ACQUISITION DE DONNEES ET SURVEILLANCE EN LIGNE DU DETECTEUR D'ONDES GRAVITATIONNELLES VIRGO

摘要

This document presents mainly my works in the Virgo experiment that search for gravitational waves.Nevertheless, I recall in a short introduction my activities in the NOMAD experiment and I outline,in a first chapter, the status of the detection of neutrinos. Then, I describe at chapter 2the status of the gravitational waves interferometric detection. The third chapter,describing the Virgo experiment, is followed by three chapters describing the domainswhere I have contributed mostly to the experiment: the data acquisition system,the online detector monitoring and the search for glitches in the data. Finally,a last chapter, more general, makes an overview of my outreach activities tothe citizens and to the scholars.Virgo is a 3 km long interferometer aiming at the detection of gravitational wavesfrom astrophysical sources. Those waves are space-time deformations, consequence ofthe General Relativity theory. Arriving on Earth, they make tiny modifications of distancesthat can be theoretically detectable by interferometry.I have contributed to the construction and commissioning of the Virgo interferometer,since 1997, by participating to the conception, realization and improvements of thedata acquisition system. I have more particularly created the data collector and I haveheavily contributed to the development of the library that manages the data transferunder frame format in the data acquisition chain. This library has provided a greatflexibility of the data acquisition and online processing architectures, all alongthe detector's commissioning The data acquisition currently sustains a data rate ofabout 20 MBytes/s (8 MBytes/s after data compression) with a mean latency of 2 secondsand a data loss below 0.3%.I have also created a software, the dataDisplay that allows to read the data onlineor offline, to visualize various types of plots (time plots, spectra, coherence,transfer function, distributions 1D or 2D, spectrograms, etc...) and to listen to the data.This software uses a graphical interface based on Xforms and a visualisation based onthe Root library developed at CERN. The dataDisplay is now used as a standard toolby the Virgo collaboration, from control roomfor online detector monitoring or offline for the analysis of the recorded data.In addition, I strongly participate to the data qualification, in particular by providingthe software tools that allow to configure easily the algorithms that monitor online thedetector and its environment. Moreover, I contribute to the search for glitches in theinterferometer's signals and I have the responsibility to put online the algorithms thatstudy the detector's noise. This work is motivated by the fact that the understanding ofthe interferometer is mandatory before any gravitational waves search.Finally, since several years, I interested in outreach activities and, from 2002 to 2007,I have been in charge of communication at LAPP. In this scope, I made contacts with schools,associations and municipalities in order to promote the curiosity for sciences and thescientific method. By several means (conferences at secondary schools, visits organizedat LAPP and based on a permanent exposition, public conferences, participations tolaboratory Open Doors, creation of web pages), I have tried to excite the interest of youngpublic to sciences, to make understand what is scientific research and to show what are itslinks with the everyday life.