Near-field speckle-scanning-based x-ray imaging

The x-ray near-field speckle-scanning concept is an approach recently introduced to obtain absorption, phase, and dark-field images of a sample. In this paper, we present ways of recovering from a sample its ultrasmall-angle x-ray scattering distribution using numerical deconvolution. We also show how to access the 2D phase gradient signal from random step scans, the latter having the potential to elude the flat-field correction error. Each feature is explained theoretically and demonstrated experimentally at a synchrotron x-ray facility.Comment: 8 figures, 9 page

Métrologie en ligne de faisceaux et d'optiques X de synchrotrons

Cette thèse présente des travaux de recherche de métrologie en ligne de faisceaux de rayons X dans les installations synchrotrons. Deux approches principales ont été étudiées pour extraire la phase d'un front d'onde X : les méthodes utilisant des réseaux optiques et celles utilisant l'effet speckle dans le domaine X. L'interféromètre à réseaux X est l'outil le plus répandu résentatif de la première catégorie. Ses performances et son potentiel furent étudiés dans diverses situations de métrologie en ligne. Les méthodes utilisant le speckle X sont des techniques originales développées au cours de ce projet. Elles utilisent des membranes faites de petits grains diffusants, dont seule la distribution statistique est connue, pour permettre la modulation du front d'onde. Les différentes techniques furent déployées expérimentalement sur les lignes de lumière BM05 de l'ESRF et B16 de Diamond Light Source. Leurs implémentations servirent à la caractérisation de différents composants optiques utilisés pour manipuler les faisceaux synchrotron X et à l'étude de la faisabilité de micro imagerie par contraste de phase avec les sus citées techniques.This thesis presents research and development work on synchrotron X-ray at-wavelength metrology methods. Two approaches for measuring the phase of an X-ray wavefront were studied: the grating-based and the speckle-based methods. The X-ray grating interferometer is the most widespread technique representative of the first category. Its performance and potential in various situations encountered in at-wavelength metrology was investigated. Speckle methods are X-ray phase sensing techniques newly developed during this thesis project. They make use of membranes with small statistical features to modulate the beam wavefront. The different methods were deployed experimentally at the beamlines BM05 of the ESRF and B16 of the Diamond Light Source. Their implementation permitted the characterization of various kinds of optical elements used to manipulate synchrotron X-ray beamsas well as the feasibility study of micro phase contrast imaging using the two methods described above.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Leptospiroses et lésions oculaires chez le Chien

Rossi Paul, Kolochine-Erber B., Berujon J. Leptospiroses et lésions oculaires chez le Chien. In: Bulletin de l'Académie Vétérinaire de France tome 106 n°8, 1953. pp. 451-455

Directional dark-field implicit x-ray speckle tracking using an anisotropic-diffusion Fokker-Planck equation

When a macroscopic-sized non-crystalline sample is illuminated using coherent x-ray radiation, a bifurcation of photon energy flow may occur. The coarse-grained complex refractive index of the sample may be considered to attenuate and refract the incident coherent beam, leading to a coherent component of the transmitted beam. Spatially-unresolved sample microstructure, associated with the fine-grained components of the complex refractive index, introduces a diffuse component to the transmitted beam. This diffuse photon-scattering channel may be viewed in terms of position-dependent fans of ultra-small-angle x-ray scatter. These position-dependent fans, at the exit surface of the object, may under certain circumstances be approximated as having a locally-elliptical shape. By using an anisotropic-diffusion Fokker-Planck approach to model this bifurcated x-ray energy flow, we show how all three components (attenuation, refraction and locally-elliptical diffuse scatter) may be recovered. This is done via x-ray speckle tracking, in which the sample is illuminated with spatially-random x-ray fields generated by coherent illumination of a spatially-random membrane. The theory is developed, and then successfully applied to experimental x-ray data

Botulisme du Canard, son traitement

Rossi Paul, Berujon J. Botulisme du Canard, son traitement. In: Bulletin de l'Académie Vétérinaire de France tome 103 n°7, 1950. pp. 365-369