Virgo Antenna in Càscina

The structure of the Virgo Antenna is now complete: an overall view is shown in the figure; the goal in sensitivity of the full Interferometer (a suspended Michelson with perpendicular arms constituted by two 3 km Fabry-Pérot resonant cavities) is represented below. A very sophisticated structure (the Superattenuator, a tower 10 m high) has been designed in order to suspend test masses (mirrors and beam-splitter). A power recycling cavity and a 144 m long Mode Cleaner guarantee a high power injection and a “pure” TEM00 for the beam generated by a 20 W Nd:Yag laser (l = 1064 nm). The Commissioning of the Central Interferometer (a suspended 6 m Michelson, without 3 km arms) is now ended: sensitivity reached during engineering runs is shown in the last figure.