Inward Bound: Studying the Galactic Centre with NAOS/CONICA

We report on the first results obtained using adaptive optics measurements of the Galactic Centre done with NAOS/CONICA.Comment: 19 pages, 7 figure

Simulations Monte Carlo et étude théorique des dommages induits par les particules ionisantes à l’échelle macroscopique ainsi qu’à l’échelle moléculaire

The work presented in this thesis can be placed in the context of biological damage simulation. Webegin with a macroscopic study where we question the relevance of absorbed-dose-based treatmentplanning. Then we move on to a micro-dosimetry study where we suggest the use of morebiologically relevant probes for damage, such as DNA strand breaks. More focus is given to thefundamental considerations on which the simulations are based, particularly the interaction crosssections. Due to the complexity of the biological medium, the interaction cross sections with waterare often used to simulate the behavior of particles. We develop a parallel user-friendly algorithmthat can provide the ionization cross sections for any molecular target, making use of particular toolsthat allow to overcome the computational difficulties, which makes our program particularlyinteresting for complex molecules. We provide preliminary results for water, ammonia, formic acidand Tetrahydrofuran.Le travail présenté dans cette thèse se place dans le contexte de la simulation de dommages biologiques. D'abord une étude macroscopique met en question la pertinence des plans de traitement basés sur la dose absorbée et le passage à une étude de micro-dosimétrie permet l'utilisation de paramètres biologiques plus pertinents, tels que les cassures de brins d'ADN. La validité des sections efficaces d'interaction sur lesquelles se basent ces simulations est discutée en plus de détails. Suite à la complexité du milieu biologique, les sections efficaces d'interaction avec l'eau sont souvent utilisées. Nous développons un algorithme qui permet de fournir les sections efficaces d'ionisation pour n'importe quelle cible moléculaire, en utilisant des outils qui permettent de surmonter les difficultés de calcul, ce qui rend notre programme particulièrement intéressant pour les molécules complexes. Nous fournissons des résultats pour l'eau, l'ammoniac, l'acide formique et le tétrahydrofurane

Triple differential cross sections for the ionization of tetrahydrofuran by electron impact

International audienc

Triply Differential Ionization Cross Sections of atomic and molecular targets by single electron impact

We present numerically calculated triply differential cross sections for the simple ionization of two targets, atomic hydrogen and ammonia, in the First Born Approximation framework with one Coulomb wave describing the ejected electron. The partial wave series of the wavefunctions centered around the same origin were used and the intial state molecular wavefunction was derived using information provided by Gaussian03 software for ammonia. The theoretical results are calculated in the geometrical settings and kinematical conditions of previous experiments and are compared to published experimental and theoretical data. The results show good agreement with previous studies based on the same model for hydrogen. The general shape of the triply differential cross sections obtained for ammonia are in acceptable agreement with experimental data in the binary region but not in the recoil region where our simple framework fails to reconstruct the recoil peaks

Triply Differential Ionization Cross Sections of atomic and molecular targets by single electron impact

We present numerically calculated triply differential cross sections for the simple ionization of two targets, atomic hydrogen and ammonia, in the First Born Approximation framework with one Coulomb wave describing the ejected electron. The partial wave series of the wavefunctions centered around the same origin were used and the intial state molecular wavefunction was derived using information provided by Gaussian03 software for ammonia. The theoretical results are calculated in the geometrical settings and kinematical conditions of previous experiments and are compared to published experimental and theoretical data. The results show good agreement with previous studies based on the same model for hydrogen. The general shape of the triply differential cross sections obtained for ammonia are in acceptable agreement with experimental data in the binary region but not in the recoil region where our simple framework fails to reconstruct the recoil peaks