The VIRGO antenna for gravitational wave detection is a very sensitive interferometer. All the noise sources are very low and continuously monitored by a complex monitoring system. This is a modular ...system whose architecture has been designed to guarantee the fulfillment of present and future VIRGO needs. Particular care has been devoted both to the management of probes different in type, sensitivity, and bandwidth distributed along the whole antenna and to the system integration within the main VIRGO data acquisition system architecture. The goal of this system is not only a distributed synchronous acquisition, hut also an on-line pre-analysis of environmental quantities necessary to implement a real-time data quality control. (Author)
A numerical procedure for noise uncoupling is described. The procedure is applied to a Michelson interferometer and is effective in seismic and acoustic noise uncoupling from the output signal of the ...interferometer. Due to the low data flow coming from the instrumentation, this uncoupling can be performed in real time.
The VIRGO antenna for gravitational wave detection is a very sensitive interferometer. All the noise sources are very low and continuously monitored by a complex monitoring system. This is a modular ...system whose architecture has been designed to guarantee the fulfillment of present and future VIRGO needs. Particular care has been devoted both to the management of probes different in type, sensitivity, and bandwidth distributed along the whole antenna and to the system integration within the main VIRGO data acquisition system architecture. The goal of this system is not only distributed synchronous acquisition, but also an on-line pre-analysis of environmental quantities necessary to implement a real-time data quality control.
The gravitational wave detector VIRGO aims at extending the detection band down to a few Hertz by isolating the mirrors of the interferometer from seismic noise. This result is achieved by hanging ...each mirror through an elastic suspension (Superattenuator), designed to filter mechanical vibrations in all the degrees of freedom. An experimental upper limit of the mirror residual seismic noise at a few Hertz is provided in this paper. This is lower than the thermal noise floor, expected to limit the antenna sensitivity in the low frequency range.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Virgo is a laser Michelson interferometer with 3-km long Fabry-Perot in the arms, aiming at the detection of gravitational waves emitted by astrophysical sources in the frequency band from 10 Hz to ...few kHz. The core of the detector, the central interferometer, was installed first. It is a recycled Michelson interferometer, with 6-m long arms, obtained by replacing the 3-km long Fabry- Perot cavities with high reflectivity mirrors and using the same components designed for Virgo. In particular all the mirrors of the interferometer are suspended from the seismic isolators that represent the main unique characteristic of the Virgo detector. The interferometer has been controlled by means of a fully digital control system, capable of monitoring and controlling the relative position of the mirrors with an accuracy of 10 exp -12 m. The best displacement sensitivity was 10 exp -13 m/sq rt Hz at 10 Hz and 8 x 10 exp -17 m/sq rt Hz above 1 kHz. This article describes the detector configuration, the tests performed in view of commissioning the full detector and the main results obtained.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We present the lock acquisition algorithm used for the central interferometer of the gravitational wave detector Virgo (CITF). The CITF was a preliminary step in the construction of the Virgo ...detector, which allowed to test the main components of the instrument. The problems related to the lock acquisition are discussed, together with the key points of the algorithm. Computer simulation in the time domain of the detector was crucial to develop and test the algorithm. A comparison between simulation of the lock acquisition and the corresponding experimental results is shown.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The analysis of data coming from interferometric antennas for gravitational
waves detection may require a huge amount of computing power. The usual
approach to the detection strategy is to set-up ...computer farms able to perform
several tasks in parallel, exchanging data through network links. In this paper
a new computation strategy is presented. This strategy is based on the GRID
environment that allows several geographically distributed computing resources
to exchange data and programs in secure way, using standard infrastructures.
The computing resources can be geographically distributed also on a large
scale. Some preliminary tests were performed using a subnetwork of the GRID
infrastructure, producing good results in terms of distribution efficiency and
time duration.
