Дисертації з теми "L'imagerie par la diffraction cohérente"
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Samaan, Julien. "Étude et applications de l'imagerie sans lentille par diffraction cohérente." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS557/document.
Повний текст джерелаThis dissertation is dedicated to coherent diffractive imaging. Firstly, we present the conception and experimental implementation of a compact imaging system, working on this principle. It is made of an UV laser diode (λ = 400 nm), a CCD camera,and a platform to place the sample. The coherent beam coming from the diode illuminates the sample, and the diffraction pattern is recorded by the camera. Back-propagating the detected field should allow, in principle, to derive the sample’s profile. Nevertheless, the field’s phase, lost during the detection, forces us to use “phase retrieval” methods, this quantity being necessary to the inversion process. Several techniques have been used for that purpose. Fourier Transform Holography (FTH), for example, is a deterministic method thatconsists in using a circular reference, closely drilled nearby the sample. The phase is encoded in the diffraction pattern, in the form of interference fringes coming from the object and the reference. Then, a simple inverse Fourier Transform of the signal leads the profile of the sample. An iterative method has also been implemented, based on a set of constraints in the real and reciprocal spaces. In particular, the illuminated object must be “isolated”, i.e. smaller than the incident beam. Although this method is non-deterministic, we will see thatit is more robust and gives better resolutions than the holographic cases. This study is the starting point of three-dimensional imaging. We present a first deterministic method, based on FTH. For this purpose, a “holographic pupil” is used and serves as a support for a first 2D reconstruction of the field. The latter is then back-propagated towards the sample closely placed, in order to realize an entirely numerical focusing on it. The “isolation constraint” is then removed by the use of this pupil. However, with this method, the field of view is limitedby the pupil’s diameter. In order to observe larger samples, the “in-line holography” technique has been exploited as well. It consists in illuminating the object with a spherical wave and recording the interference fringes (or “hologram”). A back-propagation is made after the fact in order to do the focusing on the sample. The divergent nature of the beam allows for reaching several millimeters for the lateral field of view. The “twin image problem”, inherent to this configuration, is solved via an iterative algorithm coupled to the back-propagation process. Three-dimensional reconstructions have been made on varied samples, with these two methods — pupil reconstruction and in-line holography. In both cases, reconstruction interfaces have been implemented and work during the detection, in order to observe the object in real time. We then have a compact and complete lens-less imaging prototype. Finally, we present the application of a phase retrievaltechnique, named LIFT (LInearized Focal plane Technique), applied to a Shack-Hartmann wavefront sensor. Usually, such sensors have a spatial resolution that is limited by the micro-lenses size : only the local slopes, i.e. tip and tilt, are retrieved. The LIFT consists in determining the phase at the scale of each micro-lens, by exploiting the corresponding spot profile. Interaction matrices are calculated in order to linearize the relation between the real space (micro-lenses) and the reciprocal space (CCD chip), and an iterative loop allows for increasing this linearity domain. With this technique, a gain in spatial resolution by a factor 3 is expected
Liu, Xu. "Development of an extreme ultraviolet laser beamline for at wavelength metrology." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP045.
Повний текст джерелаThe partnership established between CEA/LIDYL and the SME Imagine Optic (IO) at the beginning of 2020 led to the creation of the joint laboratory NanoLite, dedicated to the development of optical systems specialized in metrology at short wavelengths. This laboratory focuses notably on the extreme ultraviolet (EUV, 10-100 nm) domain, crucial for various sectors such as synchrotron radiation facilities, microelectronics (lithography), and academic research (attosecond physics).The present CIFRE thesis focuses on the development of a compact and high-performance beamline in the EUV range, based on the generation of high-order harmonic (HHG). This nonlinear phenomenon enables the production of spatially coherent radiation in the EUV range from femtosecond laser pulses. The construction of this beamline relies on a new laser system with a repetition rate of 100 kHz, generating pulses of 50 fs. This thesis manuscript addresses the various technical aspects necessary, from optics to mechanics, vacuum to electronics, and software programming for data acquisition and processing.The developed beamline has been operational since October 2022. The implemented and tested industrial applications, such as the calibration of EUV HASO wavefront sensors, inspection of the surface quality of EUV optics, and wavefront measurement modalities by stitching, are described in this manuscript.Another possible approach for metrology, complementary to wavefront characterization, is offered by nanometric coherent diffraction imaging. Ptychography, a technique that allows the study of extended samples without sacrificing spatial resolution, enables the reconstruction of spatial characteristics (amplitude and phase) of the illumination beam. Various applications of ptychography are presented, including a study of the influence of the spectral width of the source and a new self-probed imaging configuration in which the sample and the radiation source are coincident. Finally, ptychography is applied for the characterization of the EUV focus of the beamline.All these achievements have validated the performance of the beamline and have revealed possible avenues for further optimization
Davidoiu, Valentina. "Approches non linéaire en imagerie de phase par rayons X dans le domaine de Fresnel." Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00952854.
Повний текст джерелаGe, Xunyou. "Imagerie ultrarapide à l'échelle nanométrique par diffraction XUV cohérente." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00828058.
Повний текст джерелаGe, Xunyou. "Imagerie ultrarapide à l’échelle nanométrique par diffraction XUV cohérente." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112361/document.
Повний текст джерелаUltrafast imaging of isolated objects with nanometric spatial resolution is a great challenge in our time. The lensless imaging techniques have shown great potential to answer this challenge. In lensless imaging, one can reconstruct sample images from their diffraction patterns with computational algorithms, which replace the conventional lens systems. Using ultrafast and coherent light sources, such as free electron laser and high order harmonics, one can investigate dynamic phenomena at the femtosecond time scale. In this thesis work, I present the lenless imaging experiments using XUV radiation provided by a laser driven high order harmonic beamline. The manuscript is composed of an introduction, a chapter of theoretical background, three chapters of main research work and a general conclusion with perspectives. The first part of this work concerns the development of the harmonic beamline to optimize the illumination condition for lensless imaging. The second part concentrates on the imaging techniques: the Coherent Diffraction Imaging (CDI), the Fourier Transform Holography (FTH) and the Holography using extended references (HERALDO). The reconstructions have achieved 78 nm spatial resolution in case of CDI and 112 nm resolution in case of HERALDO, both in single-shot regime corresponding to a temporal resolution of 20 fs. The third part presents the first physical application on the harmonic beamline using the lensless imaging. Samples with magnetic nano-domains have been studied with sub-100 nm spatial resolution, which paves the way for ultrafast magnetic dynamic studies. At the end, single-shot 3D imaging and further beamline development have been discussed
Wang, Fan. "Imagerie nanométrique 2D et 3D ultrarapide par diffraction cohérente." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112226/document.
Повний текст джерелаCoherent diffraction is an amazing art by its experimental simplicity: a coherent XUV source illuminates a single, isolated sample, and the diffraction pattern of the object is recorded by a CCD camera. An inversion of the diffraction pattern to an image in real space is possible through an approach based on iterative algorithms. The techniques for Fourier transform holography, for which reference is placed near the object to be imaged, allow the direct reconstruction of the image, even when the quality of the experimental data is worse. We have a laboratory sufficiently intense compact XUV source for this type of experience. The ultrashort XUV pulses (from femtosecond to attosecond) are produced by selecting high order harmonics of a femtosecond infrared laser which is focused into a cell of rare gas. We recently demonstrated the feasibility of using this source for coherent diffraction imaging with a spatial resolution of 78 nm. Furthermore, we demonstrated experimentally a holographic technique with extended reference and obtained a resolution of 110 nm in single shot (i.e. an integration time of 20 femtoseconds). A perception of an object in three dimensions gives us a better understanding thereof. A nanoscale 3D imaging techniques are from tomographic techniques of electron microscopy. However, many shots required (from different angles) make these techniques obsolete during the study time-resolved irreversible phenomena on non-reproducible samples. In this context, the aim of my thesis is to extend the 2D imaging techniques for 3D perception of nanoscale (physical, biological ) objects, while preserving the ultrafast appearance. The development of a new technology of 3D coherent imaging in single view, named ‘ankylography’, proposed by Professor Miao J. UCLA [Raines et al., Nature 2010] was made in progress. This technique allows reconstructing a 3D image of the sample after a single diffraction image. Its basic principle is to find the depth of a 3D object by the longitudinal constructive interference. However, this technique is more requested in both the quality of experimental data and the computer hardware and analysis. The other idea for 3D imaging is to imitate human vision using two coherent beams X arriving simultaneously on the sample but with a small angle. In this scheme, we use references near the target object (i.e. holography) to improve the signal to noise ratio in the diffraction pattern (hologram). Two holograms are then collected on the same detector. The inverse Fourier of each hologram forms two images from different views of the object. Parallax is thus produced. The stereo reconstruction of the object is performed by computer. Finally, the demonstration of applications will be considered after my thesis. This imaging of biological objects (such as nanoplanktons already collected and prepared CEA). And we are also interested in the study of 3D nanoscale objects (azo-polymers) movement on ultrashort time. Furthermore, another important application will be to study the ultra-fast phase transition such as nano-magnetic field where demagnetization phenomena induced by femtosecond pulse occurs
Mastropietro, Francesca. "Imagerie de nanofils uniques par diffraction cohérente des rayons X." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00716410.
Повний текст джерелаDjaker-Oudjhara, Nadia. "Microscopie par diffusion cohérente Raman CARS : application à l'imagerie des milieux biologiques." Aix-Marseille 3, 2006. http://www.theses.fr/2006AIX30038.
Повний текст джерелаCoherent anti-Stokes Raman scattering microscopy (CARS) is a new approach for chemical imaging of molecular systems, with high sensitivity, high spatial resolution, and three dimensional sectioning capability, without using fluorophores that are prone to photobleaching. This technique permits to map selectively molecular species, by using vibrational properties of their chemical bounds. CARS is described by a four wave-mixing process, where the signal intensity depends nonlinearly on the incident intensities, and generated in a direction determined by the phase-matching condition. The approach of this work was to realize a CARS microscope, allowing biological systems imaging without any labelling or staining. Studies were undertaken showing the potentialities of this tool, as well as its characterization in the spatial and spectral domain
Pinsolle, Edouard. "Etude des ondes de densité de charge par diffraction cohérente des rayons X." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00789152.
Повний текст джерелаBeutier, Guillaume. "Etude de nanostructures magnétiques par diffraction résonante et cohérente des rayons X mous." Grenoble INPG, 2005. http://www.theses.fr/2005INPG0154.
Повний текст джерелаSoft X-rays (~400-1500 eV) are among the best probes to study ferromagnetic nanostructures. Their wavelength (1-3 nm) is very weil suited to the characterisic lengthscales of these systems : magnetic storage is investigated in ferromagnetic thin films whose thickness and typical magnetic domain size are in the 10-100 nanometers range. Moreover, transition metals, which are commonly used in these materials, have their L3 edge in the soft x-ray energy range. This resonance enhances the x-rays sensitivity to local magnetic moments. Ln this thesis, we show that this sensitivity is useful to study the 3-dimensional configuration of magnetic moments. We study here the case of FePd thin films. By filtering the synchrotron beam with a 10-micrometer sized pinhole, a very coherent beam is selected. Its diffraction pattern, measured with a CCD camera used as a single photon detector, is a high resolution measurement of the Fourier Transform modulus of the object. We present here the coherent magnetic scattering from a FePd microstructure and from a grating of parallel nanolines with perpendicular magnetisation. The recontruction of the exacte magnetic configuration of the nanolines is discussed
Cassin, Rémy. "Imagerie nanométrique ultra-rapide par diffraction cohérente de rayonnement XUV produit par génération d'harmoniques d'ordre élevés." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS591/document.
Повний текст джерелаThe aim of this dissertation is todevelop new lensless single shot imagingtechnique in 2D and 3D with XUV harmonicsources which can be applied to study biologicalobjects and phase objects. Firstly, we introducethe theory underlying lensless imagingtechniques and we describe the methods usedduring this thesis to reconstruct the light fielddiffracted by the studied object. The imagingtechniques are split in two categories: iterativeand holographic. The iterative methodsreconstruct the phase of the diffracted wavefront using constraints in the Fourier space andthe reel space. With the holographic techniques,the phase is encoded directly in the interferencefringes between the reference and the objectwithin the diffraction pattern. We discuss theexperimental parameters required to achieve animage reconstruction and we compare therespective advantages of the two types ofmethod. Then, we describe the experimentalparameters of the XUV beam produced by highharmonic generation (HHG) and we brieflyexplain the theory of the HHG. The next sectiondiscusses the parameters the quality of thereconstructed image. We show how to improvethe resolution and the signal to noise ratio usingthe HERALDO technique in the low fluxregime.We then show the result of a new technique forthe single shot characterization of the spatialcoherence of XUV beams. Indeed, the spatialcoherence is a critical parameter for coherentdiffractive imaging techniques. Using a NRA ofreference holes, we measure the spatialcoherence for each distance between each pairof holes, without the knowledge of the intensitydistribution on the sample. We show that thespatial coherence has a gaussian distribution andthat its diameter varies according to thegeneration parameters of the harmonic beam.We also study quantitatively the effect of multishotsaccumulation of the diffraction pattern onthe apparent coherence of the beam. We alsoshow the result of phase object imaging usingcoherent diffractive imaging with a harmonicsource. To our knowledge, this if the first timesuch result has been achieved. The rest of thedissertation present new lensless imaging 3Dtechniques using harmonic sources. The first ofthe last two experiments shown is a lenslesssingle shot stereo 3D technique. It is the first oneallowing a 3D reconstruction from a singleacquisition, with a nanometer spatial resolutionand a femtosecond temporal resolution, withoutusing \textit{a priori} knowledge of the samplestudied. This method has a vast spectrum ofapplication and is particularly interesting for thestructural study of biological sample sensitive toradiation damage and for the study of nonreversibledynamical phenomena in 3D.Furthermore, this can easily be implemented inFELs and synchrotrons to reach even betterspatial resolution. The second 3D experimentshown in this thesis is a proof of concept ofcryptotomography using a high harmonic sourcein a low flux regime. To reconstruct the 3Dvolume of the sample, cryptotomographie usesdiffraction pattern acquired for unknown sampleorientations and therefore non-classified. Thelow flux regime used here simulate the flux of aharmonic source generated in the water window.We conclude from this experiment that, with theproper experimental conditions, the diffractionsignal is sufficient to allow the classification byorientation of the diffraction patterns. Withenough diffraction pattern and angles of thesample recorded, we can achieve a 3Dreconstruction of the sample. This result impliesthat the cryptotomography of biological objectsusing a water window harmonic source ispossible
Vaxelaire, Nicolas. "Etude des Inhomogénéités de Déformation dans les Films Minces Polycristallins par Diffraction X Cohérente." Phd thesis, Université Paul Cézanne - Aix-Marseille III, 2011. http://tel.archives-ouvertes.fr/tel-00622848.
Повний текст джерелаGauthier, David. "Imagerie nanométrique ultra-rapide par diffraction cohérente de rayonnement extrême-UV produit par génération d'harmoniques d'ordre élevé." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00734344.
Повний текст джерелаHerail, Christophe. "Etude et réalisation d'un système de mesure rapide de champs acoustiques : applications à l'imagerie médicale en tomographie par diffraction." Paris 11, 1989. http://www.theses.fr/1989PA112194.
Повний текст джерелаThis thesis contributes to the experimental study of ultrasound imaging with the so-called diffraction tomography method in which the diffraction phenomena inside the object under investigation are taken into account. The work was carried out in three steps: - Implementing a linear network of electronically scanned sensors within an ongoing experiment and solving the problem of inter-element coupling. - Designing and making a new electronic device in order to measure the acoustical pressure field then exploited by a microcomputer which both drives the experimental set-up and computes the images. This device was carefully conceived and made, so as to obtain performances (e. G. Noise level, accuracy, temperature stability) compatible with the requirement of the reconstruction method. - Conducting various experiments on objects of simple shapes (phantoms) and on a real biological object, and last, carrying out a qualitative study of thermography with differential imaging
Yuan, Yijia. "Diffusion de la lumière par un objet irrégulier pour l'application à l'imagerie des sprays." Rouen, 2012. http://www.theses.fr/2012ROUES044.
Повний текст джерелаThe particle-light interaction (light scattering) is the basic issue for the development and improvement of optical metrology. The rigorous theories are not suitable for irregular particles. Then, numerical methods have been developed, but they are still limited to small particles. It remains approximate methods of type geometrical optics. The aim of this thesis is to predict accurately the interaction between light and large objects of any shape. On the basis of geometrical optics, we have developed two approximate methods: vectorial complex ray model (VCRM) and Monte Carlo ray tracing of wave (MCRTW). They take into account the wave properties such as polarization, phase and divergence or convergence of the wave to predict correctly the interferences. The two models have been validated by comparison with the Lorenz-Mie theory for a spherical particle. We have also used them to predict the scattering patterns of a non-spherical particle, a spheroid. The scattering diagrams simulated by the two models correspond remarkably between them. The model can be adapted to particle of any shape. To consider the diffraction of a light ray or a photon, the Heisenberg uncertainty (HU) model has been studied and improved. Our diffraction model can accurately predict the diffraction by an aperture of complex shape and two apertures. We have developed a model of interaction between light and any object sufficiently precise to be applied to images of spray
Ferrayé, Ralph. "Développement d'un algorithme de diffraction inverse par déformations eulériennes de courbes de niveaux pour la reconstruction d'images microondes : application à l'imagerie radar." Nice, 2002. http://www.theses.fr/2002NICE5719.
Повний текст джерелаWe present a boundary-oriented method for 2D electromagnetic inverse scattering, in TM polarization and time-harmonic dependence. The method consists in moving some contours under a normal deformation velocity until they fit the contours of the unknown objects. The deformation velocity is appropriately chosen in such a way that a cost function, based on far-field data, is decreased after each elementary deformation. The contours of the mooring objects are viewed as the zero level set of a Hamilton-Jacobi PDE expressing the conservation of the level sets under a given velocity field. Level set methods add quite valuable features to the inverse procedure such as easy regularization of the contours with the introduction of a curvature term in the velocity field and automatic breaking and merging capability. The method uses a direct scattering algorithm based on boundary integral equations and on a kinematical description of the contours. Instead of working with the physical currents, that may be singular at corner points, pseudo-currents are introduced. The deformation velocity, written with respect to the well-behaved pseudo-currents, turns out to be highly accurate, therefore giving highly accurate constructions. The frequency hopping technique plays a very important role, as low frequencies make it possible to localize the objects and to reconstruct them roughly, and then higher frequencies allow finer details to retrieve. Very accurate reconstructions are given of several objects in presence, starting from one single initial object illustrating in the process the breaking capability of level set methods. Reconstruction results using noise-corrupted data, as well as stemming from configurations with limited coverage of the incident fields are also given
LOBEL, PIERRE, and Michel Barlaud. "Problemes de diffraction inverse : reconstruction d'image et optimisation avec regularisation par preservation des discontinuites - application a l'imagerie microonde." Nice, 1996. http://www.theses.fr/1996NICE4989.
Повний текст джерелаNounouh, Soufiane. "Protocoles de mesure et de calibrage de champs électromagnétiques en vue de l'imagerie par diffraction d'objets faiblement enfouis." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4750/document.
Повний текст джерелаThis thesis is devoted to the development of a microwave system dedicated to subsurface imaging applications. The analysis of the measured wave after the interaction with the medium allows to retrieve the electromagnetic properties of the probed structure. Here, we choose a single frequency operating mode combined with a multistatic configuration in order to improve the information diversity.Quantitative imaging requires a high-precision calibration of the measured data even after a careful correction of experimental errors. Thus, a calibration method is proposed, exploiting the measurement in free-space of the radiation pattern of each antenna. These patterns are quantitatively modeled thanks to an optimized linear combination of elementary sources positioned on the antenna's aperture. This simple and efficient calibration avoids additional measurements with calibration objects. This method provides successful results in a 2D free space scattering problem, as well as in the shallowly buried targets case.The calibrated data serve as inputs to inversion algorithms. As localization is concerned, very satisfactory detection results are obtained. Regarding the characterization aspects, the results indicate that the stratified configuration is less suitable than the free space configuration, due to its lack of spatial information. In order to improve the signal-to-noise ratio, some amendments are made to the experimental configuration (different antennas with or without orientation). Although the permittivity reconstructions are perfectible, the first results are promising especially since no a-priori on the targets has been inserted in the inversion algorithm so far
Tondusson, Marc. "Étude d'architectures lasers solides, multiaxes et multipassages, à volumes de gain distribués pompés longitudinalement par diodes lasers fibrées." Limoges, 2002. http://www.theses.fr/2002LIMO0003.
Повний текст джерелаThis work concerns the search of new end-pumped solid state laser designs. For which the pump power is divided in several zones in the gain medium. These methods distribute the thermal load to avoid the appareance of aberrations which disturb the spatial profile of the emitted laser beam
Ayasso, Hacheme. "Une approche bayesienne de l'inversionApplication à l'imagerie de diffraction dans les domaines micro-onde et optique." Paris 11, 2010. http://www.theses.fr/2010PA112251.
Повний текст джерелаLn this work, we are interested in scattering imaging in 2D and 3D configurations, where our objective is to reconstruct an image (contrast function) of an unknown object using measurements of the scattered field that results from the interaction between the unknown object and a known incident field whose propagation direction and frequency can be varied. The difficulty of this problem lies in the non-linearity of the forward model and in the ill-posed nature of the inverse problem which requires the introduction of prior information (regularization). For this purpose, we use a Bayesian approach with a joint estimation of the object contrast, currents induced inside the objects and other model parameters. The forward continuous model is described by two coupled integral equations. The discrete counterparts of the latter are obtained by means of the method of moments (MoM). For the inversion, the Bayesian approach allows us to model our knowledge about the object in a probabilistic way. For the given applications, the object under test is known to be composed of a finite number of materials, which implies that the desired image consists of a finite number of compact homogeneous regions. This justifies the choice of a prior model based upon a mixture of Gaussian with a hidden Markovian variable that represents the label of the regions. The nonlinear nature of the forward model and the use of this prior leads to joint posterior estimators which are intractable. Therefore, an approximation of the posterior distribution is needed. Two approaches are possible: a numerical approach, for example MCMC, and an analytical approach as the variational Bayesian approach. We have tested both approaches and both of them yield very good reconstruction results compared to classical methods. However, the variational Bayesian approach allows a much faster reconstruction as compared to the MCMC stochastic sampling method
Verezhak, Mariana. "Caractérisation multi-échelle du minéral osseux : apport de l'imagerie structurale par contraste de diffraction des rayons X et d'électrons." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY070/document.
Повний текст джерелаBone tissue is a biological composite material organized in several hierarchical levels that spread over more than 8 orders of magnitude in length scales, which is made of three principal components: collagen molecules, mineral nanocrystals and water. A fundamental understanding of how the mineral structure of bone tissue is organized at different length scales is essential for the biomedical community. To answer this demand, we applied novel methods currently in development for materials science to characterize the mineral phase: coherent X-ray diffraction imaging (CXDI), automated crystal orientation mapping with transmission electron microscope (ACOM-TEM) and pair distribution function analysis (PDF) of X-ray diffraction patterns.Bone tissue was investigated from its sub-angstrom arrangement, taking into account chemical composition and interatomic bond lengths shifts, through individual crystal organization (one crystal with respect to the next), to their micrometer organization with nanometer resolution, also allowing resolving the nanoporosity structure within the tissue.Beside the investigation of native bovine tissues, heated bones that are of interest in archeology, anthropology and forensic science, were used as a model to test for the applicability and sensitivity of the different methods for such biological materials. Moreover, a first insight into pathological bone tissues enabled to show that the structural differences of particular pathologies in comparison to healthy state can be observed already at the sub-angstrom scale (as seen from interatomic bonds shifts).The sample preparation described, the experimental setups and data analysis schemes could, furthermore, be applied to bone tissue at different anatomical location, with different degree of tissue maturation, to different species and pathological cases. Bone-like tissues such as dentin and antler as well as inorganic multiscale-porous materials could also be analyzed by the proposed scheme.Understanding the nanostructural characteristics of bone tissue is therefore useful to identify key structural markers of pathological human bone. This strategy could have an impact on future developments of new tools for diagnostic or to assess the effectiveness of pharmaceutical treatments
Girard, Gaétan. "Développement des méthodes de Ptychographie et diffraction cohérente des rayons X en géométrie de Bragg : application à l'étude de nano-structures." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALY010.
Повний текст джерелаNanotechnologies rely on the introduction of strain engineering to enhance semiconductor devices performances. As a consequence, non-invasive characterization methods with high spatial resolution and strain sensitivity on low-amount-of-matter samples are required. This PhD work focuses on methodology of X-ray diffraction techniques performed in the Bragg geometry, which allows probing the structural properties of crystalline samples. Firstly, the Scanning X-ray Diffraction Microscopy technique, developed on a fast-timescale at the ESRF ID01 undulator beamline, is described through a thorough analysis of an experiment performed on ultra-thin strained SiGe-on-insulator patterns. Secondly, this manuscript focuses on two coherent diffraction imaging techniques, namely Bragg CDI, which yields complex density and strain map of nano-meso crystalline objects, and Ptychography, which use translational diversity to produce quantitative maps of complex transmission function of non-crystalline objects. The motivation developed in this PhD work is to combine these two techniques that both promote highly sensitive phase-contrast properties, in order to provide ultra-high resolution on complex/extended samples. Bragg Ptychography is thus introduced, along with algorithmic descriptions and considerations on the X-ray beam characterization, the latter being still a key component for successful reconstructions
Ayasso, Hacheme. "Une approche bayésienne de l'inversion. Application à l'imagerie de diffraction dans les domaines micro-onde et optique." Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00564015.
Повний текст джерелаVautrin, Denis. "Régularisation et optimisation pour l'imagerie sismique des fondations de pylônes." Phd thesis, Ecole centrale de nantes - ECN, 2011. http://tel.archives-ouvertes.fr/tel-00692589.
Повний текст джерелаMarticke, Fanny. "Optimization of an X-ray diffraction imaging system for medical and security applications." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT055/document.
Повний текст джерелаX-ray diffraction imaging is a powerful noninvasive technique to identify or characterize different materials. Compared to traditional techniques using X-ray transmission, it allows to extract more material characteristic information, such as the Bragg peak positions for crystalline materials as well as the molecular form factor for amorphous materials. The potential of this technique has been recognized by many researchers and numerous applications such as luggage inspection, nondestructive testing, drug detection and biological tissue characterization have been proposed.The method of energy dispersive X-ray diffraction (EDXRD) is particularly suited for this type of applications as it allows the use of a conventional X-ray tube, the acquisition of the whole spectrum at the same time and parallelized architectures to inspect an entire object in a reasonable time. The purpose of the present work is to optimize the whole material characterization chain. Optimization comprises two aspects: optimization of the acquisition system and of data processing. The last one concerns especially the correction of diffraction pattern degraded by acquisition process. Reconstruction methods are proposed and validated on simulated and experimental spectra. System optimization is realized using figures of merit such as detective quantum efficiency (DQE), contrast to noise ratio (CNR) and receiver operating characteristic (ROC) curves.The first chosen application is XRD based breast imaging which aims to distinguish cancerous tissues from healthy tissues. Two non-multiplexed collimation configurations combining EDXRD and ADXRD are proposed after optimization procedure. A simulation study of the whole system and a breast phantom was realized to determine the required dose to detect a 4 mm carcinoma nodule. The second application concerns detection of illicit materials during security check. The possible benefit of a multiplexed collimation system was examined
Cherkas, Oxana. "Manufacturing and characterization of porous calcium carbonate for industrial applications." Thesis, Le Mans, 2018. http://www.theses.fr/2018LEMA1003.
Повний текст джерелаThe aim of this thesis was to synthesize porous calcium carbonate (CaCO3) particles for industrial applications as fillers for cigarette paper as well as a matrix for flavour encapsulation. We show that we can control the fabrication of porous particles of vaterite with a given size by tuning the parameters of synthesis. After the synthesis, the stability of vaterite in aqueous solution and at high temperature was studied. The phase transition was analyzed by XRD and coherent X-ray diffraction imaging that allows us to have a 3D-image of the particles. Finally, particles of 1-2 μm size with 20% porosity were reproducibly synthesized. Prepared vaterite particles were introduced as a filler in cigarette paper, with the goal to evaluate their impact on the physical properties of papers as well as on the reduction of some harmful compounds during the smoking. It was demonstrated that the use of vaterite can increase the diffusivity of paper and reduce the CO emission in the mainstream smoke. We also show that the use of X-ray absorption and diffraction can provide an estimation of the filler fraction and porosity of the papers in a non-destructive way. The encapsulation of flavours in CaCO3 particles was performed by co-crystallization and molecular inclusion. It was demonstrated that CaCO3 can be used as a matrix for flavour impregnation with more than 55% of encapsulation efficiency. Flavoured particles was added in paper for sensory evaluation. We shown that it is possible, to flavour the final product with flavoured calcium carbonate particles
Piault, Pierre. "Modélisation numérique et caractérisation des défauts dans les miroirs multicouches en vue de leur application en imagerie X cohérente." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLO008/document.
Повний текст джерелаMultilayer mirrors find numerous X-ray applications in synchrotron and X-rays free electron lasers. These multilayers optical devices must take up new challenges raised with the upgrade these radiation sources. To study the origin of intensity contrast in reflected beam, experimental measurements and numerical modeling were performed.Several techniques for multilayer structure charactérization have been implemented at the ESRF beamline BM05. Measurements methods based on 'Rocking Curve Imaging' and 'theta/2theta' Imaging were performed and applied for the first time to multilayer mirrors. Measurements of the wavefront reflected by multilayers were performed using holography and near field speckle techniques. The results obtained allowed a better understanding of the phase effects induced by multilayer reflection of their origin and to reconstruct the topography of the height defects within a multilayer mirror using the numerical model developped in the course of this PhD thesis.A numerical model based on Takagi-Taupin equations was modified to account for defects present in the multilayer mirror structure. Simulations for simple defects were performed to evaluate performance and limits of the numerical model. The propagation and the coherence of the reflected beam were simulated. The measurement and simulation results show the main influence of defect heights on the generation of the intensity contrast observed. The simulations also lead to conclude the equivalency phase effect resulting of the same height defects in multilayers mirror structure and reflecting surface.These modelization and simulations results can be usefull to specify defect feature which minimise reflected intensity contrast. The new developped experimental technics will allows X-rays caracterization for next multilayer mirrors
Huijts, Julius. "Broadband Coherent X-ray Diffractive Imaging and Developments towards a High Repetition Rate mid-IR Driven keV High Harmonic Source." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS154/document.
Повний текст джерелаSoft X-ray sources based on high harmonic generation are up to now unique tools to probe dynamics in matter on femto- to attosecond timescales. High harmonic generation is a process in which an intense femtosecond laser pulse is frequency upconverted to the UV and soft X-ray region through a highly nonlinear interaction in a gas. Thanks to their excellent spatial coherence, they can be used for lensless imaging, which has already led to impressive results. To use these sources to the fullest of their potential, a number of challenges needs to be met: their brightness and maximum photon energy need to be increased and the lensless imaging techniques need to be modified to cope with the large bandwidth of these sources. For the latter, a novel approach is presented, in which broadband diffraction patterns are rendered monochromatic through a numerical treatment based solely on the spectrum and the assumption of a spatially non-dispersive sample. This approach is validated through a broadband lensless imaging experiment on a supercontinuum source in the visible, in which a binary sample was properly reconstructed through phase retrieval for a source bandwidth of 11 %. Through simulations, the numerical monochromatization method is shown to work for hard X-rays as well, with a simplified semiconductor lithography mask as sample. A potential application of lithography mask inspection on an inverse Compton scattering source is proposed, although the conclusion of the analysis is that the current source lacks brightness for the proposal to be realistic. Simulations with sufficient brightness show that the sample is well reconstructed up to 10 % spectral bandwidth at 8 keV. In an extension of these simulations, an extended lithography mask sample is reconstructed through ptychography, showing that the monochromatization method can be applied in combination with different lensless imaging techniques. Through two synchrotron experiments an experimental validation with hard X-rays was attempted, of which the resulting diffraction patterns after numerical monochromatization look promising. The phase retrieval process and data treatment however require additional efforts.An important part of the thesis is dedicated to the extension of high harmonic sources to higher photon energies and increased brightness. This exploratory work is performed towards the realization of a compact high harmonic source on a high repetition rate mid-IR OPCPA laser system, which sustains higher average power and longer wavelengths compared to ubiquitous Ti:Sapphire laser systems. High repetition rates are desirable for numerous applications involving the study of rare events. The use of mid-IR wavelengths (3.1 μm in this work) promises extension of the generated photon energies to the kilo-electronvolt level, allowing shorter pulses, covering more X-ray absorption edges and improving the attainable spatial resolution for imaging. However, high repetition rates come with low pulse energies, which constrains the generation process. The generation with longer wavelengths is challenging due to the significantly lower dipole response of the gas. To cope with these challenges a number of experimental configurations is explored theoretically and experimentally: free-focusing in a gas-jet; free-focusing in a gas cell; soliton compression and high harmonic generation combined in a photonic crystal fiber; separated soliton compression in a photonic crystal fiber and high harmonic generation in a gas cell. First results on soliton compression down to 26 fs and lower harmonics up to the seventh order are presented.Together, these results represent a step towards ultrafast lensless X-ray imaging on table-top sources and towards an extension of the capabilities of these sources
Rollet, Nicolas. "Etude des propriétés de coordination de nouveaux ligands macrocycliques vis-à-vis de cations métalliques en vue de l'utilisation de leurs complexes pour l'imagerie médicale nucléaire." Phd thesis, Université de Bourgogne, 2011. http://tel.archives-ouvertes.fr/tel-00674037.
Повний текст джерелаDjaker, Nadia. "Microscopie par diffusion cohérente RamanCARS: Application à l'imagerie des milieuxbiologiques." Phd thesis, 2006. http://tel.archives-ouvertes.fr/tel-00121943.
Повний текст джерелаm´ethode r´ecente d'imagerie dont le contraste provient de l'excitation r´eso-
nante s´elective de vibrations mol´eculaires intrins`eques d'une liaison ou d'un
ensemble de liaisons chimiques. Cette technique pr´esente l'avantage de s'af-
franchir de tout marqueur fluorescent qui peut ˆetre toxique pour un orga-
nisme biologique vivant. Elle permet aussi d'avoir une tr`es grande sensibilit´e
et une forte r´esolution spatiale, comparable `a celle de la microscopie confo-
cale. Le travail de cette th`ese concerne la r´ealisation d'un microscope CARS,
et sa mise en application `a diff´erents domaine de l'imagerie bio-m´edicale. Des
´etudes ont ´et´e men´ees d´emontrant les potentialit´es de cet outil, ainsi que sa
caract´erisation dans le domaine spatiale et spectral.
Beutier, Guillaume. "ETUDE DE NANOSTRUCTURESMAGNÉTIQUES PAR DIFFRACTIONRÉSONANTE ET COHÉRENTE DESRAYONS X MOUS." Phd thesis, 2005. http://tel.archives-ouvertes.fr/tel-00108493.
Повний текст джерелаdes rayons X mous. Les échantillons étudiés sont des empilements de couches minces
épitaxiées d'alliages de FePd et des multicouches de Co/Pt déposées sur des substrats de Silicium
nanostructurés. Dans une première partie, les échantillons sont présentés et caractérisés par des
techniques conventionnelles de laboratoire, ainsi que par des mesures de neutrons. En outre, une
modélisation micromagnétique est décrite. Dans une deuxième partie, la diffusion des rayons X
mous par les couches de FePd est mesurée au seuil L3 du Fer et modélisée afin de tirer des informations
sur la configuration magnétique périodique des échantillons. Dans une troisième partie,
j'utilise un faisceau cohérent de rayons X mous afin de caractériser en détail la configuration
magnétique d'échantillons modèles. A cette fin, un dispositif instrumental est développé et une
méthodologie est décrite pour le comptage des photons sur une camera CCD. Un algorithme de
Monte-Carlo est proposé et discuté en vue de reconstruire la configuration magnétique exacte
d'un réseau de nanolignes à aimantation perpendiculaire.