The challenges of this project consist in simulating through laboratory experiments, the chemical evolution of interstellar ices, and grains to understand the evolution of the organic matter during the life cycle of interstellar grains. Currently, our team is developing two complementary approaches to study this evolution. First, we are investigating the chemical reactivity that can occur within analogs of pristine or cometary ices, by working on small size systems (two or three reactants). Second, we are investigating the characterization of refractory residues formed during photolysis and warming of ice analogs without any degradation using an orbitrap apparatus. We propose to develop a new approach, which consists in implementing an analytical system for the Volatile Analyses coming from the Heating of Interstellar Ice Analogs, the VAHIIA project. This new device will help us to get a better understanding of the chemical reactions that lead to the formation of refractory residues. It will also give crucial information on species that would sublimate during the warming of cometary nucleus. This system will consist in coupling to an ultra-high vacuum cryogenic system, a gas chromatography including a mass spectrometer in order to analyze gas species sublimating during the heating of ice analogs. Therefore, the VAHIIA project will be the missing link between the two existing projects, and the whole will provide a comprehensive experimental approach aiming to trace the chemical history of such analogs by studying the reactivity of ice at low temperature, analyzing the volatile species sublimating during the warming, and characterizing the non-volatile residues resulting from the latter. The VAHIIA project has been already submitted in 2011. The scientific program of the 2012 application is quite the same that of the previous application. The major modifications are present in the description by tasks of this application, and in the request resources. We call such funding for the purchase of the GC-MS device, and for a two years recruitment of a post-doctor, which objectives will be to participate in GC-MS development and analysis . Furthermore, a detail reply to the “retour au coordinateur” is given in section 3 of the annex document.

In a fusion plasma, ions escape from the plasma core and hit the reactor's walls where they remain implanted. During operation, the walls are hot (~900 K) and while absorbing hydrogen isotopes and helium they also release them. This implantation/degassing process is called recycling. The recycling process affects mainly the tungsten divertor which receives the highest power fluxes (up to 40 MW/m²). The interaction of intense particle fluxes with walls can induce changes in the surface condition and thermo-mechanical properties of plasma facing components and thus affecting the proper functioning of the reactor. For these reasons, in the framework of the LETHE project, we will experimentally study changes in the recycling process induced by He/wall and light/wall interactions. Such studies are necessary to predict how the walls will behave during plasma operation in tokamaks. The experiments will be carried out using an ultra-high vacuum device allowing to characterize the atomic composition of sample surfaces, to implant helium with ion beams or plasma, and to quantify the species trapped in the volume of the materials by using the temperature-programmed desorption technique. Three are the main objectives of the LETHE project: 1. Understanding the physical mechanisms underlying the degradation of materials (e.g. blister formation) and the change in their physico-chemical properties after He implantation/thermo-desorption cycles. Moreover, an in situ spectroscopic ellipsometer, installed in the framework of the LETHE project, will allow to probe the degradation of the surface of materials during ion-surface interaction. 2. The study of the influence of thermal loads in the recycling process and, consequently, on the parameters of the edge plasma. Thermal loads, simulated by a high-power laser, reaching pre-implanted samples, will induce sudden desorption of trapped species which, consequently, will perturb the plasma. The properties of the plasma (e.g. temperature and density) will be measured by a Langmuir probe. 3. Development of an optical method to prevent surface degradation, e.g. blistering, which can lead to plasma disruption.

Point defects in crystals occur when an atom is missing or is in an irregular position. After an initial skepticism, they spiked interest because of their possible applications as qubits in quantum computers. A strong and stable photoluminescence at room temperature (RT) and a single photon emission are the needed requirements. Point defects in hexagonal Boron Nitride(hBN) have been experimentally identified as RT stable single photon sources. In the photoluminescence spectrum of hBN there are different emission lines at transition energies ranging over the visible and the UV spectrum, and well-resolved phonon replica at lower energies. Whereas a considerable effort has been made so far and several color centers candidate have already been suggested, their exact nature remains uncertain. This project aims to solve some controversies related to the interpretation of defect related emission lines, with a special care for the study of the local vibrations at the origin of phonon replica.

The HYDRAE project will explore the almost entirely unknown physical properties of neutral aromatic radicals, both in the isolated gas phase and in aggregates with solvent molecules. Dehydrogenated/ hydrogenated radicals intervene in all concerted Proton Coupled Electron Transfer (PCET) processes, which are the basis of many critical biological reactions. These species are also implicated in molecular hydrogen formation in the interstellar medium and in soot formation. We propose to study the UV-visible and IR spectroscopy of this largely unexplored class of molecular system, to determine the influence of heteroatoms or chemical functionalisation (amino, carbonyl, etc), size of the aromatic chromophore, and solvation upon the radical’s formation, structure and stability. These questions will be addressed by performing electronic spectroscopy and mass spectrometry on functionalised aromatic molecules in their (de)hydrogenated forms in a cryogenically-cooled ion trap or supersonic jet.

This project addresses issues related to hydrogen negative-ion sources for future fusion reactors. These sources are based on low-pressure low-temperature H2 plasmas in which caesium (Cs) metal is injected in vapor form. Cs is depositing on all surfaces in contact with the plasma and greatly enhances H- negative-ion surface production. Because Cs is polluted very quickly due to its high chemical reactivity, it has to be injected continuously leading to its accumulation inside the source. It implies severe maintenance issues that are manageable in a research reactor but that are unsustainable for a nuclear power plant. Cs alternative materials, besides being efficient for negative-ion production, have also to sustain erosion induced by the plasma, pollution by impurities and harsh mechanical and temperature constraints. As a consequence, no solution has been found to date to replace Cs whose continuous injection guarantees the source efficiency, but at the same time signs its inadequacy with the specifications of a power plant. We propose to extend the advantage of the continuous renewal of Cs to potentially any material efficient for H- surface production. The main idea is to use alternative materials in the form of micro-particles shortly transiting inside the plasma to eliminate pollution or erosion problems. This solution would not only increase the negative-ion production due to the large specific area of the micro-particles, but would also highly enhance H- extraction thanks to their acceleration by the potential difference between micro-particles and plasma. This project aims at addressing the physics required to develop this highly innovative solution, from negative-ion production and extraction to fundamental aspects related to negative-ion emitting micro-particles behavior in plasma.