The optical design of a soft X-ray (90-1100~eV) emission spectrometer for the Resonant Elastic and Inelastic X-ray Scattering (REIXS) beamline to be implemented at the CLS is presented. An overview of soft X-ray optical theory as it relates to diffraction gratings is given. The initial constraints and the process that led to this design are outlined. Techniques and software tools that were developed, using ray-tracing and diffraction grating efficiency calculations, are discussed. The analysis completed with these tools to compare existing soft X-ray emission spectrometer designs is presented. Based on this analysis, a new design with superior performance for this application is proposed and reviewed. This design employs Rowland circle geometry to achieve a resolving power in excess of 2,500 in the range of interest. In addition, a novel design is proposed for a larger extremely high resolution spectrometer which will provide resolving powers exceeding 10,000 throughout the higher end of this range. A review is given of research into the components, manufacturing techniques and tolerances that will be required to produce this spectrometer.

The heart is one of the most important organs of the human body and cardiovascular diseases remain the biggest cause of deaths worldwide. Today, due to the aging of the population and the growing demand for cardiovascular implants, improving the performance of artificial surfaces of vascular prostheses is highly desired. The common material for fabricating prostheses, such as stents used to remedy narrow and weak arteries, is Fluorocarbon polymers or expanded Polytetrafluoroethylene (ePTFE, Gore-tex). Although these polymers are well known for chemical inertness, thermal stability and low friction, they can cause early thrombosis (forming clot) and coagulation in blood vessels and require periodic replacement. Modifying the surface properties of Polytetrafluoroethylene (PTFE) by coating with carbon-based materials may improve its blood compatibility. Carbon-based coatings have properties similar to biomedical components, such as low friction, bioinertness, high wear resistance and exceptional hardness. Plasma processing methods are commonly used for coating thin films on various materials including carbon-based components. Plasma-based processes are also widely used in the aerospace, automotive, steel and biomedical industries. For example, extending the lifetime of surgically implanted hip joints and cutting tools are biomedical and industrial applications of plasma-based material processing respectively. Plasma-assisted deposition techniques are commonly used for carbon-based coating including nitrogen-doped amorphous carbon (a-C) films. In this thesis, PTFE samples with different thickness and roughness characteristics are used as substrates and diamond-like carbon (DLC) is deposited on them by simultaneous plasma-assisted sputtering and chemical vapour deposition (CVD). Hot filament plasma and ICP (Inductively coupling plasma) are used to coat DLC on PTFE and silicon (Si) substrates under various plasma conditions. The latter is the first report on the techniques to coat DLC by ICP plasma sputtering. This new technique (ICP-sputtering) is developed to improve low deposition rate and high temperature deposition of previous method (Hot filament plasma sputtering). Advantageous of this new developed method (ICP-sputtering) are discussed and compared with the previous method in this thesis. Various amount of nitrogen is introduced to the plasma chambers and the effect of nitrogen dopant is also studied using different characterization techniques for chemical, electronic and morphological properties of coated films. sp2 and sp3 contents were also estimated in amorphous carbon (a-C) and nitrogenated amorphous carbon (a-CN) films. Characterization techniques used for in this thesis are including SEM (scanning electron microscopy), AFM (atomic force microscopy), Raman spectroscopy, XAS (x-ray absorption spectroscopy), XES (x-ray emission spectroscopy), XPS (x-ray photoelectron spectroscopy) and XRD (x-ray diffraction).

The donor-acceptor couple CuPc/C60 has been the subject of recent studies in organic solar cells due to its combined abilities in light absorption (CuPc) and charge transport (C60). By better understanding the electronic and geometric nature of the system it is possible to shed light on how the molecules act under different conditions. In this study the geometric properties for three different configurations have been studied by means of Density Functional Theory (DFT). By comparing the molecular structure of pristine CuPc with the structure of CuPc in the presence of C60, a slight elongation of the bonds is observed when the fullerene is present. This is especially true for the Cu-N bonds. By further including van der Waals interactions, no change in bond lengths is observed. This, in turn, suggests that, most likely, the interaction between the two molecules is relatively weak and the C60 will not have a major influence on the electronic structure of CuPc. The N1s X-ray Photoelectron Spectroscopy (XPS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) calculations confirm these conclusions, as only very small changes in peak positions are observed when comparing pristine CuPc with CuPc/C60. / Tack vare sina egenskaper inom absorption och laddningsöverföring har CuPc och fullerenen C60 varit föremål för omfattande studier bland forskare inom organiska solceller. Genom att få större förståelse för den geometriska såväl som den elektroniska konfigurationen inom och mellan paret kan man förutse hur dessa kommer att bete sig i olika sammansättningar. I denna studie har de geometriska förutsättningarna studerats där olika konfigurationer beräknats genom täthetsfunktionalteori (DFT). Genom att mäta bindningslängderna mellan koppar, kol och de olika typer av kväve i CuPc i de olika systemen, kan det inses att bindningarna förlängs då C60 läggs till. Då van der Waals-interaktioner inkluderades observerades ingen större förändring i bindingslängderna i jämförelse med fallet utan van der Waals-interaktioner. Detta tyder på att växelverkan mellan de två molekylerna är relativt svag och att C60-fullerenen ej har någon större påverkan på elektronkonfigurationen i CuPc. Beräkningarna av N1s X-ray Photoelectron Spectroscopy (XPS) och Near Edge X-ray Absorption Fine Structure (NEXAFS) stödjer denna slutsats då endast små skiftningar i topparna observerades vid jämförelse mellan rent CuPc och CuPc/C60.

<p>The electronic structures of the nucleobases, 5-fluorouracil compounds, DNA, metallic DNA, and samples of boron nitride are investigated. Soft X-ray absorption (XAS) and emission (XES) spectroscopy using synchrotron radiation are used to probe the unoccupied and occupied partial densities of electronic states, respectively. Hartree-Fock and density functional theory calculations have been included to compare with experimental results.</p> <p>A systematic approach to understanding the complicated electronic structure of DNA and metallic DNA systems is to initially examine smaller components. Detailed experiment and theory for both absorption and emission spectroscopy was. performed for the nucleobases and 5-fluorouracil compounds. Main transitions in the XAS and XES spectra are identified. X-ray spectroscopy has proven to be extremely sensitive to changes in the environment of various DNA samples. The local chemical environment plays an important role in determining the electronic structure of DNA. In agreement with previous results indicating metallic DNA is more efficient at the transfer of electrons than DNA, XES measurements reveal that there are a higher number of charge carriers in the metallic system. Both liquid and powder samples of (Ni)·M-DNA are found to have a high spin Ni(II) configuration. The drying process significantly alters the electronic structure of the metallic DNA sample. A comparison of high quality single crystals and thin films of boron nitride found that differences between the electronic structures of the nanocrystalline films and the single crystal samples exist, and the surface roughness of the substrate plays an important role in determining the structure of the resulting deposited film.</p>

<p>The electronic structures of the nucleobases, 5-fluorouracil compounds, DNA, metallic DNA, and samples of boron nitride are investigated. Soft X-ray absorption (XAS) and emission (XES) spectroscopy using synchrotron radiation are used to probe the unoccupied and occupied partial densities of electronic states, respectively. Hartree-Fock and density functional theory calculations have been included to compare with experimental results.</p> <p>A systematic approach to understanding the complicated electronic structure of DNA and metallic DNA systems is to initially examine smaller components. Detailed experiment and theory for both absorption and emission spectroscopy was. performed for the nucleobases and 5-fluorouracil compounds. Main transitions in the XAS and XES spectra are identified. X-ray spectroscopy has proven to be extremely sensitive to changes in the environment of various DNA samples. The local chemical environment plays an important role in determining the electronic structure of DNA. In agreement with previous results indicating metallic DNA is more efficient at the transfer of electrons than DNA, XES measurements reveal that there are a higher number of charge carriers in the metallic system. Both liquid and powder samples of (Ni)·M-DNA are found to have a high spin Ni(II) configuration. The drying process significantly alters the electronic structure of the metallic DNA sample. A comparison of high quality single crystals and thin films of boron nitride found that differences between the electronic structures of the nanocrystalline films and the single crystal samples exist, and the surface roughness of the substrate plays an important role in determining the structure of the resulting deposited film.</p>

Based on a previously completed design for a soft X-ray (50-1100 eV) emission spectrometer, an endstation was constructed for the Resonant Elastic and Inelastic X-ray Scattering (REIXS) beamline at the CLS. The optical design employed techniques and software tools developed in-house using ray-tracing and diffraction grating efficiency calculations to analyze and compare existing designs and to propose a new design with superior performance. This design employs Rowland circle geometry to achieve a theoretical resolving power in excess of 2,500 in our range of interest. In addition, a novel optical design for a larger extremely high resolution spectrometer has been completed to provide theoretical resolving powers exceeding 10,000 throughout the higher end of the spectrum. To accommodate this optical design a completely new mechanical design was required, involving significant mechanical, electrical, vacuum and software engineering. Countless custom fabricated parts were required along with numerous o -the-shelf secondary instruments and systems. All told, this entirely student-managed project has cost over $1.5M and taken over 5 years. Construction is finally complete and the endstation is currently being commissioned. Necessary design changes made during the mechanical design process resulting in the selection of a more suitable, but lower resolution, detector. This reduced the theoretical maximum resolving power to 1,800 for the first order gratings and roughly 5,000 for the third order gratings. Commissioning is still underway, but first order resolutions in the range of 1,000 - 2,000 have been recorded as have third order resolutions exceeding 4,000. Publication quality data has been collecting by members of this research group and invited external users have successfully grown and measured samples here. Two of the optical elements required rework and upon their delivery the system commissioning will be completed and peer-reviewed access will begin.

Cette thèse traite de la prise en compte de l'impact des procédés d'assemblage thermomécanique sur la géométrie de la caisse en blanc lors de la phase de conception d'un véhicule, chez PSA Peugeot-Citroën. Pour cela, on souhaite développer un outil de prévision des déformations induites par les procédés de soudo-brage - plasmatron et laser - lors de l'assemblage du pavillon sur le côté de la caisse. Les pièces - de dimensions métriques - sont composées de tôles fines d'épaisseur 0,67 mm en acier XES. Afin de réaliser une simulation numérique du procédé, il est nécessaire d'identifier un certain nombre de modèles, objets de cette thèse. Dans un premier temps des essais de soudo-brasage en laboratoire ont été réalisés afin de définir les domaines de validité de l'étude, d'identifier des modèles de sources de chaleur, et de déterminer les coefficients d'échange thermique avec l'extérieur. Une étude spécifique d'identification des lois de comportement des matériaux mis en jeu, sur toute la gamme de température, a également été réalisée. Pour cela, une méthode de mesure de champs par corrélation d'images numériques à haute température a été développée, qui a permis d'identifier complètement les paramètres de la loi de comportement de l'acier XES. Pour finir, de façon à réaliser la validation de la simulation numérique, ces travaux de thèse ont été l'occasion de développer une nouvelle méthode de calibration pour la stéréocorrélation d'images basée sur la connaissance a priori de la géométrie de l'objet observé, en considérant sa forme théorique via son modèle CAO. Cette méthode est tout particulièrement adaptée aux dimensions des structures étudiées ici. / This study is about the impact of thermo-mechanical assembly processes of metal sheets, in the automotive industry context. The aim is to predict thermally induced deformations by using a numerical tool. We are particularly interested in Plasmatron and laser brazing processes that are used to assemble an automotive roof and the body side of the vehicle. Parts are made from 0,67 mm thickness XES thin metal sheet of about one meter length. To validate such complex non-linear numerical simulations with experimental observations, it is necessary to develop well-controlled and highly instrumented tests. In a first step, experimental welding brazing tests are carried out in order to identify validity domains, heat source model and thermal coefficients of exchange. In a second step, high temperature tension tests are performed to identify the behaviour of each material. These tests are instrumented with a new DIC protocol in order to measure displacement fields from 20°C to 1000°C. Finally, in order to validate the thermo-mechanical simulation, in-situ 3D Digital Image Correlation (stereo-correlation) measurements were performed during the welding-brazing assembly. For this purpose and due to the geometry of the involved parts, a new calibration method, based on the CAD part geometry has been developed.

This thesis is centred around the study materials with novel electronic properties, including transition metals interacting with semiconductors and unique molecular systems. The idea of advancing modern computing is the basis for motivating the work in that the projects all have potential to be used in novel applications that would impact the efficiency and/or execution of current technology. We have studied two variations of transition metals as they appear in materials and two molecular systems. As for the transition metals interacting with semiconductors, we first discuss transition metal atoms introduced as impurities to a semiconductor lattice, and second, we discuss transition metal oxides that are naturally semiconducting. We have used a number of experimental and theoretical techniques to better understand these groups of materials. Materials prepared through high quality synthesis techniques were studied using x-ray spectroscopy made possible by synchrotron light sources. Computational software then allowed for the experiments to be interpreted by comparing them to the simulations. In the study of transition metals as impurities, we chose the Co:MoS2 system because MoS2 has had promising results with other transition metal dopants. We examined the electronic structure for two purposes: (1) to determine the local bonding environment and locations of the cobalt atoms in order to better understand the behaviour of Co as an impurity; and (2) the overall band gap of the system so that we could evaluate the system’s potential for use in applications. Experimental results combined with our theoretical simulations led us to conclude that the samples available were all metallic, and at low concentrations cobalt atoms were able to substitute directly into the MoS2 lattice. An examination of copper (II) oxide allowed us to investigate the ability to tune the band gap of a known semiconductor through a synthesis process that applied axial pressure to the sample. For a collection of samples prepared at different pressures, x-ray spectroscopy methods showed an increasing band gap with increasing synthesis pressure, a result that is most encouraging for the field of band gap engineering. Using soft x-ray spectroscopy to examine the conduction and valence bands of the two molecular systems, the potassium-doped hydrocarbons and Li2RuO3, was important for drawing conclusions about the materials’ composition and behaviour. Results showed the introduction of new states at the lower edge of the conduction band of K:phenanthrene, a possible reason for its low-temperature superconductivity. Li2RuO3’s electronic structure was examined and compared to calculations performed by collaborators.

Dans ce travail, nous nous concentrons sur la caractérisation de l'environnement physico-chimique des éléments présents dans des multicouches à base de cobalt qui travaillent dans les domaines des rayons X mous et extrême ultra-violet (EUV). L'observation des modifications des interface des deux systèmes Co/Mo2C et Co/Mo2C/Y lors du recuit est important pour l'amélioration de leurs performance optique. Ils ont été étudiés en combinant des méthodes non destructives, spectroscopie d'émission des rayons X, résonance magnétique nucléaire, réflectométrie de rayons X et des méthodes destructrices, spectrrométrie de masse d'ions secondaires par temps de vol et la Microscopie électronique en transmission pour étudier leurs propriétés interfaciales. Ce travail vise non seulement à la conception et la fabrication de nouveaux éléments optiques pour faire face au développement des sources et des applications dans les demaines des rayons X mous et l'EUV, mais aussi à développer une méthodologie combinant des simulations et des expérimentations consacrée à l'analyse des interfaces dans structures multicouches afin d'améliorer leur propriétés optiques. / In this work, we focus on the characterization of physico-chemical environment of the element present in Co-based multilayers working in the soft x-ray and EUV ranges. The observation of interface changes of both systems Co/Mo2C and Co/Mo2C/Y upon annealing is important for improving their optical performance. They were studied by combining non-destructive methods, x-ray emission spectroscopy, nuclear magnetic resonance spectroscopy, x-ray reflectometry and destructive methods, time-of-flight secondary ions mass spectroscopy and transmission electron microscopy to investigate their interface properties. This work aims not only at designing and fabricating new optical elements to face the development of sources and applications in the EUV and soft x-ray ranges, but also at developing a methodology combining simulations and experiments devoted to the interface analysis in these multilayer structures in order to improve their optical properties.

The electronic and magnetic structure of the colossal magneto resistance material La1-xSrxMnO3, the high-k and strain tailoring compounds REScO3 (Sm, Gd, Dy) and the multiferroic LuFe2O4 was investigated by means of x-ray spectroscopic techniques. SQUID measurements of La1-xSrxMnO3 (x = 0.125, 0.17, 0.36) were compared with XMCD results. The very good agreement between these two experiments proofs the applicability of the correction factor for the spin magnetic moment and the importance of charge transfer. The magnetic moment measured by SQUID and that determined from XMCD proofs that the magnetic moment is completely localized at the Mn ions for different temperatures and magnetic fields. For x = 0.125 the orbital magnetic moment determined from XMCD corresponds to the structural changes in the phase diagram. Additionally the measured orbital moments correspond to anomalies in magnetization versus temperature curves. The magnetic and electronic structure of the rare earth scandates (SmScO3, GdScO3 and DyScO3) were investigated by means of XPS, XES, XAS, SQUID and neutron powder diffraction. The magnetic measurements reveal antiferromagnetic coupling at low temperatures in agreement with neutron diffraction data. With XAS and XES at the O K-edge in comparison with band structure calculations of the unoccupied oxygen states, the band gaps of REScO3 were determined and it was found that these values are corresponding to the Sc-O mean distances. The electronic and magnetic structure of LuFe2O4 was presented. The valence state of Fe ions was determined to 50% divalent and 50% trivalent by XPS of Fe 2p and 3s levels. The big orbital magnetic moment found by XMCD could explain a discrepancy between the magnetic measurements and the spin configuration, which was confirmed by XMCD.