Search results for "Instrument"
showing 10 items of 5652 documents
Modélisation, Analyse et Traitement de l'Information
2016
Mes activités de recherche s’articulent, d’une part, autour de l’instrumentation et du génie biomédical,et, d’autre part, autour du traitement et de la transmission non linéaire de l’information. Elles sebasent sur la modélisation des signaux à partir de modèles non linéaires (principalement modèles deréaction-diffusion. . . ) continus (EDP) et discrets (numériques). Dans cette partie, d’un point de vuefondamental, des phénomènes dynamiques complexes ou chaotiques sont caractérisés à travers l’analyse,la classification, la reconnaissance des motifs dans des signaux physiologiques ou issus des circuitsélectroniques. Un autre axe sur lequel je travaille concerne l’analyse et le traitement des…
Methodology for assessment of measuring uncertainties of articulated arm coordinates measuring machine
2014
International audience; The Articulated Arm Coordinate Measuring Machines (AACMM) have gradually evolved and are increasingly used in mechanic industry. At present, measurement uncertainties relating to the use of these devices are not yet well-quantified. The work carried out consists on determining the measurement uncertainties of a mechanical part by an Articulated Arm Coordinate Measuring Machine. The studies aiming to develop a model of measurement uncertainties are based on the Monte Carlo method developed in Supplement 1 of the Guide to Expression of Uncertainty in Measurement [1] but also identifying and characterizing the main sources of uncertainty. A Multi-level Monte Carlo appro…
Une architecture programmable de traitement des impulsions zéro-temps mort pour l'instrumentation nucléaire
2015
In the field of nuclear instrumentation, digital signal processing architectures have to deal with the poissonian characteristic of the signal, composed of random arrival pulses which requires current architectures to work in dataflow. Thus, the real-time needs implies losing pulses when the pulse rate is too high. Current architectures paralyze the acquisition of the signal during the pulse processing inducing a time during no signal can be processed, this is called the dead time. These issue have led current architectures to use dedicated solutions based on reconfigurable components such as FPGAs. The requirement of end users to implement a wide range of applications on a large number of …
The INTEGRAL/SPI response and the Crab observations
2004
The Crab region was observed several times by INTEGRAL for calibration purposes. This paper aims at underlining the systematic interactions between (i) observations of this reference source, (ii) in-flight calibration of the instrumental response and (iii) the development and validation of the analysis tools of the SPI spectrometer. It first describes the way the response is produced and how studies of the Crab spectrum lead to improvements and corrections in the initial response. Then, we present the tools which were developed to extract spectra from the SPI observation data and finally a Crab spectrum obtained with one of these methods, to show the agreement with previous experiments. We …
Results from the ULTRA experiment in the framework of the EUSO project
2005
The detection of Cerenkov light from EAS in a delayed coincidence with fluorescence light gives a strong signature to discriminate protons and neutrinos in cosmic rays. For this purpose, the ULTRA experiment has been designed with 2 detectors: a small EAS array (ETscope) and an UV optical device including wide field (Belenos) and narrow field (UVscope) Cerenkov light detectors. The array measures the shower size and the arrival direction of the incoming EAS, while the UV devices, pointing both to zenith and nadir, are used to determine the amount of direct and diffused coincident Cerenkov light. This information, provided for different diffusing surfaces, will be used to verify the possibil…
Requirements and simulation study of the performance of EUSO as external payload on board the international space station
2005
The "Extreme Universe Space Observatory - EUSO" has been conceived as the first Space mission devoted to the investigation of Ultra High Energy Cosmic Ray, using the Earth's atmosphere as a giant detector. The scientific objectives of the experiment are to observe the UHECR spectrum above the GZK energy, with an improvement of one order of magnitude in the statistics of collected events with respect to the existing experiments, in such a way to study the source distribution in a full sky survey, as well as to open the channel (set a confidence limit) on the neutrino astronomy in this energy range. Supposed to be accommodated as external payload on board the International Space Station, EUSO…
Constraints on the origin of cosmic rays above 10^18 eV from large-scale anisotropy searches in data of the Pierre Auger Observatory
2012
A thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above 10(18) eV at the Pierre Auger Observatory is reported. For the first time, these large-scale anisotropy searches are performed as a function of both the right ascension and the declination and expressed in terms of dipole and quadrupole moments. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Upper limits on dipole and quadrupole amplitudes are derived under the hypothesis that any cosmic ray anisotropy is dominated by such moments in this energy range. These upper limits provide constraints on the production of cosmic rays above 10(…
The rapid atmospheric monitoring system of the Pierre Auger Observatory
2012
The Pierre Auger Observatory is a facility built to detect air showers produced by cosmic rays above 1017 eV. During clear nights with a low illuminated moon fraction, the UV fluorescence light produced by air showers is recorded by optical telescopes at the Observatory. To correct the observations for variations in atmospheric conditions, atmospheric monitoring is performed at regular intervals ranging from several minutes (for cloud identification) to several hours (for aerosol conditions) to several days (for vertical profiles of temperature, pressure, and humidity). In 2009, the monitoring program was upgraded to allow for additional targeted measurements of atmospheric conditions shor…
Interpretation of the depths of maximum of extensive air showers measured by the Pierre Auger Observatory
2013
To interpret the mean depth of cosmic ray air shower maximum and its dispersion, we parametrize those two observables as functions of the first two moments of the ln A distribution. We examine the goodness of this simple method through simulations of test mass distributions. The application of the parameterization to Pierre Auger Observatory data allows one to study the energy dependence of the mean ln A and of its variance under the assumption of selected hadronic interaction models. We discuss possible implications of these dependences in term of interaction models and astrophysical cosmic ray sources.
Limits on a muon flux from Kaluza-Klein dark matter annihilations in the Sun from the IceCube 22-string detector
2010
A search for muon neutrinos from Kaluza-Klein dark matter annihilations in the Sun has been performed with the 22-string configuration of the IceCube neutrino detector using data collected in 104.3 days of live-time in 2007. No excess over the expected atmospheric background has been observed. Upper limits have been obtained on the annihilation rate of captured lightest Kaluza-Klein particle (LKP) WIMPs in the Sun and converted to limits on the LKP-proton cross-sections for LKP masses in the range 250 -- 3000 GeV. These results are the most stringent limits to date on LKP annihilation in the Sun.