Orientador: Antônio Rubens Britto de Castro / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-16T08:21:17Z (GMT). No. of bitstreams: 1 Grizolli_WalanCesar_M.pdf: 22164883 bytes, checksum: 87cb39dcd42129ec1d9a3f9ec6fcba09 (MD5) Previous issue date: 2010 / Resumo: Diversas áreas da ciência moderna têm sido beneficiadas pelo uso da radiação síncrotron. As técnicas disponveis em laboratórios deste tipo abrangem pesquisas em ciências básicas como Física, Química e Biologia bem como em áreas como engenharia de materiais e farmacologia. Em particular, o uso do espectro de raios-x duros (8-20keV) das fontes síncrotron atuais e crucial para técnicas estruturais como difração e cristalografia. Estas técnicas estão disponíveis para a comunidade científica brasileira no Laboratório Nacional de Luz Síncrotron (LNLS), cujas linhas de luz estão abertas a usuários externos desde 1997. As instalações do LNLS vem sendo constantemente aperfeiçoadas, permitindo o estudo de novos casos científicos como consequência destas melhorias. Neste trabalho estudamos as propriedades da fonte de radiação síncrotron do LNLS e realizamos um projeto óptico para uma linha de luz direcionada a cristalografia de proteínas. Com uso de simulações computacionais propomos opções para melhoria do fluxo de flotons nas linhas de cristalografia de proteínas já existentes. Nossos estudos apontam para a viabilidade de construção de uma linha lateral a linha de luz MX2, utilizando a mesma fonte Wiggler já instalada, com fluxo proporcional à linha central. / Abstract: Distinct research fields in modern science have taken advantage of synchrotron radiation. The techniques that are available in such laboratories have a very broad scope, ranging from basic sciences such as Physics, Chemistry and Biology, to applied fields as engineering and pharmacology. In particular, the use of hard x-ray spectrum (8-20keV) from modern synchrotron sources is crucial for structural techniques such as diffraction and crystallography. These techniques have been available to the Brazilian scientific community since 1997, when the Brazilian Synchrotron Light Laboratory (LNLS) facilities were opened to external users. The LNLS beamlines have constantly evolved , allowing the users to perform novel experiments as a consequence of instrumental improvements. In this work we study the properties of the LNLS sources and propose solutions for the optics of a beamline dedicated to protein crystallography. By using computer simulations we propose options to enhance the photon flux in the pre-existing protein crystallography beamlines. Our results point out to the feasibility of a lateral beamline using the MX2 wiggler source, with similar flux to the central beamline. / Mestrado / Física / Mestre em Física

We obtained X-ray XMM-Newton observations of the open cluster Berkeley 87 and the massive star-forming region (SFR) ON 2. In addition, archival infrared Spitzer Space Telescope observations were used to study the morphology of ON 2, to uncover young stellar objects, and to investigate their relationship with the X-ray sources. It is likely that the SFR ON 2 and Berkeley 87 are at the same distance, 1.23 kpc, and hence are associated. The XMM-Newton observations detected X-rays from massive stars in Berkeley 87 as well as diffuse emission from the SFR ON 2. The two patches of diffuse X-ray emission are encompassed in the shell-like H II region GAL 75.84+0.40 in the northern part of ON 2 and in the ON 2S region in the southern part of ON 2. The diffuse emission from GAL 75.84+0.40 suffers an absorption column equivalent to AV ≈ 28 mag. Its spectrum can be fitted either with a thermal plasma model at T ≳ 30 MK or by an absorbed power-law model with γ ≈ −2.6. The X-ray luminosity of GAL 75.84+0.40 is LX ≈ 6 × 1031 erg s−1. The diffuse emission from ON 2S is adjacent to the ultra-compact H II (UCH II) region Cygnus 2N, but does not coincide with it or with any other known UCH II region. It has a luminosity of LX ≈ 4 × 1031 erg s−1. The spectrum can be fitted with an absorbed power-law model with γ ≈ −1.4. We adopt the view of Turner & Forbes that the SFR ON 2 is physically associated with the massive star cluster Berkeley 87 hosting the WO-type star WR 142. We discuss different explanations for the apparently diffuse X-ray emission in these SFRs. These include synchrotron radiation, invoked by the co-existence of strongly shocked stellar winds and turbulent magnetic fields in the star-forming complex, cluster wind emission, or an unresolved population of discrete sources.

Le rayonnement synchrotron dans la gamme d'énergie des rayons X tendres (2-13 keV) permet l'excitation/ionisation d'atomes et de molécules en couche profonde. Les états ainsi peuplés ont des durées de vie ultra-courtes, de l'ordre de la femtoseconde. Les atomes vont alors se relaxer par émission d'un photon ou d'un électron. Dans cette thèse, nous avons utilisé la spectroscopie d'électrons afin d'étudier les différents processus induits par l'interaction entre la matière et un rayonnement très énergétique. Dans la première partie, la durée de vie des états électroniques excités est utilisée comme une horloge interne permettant la mesure du mouvement nucléaire à l'échelle de temps sub-femtoseconde. Les élargissements naturels dus à la durée de vie des états électroniques peuplés sont suffisamment grands pour que ces états se recouvrent, permettant l'excitation simultanée de plusieurs états intermédiaires pouvant causer des phénomènes d'interférences lors de l'étape de relaxation. C'est le sujet de la deuxième partie de cette thèse, où nous présentons un modèle permettant d'extraire ces termes d'interférences. Dans la dernière partie, nous montrons qu'il est également possible de peupler des états électroniques multiplement excités/ionisés, et que notre dispositif expérimental permet d'en extraire les durées de vie, ainsi que de résoudre toutes les contributions se recouvrant dans les spectres d'électrons. Le fil d'Ariane de ce travail est de tenter d'appréhender les différents processus de corrélations électroniques suite à l'excitation du système étudié via un photon de haute énergie, comme le partage d'excès d'énergie ou de moment angulaire entre plusieurs électrons. / Synchrotron radiation in the tender x-ray energy range (2-13 keV) allows deep core-shell excitation/ionization of atoms and molecules. The electronic states populated have ultrashort lifetimes, in the order of one femtosecond. The atoms will then relax through emission of a photon or an electron. In this thesis, we used electron spectroscopy as a tool to study the different processes implied by the interaction between the matter and highly energetic radiation. In the first part, the lifetime of the excited electronic states is used as an intern clock allowing to measure nuclear dynamics in the sub-femtosecond timescale. The lifetime broadenings of the populated electronic states are large enough so that these states overlap, thus allowing their coherent excitation which may lead to interferences phenomena during the relaxation step. This is the subject of the second part of this work, in which we present a model that allows the extraction of these interference terms. In the last part, we show it is also possible to form multiply excited/ionized electronic states, and that our experimental setup allows to measure their lifetimes, and the disentanglement of the many contributions overlapping in the electron spectra. The Ariadne’s thread of this work is to try to apprehend the different electronic correlation processes following the excitation of the studied system by a highly energetic photon, such as how electrons share the incident excess energy or the angular momentum transferred by the incident photon.

Cette thèse vise à améliorer la méthode d'analyse du fond continu inélastique afin de l'appliquer à des cas qui présentent un intérêt technologique. En effet, ces améliorations sont cruciales car elles portent sur des critères de précision et de gain de temps, plus particulièrement pour l’étude de dispositifs présentant plusieurs couches profondément enterrées de matériaux bien distincts. Ainsi, l'analyse du fond continu inélastique associée à la spectroscopie de photoélectrons à rayons X durs (HAXPES) présente un grand intérêt car l’HAXPES permet de sonder plus profondément dans un échantillon qu'avec la spectroscopie de photoélectrons à rayons X classique (XPS). Ce présent travail porte sur des échantillons technologiquement pertinents, principalement des transistors à haute mobilité d'électrons (HEMTs), à certaines étapes cruciales de leur processus de fabrication, tels que des recuits. Il est donc très important que ces analyses soient effectuées de manière non destructive afin de préserver les interfaces enterrées. Ce sont souvent l'emplacement de phénomènes complexes qui sont critiques pour les performances du dispositif et une meilleure compréhension est une condition préalable à l’amélioration des dispositifs. Dans ce travail, les phénomènes de diffusion en profondeur sont étudiés grâce à l’analyse du fond continu inélastique associée à l’HAXPES (en utilisant le logiciel QUASES) pour des profondeurs allant jusqu'à 60 nm. Les résultats de distribution en profondeur présentent des écarts par rapport aux mesures TEM inférieures à 5%. Le choix des paramètres d'entrée de la méthode est discuté pour une large gamme d'échantillons et des règles simples en sont issues qui rendent l'analyse réelle plus facile et plus rapide à effectuer. Enfin, il a été montré que la spectromicroscopie faite avec la technique HAXPEEM peut fournir des spectres à chaque pixel utilisables pour l’analyse du fond continu inélastique. Cela peut fournir une cartographie 3D de la distribution en profondeur des éléments de manière non-destructive. / This thesis aims at improving the inelastic background analysis method in order to apply it to technologically relevant samples. Actually, these improvements are utterly needed as they concern criteria of accuracy and time saving particularly for analysis of devices presenting deeply buried layers with different materials. For this purpose, the interest of the inelastic background analysis method is at its best when combined with hard X-ray photoelectron spectroscopy (HAXPES) because HAXPES allows to probe deeper in the sample than with conventional X-ray photoelectron spectroscopy (XPS). The present work deals with technologically relevant samples, mainly the high-electron mobility transistor (HEMT), at some crucial steps of their fabrication process as annealing. Actually, it is very important that these analyses shall be performed non-destructively in order to preserve the buried interfaces. These are often the location of complex phenomena that are critical for device performances and a better understanding is often a prerequisite for any improvement. In this thesis, the in-depth diffusion phenomena are studied with the inelastic background analysis technique (using the QUASES software) combined with HAXPES for depth up to 60 nm. The depth distribution results are determined with deviations from TEM measurements smaller than a typical value of 5%. The choice of the input parameters of the method is discussed over a large range of samples and simple rules are derived which make the actual analysis easier and faster to perform. Finally, it was shown that spectromicroscopy obtained with the HAXPEEM technique can provide spectra at each pixel usable for inelastic background analysis. This is a proof of principle that it can provide a 3D mapping of the elemental depth distribution with a nondestructive method. / Denne afhandling har til formål at forbedre den uelastiske baggrundsanalysemetode til anvendelser i den til teknologiske industri. Faktisk er disse forbedringer absolut nødvendige, for at opnå nøjagtighed og tidsbesparelse, især for analyse af prøver med dybt begravede lag af forskellige materialer. Til det formål er interessen for den uelastiske baggrundsanalysemetode bedst i kombination med hård røntgenfotoelektron-spektroskopi (HAXPES), fordi HAXPES gør det muligt at probe dybere i prøven end med konventionel røntgenfotoelektron-spektroskopi (XPS). Dette arbejde beskæftiger sig med teknologisk relevante prøver, hovedsagelig høj-elektron mobilitetstransistor (HEMT), på nogle afgørende trin i deres fremstillingsproces som fx annealing. Faktisk er det meget vigtigt, at disse analyser udføres på en ikke-destruktiv måde for at bevare de begravede grænseflader. Det er ofte her de komplekse fysiske fænomener opstår, som er kritiske for fuktionaliteten, og en bedre forståelse af grænsefladerne er ofte en forudsætning for at kunne forbedre denne. I denne afhandling studeres de dybdegående diffusionsfænomener med den uelastiske baggrundsanalyse teknik (ved hjælp af QUASES software) kombineret med HAXPES for dybder op til 60 nm. Dybdestributionsresultaterne har afvigelser fra TEM-målinger mindre end en typisk værdi på 5%. Valget af input parametre for metoden er diskuteret på bagground af et stort udvalg af prøver samt omfattende simuleringer og enkle regler er udledt, hvilket gør den praktiske analyse nemmere og hurtigere at udføre. Endelig blev det vist, at spektromikroskopi opnået med HAXPEEM-teknikken kan tilvejebringe spektre ved hver enkelt pixel som kan anvendes til uelastisk baggrundsanalyse. Dette viser at i princippet kan en 3D-billeddannelse af den elementære dybdefordeling bestemmes ikke destruktivt.

Dans les tokamaks, Sous l'application champ de électrique, les électrons sont accélérés et en même temps, ils subissent une force de friction due aux collisions avec les autres particules du plasma. Cependant, une fraction de la population totale d'électrons peuvent surmonter la force de friction et atteindre une vitesse proche de la vitesse lumière. Ces électrons relativistes sont découplés du plasma et sont appelés électrons runaway (ER). Ils peuvent apparaître lors des différentes phases d'une décharge de plasma. Par exemple, dans la phase de démarrage ou alors pendant les disruptions, au cours desquelles une fraction importante du courant plasma peut être convertie en ER ayant une énergie pouvant atteindre quelques dizaines de MeV. Les ER créés pendant la phase de perturbation peuvent causer des dommages aux premiers composants murs si un dépôt localisé de forte puissance se produit. ITER étant un tokamak de grande taille et un projet coûteux, la génération d'ER n'est pas souhaitable. La viabilité de la machine nécessite que les ER soient détectés en temps réel. La thèse fournit une étude détaillée dans cette direction pour le développement des deux principaux diagnostics sur ITER impliqués dans les mesures de paramètres pour les ER, à savoir, le moniteur de rayons X durs qui détecte le rayonnement de bremsstrahlung et les caméras visibles et infrarouges qui détectent le rayonnement synchrotron. Une solution de conception unique a été proposée pour le moniteur HXRM et est développée ici et optimisée. Pour les caméras, une modélisation des signaux est effectuée pour la première fois. Pour ce faire, un code de calcul a été développé et validé sur différents tokamaks. / In tokamaks, under the application of the electric field, a small fraction of the total electrons population can overcome collisional drag force and attain high velocity close to the speed of light. These relativistic electrons are called Runaway-Electrons (REs). The REs can occur during different phases of a plasma discharge. REs created during the disruptions phase can form a high energetic RE-beam that poses a risk to damage the first wall components if localized high power deposition takes place. ITER being a large size tokamak and an expensive project, generation of REs is not desirable during any phases of a plasma discharge. Detection of these REs and measurements of its parameters are important for the tokamak operation. Hence, RE diagnostics have to be in place to aid the commissioning of the disruption mitigation system and also for the post-event analysis to improve the reliability of RE avoidance. The present thesis gives a detailed study in this direction for the development of the two principal ITER Diagnostics involved in RE parameter measurements, namely the Hard X-Ray Monitor (HXRM) that detects bremsstrahlung radiation and the Visible and Infrared Cameras that detect synchrotron radiation. A unique design solution has been given for the HXRM and is developed, R&D tests were performed and optimized in line with this understanding. For the cameras, it is predicted for the first time which images and signal intensity can be expected. To achieve this, a simple but comprehensive code has been developed and validated on tokamaks that can predict RE parameters and corresponding diagnostic signals which may have further uses also in the context of RE avoidance.

La technologie Lithium-air développée par EDF utilise une électrode à air qui fonctionne avec un électrolyte aqueux ce qui empêche l’utilisation de lithium métal non protégé comme électrode négative. Une membrane céramique (LATP:Li1+xAlxTi2-x(PO4)3) conductrice d’ion Li+ est utilisée pour séparer le milieu aqueux de l’électrode négative. Cependant, cette céramique n'est pas stable au contact du lithium, il est donc nécessaire d'intercaler entre le lithium et la céramique un matériau conducteur des ions Li+. Celui-ci devant être stable au contact du lithium et empêcher ou fortement limiter la croissance dendritique. Ainsi, ce projet s'est intéressé à l'étude d'électrolytes copolymères à blocs (BCE).Tout d'abord, l'étude des propriétés physico-chimiques spécifiques de ces BCEs en cellule lithium-lithium symétrique a été réalisée notamment les propriétés de transport (conductivités, nombre de transport), et la résistance à la croissance dendritique du lithium. Puis dans un second temps, l'étude des composites BCE-céramique a été mise en place. Nous nous sommes en particulier focalisés sur l'analyse du transfert ionique polymère-céramique.Plusieurs techniques de caractérisation ont été utilisées telles que la spectroscopie d'impédance électrochimique (transport et interface), le SAXS (morphologies des BCEs), la micro-tomographie par rayons X (morphologies des interfaces et des dendrites).Pour des électrolytes possédant un nombre de transport unitaire (single-ion), nous avons obtenus des résultats remarquables concernant la limitation à la croissance dendritique. La micro-tomographie des rayons X a permis de montrer que le mécanisme de croissance hétérogène dans le cas des single-ion est très différent de celui des BCEs neutres (t+ < 0.2). / The lithium-air (Li-air) technology developed by EDF uses an air electrode which works with an aqueous electrolyte, which prevents the use of unprotected lithium metal electrode as a negative electrode. A Li+ ionic conductor glass ceramic (LATP:Li1+xAlxTi2-x(PO4)3) has been used to separate the aqueous electrolyte compartment from the negative electrode. However, this glass-ceramic is not stable in contact with lithium, it is thus necessary to add between the lithium and the ceramic a buffer layer. In another hand, this protection should ideally resist to lithium dendritic growth. Thus, this project has been focused on the study of block copolymer electrolytes (BCE).In a first part, the study of the physical and chemical properties of these BCEs in lithium symmetric cells has been realized especially transport properties (ionic conductivities, transference number), and resistance to dendritic growth. Then, in a second part, the composites BCE-ceramic have been studied.Several characterization techniques have been employed and especially the electrochemical impedance spectroscopy (for the transport and the interface properties), the small angle X-ray scattering (for the BCE morphologies) and the hard X-ray micro-tomography (for the interfaces and the dendrites morphologies). For single-ion BCE, we have obtained interesting results concerning the mitigation of the dendritic growth. The hard X-ray micro-tomography has permitted to show that the mechanism involved in the heterogeneous lithium growth in the case of the single-ion is very different from the one involved for the neutral BCEs (t+ < 0.2).

Hard x rays come along with a variety of extraordinary properties which make them an excellent probe for investigation in science, technology and medicine. Their large attenuation length in matter opens up the possibility to use hard x-rays for non-destructive investigation of the inner structure of specimens. Medical radiography is one important example of exploiting this feature. Since their discovery by W. C. Röntgen in 1895, a large variety of x-ray analytical techniques have been developed and successfully applied, such as x-ray crystallography, reflectometry, fluorescence spectroscopy, x-ray absorption spectroscopy, small angle x-ray scattering, and many more. Each of those methods reveals information about certain physical properties, but usually, these properties are an average over the complete sample region illuminated by the x rays. In order to obtain the spatial distribution of those properties in inhomogeneous samples, scanning microscopy techniques have to be applied, screening the sample with a small x-ray beam. The spatial resolution is limited by the finite size of the beam. The availability of highly brilliant x-ray sources at third generation synchrotron radiation facilities together with the development of enhanced focusing x-ray optics made it possible to generate increasingly small high intense x-ray beams, pushing the spatial resolution down to the sub-100 nm range. During this thesis the prototype of a hard x-ray scanning microscope utilizing microstructured nanofocusing lenses was designed, built, and successfully tested. The nanofocusing x-ray lenses were developed by our research group of the Institute of Structural Physics at the Technische Universität Dresden. The prototype instrument was installed at the ESRF beamline ID 13. A wide range of experiments like fluorescence element mapping, fluorescence tomography, x-ray nano-diffraction, coherent x-ray diffraction imaging, and x-ray ptychography were performed as part of this thesis. The hard x-ray scanning microscope provides a stable x-ray beam with a full width at half maximum size of 50-100 nm near the focal plane. The nanoprobe was also used for characterization of nanofocusing lenses, crucial to further improve them. Based on the experiences with the prototype, an advanced version of a hard x-ray scanning microscope is under development and will be installed at the PETRA III beamline P06 dedicated as a user instrument for scanning microscopy. This document is organized as follows. A short introduction motivating the necessity for building a hard x-ray scanning microscope is followed by a brief review of the fundamentals of hard x-ray physics with an emphasis on free-space propagation and interaction with matter. After a discussion of the requirements on the x-ray source for the nanoprobe, the main features of synchrotron radiation from an undulator source are shown. The properties of the nanobeam generated by refractive x-ray lenses are treated as well as a two-stage focusing scheme for tailoring size, flux and the lateral coherence properties of the x-ray focus. The design and realization of the microscope setup is addressed, and a selection of experiments performed with the prototype version is presented, before this thesis is finished with a conclusion and an outlook on prospective plans for an improved microscope setup to be installed at PETRA III. / Aufgrund ihrer hervorragenden Eigenschaften kommt harte Röntgenstrahlung in vielfältiger Weise in der Wissenschaft, Industrie und Medizin zum Einsatz. Vor allem die Fähigkeit, makroskopische Gegenstände zu durchdringen, eröffnet die Möglichkeit, im Innern ausgedehnter Objekte verborgene Strukturen zum Vorschein zu bringen, ohne den Gegenstand zerstören zu müssen. Eine Vielzahl röntgenanalytischer Verfahren wie zum Beispiel Kristallographie, Reflektometrie, Fluoreszenzspektroskopie, Absorptionsspektroskopie oder Kleinwinkelstreuung sind entwickelt und erfolgreich angewendet worden. Jede dieser Methoden liefert gewisse strukturelle, chemische oder physikalische Eigenschaften der Probe zutage, allerdings gemittelt über den von der Röntgenstrahlung beleuchteten Bereich. Um eine ortsaufgelöste Verteilung der durch die Röntgenanalyse gewonnenen Information zu erhalten, bedarf es eines sogenannten Mikrostrahls, durch den die Probe lokal abgetastet werden kann. Die dadurch erreichbare räumliche Auflösung ist durch die Größe des Mikrostrahls begrenzt. Aufgrund der Verfügbarkeit hinreichend brillanter Röntgenquellen in Form von Undulatoren an Synchrotronstrahlungseinrichtungen und des Vorhandenseins verbesserter Röntgenoptiken ist es in den vergangen Jahren gelungen, immer kleinere intensive Röntgenfokusse zu erzeugen und somit das räumliche Auflösungsvermögen der Röntgenrastermikroskope auf unter 100 nm zu verbessern. Gegenstand dieser Arbeit ist der Prototyp eines Rastersondenmikroskops für harte Röntgenstrahlung unter Verwendung refraktiver nanofokussierender Röntgenlinsen, die von unserer Arbeitsgruppe am Institut für Strukturphysik entwickelt und hergestellt werden. Das Rastersondenmikroskop wurde im Rahmen dieser Promotion in Dresden konzipiert und gebaut sowie am Strahlrohr ID 13 des ESRF installiert und erfolgreich getestet. Das Gerät stellt einen hochintensiven Röntgenfokus der Größe 50-100 nm zur Verfügung, mit dem im Verlaufe dieser Doktorarbeit zahlreiche Experimente wie Fluoreszenztomographie, Röntgennanobeugung, Abbildung mittels kohärenter Röntgenbeugung sowie Röntgenptychographie erfolgreich durchgeführt wurden. Das Rastermikroskop dient unter anderem auch dem Charakterisieren der nanofokussierenden Linsen, wobei die dadurch gewonnenen Erkenntnisse in die Herstellung verbesserten Linsen einfließen. Diese Arbeit ist wie folgt strukturiert. Ein kurzes einleitendes Kapitel dient als Motivation für den Bau eines Rastersondenmikroskops für harte Röntgenstrahlung. Es folgt eine Einführung in die Grundlagen der Röntgenphysik mit Hauptaugenmerk auf die Ausbreitung von Röntgenstrahlung im Raum und die Wechselwirkungsmechanismen von Röntgenstrahlung mit Materie. Anschließend werden die Anforderungen an die Röntgenquelle besprochen und die Vorzüge eines Undulators herausgestellt. Wichtige Eigenschaften eines mittels refraktiver Röntgenlinsen erzeugten Röntgenfokus werden behandelt, und das Konzept einer Vorfokussierung zur gezielten Anpassung der transversalen Kohärenzeigenschaften an die Erfordernisse des Experiments wird besprochen. Das Design und die technische Realisierung des Rastermikroskops werden ebenso dargestellt wie eine Auswahl erfolgreicher Experimente, die am Gerät vollzogen wurden. Die Arbeit endet mit einem Ausblick, der mögliche Weiterentwicklungen in Aussicht stellt, unter anderem den Aufbau eines verbesserten Rastermikroskops am PETRA III-Strahlrohr P06.

Hard x rays come along with a variety of extraordinary properties which make them an excellent probe for investigation in science, technology and medicine. Their large attenuation length in matter opens up the possibility to use hard x-rays for non-destructive investigation of the inner structure of specimens. Medical radiography is one important example of exploiting this feature. Since their discovery by W. C. Röntgen in 1895, a large variety of x-ray analytical techniques have been developed and successfully applied, such as x-ray crystallography, reflectometry, fluorescence spectroscopy, x-ray absorption spectroscopy, small angle x-ray scattering, and many more. Each of those methods reveals information about certain physical properties, but usually, these properties are an average over the complete sample region illuminated by the x rays. In order to obtain the spatial distribution of those properties in inhomogeneous samples, scanning microscopy techniques have to be applied, screening the sample with a small x-ray beam. The spatial resolution is limited by the finite size of the beam. The availability of highly brilliant x-ray sources at third generation synchrotron radiation facilities together with the development of enhanced focusing x-ray optics made it possible to generate increasingly small high intense x-ray beams, pushing the spatial resolution down to the sub-100 nm range. During this thesis the prototype of a hard x-ray scanning microscope utilizing microstructured nanofocusing lenses was designed, built, and successfully tested. The nanofocusing x-ray lenses were developed by our research group of the Institute of Structural Physics at the Technische Universität Dresden. The prototype instrument was installed at the ESRF beamline ID 13. A wide range of experiments like fluorescence element mapping, fluorescence tomography, x-ray nano-diffraction, coherent x-ray diffraction imaging, and x-ray ptychography were performed as part of this thesis. The hard x-ray scanning microscope provides a stable x-ray beam with a full width at half maximum size of 50-100 nm near the focal plane. The nanoprobe was also used for characterization of nanofocusing lenses, crucial to further improve them. Based on the experiences with the prototype, an advanced version of a hard x-ray scanning microscope is under development and will be installed at the PETRA III beamline P06 dedicated as a user instrument for scanning microscopy. This document is organized as follows. A short introduction motivating the necessity for building a hard x-ray scanning microscope is followed by a brief review of the fundamentals of hard x-ray physics with an emphasis on free-space propagation and interaction with matter. After a discussion of the requirements on the x-ray source for the nanoprobe, the main features of synchrotron radiation from an undulator source are shown. The properties of the nanobeam generated by refractive x-ray lenses are treated as well as a two-stage focusing scheme for tailoring size, flux and the lateral coherence properties of the x-ray focus. The design and realization of the microscope setup is addressed, and a selection of experiments performed with the prototype version is presented, before this thesis is finished with a conclusion and an outlook on prospective plans for an improved microscope setup to be installed at PETRA III.:1 Introduction ............................................... 1 2 Basic Properties of Hard X Rays ............................ 3 2.1 Free Propagation of X Rays ............................... 3 2.1.1 The Helmholtz Equation ................................. 4 2.1.2 Integral Theorem of Helmholtz and Kirchhoff ............ 6 2.1.3 Fresnel-Kirchhoff's Diffraction Formula ................ 8 2.1.4 Fresnel-Kirchhoff Propagation .......................... 11 2.2 Interaction of X Rays with Matter ........................ 13 2.2.1 Complex Index of Refraction ............................ 13 2.2.2 Attenuation ............................................ 15 2.2.3 Refraction ............................................. 18 3 The X-Ray Source ........................................... 21 3.1 Requirements ............................................. 21 3.1.1 Energy and Energy Bandwidth ............................ 21 3.1.2 Source Size and Divergence ............................. 23 3.1.3 Brilliance ............................................. 23 3.2 Synchrotron Radiation .................................... 24 3.3 Layout of a Synchrotron Radiation Facility ............... 27 3.4 Liénard-Wiechert Fields .................................. 29 3.5 Dipole Magnets ........................................... 31 3.6 Insertion Devices ........................................ 36 3.6.1 Multipole Wigglers ..................................... 36 3.6.2 Undulators ............................................. 37 4 X-Ray Optics ............................................... 39 4.1 Refractive X-Ray Lenses .................................. 40 4.2 Compound Parabolic Refractive Lenses (CRLs) .............. 41 4.3 Nanofocusing Lenses (NFLs) ............................... 43 4.4 Adiabatically Focusing Lenses (AFLs) ..................... 45 4.5 Focal Distance ........................................... 46 4.6 Transverse Focus Size .................................... 50 4.7 Beam Caustic ............................................. 52 4.8 Depth of Focus ........................................... 53 4.9 Beam Divergence .......................................... 53 4.10 Chromaticity ............................................ 54 4.11 Transmission and Cross Section .......................... 55 4.12 Transverse Coherence .................................... 56 4.12.1 Mutual Intensity Function ............................. 57 4.12.2 Free Propagation of Mutual Intensity .................. 57 4.12.3 Mutual Intensity In The Focal Plane ................... 58 4.12.4 Diffraction Limited Focus ............................. 59 4.13 Coherent Flux ........................................... 60 4.14 Two-Stage Focusing ...................................... 64 4.14.1 The Prefocusing Parameter ............................. 65 4.14.2 Required Refractive Power ............................. 67 4.14.3 Flux Considerations ................................... 70 4.14.4 Astigmatic Prefocusing ................................ 75 5 Nanoprobe Setup ............................................ 77 5.1 X-Ray Optics ............................................. 78 5.1.1 Nanofocusing Lenses .................................... 79 5.1.2 Entry Slits ............................................ 82 5.1.3 Pinhole ................................................ 82 5.1.4 Additional Shielding ................................... 83 5.1.5 Vacuum and Helium Tubes ................................ 83 5.2 Sample Stages ............................................ 84 5.2.1 High Resolution Scanner ................................ 84 5.2.2 High Precision Rotational Stage ........................ 85 5.2.3 Coarse Linear Stages ................................... 85 5.2.4 Goniometer Head ........................................ 85 5.3 Detectors ................................................ 86 5.3.1 High Resolution X-Ray Camera ........................... 86 5.3.2 Diffraction Cameras .................................... 89 5.3.3 Energy Dispersive Detectors ............................ 91 5.3.4 Photodiodes ............................................ 93 5.4 Control Software ......................................... 94 6 Experiments ................................................ 97 6.1 Lens Alignment ........................................... 97 6.2 Focus Characterization ................................... 99 6.2.1 Knife-Edge Scans ....................................... 100 6.2.2 Far-Field Measurements ................................. 102 6.2.3 X-Ray Ptychography ..................................... 103 6.3 Fluorescence Spectroscopy ................................ 105 6.3.1 Fluorescence Element Mapping ........................... 107 6.3.2 Fluorescence Tomography ................................ 110 6.4 Diffraction Experiments .................................. 111 6.4.1 Microdiffraction on Phase Change Media ................. 112 6.4.2 Microdiffraction on Stranski-Krastanow Islands ......... 113 6.4.3 Coherent X-Ray Diffraction Imaging of Gold Particles ... 115 6.4.4 X-Ray Ptychography of a Nano-Structured Microchip ...... 117 7 Conclusion and Outlook ..................................... 121 Bibliography ................................................. 125 List of Figures .............................................. 139 List of Publications ......................................... 141 Danksagung ................................................... 145 Curriculum Vitae ............................................. 149 Erklärung .................................................... 151 / Aufgrund ihrer hervorragenden Eigenschaften kommt harte Röntgenstrahlung in vielfältiger Weise in der Wissenschaft, Industrie und Medizin zum Einsatz. Vor allem die Fähigkeit, makroskopische Gegenstände zu durchdringen, eröffnet die Möglichkeit, im Innern ausgedehnter Objekte verborgene Strukturen zum Vorschein zu bringen, ohne den Gegenstand zerstören zu müssen. Eine Vielzahl röntgenanalytischer Verfahren wie zum Beispiel Kristallographie, Reflektometrie, Fluoreszenzspektroskopie, Absorptionsspektroskopie oder Kleinwinkelstreuung sind entwickelt und erfolgreich angewendet worden. Jede dieser Methoden liefert gewisse strukturelle, chemische oder physikalische Eigenschaften der Probe zutage, allerdings gemittelt über den von der Röntgenstrahlung beleuchteten Bereich. Um eine ortsaufgelöste Verteilung der durch die Röntgenanalyse gewonnenen Information zu erhalten, bedarf es eines sogenannten Mikrostrahls, durch den die Probe lokal abgetastet werden kann. Die dadurch erreichbare räumliche Auflösung ist durch die Größe des Mikrostrahls begrenzt. Aufgrund der Verfügbarkeit hinreichend brillanter Röntgenquellen in Form von Undulatoren an Synchrotronstrahlungseinrichtungen und des Vorhandenseins verbesserter Röntgenoptiken ist es in den vergangen Jahren gelungen, immer kleinere intensive Röntgenfokusse zu erzeugen und somit das räumliche Auflösungsvermögen der Röntgenrastermikroskope auf unter 100 nm zu verbessern. Gegenstand dieser Arbeit ist der Prototyp eines Rastersondenmikroskops für harte Röntgenstrahlung unter Verwendung refraktiver nanofokussierender Röntgenlinsen, die von unserer Arbeitsgruppe am Institut für Strukturphysik entwickelt und hergestellt werden. Das Rastersondenmikroskop wurde im Rahmen dieser Promotion in Dresden konzipiert und gebaut sowie am Strahlrohr ID 13 des ESRF installiert und erfolgreich getestet. Das Gerät stellt einen hochintensiven Röntgenfokus der Größe 50-100 nm zur Verfügung, mit dem im Verlaufe dieser Doktorarbeit zahlreiche Experimente wie Fluoreszenztomographie, Röntgennanobeugung, Abbildung mittels kohärenter Röntgenbeugung sowie Röntgenptychographie erfolgreich durchgeführt wurden. Das Rastermikroskop dient unter anderem auch dem Charakterisieren der nanofokussierenden Linsen, wobei die dadurch gewonnenen Erkenntnisse in die Herstellung verbesserten Linsen einfließen. Diese Arbeit ist wie folgt strukturiert. Ein kurzes einleitendes Kapitel dient als Motivation für den Bau eines Rastersondenmikroskops für harte Röntgenstrahlung. Es folgt eine Einführung in die Grundlagen der Röntgenphysik mit Hauptaugenmerk auf die Ausbreitung von Röntgenstrahlung im Raum und die Wechselwirkungsmechanismen von Röntgenstrahlung mit Materie. Anschließend werden die Anforderungen an die Röntgenquelle besprochen und die Vorzüge eines Undulators herausgestellt. Wichtige Eigenschaften eines mittels refraktiver Röntgenlinsen erzeugten Röntgenfokus werden behandelt, und das Konzept einer Vorfokussierung zur gezielten Anpassung der transversalen Kohärenzeigenschaften an die Erfordernisse des Experiments wird besprochen. Das Design und die technische Realisierung des Rastermikroskops werden ebenso dargestellt wie eine Auswahl erfolgreicher Experimente, die am Gerät vollzogen wurden. Die Arbeit endet mit einem Ausblick, der mögliche Weiterentwicklungen in Aussicht stellt, unter anderem den Aufbau eines verbesserten Rastermikroskops am PETRA III-Strahlrohr P06.:1 Introduction ............................................... 1 2 Basic Properties of Hard X Rays ............................ 3 2.1 Free Propagation of X Rays ............................... 3 2.1.1 The Helmholtz Equation ................................. 4 2.1.2 Integral Theorem of Helmholtz and Kirchhoff ............ 6 2.1.3 Fresnel-Kirchhoff's Diffraction Formula ................ 8 2.1.4 Fresnel-Kirchhoff Propagation .......................... 11 2.2 Interaction of X Rays with Matter ........................ 13 2.2.1 Complex Index of Refraction ............................ 13 2.2.2 Attenuation ............................................ 15 2.2.3 Refraction ............................................. 18 3 The X-Ray Source ........................................... 21 3.1 Requirements ............................................. 21 3.1.1 Energy and Energy Bandwidth ............................ 21 3.1.2 Source Size and Divergence ............................. 23 3.1.3 Brilliance ............................................. 23 3.2 Synchrotron Radiation .................................... 24 3.3 Layout of a Synchrotron Radiation Facility ............... 27 3.4 Liénard-Wiechert Fields .................................. 29 3.5 Dipole Magnets ........................................... 31 3.6 Insertion Devices ........................................ 36 3.6.1 Multipole Wigglers ..................................... 36 3.6.2 Undulators ............................................. 37 4 X-Ray Optics ............................................... 39 4.1 Refractive X-Ray Lenses .................................. 40 4.2 Compound Parabolic Refractive Lenses (CRLs) .............. 41 4.3 Nanofocusing Lenses (NFLs) ............................... 43 4.4 Adiabatically Focusing Lenses (AFLs) ..................... 45 4.5 Focal Distance ........................................... 46 4.6 Transverse Focus Size .................................... 50 4.7 Beam Caustic ............................................. 52 4.8 Depth of Focus ........................................... 53 4.9 Beam Divergence .......................................... 53 4.10 Chromaticity ............................................ 54 4.11 Transmission and Cross Section .......................... 55 4.12 Transverse Coherence .................................... 56 4.12.1 Mutual Intensity Function ............................. 57 4.12.2 Free Propagation of Mutual Intensity .................. 57 4.12.3 Mutual Intensity In The Focal Plane ................... 58 4.12.4 Diffraction Limited Focus ............................. 59 4.13 Coherent Flux ........................................... 60 4.14 Two-Stage Focusing ...................................... 64 4.14.1 The Prefocusing Parameter ............................. 65 4.14.2 Required Refractive Power ............................. 67 4.14.3 Flux Considerations ................................... 70 4.14.4 Astigmatic Prefocusing ................................ 75 5 Nanoprobe Setup ............................................ 77 5.1 X-Ray Optics ............................................. 78 5.1.1 Nanofocusing Lenses .................................... 79 5.1.2 Entry Slits ............................................ 82 5.1.3 Pinhole ................................................ 82 5.1.4 Additional Shielding ................................... 83 5.1.5 Vacuum and Helium Tubes ................................ 83 5.2 Sample Stages ............................................ 84 5.2.1 High Resolution Scanner ................................ 84 5.2.2 High Precision Rotational Stage ........................ 85 5.2.3 Coarse Linear Stages ................................... 85 5.2.4 Goniometer Head ........................................ 85 5.3 Detectors ................................................ 86 5.3.1 High Resolution X-Ray Camera ........................... 86 5.3.2 Diffraction Cameras .................................... 89 5.3.3 Energy Dispersive Detectors ............................ 91 5.3.4 Photodiodes ............................................ 93 5.4 Control Software ......................................... 94 6 Experiments ................................................ 97 6.1 Lens Alignment ........................................... 97 6.2 Focus Characterization ................................... 99 6.2.1 Knife-Edge Scans ....................................... 100 6.2.2 Far-Field Measurements ................................. 102 6.2.3 X-Ray Ptychography ..................................... 103 6.3 Fluorescence Spectroscopy ................................ 105 6.3.1 Fluorescence Element Mapping ........................... 107 6.3.2 Fluorescence Tomography ................................ 110 6.4 Diffraction Experiments .................................. 111 6.4.1 Microdiffraction on Phase Change Media ................. 112 6.4.2 Microdiffraction on Stranski-Krastanow Islands ......... 113 6.4.3 Coherent X-Ray Diffraction Imaging of Gold Particles ... 115 6.4.4 X-Ray Ptychography of a Nano-Structured Microchip ...... 117 7 Conclusion and Outlook ..................................... 121 Bibliography ................................................. 125 List of Figures .............................................. 139 List of Publications ......................................... 141 Danksagung ................................................... 145 Curriculum Vitae ............................................. 149 Erklärung .................................................... 151