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FLASH Modalities Track (Oral Presentations) Proton beam flash online monitoring at Arronax Cyclotron
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Measurement of the bulk radioactive contamination of detector-grade silicon with DAMIC at SNOLAB
No full textInternational audienceWe present measurements of bulk radiocontaminants in the high-resistivity silicon CCDs from the DAMIC experiment at SNOLAB. We utilize the exquisite spatial resolution of CCDs to discriminate between α and β decays, and to search with high efficiency for the spatially-correlated decays of various radioisotope sequences. Using spatially-correlated β decays, we measure a bulk radioactive contamination of 32Si in the CCDs of 140 ± 30 μBq/kg, and place an upper limit on bulk 210Pb of < 160 μBq/kg. Using similar analyses of spatially-correlated α and β decays, we set upper limits of < 11 μBq/kg (0.9 ppt) on 238U and < 7.3 μBq/kg (1.8 ppt) on 232Th in the bulk silicon. The ability of DAMIC CCDs to identify and reject spatially-coincident backgrounds, particularly from 32Si, has significant implications for the next generation of silicon-based dark matter experiments, where β's from 32Si decay will likely be a dominant background
Étude de la dépendance en énergie des flux elliptique et triangulaire pour les particules identifiées dans le Beam Energy Scan avec l’expérience STAR et le générateur d’événements EPOS
No full textStudying the properties of the collective expansion of matter created in heavy-ion collisions provides a unique tool to understand better the nonperturbative aspect of QCD. Input from both the theoretical and the experimental side is needed. Hydrodynamic calculations predict anisotropies in particle production, as a consequence of asymmetries in the initial state of the system's evolution. Measurements of the systematics (energy-, system- dependence) of these anisotropies allow one not only to validate theoretical ideas but also to determine the unknown elements, like plasma properties (EoS), thermalization processes. The broadening of our knowledge in these topics is the main goal of the thesis. The experimental methods were used to provide insight into the investigation of the anisotropies in the expansion of the particles and antiparticles, while the theoretical approach was used for the EoS studies.L'étude des propriétés de l'expansion collective de la matière créée dans les collisions d'ions lourds est un outil unique, permettant de mieux comprendre les aspects non-perturbatifs de la QCD, et nécessitant un travail tant sur le plan théorique que sur le plan expérimental. D'une part, des calculs d'évolution hydrodynamique prédisent, en conséquence de l'asymétrie du système dans l'état initial, une anisotropie dans la production des particules finales. D'autre part, les mesures de cette anisotropie, en fonction du système et de l'énergie considérés, permettent non seulement de valider les prédictions théoriques, mais aussi de déterminer des éléments inconnus comme les propriétés du plasma créé lors de ces collisions (e.g. son équation d'état), ou bien les processus de thermalisation mis en jeu. Améliorer nos connaissances sur ce sujet est le principal objectif de cette thèse. Les méthodes expérimentales décrites ont pour objectif de donner un aperçu de la mesure de l'anisotropie de l'expansion des particules et anti-particules, tandis que les approches théoriques ont été utilisées pour étudier l'équation d'état de la matière
Rare decays with radial detector: A Spherical Proportional Counter (SPC) R&D for the neutrinoless double beta decay search
No full textInternational audienceThis proceedings is intended to briefly expose the progress of theR2D2 R&D toward a potential ton-scale experiment for the neutrinoless double betadecay searches. We focus our studies on the energy resolution measurements andon the integration of a light sensor for drift-time measurements
Atomistic modeling of the structure and dynamcis of aqueous NaCl and Na2SO4 solutions at the interface with ettringite crystals
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On the Relative Hydrophilicity and Hydrophobicity of Clayey Materials' Surfaces
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Recent advances and perspectives of the atomistic computational modeling of mineral-solution interfaces with the ClayFF force field
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Competition between diffusion and rapid expansion andits impact on critical fluctuations in heavy-ion collisions.
No full textInternational audienceWe study the impact of the competition between the expansion of the medium created in heavy-ion collisions and its diffusive properties on the critical fluctuations of the net-baryon density. As the relaxation time of the fluctuations is connected with the diffusive properties, the latter determine the in- or out-of-equilibrium nature of the net-baryon density fluctuations during the fireball evolution. This may result in important consequences for the phenomenological interpretation of heavy-ion collision data. We study three possible situations that can occur as a result of the competition between diffusion and expansion and discuss the impact of this competition on the integrated second and fourth order cumulants of net-baryon density fluctuations at freeze-out in these situations
Estimation of the vitrified canister production for a PWR fleet with the CLASS code
No full textInternational audienceThis article presents an assessment of fuel cycle parameter impact on waste production through the prism of vitrified container and minor actinide masses, using a scenario simulated with the CLASS code. The number of canister introduces a new focus on waste production estimation for a nuclear fleet, as it helps to set the repository size for deep geological disposal of high level waste. To evaluate the number of canisters, dedicated developments to model a simplified waste vitrification unit in the CLASS package are presented. It relies on artificial neural network estimations of decay heat, α radiation and mass content, for different material flow coming from reprocessing and sent to vitrification. Then, the studied scenario considers a transition from a PWRs plutonium mono-recycling fleet to a plutonium multi-recycling fleet. Vitrified waste container production is calculated as a function of different material reprocessing options. Simulations shows that up to 19% variation may be observed (in 2060) in canisters’ total number depending on the different assumptions. Impact of vitrification parameters such as the size of buffer before vitrification is also analysed and the importance of mixing material coming from MOX and MIX spent fuels with material from UOX spent fuels is clearly established.</jats:p