Speaker
Description
For ground-based GW detectors, seismic vibration is the dominating source
of noise in low frequency region (0.1 to 10 Hz), limiting both sensitivity
and duty cycle. Thanks to high performant suspension systems, like the
Virgo Superattenuator, the presently operational 2nd generation advanced
GW antennas have extended their detection band down to 10 Hz. The plan for
future 3rd generation detectors, like the Einstein Telescope (ET) aim to
further extend the detection band down to 2-3 Hz. This requires,
underground locations, where seismic noise is about 100 time smaller than
on surface, together to other technological improvements like cryogenic
payloads
and reduced thermal noise. Anyway to achieve the attenuation value of
10^-18m/sqrt(Hz) at few Hz, the suspensions of the optical components must
be upgraded with respect to the 2nd generation ones, in order to improve
seismic attenuation in low frequency and reduce as far as possible
the frequency of mechanical resonances below the detection band. In this
poster, preliminary studies and performances of a seismic isolation system
adopting a nested, double inverted pendulum will be presented. Residual
motion of the test mass, calculated by combining the transfer function and
seismic noise measured at Sos-Enattos site, will be compared with respect
the nominal ET’s sensitivity curve for evaluating benefits, limits and
technological challenges connected to the development of this system,and
define requirements for control strategies.
