Successfully implemented in GEO and Virgo+, the monolithic suspensions are one of the most important upgrades in the second generation of gravitational wave interferometric detectors, including ...Advanced LIGO (aLIGO) and Advanced Virgo (AdV). Characterized by a very low thermal noise, monolithic suspensions are essential for improving the interferometers sensitivity at low frequencies (10-100Hz). In Advanced Virgo their installation was delayed because of a contamination problem in the vacuum system: dust produced by scroll pumps was injected in the main vacuum chambers during the venting processes, damaging the fibers and ultimately causing their repeated failure. The effort to explain and resolve this issue was useful to further confirm the suspensions' reliability and our control on the production process. Moreover, we developed and implemented new tools and procedures to certify each part of the monolithic suspensions. In the meanwhile, in order to join aLIGO during its second Observation Run (O2), a temporary steel suspension was implemented, based on the initial Virgo design. That solution allowed us to contribute to the first three-detector observation of a gravitational wave (GW) (1), and to the first observation of a coalescing neutron star binary (2) In the near future the monolithic suspensions will be reinstalled along with additional upgrades of Virgo.
Collective lattice dynamics determine essential aspects of condensed matter, such as elastic and thermal properties. These exhibit strong dependence on the length-scale, reflecting the marked ...wavevector dependence of lattice excitations. The extreme ultraviolet transient grating (EUV TG) approach has demonstrated the potential of accessing a wavevector range corresponding to the 10s of nm length-scale, representing a spatial scale of the highest relevance for fundamental physics and forefront technology, previously inaccessible by optical TG and other inelastic scattering methods. In this manuscript we report on the capabilities of this technique in the context of probing thermoelastic properties of matter, both in the bulk and at the surface, as well as discussing future developments and practical considerations.
The Advanced Virgo monolithic fused silica suspension Aisa, D.; Aisa, S.; Campeggi, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2016, Letnik:
824
Journal Article
Recenzirano
The detection of gravitational waves is one of the most challenging prospects faced by experimental physicists. Suspension thermal noise is an important noise source at operating frequencies between ...approximately 10 and 30Hz, and represents a limit to the sensitivity of the ground based interferometric gravitational wave detectors. Its effects can be reduced by minimizing the losses and by optimizing the geometry of the suspension fiber as well as its attachment system. In this proceeding we will describe the mirrors double stage monolithic suspension system to be used in the Advanced Virgo (AdV) detector. We also present the results of the thermal noise study, performed with the help of a finite elements model, taking into account the precise geometry of the fibers attachment systems on the suspension elements. We shall demonstrate the suitability of this suspension for installation in AdV.
•Suspension system design for the test masses of the gravitational wave detectors.•Finite element model studies.•Suspension thermal noise studies.
KAGRA is a 3-km interferometric gravitational wave telescope located in the Kamioka mine in Japan. It is the first km-class gravitational wave telescope constructed underground to reduce seismic ...noise, and the first km-class telescope to use cryogenic cooling of test masses to reduce thermal noise. The construction of the infrastructure to house the interferometer in the tunnel, and the initial phase operation of the interferometer with a simple 3-km Michelson configuration have been completed. The first cryogenic operation is expected in 2018, and the observing runs with a full interferometer are expected in 2020s. The basic interferometer configuration and the current status of KAGRA are described.
Each mirror of the interferometric gravitational wave antenna
Virgo is attached to a
Superattenuator, a chain of mechanical filters designed to suppress seismic vibrations, starting from a few Hz. ...The filter chain attenuation has been measured by exciting its suspension point with sinuisodal forces and using the interferometer as sensor. The attenuation, measured at different frequencies, is compliant with the requirements of the next generation antenna
Advanced Virgo. In the third generation detector
Einstein Telescope, the attenuation is sufficient above 3
Hz, independently of the underground site choice.
Precise low-frequency internal friction measurements on vitreous silica, taken over a wide temperature (4K < T < 300K) and frequency range (40 Hz < v < 14 kHz), show remarkable similarities, but also ...suggestive differences with recent light scattering experiments. In the interval 30K < T < 110K, the exponent a of the power law relaxational spectrum turns out to be proportional to T - Tk, with a minimum at around Tk = 13K. This phenomenon is interpreted as a manifestation of thermal activation in an asymmetric double well system, the asymmetry being associated to quenched spatial disorder. For T > 160 K the loss angle develops a distinct step-like structure followed by a plateau, both independent of v, thus signalling the onset of a competing relaxation mechanism with much higher an activation energy.
Low-frequency losses in silica glass at low temperature Travasso, F.; Bosi, L.; Dari, A. ...
Materials science & engineering. A, Structural materials : properties, microstructure and processing,
09/2009, Letnik:
521
Journal Article, Conference Proceeding
Recenzirano
Precise low-frequency internal friction measurements on vitreous silica, taken over a wide temperature (
4
K
<
T
<
300
K) and frequency range (40
Hz
<
ν
<
14
kHz), show remarkable similarities, but ...also suggestive differences with recent light-scattering experiments. In the interval
30
K
<
T
<
110
K, the exponent
α
(
T
)
of the power-law relaxational spectrum at low frequencies turns out to be proportional to
T
−
T
k
, with a minimum at around
T
k
=
13
K. This phenomenon is interpreted as a manifestation of quenched spatial disorder.
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