of a full scale prototype of the last suspension stage, suspending an aluminum dummy mass, were tested and the mechanical behaviour of the suspension is currently studied in vacuum. The obtained results, crucial to finalize the design of the silica suspension elements for the advanced version of the interferometer, are reported.