A5036240962- Nuclear Materials and Properties
- Radioactive element chemistry and processing
- Nuclear reactor physics and engineering
- Nuclear materials and radiation effects
- Laser-induced spectroscopy and plasma
- Ion-surface interactions and analysis
- Laser-Matter Interactions and Applications
- Laser Material Processing Techniques
- Laser-Plasma Interactions and Diagnostics
- Astro and Planetary Science
- Nuclear Physics and Applications
- Integrated Circuits and Semiconductor Failure Analysis
- Fusion materials and technologies
- Planetary Science and Exploration
- Crystallization and Solubility Studies
- Semiconductor materials and devices
- X-ray Diffraction in Crystallography
- High-pressure geophysics and materials
- Nuclear physics research studies
- Regional Development and Policy
- Electron and X-Ray Spectroscopy Techniques
- Photorefractive and Nonlinear Optics
- Laser Design and Applications
- Rare-earth and actinide compounds
- Ionosphere and magnetosphere dynamics
CEA Cadarache
2011-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2015-2024
Université de Montpellier
2020-2024
CEA Marcoule
2015-2024
CEA Grenoble
1982-2024
Laboratoire Interactions, Dynamiques et Lasers
2021-2023
CEA Paris-Saclay
1992-2023
Université d'Orléans
2004-2022
Centre National de la Recherche Scientifique
1988-2022
Direction des énergies
2011-2021
We report here the first direct observation of U(V) in uranium binary oxides and analyze gradual conversion U oxidation state mixed systems. Our finding clarifies previous contradicting results provides important input for geological disposal spent fuel, recycling applications, chemistry species.
Intrinsic properties of a compound (e.g., electronic structure, crystallographic optical and magnetic properties) define notably its chemical physical behavior. In the case nanomaterials, these fundamental depend on occurrence quantum mechanical size effects considerable increase surface to bulk ratio. Here, we explore dependence both crystal CeO2 nanoparticles (NPs) with different sizes by state-of-the art spectroscopic techniques. X-ray diffraction, photoelectron spectroscopy, high-energy...
Using a very sensitive time-resolved interferometric technique, we study the laser induced carrier trapping dynamics in wide band-gap crystals with 100 fs temporal resolution. The fast of electrons is associated formation self-trapped excitons (STE's). STE's kinetics does not depend on pump intensity ${\mathrm{SiO}}_{2}$, while rate increases NaCl excitation density. We interpret this result as direct evidence exciton first case, and an electronic following hole second. This explained terms...
We report the first space-time observation of ultrafast excitation and relaxation an electron gas pumped into conduction band a wide band-gap insulator by intense subpicosecond laser pulse. The experiment is based on new phase-sensitive technique which allows resolution 120 fs in time 5 \ensuremath{\mu}m space. In crystalline amorphous Si${\mathrm{O}}_{2}$, no evidence expansion has been observed mean trapping 150 for photogenerated carriers measured.
We present and characterize a very efficient optical device that employs the plasma mirror technique to increase contrast of high-power laser systems. Contrast improvements higher than 10(4) with 50% transmission are shown be routinely achieved on typical 10 TW system when pulse is reflected two consecutive mirrors. Used at end system, this double preserves spatial profile initial beam, unaffected by shot-to-shot fluctuations, suitable for most high peak power use generation high-order...
In addition to standard trade gains, regional agreements (RTAs) can promote peaceful relations by increasing the opportunity cost of conflicts. Country pairs with large gains from RTAs and a high probability conflict should be more likely sign an RTA. Using data 1950 2000, we show that this complementarity between economic politics determines geography RTAs. We disentangle political factors theory-driven empirical estimation find country higher frequency past wars are RTAs, so larger gains....
ABSTRACT The COmetary Secondary Ion Mass Analyser instrument on board ESA's Rosetta mission has collected dust particles in the coma of comet 67P/Churyumov–Gerasimenko. During early-orbit phase mission, and particle agglomerates have been imaged analyzed inner at distances between 100 km 10 off cometary nucleus more than 3 AU from Sun. We identified 585 14 μ m size. are low impact speeds constitute a sample impacting fragmenting targets. sizes range up to sub-millimeter differential flux...
A $\ensuremath{\gamma}$-ray source with an intense component around the giant dipole resonance for photonuclear absorption has been obtained via bremsstrahlung of electron bunches driven by a 10-TW tabletop laser. 3D particle-in-cell simulation proves achievement nonlinear regime leading to efficient acceleration several sequential per each laser pulse. The rate yield in region ($8<{E}_{\ensuremath{\gamma}}<17.5\text{ }\text{ }\mathrm{MeV}$) was measured, through radio activation gold...
Partitioning and transmutation (P&T) of minor actinides (MA) is currently studied to reduce the nuclear waste inventory. In this context, fabrication MA bearing materials great interest achieve an effective recycling these highly radioactive elements. To ensure in-pile behavior, oxide fuels have respect several criteria including preservation fluorite structure defined oxygen metal ratio (O/M). case Am materials, such as U(1-y)Am(y)O(2±x) (y = 0.10, 0.15, 0.20), O/M determination quite...
Abstract The MARS beamline at the SOLEIL synchrotron is dedicated to characterization of radioactive material samples. One great advantage possibility characterize about 380 radionuclides by different X-ray techniques in same place. This facility unique Europe. A wide energy range from around 3.5 keV 36 K-edges K Cs, and L3 edges Cd Am beyond can be used. optimized for absorption spectroscopy (XANES/EXAFS), powder diffraction (XRD) but x-ray fluorescence (XRF) analysis, High Energy...
We report and discuss here the unambiguous uranium valence state determination on complex compound [Ni(H2O)4]3[U(OH,H2O)(UO2)8O12(OH)3] by using high-energy-resolution fluorescence detection-X-ray absorption near-edge structure spectroscopy (HERFD-XANES). The spectra at both U L3- M4-edges confirm that all five nonequivalent atoms are solely in hexavalent form this compound, as previously suggested bond-valence-sum analysis X-ray diffraction pattern refinement. Moreover, presence of preedge...
The Close-Up Imager (CLUPI) onboard the ESA ExoMars Rover is a powerful high-resolution color camera specifically designed for close-up observations. Its accommodation on movable drill allows multiple positioning. science objectives of instrument are geological characterization rocks in terms texture, structure, and search potential morphological biosignatures. We present CLUPI objectives, performance, technical description, followed by description instrument's planned operations strategy...
Abstract To assure the safety of oxide-fuel based nuclear reactors, knowledge atomic-scale properties U 1−y M y O 2±x materials is essential. These compounds show complex chemical properties, originating from fact that actinides and rare earths may occur with different oxidation states. In these mostly ionic materials, aliovalent cationic configurations can induce changes in oxygen stoichiometry, dramatic effects on fuel. First studies Am indicated exhibit particularly electronic...
We report the investigation of onset an absorption band in UV crystalline quartz () induced by intense femtosecond laser pulse. Using a conventional pump - probe technique, we have measured absorptions at 219 nm (5.66 eV) and 240 (5.16 as functions time, two different temperatures (10 300 K). The rise time is to be 150 . It independent wavelength sample temperature. coefficients are similar both wavelengths values room temperature about twice these 10 K. attribute ultra-fast formation...