Orateur
Description
Among the noises affecting gravitational wave detectors, Newtonian Noise results from variations in the gravity field induced by fluctuations of the mass distribution in the vicinity of sensitive optical elements, in particular test masses. This paper focuses on the modeling of Newtonian Noise of acoustic origin, i.e. resulting from the presence of an infrasound acoustic field in experimental rooms.
The study shows that acoustic noise in the NEB and WEB terminal buildings of the Virgo detector is mainly generated by the air-conditioning system. The acoustic field in these buildings, simulated by a finite element code, exhibits modal behavior in the frequency range studied [0-30Hz], which is validated by direct measurement using an antenna of infrasound microphones.
The resulting Newtonian Noise is estimated and compared with the sensitivity level of Advanced Virgo. The possibilities of limiting this noise by controlling the acoustic level are explored, in particular by estimating the effect of adding acoustic absorbing material, the effect of reducing the fan rotation speed, and the effect of modifying the position of the air injection and suction points.
