Abstract : 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 2
the status of the gravitational waves interferometric detection. The third chapter,
describing the Virgo experiment, is followed by three chapters describing the domains
where 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 to
the citizens and to the scholars.
Virgo is a 3 km long interferometer aiming at the detection of gravitational waves
from astrophysical sources. Those waves are space-time deformations, consequence of
the General Relativity theory. Arriving on Earth, they make tiny modifications of distances
that 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 the
data acquisition system. I have more particularly created the data collector and I have
heavily contributed to the development of the library that manages the data transfer
under frame format in the data acquisition chain. This library has provided a great
flexibility of the data acquisition and online processing architectures, all along
the detector's commissioning The data acquisition currently sustains a data rate of
about 20 MBytes/s (8 MBytes/s after data compression) with a mean latency of 2 seconds
and a data loss below 0.3%.
I have also created a software, the dataDisplay that allows to read the data online
or 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 on
the Root library developed at CERN. The dataDisplay is now used as a standard tool
by the Virgo collaboration, from control room
for online detector monitoring or offline for the analysis of the recorded data.
In addition, I strongly participate to the data qualification, in particular by providing
the software tools that allow to configure easily the algorithms that monitor online the
detector and its environment. Moreover, I contribute to the search for glitches in the
interferometer's signals and I have the responsibility to put online the algorithms that
study the detector's noise. This work is motivated by the fact that the understanding of
the 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 the
scientific method. By several means (conferences at secondary schools, visits organized
at LAPP and based on a permanent exposition, public conferences, participations to
laboratory Open Doors, creation of web pages), I have tried to excite the interest of young
public to sciences, to make understand what is scientific research and to show what are its
links with the everyday life.