1,734,757 research outputs found
Virgo an interferometer for gravitational wave detection
No full textGravitational waves propagating from rapidly accelerating star masses can be detected by means of interferometric techniques. The Virgo detector is a Michelson interferometer, with two 3 km long Fabry-Perot cavities, that is going to be built in the countryside of Pisa (Italy). Principles of interferometric gravitational wave detection, and the main noise sources in the Virgo apparatus are treated. The Virgo optical scheme and its main components are also described. Finally, an overview on the status of works at the Virgo site is presented. © 2000 by the American College of Cardiology
The VIRGO experiment
No full textThe status of the VIRGO experiment, as of summer 2000 is presented: we report on the progress in the construction and the next steps are briefly illustrated
The VIRGO suspensions
No full textThe VIRGO suspensions are chains of passive mechanical filters designed to isolate the interferometer mirrors from seismic noise starting from a few Hz. In order to reduce the low-frequency swing of the mirror along the beam, an active control system, acting at the level of the suspension point, damps the main resonant modes of the system (all below 2.5 Hz). Another control loop, at the level of the optical payload, makes use of a digital camera monitoring the mirror position in all six degrees of freedom. Its main goal is to decrease the rms angular displacements of the mirror, on a time scale of several minutes, down to less than I murad. All the seven suspensions of the VIRGO central interferometer are presently in operation, while the assembly of the last two, for the terminal mirrors, is in progress, The design and performance of the system are described in this paper
Interferometer signal detection system for the VIRGO experiment
No full textVIRGO is a laser interferometer aiming at the first detection of gravitational waves emitted by astrophysical sources. The signal detection system consists of all the output optics and the electronics necessary for the measurement of the interferometer output signal. An output mode cleaner has been developed in this context. The system has been installed at the detector site and is now being used for the central interferometer, the first step in the construction of VIRGO. The first results obtained so far are presented
Status of Virgo
No full textIn this paper, we present the status of the VIRGO interferometer, the French–
Italian gravitational wave detector. During the last two years the construction
of the apparatus has been completed. At the same time, the commissioning
of the detector central part, the VIRGO central interferometer, has been used
to test all the technical solutions and in particular the most original part: the
seismic isolation system. In the next few months the commissioning of the
whole detector will start with the alignment and the locking of one of the two
3 km long Fabry–Perot cavities
Sensing and control in Virgo experiment
No full textThe gravitational wave detector Virgo is presently under commissioning. A large part of the last year has been spent for control activities, such as the longitudinal locking. This work has been carried out with steps of increasing complexity: locking a simple Fabry-Perot cavity, then a Michelson interferometer with Fabry-Perot cavities in both arms, and finally recycling the light beam into the interferometer
Calibration of the VIRGO central interferometer
No full textThis paper describes the calibration procedures developed for the commissioning of the VIRGO central interferometer, as well as their main results obtained during the engineering runs that occurred during that phase. The issue of the detector response monitoring is also addressed, and a preliminary test to produce reconstructed data is reported
Interferometer signal detection system for the VIRGO experiment
No full textVIRGO is a laser interferometer aiming at the first detection of gravitational waves emitted by astrophysical sources. The signal detection system consists of all the output optics and the electronics necessary for the measurement of the interferometer output signal. An output mode cleaner has been developed in this context. The system has been installed at the detector site and is now being used for the central interferometer, the first step in the construction of VIRGO. The first results obtained so far are presented
Advanced Virgo+ status and future perspectives
No full textThe Virgo detector contributed to the observations in the O3 observing run and increased its sensitivity from the
initial 46 up to 60 Mpc during the run. The detector has undergone to a series of improvements since the end of
the O3 observing run in view of O4, as the implementation of an additional recycling cavity at the output of the
interferometer – the Signal Recycling cavity (SRC) – to broaden the sensitivity band, the Frequency Dependent
Squeezing (FDS) to reduce quantum noise at all frequencies, and a new higher power laser.
Some criticality have emerged mainly due to the presence in Virgo of marginally stable recycling cavities with
respect to the stable recycling cavities present in the LIGO detectors, which increases the difficulty in controlling
the interferometer in presence of defects as those introduced by the high power on the mirrors. This resulted
in a delayed joining the O4 run due to a longer than expected commissioning phase. At present the detector is
running with a lower laser power (and a lower sensitivity w.r.t. the project design).
A new stop of about 2 yr is planned between O4 and O5 starting in 2027, to implement new upgrades (phase
II). To improve the stability of the interferometer, we are considering a large upgrade to introduce stable cavities
and this will imply heavy infrastructural works also with the minimal design. The aim is to reach a Binary
Neutron Star (BNS) sensitivity larger than 100 Mpc.
Plans are being made for the post-O5 period as a bridge between 2nd and 3rd generation detectors and a new
collaborative effort has born under the name of Virgo nEXT with the aim to keep and push the infrastructure
and maintain alive the communit
The monolithic suspension for the Virgo interferometer
No full textMonolithic fused silica suspensions are needed to reduce the suspension thermal noise level in future, ground-based gravitational wave 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 behavior 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. © 2010 IOP Publishing Ltd
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