Ziele wie eine hohe Auflösung und ein hoher Durchsatz sind bisher in der Elektronenstrahllithografie nicht gleichzeitig erreichbar; es existieren daher die Belichtungskonzepte Gaussian-Beam und Variable-Shaped-Beam (VSB), die auf Hochauflösung respektive Durchsatz optimiert sind. In dieser Arbeit wird der experimentelle Kreuzvergleich beider Belichtungskonzepte mit Hilfe chemisch verstärkter und nicht verstärkter Lacksysteme präsentiert. Als quantitativer Parameter wurde die Gesamtunschärfe eingeführt, die sich durch quadratische Addition der auflösungslimitierenden Fehlerquellen, also Coulomb-Wechselwirkungen (Strahlunschärfe), Lackprozess (Prozessunschärfe) und Proximity-Effekt (Streuunschärfe), ergibt. Für den Vergleich wurden wohldefinierte Prozesse auf 300 mm Wafern entwickelt und umfassend charakterisiert. Weitere Grundlage ist die Anpassung oder Neuentwicklung spezieller Methoden wie Kontrast- und Basedosebestimmung, Doughnut-Test, Isofokal-Dosis-Methode für Linienbreiten und Linienrauheit sowie die Bestimmung der Gesamtunschärfe unter Variation des Fokus. Es wird demonstriert, dass sich mit einer kleineren Gesamtunschärfe die Auflösung dichter Linien verbessert. Der direkte Vergleich der Gesamtunschärfen beider Belichtungskonzepte wird durch die variable Strahlunschärfe bei VSB-Schreibern erschwert. Da für die Bestimmung der Gesamtunschärfe keine Hochauflösung nötig ist, wird das Testpattern mit größeren Shots belichtet und induziert somit eine größere Gesamtunschärfe. Es wird gezeigt, dass die Prozessunschärfe den größten Anteil der Gesamtunschärfe stellt. Außerdem spielt die Streuunschärfe bei Lackdicken kleiner 100 nm und Beschleunigungsspannungen von 50 kV oder größer keine Rolle. / Up to now, targets like high resolution and high throughput can not be achieved at the same time in electron beam lithography; therefore, the exposure concepts Gaussian-Beam and Variable-Shaped-Beam (VSB) exist, which are optimized for high resolution and throughput, respectively. In this work, the experimental cross-comparison of both exposure concepts is presented using chemically amplified and non-chemically amplified resist systems. For quantification the total blur parameter has been introduced, which is the result of the quadratic addition of the resolution limiting error sources, like Coulomb interactions (beam blur), resist process (process blur) and proximity-effect (scatter blur). For the comparison, well-defined processes have been developed on 300 mm wafers and were fully characterized. Further basis is the adaption or the new development of special methods like the determination of contrast and basedose, the doughnut-test, the isofocal-dose-method for line widths and line roughness as well as the determination of the total blur with variation of the focus. It is demonstrated, that the resolution of dense lines is improved with a smaller total blur. The direct comparison of the total blur values of both exposure concepts is complicated by the variable beam blur of VSB writers. Since high resolution is not needed for the determination of the total blur, the test pattern is exposed with larger shots on the VSB writer, which induces a larger total blur. It is shown that the process blur makes the largest fraction of the total blur. The scatter blur is irrelevant using resist thicknesses smaller than 100 nm and acceleration voltages of 50 kV or larger.

This thesis discusses optoelectronic devices at mm-wave frequencies, focusing on optoelectronic beamforming and non-mechanical beam steering based on an optically excited Fresnel zone plate plasma. The optically controlled zone plate, termed the photo-injected Fresnel zone plate antenna (piFZPA) within this work, is introduced and a comprehensive theoretical framework developed. The design and optimisation of Fresnel zone plates are detailed, which determine the inherent performance of the piFZPA. A range of zone plates were designed, fabricated, and characterised at 94 GHz with up to 46 dBi gain, -26 dB sidelobe levels, and 67% aperture efficiency being measured for a quarter-wave design. The control of (sub) mm-wave beams by optical modulation of the complex permittivity of a semiconductor substrate is discussed. The significance of the free-carrier plasma dynamics, the effective lifetime, surface recombination, and the limits of the substrate which are imposed by the spatial resolution of the free-carrier plasma are highlighted, with the optimisation of these parameters discussed. The passivation quality of high-resistivity silicon wafers were characterised using a mm-wave photoconductance decay method, which yielded lifetime improvements from τ[subscript(eff)] = 60 us up to τ[subscript(eff)] ≈ 4,000 us, resulting in lowered recombination velocities (S = 15 cm/s). W-band characterisations of the passivated wafers illustrate the significance of surface recombination, with measured attenuations of up to 24 dB. Novel theoretical models are developed throughout this thesis, which yield insight into the requirements of optoelectronic devices, and are shown to agree well with measured data. The theoretical framework developed details the requirements, limitations, suitability, and design of piFZPAs at any frequency. A range of transmission-type piFZPAs are demonstrated and characterised at 94 GHz, both on-axis and off-axis, based on a novel architecture, with up to 8% aperture efficiency. Finally, the hybridisation of the piFZPA technique and well established visible display technologies, which has been developed throughout this thesis, enable low-cost, simple, and highly flexible optoelectronic devices, highlighting this method as an attractive solution to adaptive beamforming and non-mechanical steering at mm-wave and submm-wave frequencies.

Un des défis pour les futurs projets en physique basé sur les accélérateurs de particules est le besoin de faisceaux à hautes intensités. Les effets collectifs sont cependant une limitation majeure qui peuvent détériorer la qualité du faisceau ou limiter l'intensité maximale à cause des pertes. Le CERN SPS, qui est le dernier injecteur pour le LHC, n'est actuellement pas en mesure de délivrer les faisceaux requis pour les futurs projets à cause des instabilités longitudinales.Les nombreux équipements dans la machine (les cavités RF accélératrices, les aimants d'injection et d'extraction, les brides de vide, etc.) entrainent des variations dans la géométrie et les matériaux de la chambre dans laquelle le faisceau transite. Les interactions électromagnétiques internes au faisceau (charge d'espace) et du faisceau avec son environnement sont représentées par une impédance de couplage qui affectent le mouvement des particules et mènent à des instabilités pour des intensités élevées de faisceau. Par conséquent, les sources d'impédance critiques doivent être identifiées et des solutions évaluées. Pour avoir un modèle d'impédance fiable d'un accélérateur, les contributions de tous les équipements dans l'anneau doivent être évaluées à partir de simulations et de mesures électromagnétiques. Dans cette thèse, le faisceau lui-même est utilisé comme une sonde de l'impédance de la machine en mesurant le déplacement de la fréquence synchrotronique avec l'intensité et la longueur du paquet, ainsi que la modulation de longs paquets injectés avec la tension RF éteinte. Ces mesures sont comparées avec des simulations par macroparticules en utilisant le modèle d'impédance du SPS existant, et les déviations sont étudiées pour identifier les sources d'impédance manquantes pour raffiner le modèle.L'étape suivante consiste à reproduire en simulations les instabilités mesurées pour un paquet unique durant l'accélération. Grâce à l'amélioration du modèle d'impédance, une meilleure compréhension des mécanismes de l'instabilité est rendue possible pour les faisceaux de protons et d'ions. Finalement, le modèle pour les simulations étant digne de confiance, il est utilisé pour estimer les caractéristiques du faisceau après les améliorations prévues du SPS pour le projet High Luminosity-LHC au CERN. / One of the main challenges of future physics projects based on particle accelerators is the need for high intensity beams. However, collective effects are a major limitation which can deteriorate the beam quality or limit the maximum intensity due to losses. The CERN SPS, which is the last injector for the LHC, is currently unable to deliver the beams required for future projects due to longitudinal instabilities.The numerous devices in the machine (accelerating RF cavities, injection and extraction magnets, vacuum flanges, etc.) lead to variations in the geometry and material of the chamber through which the beam is travelling. The electromagnetic interaction within the beam (space charge) and of the beam with its environment are described by a coupling impedance which affects the motion of the particles and leads to instabilities for high beam intensities. Consequently, the critical impedance sources should be identified and solutions assessed. To have a reliable impedance model of an accelerator, the contributions of all the devices in the ring should be evaluated from electromagnetic simulations and measurements.In this thesis, the beam itself is used to probe the machine impedance by measuring the synchrotron frequency shift with intensity and bunch length, as well as the line density modulation of long bunches injected with the RF voltage switched off. These measurements are compared with macroparticle simulations using the existing SPS impedance model, and the deviations are studied to identify missing impedance sources and to refine the model.The next important step is to reproduce in simulations the measured single bunch instabilities during acceleration, in single and double RF system operation. Thanks to the improved impedance model, a better understanding of instability mechanisms is achieved for both proton and ion beams.Finally, as the simulation model was shown to be trustworthy, it is used to estimate the beam characteristics after the foreseen SPS upgrades the High Luminosity-LHC project at CERN.

In this thesis, a custom quadrupole mass filter setup was established to independently investigate the impact of the most prominent ion species that are present during ion-assisted deposition. The setup was applied to the low temperature epitaxial growth of GaN thin films on 6H-SiC substrates. Atomic nitrogen ions at higher ion kinetic energies were for the first time independently identified to be the predominant cause of deteriorating crystalline qualities during growth. Precise control of the ion beam parameters yielded the capability to vary the average GaN phase content from almost purely wurtzite to the meta-stable zinc blende GaN phase. Even in case of comparably high crystalline quality, the atomic and molecular nitrogen ions were independently determined to yield distinct thin film topographies throughout the entire observed evolution of the thin film formation.:Bibliographical Description 1 Introduction 1.1 Epitaxial Thin Film Growth 1.2 Ion-Beam Assisted Deposition 1.2.1 Influence of Energetic Particles 1.2.2 Ion-atom Arrival Ratio 1.3 Gallium Nitride 2 Methods 2.1 Setup of the Deposition System 2.1.1 Knudsen Effusion Cell 2.1.2 Reflection High-Energy Electron Diffraction 2.1.3 Auger Electron Spectroscopy 2.1.4 Ion Sources 2.2 Quadrupole Mass Filter System 2.2.1 Components 2.2.2 Working Principle of a Quadrupole Mass Filter 2.2.3 Alternative Mass Filters 2.3 X-ray Diffraction and Reflectivity 2.4 Atomic Force Microscopy 2.5 Transmission Electron Microscopy 3 Results and Discussions 3.1 Characterization of the Quadrupole Mass Filter System 3.1.1 Mass Filter Performance and Resolution 3.1.2 Ion Beam Characteristics 3.1.3 Space Charge Considerations 3.1.4 Conclusions 3.2 Influence of the I/A Ratio and Ion Kinetic Energy 3.2.1 Determination of the GaN Phase Composition 3.2.2 Film Topography and Growth Mode 3.2.3 Crystal Structure and Orientation 3.2.4 Microstructure at the Interface 3.2.5 Conclusions 3.3 Impact of the Ion Species on Growth Instabilities 3.3.1 Growth Rates and Thin Film Topography 3.3.2 Crystal Structure 3.3.3 Growth Mode and RHEED pattern evolution 3.3.4 Conclusions 4 Summary and Conclusions Bibliography Complete Publication List of the Author Acknowledgments Declaration of Authorship / In dieser Arbeit wurde ein maßgefertigter Quadrupol-Massenfilteraufbau etabliert, um die Auswirkungen der prominentesten Ionenspezies, die während der ionengestützten Abscheidung vorhanden sind, unabhängig voneinander zu untersuchen. Der Aufbau wurde für das epitaktische Niedertemperatur-Wachstum von GaN-Dünnschichten auf 6H-SiC-Substraten angewendet. Atomare Stickstoffionen bei höheren kinetischen Ionenenergien wurden zum ersten Mal in der Abwesenheit anderer Spezies als die dominierende Ursache für die Verschlechterung der kristallinen Qualität während des Wachstums identifiziert. Eine präzise Kontrolle der Ionenstrahlparameter ergab die Fähigkeit, den durchschnittlichen GaN-Phasengehalt von der fast reinen Wurtzit- bis zur metastabilen Zinkblende-GaN-Phase zu variieren. Selbst bei vergleichbar hoher kristalliner Qualität weisen die mit atomaren und molekularen Stickstoffionen hergestellten Schichten unabhängig voneinander verschiedene Topographien auf, die sich während der gesamten beobachteten Entwicklung der Dünnschichtbildung deutlich abzeichneten.:Bibliographical Description 1 Introduction 1.1 Epitaxial Thin Film Growth 1.2 Ion-Beam Assisted Deposition 1.2.1 Influence of Energetic Particles 1.2.2 Ion-atom Arrival Ratio 1.3 Gallium Nitride 2 Methods 2.1 Setup of the Deposition System 2.1.1 Knudsen Effusion Cell 2.1.2 Reflection High-Energy Electron Diffraction 2.1.3 Auger Electron Spectroscopy 2.1.4 Ion Sources 2.2 Quadrupole Mass Filter System 2.2.1 Components 2.2.2 Working Principle of a Quadrupole Mass Filter 2.2.3 Alternative Mass Filters 2.3 X-ray Diffraction and Reflectivity 2.4 Atomic Force Microscopy 2.5 Transmission Electron Microscopy 3 Results and Discussions 3.1 Characterization of the Quadrupole Mass Filter System 3.1.1 Mass Filter Performance and Resolution 3.1.2 Ion Beam Characteristics 3.1.3 Space Charge Considerations 3.1.4 Conclusions 3.2 Influence of the I/A Ratio and Ion Kinetic Energy 3.2.1 Determination of the GaN Phase Composition 3.2.2 Film Topography and Growth Mode 3.2.3 Crystal Structure and Orientation 3.2.4 Microstructure at the Interface 3.2.5 Conclusions 3.3 Impact of the Ion Species on Growth Instabilities 3.3.1 Growth Rates and Thin Film Topography 3.3.2 Crystal Structure 3.3.3 Growth Mode and RHEED pattern evolution 3.3.4 Conclusions 4 Summary and Conclusions Bibliography Complete Publication List of the Author Acknowledgments Declaration of Authorship

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The work for this thesis is in line with the field of Instrumentation for Particle Accelerators, so called Beam Diagnostics. It is presented the development of a series of electro-mechanical devices called Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM). A full set of 17 BPM units (16 + 1 spare), named BPS units, were built and installed into the Test Beam Line (TBL), an electron beam decelerator, of the 3rd CLIC Test Facility (CTF3) at CERN ¿European Organization for the Nuclear Research¿. The CTF3, built at CERN by an international collaboration, was meant to demonstrate the technical feasibility of the key concepts for CLIC ¿Compact Linear Collider¿ as a future linear collider based on the novel two-beam acceleration scheme, and in order to achieve the next energy frontier for a lepton collider in theMulti-TeV scale. Modern particle accelerators and in particular future colliders like CLIC requires an extreme alignment and stabilization of the beam in order to enhance its quality, which rely heavily on a beam based alignment techniques. Here the BPMs, like the BPS-IPU, play an important role providing the beam position with precision and high resolution, besides a beam current measurement in the case of the BPS, along the beam lines. The BPS project carried out at IFIC was mainly developed in two phases: prototyping and series production and test for the TBL. In the first project phase two fully functional BPS prototypes were constructed, focusing in this thesis work on the electronic design of the BPS on-board PCBs (Printed Circuit Boards) which are based on transformers for the current sensing and beam position measurement. Furthermore, it is described the monitor mechanical design with emphasis on all the parts directly involved in its electromagnetic functioning, as a result of the coupling of the EM fields generated by the beam with those parts. For that, it was studied its operational parameters, according the TBL specifications, and it was also simulated a new circuital model reproducing the BPS monitor frequency response for its operational bandwidth (1kHz-100MHz). These prototypes were initially tested in the laboratories of the BI-PI section¿Beam Instrumentation - Position and Intensity¿ at CERN. In the second project phase the BPS monitor series, which were built based on the experience acquired during the prototyping phase, the work was focused on the realization of the characterization tests to measure the main operational parameters of each series monitor, for which it was designed and constructed two test benches with different purposes and frequency regions. The first one is designed to work in the low frequency region, between 1kHz-100MHz, in the time scale of the electron beam pulse with a repetition period of 1s and an approximate duration of 140ns. This kind of test setups called Wire Test-bench are commonly used in the accelerators instrumentation field in order to determine the characteristic parameters of a BPM (or pick-up) like its linearity and precision in the position measurement, and also its frequency response (bandwidth). This is done by emulating a low current intensity beam with a stretched wire carrying a current signals which can be precisely positioned with respect the device under test. This test bench was specifically made for the BPS monitor and conceived to perform the measurement data acquisition in an automated way, managing the measurement equipment and the wire positioning motors controller from a PC workstation. Each one of the BPS monitors series were characterized by using this system at the IFIC labs, and the test results and analysis are presented in this work. On the other hand, the high frequency tests, above the X band in the microwave spectrum and at the time scale of the micro-bunch pulses with a bunching period of 83ps (12GHz) inside a long 140ns pulse, were performed in order to measure the longitudinal impedance of the BPS monitor. This must be low enough in order to minimize the perturbations on the beam produced at crossing the monitor, which affects to its stability during the propagation along the line. For that, it was built the high frequency test bench as a coaxial waveguide structure of 24mm diameter matched at 50¿ and with a bandwidth from 18MHz to 30GHz, which was previously simulated, and having room in the middle to place the BPS as the device under test. This high frequency test bench is able to reproduce the TEM (Transversal Electro-Magnetic) propagative modes corresponding to an ultra-relativistic electron beam of 12GHz bunching frequency, so that the Scattering parameters can be measured to obtain the longitudinal impedance of the BPS in the frequency range of interest. Finally, it is also presented the results of the beam test made in the TBL line, with beam currents from 3.5A to 13A (max. available at the moment of the test). In order to determine the minimum resolution attainable by a BPS monitor in the measurement of the beam position, being the device figure of merit, with a resolution goal of 5¿m at maximum beam current of 28A according to the TBL specifications. / García Garrigós, JJ. (2013). Development of the Beam Position Monitors for the Diagnostics of the Test Beam Line in the CTF3 at CERN [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34327

[EN] The Compact Linear Collider (CLIC) is an electron-positron collider conceived for the study of High-Energy Physics in the TeV center of mass energy region, is based on a two-beam operation principle: instead of using active elements (klystrons), the necessary RF power to accelerate the Main Beam (MB) is obtained from the deceleration of a high-current, moderate energy Drive Beam (DB) in the so-called Power Extraction and Transfer Structures (PETS). These structures emit an RF signal of about 130 MW power at 12 GHz. As this frequency is above the cut-o ff frequency of the fundamental mode for the specified beam pipe dimensions (7.6 GHz), the inference propagates from the PETS to the neighboring devices, including the Beam Position Monitors (BPM). According to the CLIC Conceptual Design Report (CDR), an ef ficient beam position monitoring system for the CLIC DB decelerator needs to meet the following requirements: - It should be as simple and economic as possible, as 41580 units are required, amounting to 75% of all CLIC BPMs. - The signal processing scheme should not be a ffected by the PETS interference. This rules out processing the signals at the beam bunching frequency (12 GHz). - The resulting position signal should detect changes in the beam position whose duration is 10 ns or longer. - The required spatial resolution is 2 um for a 23 mm diameter vacuum pipe. - Wide dynamic range: the electronic acquisition system must be able to process signals with extreme levels, induced by either very high (100 A) or very low (3 A) current beams. This PhD thesis describes the electromagnetic and mechanical design of the first prototype BPM developed for the CLIC Drive Beam and its characterization tests in laboratory and with beam. The first two chapters introduce the CLIC project and review the state-of-the-art beam position monitoring techniques. Chapter 3 presents the design of the BPM. The stripline technology has been selected, as it is the only one among the most commonly used BPM techniques to present a suitable frequency response to filter out the RF interference caused by the PETS. Choosing an appropriate length for the electrodes, it is possible to tune one the periodic notches in the stripline frequency response to 12 GHz. The influence of di erent electromagnetic and geometrical aspects is also studied, such as beam coupling impedance or the ratio between longitudinal and transverse dimensions. The design of the electronic acquisition system is presented in Chapter 4, considering the project requirements in terms of resolution (2 u m), accuracy (20 um) and time resolution (10 ns). Due to the high amount of units required, the number of electronics components has been minimized. As the designed signal processing scheme is based on charge integration, it can be adapted to di erent stripline pick-ups by simply modifying the attenuator settings according to the required output signal levels. The laboratory characterization tests of the prototype stripline BPM, in the low and the high frequency ranges, performed with a thin wire and a coaxial waveguide, respectively, are described in Chapter 5. The measurement results are compared with the theoretical estimation and the electromagnetic field simulations. In addition, the high-frequency test reveals that the first prototype stripline BPM does not provide su cient suppression of the 12 GHz PETS RF interference. An additional study proposed several modifications and guidelines for a second prototype stripline BPM. Finally, Chapter 6 presents the beam tests of the prototype stripline BPM at the CLIC Test Facility 3 (CTF3) in the Test Beam Line (TBL), a scaled version of the CLIC Drive Beam decelerator. Two types of tests were performed: linearity/sensivity and resolution. These results are compared to the ones in the laboratory characterization tests. An upper bound of the resolution is estimated performing a Singular Value Decomposition (SVD) analysis. / [ES] El Colisionador Lineal Compacto (Compact Linear Collider, CLIC), un colisionador de electrones y positrones concebido en el CERN para el estudio de la Física de Altas Energías en la región de los TeV, se basa en un principio de funcionamiento de doble haz: en lugar de emplear elementos activos (klystrons) para proporcionar la potencia RF requerida para acelerar el haz principal (Main Beam, MB), ésta se obtiene de la deceleración de un haz secundario (Drive Beam, DB), de alta corriente y energía moderada, en las llamadas estructuras de extracción y transferencia de potencia (Power Extraction and Transfer Structures, PETS). Estas estructuras emiten una señal interferente RF de más de 130 MW de potencia a 12 GHz, que, por estar localizada en una frecuencia superior a la de corte del modo fundamental en el tubo de vacío del haz (7.6 GHz), se propaga por éste hacia los dispositivos adyacentes, entre los cuales se encuentran los sistemas de monitorización de la posición (Beam Position Monitor, BPM). De acuerdo con el informe conceptual de diseño de CLIC (Conceptual Design Report, CDR) , un sistema eficiente de monitorización de la posición del haz en el decelerador del haz secundario deberá cumplir los siguientes requisitos: - Debe ser lo más sencillo y económico posible, ya que se precisan 41580 unidades: el 75% de todos los BPMs de CLIC. - El procesado de señal en el sistema de adquisición deberá ser inmune a la interferencia generada en las PETS. Esto excluye la solución habitual de procesar las señales del BPM a la frecuencia de pulsado del haz (12 GHz). - La señal de posición resultante del procesado debe ser capaz de detectar cambios en la posición del haz de duración igual o mayor a 10 ns (resolución temporal). - La resolución espacial requerida es de 2 um para un tubo de vacío de 23 mm de diámetro, con una calibración precisa. - Amplio rango dinámico: el sistema electrónico de adquisición del BPM debe poder resistir los altos valores de señal provocados por los casos de desviación extrema del haz nominal (se contempla una desviación máxima de la mitad del radio del tubo), así como detectar las señales inducidas por las configuraciones de haz con menor carga de todas las previstas, cuyos niveles serán muy débiles. / [CA] El Col·lisionador Lineal Compacte (Compact Linear Collider, CLIC), un col·lisionador d'electrons i positrons concebut per l'estudi de la Física d'Altes Energies a la regió dels TeV (energía del centre de massa), es basa en un principi de funcionament de doble feix:en lloc de fer servir elements actius (klystrons) per proporcionar la potència RF requerida per accelerar el feix principal (Main Beam, MB), aquesta s'obtè de la desacceleració d'un feix secundari (Drive Beam, DB), d'alt corrent i energia moderada, a les anomenades estructures d'extracció i transferència de potència (Power Extraction and Transfer Structures, PETS). Aquestes estructures emeten una senyal interferent RF de més de 130 MW de potència a 12 GHz, que, pel fet d'estar localitzada a una freqüència superior a la de tall del mode fonamental al tub de buit del feix (7.6 GHz), es propaga a través d'aquest fins els dispositius adjacents, entre els quals trobem els sistemes de monitorització de la posició (Beam Position Monitor, BPM). D'acord amb l'informe conceptual de disseny de CLIC (Conceptual Design Report, CDR), un sistema eficient de monitorització de la posició del feix al desaccelerador del feix secundari haurà de complir els següents requisits: ¿ - Ha de ser el més senzill i econòmic possible, ja que es necessiten 41580 unitats: el 75% de tots els BPMs de CLIC. ¿ - El processat de la senyal al sistema d'adquisició haurà de ser inmune a la interferència generada als PETS. Això exclou la solució habitual de processar les senyals del BPM a la freqüència de pulsacions del feix (12 GHz). ¿- La senyal de posició resultant del processat ha de ser capaç de detectar canvis a la posició del feix de durada igual o més gran que 10 ns (resolució temporal). ¿- La resolució espaial necessària és de 2 um per a un tub de buit de 23 mm de diàmetre. ¿- Ampli rang dinàmic: el sistema electrònic d'adquisició del BPM ha de poder processar senyals amb nivells extrems, induïdes per feixos de molt alt (100 A) i molt baix (3 A) corrent. / Benot Morell, A. (2016). Beam position monitoring in the clic drive beam decelerator using stripline technology [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/64067

Resumo: O objetivo neste estudo foi avaliar as diferenças no espaço aéreo faríngeo em crianças com diferentes padrões faciais. Foram avaliadas as tomografias computadorizadas de feixe cônico de 98 indivíduos em crescimento, com idade média de 8,9 anos, divididas por sexo e faixa etária, e subdivididas de acordo com o padrão de crescimento (horizontal, vertical normal e produtores) e tipo de má oclusão (Classe I e Classe II). Utilizando um programa tridimensional, foram analisados o volume, área sagital, menor área de seção transversal e as dimensões ântero-posteriores da faringe superior e inferior. As dimensões ântero-posterior da faringe superior e inferior foi significativamente menor em indivíduos com Classe II em crianças na faixa etária entre 9 a 11 anos e a faringe superior em foi significativamente menor em crianças na faixa etária entre 5 e 7 anos com padrão de crescimento vertical. Porém, quando a faringe foi avaliada tridimensionalmente, não foram encontradas diferenças nas demais dimensões sugerindo que diferenças no padrão vertical e no tipo de má oclusão ântero-posterior (Classe I e II) não influenciam as dimensões da faringe. Não foi encontrado dimorfismo sexual. A região de maior constrição da faringe esteve presente mais freqüentemente na orofaringe (86%). Embora as dimensões lineares possam variar entre os diferentes padrões faciais, quando avaliadas tridimensionalmente, elas não foram influenciadas pelas diferentes morfologias faciais / Abstract: The aim of this study was to assess the differences in pharyngeal airway space in children with different facial patterns. Cone-beam computed tomography records of 98 growing patients with mean age of 8.9 years divided by sex and age groups and subdivided according to growth pattern (horizontal, normal and vertical growers) and type of malloclusion (Class I and Class II) were evaluated .Using a 3-dimensional virtual program the volume, sagital area, smallest cross section area, anteroposterior dimensions of superior and inferior pharynx were obtained. The anteroposterior linear dimensions of superior and inferior pharynx in children with 9 to11 years was significant smaller in patients with Class II relationship but in 3D evaluation differences were not found suggesting that anteroposterior malocclusion do not influence pharynx dimensions. The anteroposterior linear dimensions of superior , pharynx in children with 5 to7 years was significant smaller in patients with vertical growth pattern when compared to normal growers, but in 3D evaluation differences were not found suggesting that vertical pattern do not influence pharynx dimensions. No sexual dimorphism was found. The most constricted region of pharynx were mostly found at oropharynx(96%).Although linear dimensions can vary among different facial patterns, the 3-dimensional dimensions weren't influenced by different facial morphologies / Orientador: Luiz Cesar de Moraes / Coorientador: Weber José da Silva Ursi / Banca: Jefferson Luis OshiroTanaka / Banca: Edmundo Medici Filho / Mestre

This research is aimed at examining experimentally and analytically the behavior of reinforced concrete bridge pier caps strengthened with externally bonded reinforcement. In the experimental study, nine full-scale reinforced concrete bridge pier caps were built, externally strengthened with stainless steel reinforcement, and ten tested to failure. Load, deflection, and strain measurements were collected and two potential failure mechanisms were identified. In the analytical part of this work, mechanics-based equations were developed for calculating the shear strength of these types of structural elements when a diagonal shear crack is formed under loading. In addition, a combined strut-and-tie/truss model is proposed for determining the strength of reinforced concrete bridge caps with externally bonded reinforcement. Results from both experimental and analytical studies were compared and design recommendations are made for future adoption in bridge and building codes and specifications.

The equiatomic FeRh alloy undergoes a first-order phase transition from an antiferromagnetic (AFM) to a ferromagnetic (FM) state at about 370 K with a small thermal hysteresis of about 10 K around the phase transition. The transition is accompanied by a unit cell volume expansion about 1% in the c lattice parameter. During the transition the new phase nucleates in the matrix of the original phase by reaching the critical temperature followed by a growth in size upon increasing temperature further. Therefore, to understand the transition process with more details, it is desirable to investigate the nucleation and growth of both phases within the first order phase transition. In the present thesis the main focus is on the growth of FeRh thin films by means of Molecular Beam Epitaxy (MBE) technique and characterization of the magnetic and structural properties. To develop an understanding of the phase transformation in FeRh thin films the ways in which one can tune it were investigated. The following aspects concerning the FeRh system have been examined here: 1) influence of annealing temperature on the magnetic and structural response, 2) effect of film thickness on the first-order phase transition temperature as well as the saturation magnetization, 3) influence of chemical composition on the magnetic properties and 4) magnetic field-induced phase transition. To get insight to details of the transition process the magnetization dynamic has been addressed by performing Ferromagnetic resonance (FMR) experiment across the phase transition. FMR measurements determined the existence of two areas with different magnetic properties inside the film. A huge temperature difference for the beginning of the phase transition in comparison with the static magnetization measurement was observed for the equiatomic FeRh thin film prepared by MBE. Tuning of the AFM to FM phase transition in the FeRh thin film by means of low-energy/low fluence Ne+ ion irradiation was studied. Ion irradiation technique offers a quantitative control of the degree of chemical disorder by adjusting the ion fluence applied, while the penetration depth of the disordered phase can be adjusted by the ion-energy. The main results of ion irradiation are the shifting of the phase transition temperature to lower temperature and irradiation with 3×1014 ion/cm2 leads to the disappearance the AFM phase completely.