Characterisation of CVD Diamond devices as XBPMs at SOLEIL

International audienceSingle crystal CVD diamonds have been developed for use as XBPMs on the beamlines of the French synchrotron SOLEIL. These devices have been calibrated and characterized directly on the beamline following an elaborate protocol. An example is given for an XBPM installed on PROXIMA 2. This device has shown a charge collection efficiency of 100% for only 0.2V/µm with total signal-to-noise ratio better than 10^5. A complete 2D scan gives the homogeneity of the scale factors over the active surface with a very low error corresponding to 0.6µm (beam off-center and maximum calibration error). The current sensitivity measurement shows a fluctuation less than 0.02% and the responsivity is calculated to measure the incident flux. And finally, the spatial resolution for these XBPMs is better than 1µm rms at 1kHz and 100 nm rms at 5 Hz

Fast pole figure acquisition using area detectors at the DiffAbs beamline – Synchrotron SOLEIL

Structural anisotropy, for example texture, may govern important physical properties of thin film, such as electrical, magnetic and/or mechanical ones. Texture (orientation information) is typically observed and quantified by the measurement of so-called pole figures. An optimized experimental approach implemented at the DiffAbs beamline (Synchrotron SOLEIL) is presented here. Using an X-ray pixel area detector and synchrotron radiation sources, a complete pole figure (with resolutions adapted for metallic textured thin films, typically of the order of a few degrees) can be measured in time intervals as short as one minute. The necessary corrections enabling complete pole figure retrieval from the experimental data using this optimized approach are provided and discussed. A gain in measuring time by up to two orders of magnitude is found with respect to the use of a point detector (classical approach) under the same experimental conditions. Data measured using these two approaches are shown, compared and discussed

Acquisition rapide de figures polaires à l'aide de détecteurs de zone sur la ligne DiffAbs - Synchrotron SOLEIL

International audienceL'anisotropie structurelle, par exemple la texture, peut régir d'importantes propriétés physiques d'un film mince, telles que les propriétés électriques, magnétiques et/ou mécaniques. La texture (information d'orientation) est typiquement observée et quantifiée par la mesure de ce que l'on appelle les figures polaires. Une approche expérimentale optimisée mise en œuvre sur la ligne DiffAbs (Synchrotron SOLEIL) est présentée ici. À l'aide d'un détecteur de zone de pixels à rayons X et de sources de rayonnement synchrotron, une figure de pôle complète (avec des résolutions adaptées aux films minces texturés métalliques, généralement de l'ordre de quelques degrés) peut être mesurée à des intervalles de temps aussi courts qu'une minute. Les corrections nécessaires permettant la récupération complète de la figure de pôle à partir des données expérimentales en utilisant cette approche optimisée sont fournies et discutées. On constate un gain de temps de mesure jusqu'à deux ordres de grandeur par rapport à l'utilisation d'un détecteur ponctuel (approche classique) dans les mêmes conditions expérimentales. Les données mesurées à l'aide de ces deux approches sont présentées, comparées et discutées

Diffraction studies under in situ electric field using a large-area hybrid pixel XPAD detector

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Time-Resolved Pump-Probe Diffraction Experiment at SOLEIL Synchrotron: Photoinduced Spin Transition in the Molecular Crystal [TPA Fe(III) TCC] PF6

International audienceWe present the first time-resolved pump-probe experiment performed at synchrotron SOLEIL at the CRISTAL diffraction beamline. The time-resolved setup will be used in the near future for sub-ns time resolution experiments. We studied spin state switching in a [TPA Fe(III) TCC] PF6 single crystal as induced by a ¼ 6 ns laser pulse (1064 nm), by measuring the 3D diffraction volume of the 002 Bragg reflection as a function of time after excitation. The intensity profiles (rocking curves) are found to evolve at two characteristic timescales, namely hundreds of ns and few ¹s, exhibiting subtle profile changes and peak broadenings. Consistently with previous studies, we interpret these features as due to structural inhomogeneities related to laser-induced deformation wave propagation and heat diffusion, which both start from the absorbing sites

Scedosporiosis/lomentosporiosis observational study (SOS): Clinical significance of Scedosporium species identification

International audienceScedosporiosis/lomentosporiosis is a devastating emerging fungal infection. Our objective was to describe the clinical pattern and to analyze whether taxonomic grouping of the species involved was supported by differences in terms of clinical presentations or outcomes. We retrospectively studied cases of invasive scedosporiosis in France from 2005 through 2017 based on isolates characterized by polyphasic approach. We recorded 90 cases, mainly related to Scedosporium apiospermum (n = 48), S. boydii/S. ellipsoideum (n = 20), and Lomentospora prolificans (n = 14). One-third of infections were disseminated, with unexpectedly high rates of cerebral (41%) and cardiovascular (31%) involvement. In light of recent Scedosporium taxonomic revisions, we aimed to study the clinical significance of Scedosporium species identification and report for the first time contrasting clinical presentations between infections caused S. apiospermum, which were associated with malignancies and cutaneous involvement in disseminated infections, and infections caused by S. boydii, which were associated with solid organ transplantation, cerebral infections, fungemia, and early death. The clinical presentation of L. prolificans also differed from that of other species, involving more neutropenic patients, breakthrough infections, fungemia, and disseminated infections. Neutropenia, dissemination, and lack of antifungal prescription were all associated with 3-month mortality. Our data support the distinction between S. apiospermum and S. boydii and between L. prolificans and Scedosporium sp. Our results also underline the importance of the workup to assess dissemination, including cardiovascular system and brain. Lay Summary Scedosporiosis/lomentosporiosis is a devastating emerging fungal infection. Our objective was to describe the clinical pattern and to analyze whether taxonomic grouping of the species involved was supported by differences in terms of clinical presentations or outcomes

A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log10 increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence