En utilisant des solutions de production issues des technologies de Fabrication Additive (FA), l’industrie s’ouvre de nouvelles possibilités pour la fabrication de pièces à haute valeur ajoutée. Dans le but d’être pleinement exploitables, ces procédés de fabrication doivent permettre la réalisation de pièces dont la qualité est adaptée aux besoins de l’industrie. Ces travaux se concentrent sur deux points ciblés de la maîtrise de la qualité en FA appliquée à la technologie Electron Beam Melting (EBM).Le premier point abordé s’intéresse à l’impact de la position d’une pièce dans l’espace de fabrication d’une machine sur la qualité géométrique de cette pièce. Pour caractériser l’espace de fabrication de la machine Arcam A1, plusieurs séries de pièces sont fabriquées à différentes localisation de l’espace, puis comparées à leur design initial. Les écarts mesurés entre les pièces et leur géométrie souhaitée montrent que la périphérie de l’espace de fabrication est une zone sujette à d’importants défauts géométriques. Ces défauts sont caractérisés et des solutions sont proposées pour en limiter l’impact sur la qualité géométrie des pièces.Le second point traite de la porosité des pièces fabriquées. Lorsque l’apport énergétique du faisceau d’électron n’est pas adéquat pour fondre correctement la poudre, des pores peuvent se former dans le matériau des pièces fabriquées. La géométrie et le matériau des pièces rendent difficiles la détection de ses pores. Une méthode de détection est proposée pour détecter la présence de pores dans une pièce via un contrôle standardisé sur un élément qui copie les conditions de fusion de la pièce. Cette méthode propose deux alternatives de contrôle : un contrôle optique (rapide, abordable mais peu précis) et un contrôle tomographique (plus précis que le précédent mais moins rapide et abordable). Un algorithme de traitement d’image innovant a été développé dans le cadre de cette étude afin de rendre les tomographies du témoin plus fiables. / By using production solutions from Additive Manufacturing (AM) technologies, the industry is opening up new possibilities for manufacturing high added value parts. In order to be fully exploitable, these manufacturing processes must allow the production of parts whose quality is adapted to the needs of the industry. This work focuses on two aiming points of quality control in AM applied to Electron Beam Melting (EBM) technology.The first point deals with the impact of a part position in the manufacturing space of a machine on the geometric quality of this part. To characterize the manufacturing space of the Arcam A1 machine, several series of parts are manufactured at different locations of the space, then compared to their initial design. The differences measured between the parts and their desired geometry show that the periphery of the manufacturing space is a zone subject to important geometrical defects. These defects are characterized and solutions are proposed to limit the impact on the geometrical quality of parts.The second point deals with the porosity of manufactured parts. When the energy supply of the electron beam is not adequate to melt the powder properly, pores can form in the material of the manufactured parts. The geometry and material of the parts make it difficult to detect its pores. A detection method is provided to detect the presence of pores in parts via a standardized control on an item that copies the parts merging conditions. This method offers two control alternatives: an optical control (fast, affordable but not very accurate) and a tomographic control (more accurate than the previous one but slower and costlier). An innovative image processing algorithm is developed as part of this study to make the item tomography scans more reliable.

Der zukünftige Linearbeschleuniger (International Linear Collider - ILC) wird für die Teilchenforschung im Energiebereich bis zu einem Tera-Elektronenvolt (TeV scale) entwickelt. In dieser Arbeit wird der Entwurf des inneren Vorwärtsbereichs (Very Forward Region) eines Detektors füur diesen Beschleuniger beschrieben. Das Beam-Kalorimeter - eines der zwei elektromagnetischen Kalorimeter, die hier angeordnet sind - ist Gegenstand dieser Arbeit. Das Beam-Kalorimeter muss eine gute Hermetizität für hochenergetische Elektronen, Positronen und Photonen bis hinab zu sehr kleinen Polarwinkeln gewährleisten. Es dient für die schnelle Strahldiagnose und als Abschirmung des inneren Detektors gegen rückgestreute Beamstrahlungsreste und Synchrotronstrahlung. Als eine mögliche Technologie für das Beam-Kalorimeter wird eine Sandwich-Anordnung aus Diamantsensoren und Wolfram- Absorberplatten betrachtet. Es werden detaillierte Simulationen einer solchen Anordnung durchgeführt. Die Nachweiseffektivität und die Energie- sowie Winkelauflösung für elektromagnetische Schauer werden untersucht. Im Ergebnis der Simulationsrechnungen wird nachgewiesen, dass die vorgeschlagene Anordnung die Anforderungen an ein Beam-Kalorimeter erfüullt. Zusätzlich werden Untersuchungen an polykristallinem Diamantmaterial, hergestellt mittels Abscheidung aus der Dampfphase (Chemical Vapour Deposition - CVD), durchgeführt, um dessen Eigenschaften als Sensormaterial für ein Beam-Kalorimeter zu ermitteln. Die Ergebnisse der Messungen von Mustern verschiedener Hersteller werden dargestellt diskutiert. / The International Linear Collider (ILC) is being designed to explore particle physics at the TeV scale. The design of the Very Forward Region of the ILC detector is considered in the presented work. The Beam Calorimeter - one of two electromagnetic calorimeters situated there - is the subject of this thesis. The Beam Calorimeter has to provide a good hermeticity for high energy electrons, positrons and photons down to very low polar angles, serve for fast beam diagnostics and shield the inner part of the detector from backscattered beamstrahlung remnants and synchrotron radiation. As a possible technology for the Beam Calorimeter a diamond-tungsten sandwich calorimeter is considered. Detailed simulation studies are done in order to explore the suitability of the considered design for the Beam Calorimeter objectives. Detection efficiency, energy and angular resolution for electromagnetic showers are studied. At the simulation level the diamond-tungsten design is shown to match the requirements on the Beam Calorimeter performance. Studies of polycrystalline chemical vapour deposition (pCVD) diamond as a sensor material for the Beam Calorimeter are done to explore the properties of the material. Results of the measurements performed with pCVD diamond samples produced by different manufacturers are presented.

A invenção da Tomografia Computadorizada revolucionou o método de diagnóstico. Apesar de ser um exame de custo elevado, sua confiabilidade é de grande valia. Na década de noventa foram descritos os primeiros relatos da tomografia computadorizada Cone Beam para o uso na Odontologia. Esses aparelhos de tomografia computadorizada por feixe cônico, Cone Beam ou volumétrica são mais compactos, de menor custo e com menor tempo de exposição à radiação ao paciente, quando comparados aos aparelhos de tomografia computadorizada médica ou Fan Beam. Diante da grande utilização de implantes osseointegrados, algumas dificuldades foram despontando, visto que também paralelamente a este, os defeitos ósseos necessitavam de correção. Então os enxertos ósseos ou biomateriais de enxertia passaram a ser a alternativa que possibilitava a correção dessas perdas ósseas. Com o objetivo de estudar e avaliar qualitativamente os biomateriais de enxertia, inseridos em alvéolos dentais, em mandíbulas de suínos, por meio da tomografia computadorizada Cone Beam, utilizou-se de 20 mandíbulas dissecadas de porco, dos quais foram extraídos quatro dentes e nesses alvéolos foram introduzidos quatro biomateriais de enxertia de composições diferentes, com propriedades físico-químicas distintas, forma física, origem e de classificações diferentes. As mandíbulas de suínos foram submetidas a um exame de tomografia computadorizada volumétrica. As imagens obtidas foram avaliadas por um Software específico. Os resultados mostraram que não existiu diferença entre os cortes C (corte coronal) e S (corte sagital) e entre os cortes SS (corte parassagital) e o corte PAN (corte panorâmico), sendo que os corte C e S tiveram maior observação e os cortes SS e PAN, foram os de menor observação. Quanto ao material M-C (GenPhos HA TCP®, G 50, 0.5cc) foi o que obteve maior média de observação (com média 1, 81) enquanto que o M-B (OrthoGen®, G 75, 0.5cc) foi o mais difícil de ser observado, nos contes C (corte coronal) e S (corte sagital). Em relação a homogeneidade os materiais M-B (OrthoGen®, G 75, 0.5cc) e M-D (GenOx Inorg Esponjoso®) não apresentaram diferenças significativas, sendo portanto os materiais considerados menos homegêneos, quando se referem a densidade; observados nos cortes C (corte coronal) e S (corte sagital). Já os materiais M-C (GenPhos HA TCP®, G 50, 0.5cc) e M-A (Biogran® 300-350m, 50-45 mesh) segundo os p-valores não foram considerados estatisticamente diferentes, portanto os materiais que apresentaram as imagens mais homogêneas, igualmente aos demais materiais, foram observados nos cortes C (corte coronal) e S (corte sagital). O corte PAN (corte panorâmico) com média 1,43, foi a imagem que permitiu uma melhor observação dos biomateriais de enxertia. Todos os avaliadores afirmaram que identificaram o alvéolo ou o biomaterial de enxertia considerando a referência anatômica (lâmina dura). / The invention of Computed Tomography has radically changed the method of diagnosis. Even though it is a high-cost exam, its reliability is really worth it. The first reports about the use of Cone-Beam Computed Tomography in Dentistry were described during the 1990s. These conic bundle, Cone-Beam or volumetric computed tomography devices are more compact, less expensive and provide the lowest radiation dose for the patient when compared to other medical or Fan-Beam computed tomography devices. Once there has been a wide use of osseointegrated implants, some difficulties have emerged as, in parallel to this, there were some bone defects that required correction. Therefore, bone graftings or biomaterials for graftings have become an alternative that allowed correcting bone losses. With the objective to study and evaluate qualitatively the grafting biomaterial inserted pig mandibles dental cavities by Cone-Beam computed tomography, it was used 20 dissected pig mandibles, from which four teeth have been extracted and four biomaterial graftings of different compositions, different physical-chemical properties, physical shape, origin and classifications have been inserted into those cavities. The pig mandibles were submitted to a volumetric computed tomography. Images were evaluated by specific software. Results showed that there was no difference between C (coronal section) and S (sagittal section) sections, and between SS (parassagittal section) and PAN (panoramic section) sections. C and S sections had more observation and SS and PAN sections were the ones with less observation. Concerning the material, M-C (GenPhos HA TCP®, G 50, 0.5cc) was the one that obtained the highest observation average (1,81) while M-B (OrthoGen®, G 75, 0.5cc) was the most difficult to be observed on C (coronal) and S (sagittal) sections. About the homogeneity of materials, M-B (OrthoGen®, G 75, 0.5cc) and M-D (GenOx Inorg Esponjoso®) did not show significant differences, being, therefore, the materials considered the least homogeneous regarding density; observed in C (coronal) and S (sagittal) sections. According to p-values, materials M-C (GenPhos HA TCP®, G 50, 0.5cc) and M-A (Biogran® 300-350m, 50-45 mesh) were not considered statistically different. Thus the materials that presented the most homogeneous images, as well as the other materials, were observed in C (coronal) and S (sagittal) sections. The PAN (panoramic) section, with an average of 1,43, was the image that allowed the best observation of the grafting biomaterials. All evaluators affirmed to have identified the cavity of the grafting biomaterial considering the anatomic reference (hard slide).

Injection in the LHC is a delicate moment, since the LHC collimation system cannot offer adequate protection during beam transfer. For this reason, a complex chain of injection protection devices has been put in place. Among them, the SPS scrapers are the multi-turn cleaning system installed in the SPS aimed at halo removal immediately before injection in the LHC. The upgrade in luminosity of the LHC foresees beams brighter than those currently available in machine, posing serious problems to the performance of the existing injection protection systems. In particular, the integrity of beam-intercepting devices is challenged by unprecedented beam parameters, leading to interactions potentially destructive. In this context, a new design of scrapers has been proposed, aimed at improved robustness and performance. This thesis compares the two scraping systems, i.e. the existing one and the one proposed for upgrade. Unlike any other collimation system for regular halo cleaning, both are "fast" systems, characterised by the variation of the relative distance between the beam and the absorbing medium during cleaning, which enhances the challenge on energy deposition values. Assets/liabilities of the two systems are highlighted by means of numerical simulations and discussed, with particular emphasis on energy deposition in the absorbing medium, time evolution of the beam current during scraping and losses in the machine. Advantages of the system proposed for upgrade over the existing one are highlighted. The analysis of the existing system takes into account present operational conditions and addresses the sensitivity to settings previously not considered, updating and extending past studies. The work carried out on the upgraded system represents the first extensive characterisation of a multi-turn cleaning system based on a magnetic bump. Results have been obtained with the Fluka-SixTrack coupling, developed during this PhD activity from its initial version to being a state-of-art tracking tool for cleaning studies in circular machines. Relevant contributions to the development involve the handling of time-varying impact conditions. An extensive benchmark against a test of the scraper blades with beam has been carried out, to verify the reliability of results. Effcts induced in the tested blades confirm the high values of energy deposition predicted by the simulation. Moreover, the comparison with the time profile of the beam intensity measured during scraping allowed the reconstruction of the actual settings of the blades during the test. Finally, the good agreement of the quantitative benchmark against readouts of beam loss monitors finally proves the quality of the analyses and the maturity of the coupling.

Dentre as atividades parafuncionais do sistema estomatognático, pode-se salientar o bruxismo, o qual pode se manifestar tanto durante o sono (BS), quanto durante o dia (Bruxismo Diurno BD) ocorrendo em distintos estados de consciência (sono e vigília). A Classificação Internacional dos Distúrbios do Sono define o bruxismo como &ldquo;um distúrbio com movimentos de padrão desordenado do sistema mastigatório que envolve o ranger ou apertar dos dentes durante o sono&rdquo;. O diagnóstico de bruxismo é realizado clinicamente, com base no relato de uma história prévia recente de sons de ranger de dentes que ocorreram pelo menos de 3 a 5 noites por semana, durante 6 meses. A presença de facetas de desgaste dental, manifestações de dor matinal nos músculos mastigatórios, a hipertrofia do músculo masseter, a hipersensibilidade ou estalo da Articulação Temporomandibular (ATM), impressões dentais na bochecha ou língua e mobilidade dental, entre outros, são sinais característicos desta parafunção. Não obstante, frente à crescente valorização do aspecto funcional, a avaliação não deve se restringir apenas ao exame clínico. Nesse sentido, a imaginologia vem se tornando um recurso de valor inestimável para a determinação de um diagnóstico. Assim, o objetivo do presente trabalho é descrever as possíveis alterações dos componentes anatômicos da articulação temporomandibular (ATM), de crianças com bruxismo, por meio da análise de imagens obtidas pela técnica de Tomografia Computadorizada Cone Beam. Com base nos critérios de inclusão e exclusão, foram selecionados 20 indivíduos, entre 7 e 11 anos de idade, do sexo masculino e feminino, em atendimento na Clínica Infantil da FORP USP. Na avaliação clínica para diagnóstico de bruxismo, foi evidenciado a presença de todas, ou algumas das seguintes alterações: presença de facetas de desgaste dental, fraturas de restaurações, fraturas dentais, impressões dentais em bochechas e língua, dor na ATM, ruído na ATM, dor nos músculos masseter e temporal. O exame tomográfico foi realizado em um aparelho de tomografia i-CAT e durante as reconstruções multiplanares, antes de gerar as imagens, o volume total do paciente foi transferido para o scanner com a utilização do plano de Frankfurt paralelo ao solo. Na análise de variáveis categóricas, utilizou-se teste Exato de Fisher e teste de Fisher com a extensão de Freeman-Halton. Foi considerado estatisticamente significante valor de p &le; 0,05. Em algum grau, todos os pacientes relataram dor à palpação dos músculos temporal e masseter, assim como à palpação da ATM. A presença de alterações na ATM somente apresentou significância estatística na presença de osteófitos na região articular do lado direito em associação com dor na articulação temporomandibular ipsilateral (p=0,04). Erosões e esclerose não foram encontradas em nenhum paciente e aplainamento foi um achado na totalidade dos indivíduos, porém, não apresentando relação estatísticamente significante quando cruzado com achados clínicos. A presença de dor no músculo temporal e a relação horizontal côndilo-fossa contralateral, apresentaram significância estatística (p<0,05). No músculo masseter essa associação apresentou significância estatística com a relação horizontal côndilo-fossa ipsilateral (p=0,01). Os achados sugerem que o bruxismo pode promover alterações significativas nas estruturas do sistema estomatognático desde a infância. / Among the parafunctional activities of masticatory system, bruxism can be higlighted. It occurs during sleep (Sleep Bruxism - SB) or wakefulness (Awake Bruxism - DB), which occur in two different states of consciousness (sleep and wakefulness). The International Classification of Sleep Disorders defines bruxism as \"a movement disorder with a stereotyped pattern of the masticatory system that involves teeth grinding or clenching during sleep.\" Bruxism is clinically diagnosed based on reports of teeth grinding noises that occurred at least three to five nights per week for 6 months. Also, the presence of wear facets, matutinal pain in the masticatory muscles, masseter muscle hypertrophy, temporomandibular joint (TMJ) noise or hypersensitivity, dental impressions on the cheek or tongue and tooth mobility, among others, are hallmarks of this parafunction. However, the evaluation should not be restricted to clinical examination since functional aspects are gaining importance. As consequence, imaging has become an invaluable resource for diagnosis. The objective of this paper is to describe possible changes in temporomandibular joint (TMJ) anatomical components in children with bruxism by Cone Beam Computed Tomography image analysis. Based on the inclusion and exclusion criteria, Twenty 7-11-years old male and female children treated at Ribeirão Preto Pediatric Dentistry Clinic, University of São Paulo, Brazil, were selected. The presence of all or some of the following changes was used in clinical evaluation for bruxism diagnosis in the present study: presence of wear facets, fractures in fillings, dental fractures, dental impressions in cheek and tongue, TMJ pain and clicking, masseter and temporalis muscles pain. The CT scan was performed on a i-CAT CT device and during multiplanar reconstructions, before obtaining image, the total volume of the patient was transferred to the scanner using the Frankfurt plane parallel to the ground. In Statistical analysis Fisher\'s exact test and Fisher\'s test with the Freeman-Halton extension were used for categorical variables. Values of p &le; 0.05 were considered statistically significant. In the results, all patients reported pain on palpation of the temporalis and masseter muscles, as well as TMJ palpation. Erosions and sclerosis were not found. Flattening was present in all individuals, however, no statistical significance was found between this feature and clinical findings. The presence of osteophytes in the TMJ was associated with ipsilateral pain in temporomandibular joint palpation (p = 0.04). There was an association between pain in the contralateral temporal muscle and the condyle-fossa relationship in the horizontal direction (p <0.05). There was also a correlation between pain in the ipsilateral masseter muscle and the condyle-fossa relationship in the horizontal direction (p = 0.01). In conclusion, our findings suggest that bruxism can promote significant changes in the structures of the stomatognathic system since childhood.

A gelatina (GEL) é um biopolímero biodegradável e biocompatível que forma naturalmente coloides semissólidos ou hidrogéis em soluções aquosas. Sendo um polímero hidrofílico, a GEL possui propriedades estruturais e físico-mecânicas que a distinguem de polímeros hidrofílicos sintéticos. São essas características que inspiraram o desenvolvimento do presente trabalho. Para analisa-las foram desenvolvidos filmes e hidrogéis de GEL utilizando radiação ionizante mediante diferentes técnicas: irradiação por 60Co, feixe de elétrons (EB) e/ou EB pulsado. Na elaboração de filmes a base de GEL foram incorporados diferentes aditivos, tais como glicerol (GLY), álcool polivinílico (PVA), hidroxitolueno butilado (BHT), acrilamida e/ou fibra vegetal. Esse produto filmes a base de GEL foi analisado quanto às suas propriedades mecânicas, cor, absorção de água, entre outros; e irradiado com doses de 10 a 60 kGy, dependendo do aditivo. Na síntese radioinduzida de nano-hidrogéis de GEL, polietileno glicol (PEG) e a mistura (MIX) de ambos os aditivos, GEL e PEG, foram analisados a dimensão, massa molar e morfologia das nanopartículas. Houve aumento significativo da fração gel com o aumento da dose de radiação nas amostras de GEL/fibra. Os filmes a base de GEL com 10% PVA irradiados a 20 kGy apresentaram a maior resistência à perfuração. A adição de antioxidante BHT influenciou em algumas das propriedades dos filmes a base de GEL nas condições aplicadas. Em relação aos nano-hidrogéis houve redução do raio hidrodinâmico da MIX irradiada com 60Co de 68 ± 25 nm (2 kGy) para 35 ± 4 nm (5 kGy). Tanto nos filmes quanto nos nano-hidrogéis de GEL, a radiação mostrou ser uma ferramenta conveniente na modificação de materiais poliméricos. / The gelatin (GEL) is a biocompatible and biodegradable biopolymer, which naturally forms semi-solid colloids or hydrogels in aqueous solutions. As a hydrophilic polymer, the GEL has structural and physico-mechanical properties that distinguish it from synthetic hydrophilic polymers. The study of these properties led to the development of the present work. Thus, GEL-based films and hydrogels were developed using ionizing radiation technology by different techniques: irradiation with 60Co, electron beam (EB) and/or pulsed EB. The GEL based-films enriched with different additives, such as glycerol (GLY), polyvinyl alcohol (PVA), butylated hydroxytoluene (BHT), acrylamide and/or vegetal fiber, were irradiated with doses from 10 to 60 kGy, depending on the additive; some parameters like mechanical properties, color, and water absorption were analyzed. In the radio-induced synthesis of GEL nanohydrogels, polyethylene glycol (PEG) and the mixture (MIX) of additives, PEG and GEL, the size, molar mass and surface morphology of the nanohydrogels were analyzed. There was a significant increase of gel fraction with increase of the radiation dose for the GEL/fiber samples. The GEL based-films with 10% PVA irradiated at 20 kGy showed the highest puncture strength. The addition of antioxidant BHT affected on some GEL based-films properties on applied conditions. Regarding the nanohydrogels, there was a decrease of hydrodynamic radius of MIX irradiated with 60Co from 68 ± 25 nm (2 kGy) to 35 ± 4 nm (5 kGy). The radiation proved to be a convenient tool in the modification of polymeric materials for both, GEL films and hydrogels.

A gelatina (GEL) é um biopolímero biodegradável e biocompatível que forma naturalmente coloides semissólidos ou hidrogéis em soluções aquosas. Sendo um polímero hidrofílico, a GEL possui propriedades estruturais e físico-mecânicas que a distinguem de polímeros hidrofílicos sintéticos. São essas características que inspiraram o desenvolvimento do presente trabalho. Para analisa-las foram desenvolvidos filmes e hidrogéis de GEL utilizando radiação ionizante mediante diferentes técnicas: irradiação por 60Co, feixe de elétrons (EB) e/ou EB pulsado. Na elaboração de filmes a base de GEL foram incorporados diferentes aditivos, tais como glicerol (GLY), álcool polivinílico (PVA), hidroxitolueno butilado (BHT), acrilamida e/ou fibra vegetal. Esse produto filmes a base de GEL foi analisado quanto às suas propriedades mecânicas, cor, absorção de água, entre outros; e irradiado com doses de 10 a 60 kGy, dependendo do aditivo. Na síntese radioinduzida de nano-hidrogéis de GEL, polietileno glicol (PEG) e a mistura (MIX) de ambos os aditivos, GEL e PEG, foram analisados a dimensão, massa molar e morfologia das nanopartículas. Houve aumento significativo da fração gel com o aumento da dose de radiação nas amostras de GEL/fibra. Os filmes a base de GEL com 10% PVA irradiados a 20 kGy apresentaram a maior resistência à perfuração. A adição de antioxidante BHT influenciou em algumas das propriedades dos filmes a base de GEL nas condições aplicadas. Em relação aos nano-hidrogéis houve redução do raio hidrodinâmico da MIX irradiada com 60Co de 68 ± 25 nm (2 kGy) para 35 ± 4 nm (5 kGy). Tanto nos filmes quanto nos nano-hidrogéis de GEL, a radiação mostrou ser uma ferramenta conveniente na modificação de materiais poliméricos. / The gelatin (GEL) is a biocompatible and biodegradable biopolymer, which naturally forms semi-solid colloids or hydrogels in aqueous solutions. As a hydrophilic polymer, the GEL has structural and physico-mechanical properties that distinguish it from synthetic hydrophilic polymers. The study of these properties led to the development of the present work. Thus, GEL-based films and hydrogels were developed using ionizing radiation technology by different techniques: irradiation with 60Co, electron beam (EB) and/or pulsed EB. The GEL based-films enriched with different additives, such as glycerol (GLY), polyvinyl alcohol (PVA), butylated hydroxytoluene (BHT), acrylamide and/or vegetal fiber, were irradiated with doses from 10 to 60 kGy, depending on the additive; some parameters like mechanical properties, color, and water absorption were analyzed. In the radio-induced synthesis of GEL nanohydrogels, polyethylene glycol (PEG) and the mixture (MIX) of additives, PEG and GEL, the size, molar mass and surface morphology of the nanohydrogels were analyzed. There was a significant increase of gel fraction with increase of the radiation dose for the GEL/fiber samples. The GEL based-films with 10% PVA irradiated at 20 kGy showed the highest puncture strength. The addition of antioxidant BHT affected on some GEL based-films properties on applied conditions. Regarding the nanohydrogels, there was a decrease of hydrodynamic radius of MIX irradiated with 60Co from 68 ± 25 nm (2 kGy) to 35 ± 4 nm (5 kGy). The radiation proved to be a convenient tool in the modification of polymeric materials for both, GEL films and hydrogels.

The ESSnuSB will produce a high intensity neutrino super beam based on the 3 ms long proton pulses at 14 Hz from the ESS linac. With the use of a conventional normal-conducting van der Meer horn, to collect pions from the neutrino target, these 3 ms pulses will have to be compressed to of the order of 1 microsecond in order to avoid overheating of the magnet current conductors. Since this pulse compression requires costly extensions to the accelerator complex a prototype design of an alternative normal-conducting hadron collector scheme that could be operated in DC mode has been studied. The magnet has been implemented in the simulation software FLUKA and extensive research has been made to analyse and maximise the flux of charged pions inside and downsteam of the magnet. Further simulations have been made to asses the flux of on-target neutrinos from the alternative collector scheme in comparison to the corresponding flux of a van der Meer horn. Simulation results from the comparison show that the alternative magnet greatly improved the neutrino flux of a bare source but not to the extent necessary to replace the magnetic horn. A conclusion is presented on the future possibilities of an optimized design that can improve the neutrino flux.

<p>Molecular Beam Epitaxy (MBE) is a well-established method to grow low-dimensional structures for research applications. MBE has given many contributions to the rapid expanding research-area of nano-technology and will probably continuing doing so. The MBE equipment, dedicated for Silicon/Germanium (Si/Ge) systems, at Karlstads University (Kau) has been studied and started for the first time. In the work of starting the system, all the built in interlocks has been surveyed and connected, and the different subsystems has been tested and evaluated. Service supplies in the form of compressed air, cooling water and electrical power has been connected. The parts of the system, their function and some of the theory behind them are described.</p><p>The theoretical part of this master’s thesis is focused on low-dimensional structures, so-called quantum wells, wires and dots, that all are typical MBE-built structures. Physical effects, and to some extent the technical applications, of these structures are studied and described.</p><p>The experimental part contains the MBE growth of a Si/Ge quantum well (QW) structure and characterisation by Auger Electron Spectroscopy (AES). The structure, consisting of three QW of Si0,8Ge0,2 separated by thicker Si layers, was built at Linköpings University (LiU) and characterised at Chalmers University of Technology (CTH). The result of the characterisation was not the expected since almost no Ge content could be discovered but an extended characterisation may give another result.</p><p>Keywords: Silicon, Germanium, Molecular Beam Epitaxy, MBE, Quantum wells</p> / <p>Molecular Beam Epitaxy (MBE) är en väl etablerad metod när det gäller tillverkning av låg-dimensionella strukturer för forskningsändamål och lämpar sig väl för användning inom det expanderande forskningsområdet nanoteknologi. MBE utrustningen vid Karlstads universitet (Kau), som är avsedd för kisel/germanium (Si/Ge) strukturer, har studerats och startats för första gången. Under studien av systemet har alla inbyggda förreglingar utretts och anslutits och de olika delsystemen har testats och utvärderats. Tryckluft, kylvatten och el har utretts och anslutits. Systemets delar, deras funktion och i viss mån den bakomliggande teorin har studerats.</p><p>Den teoretiska delen av detta arbete är inriktad mot låg-dimensionella strukturer d.v.s. kvant brunnar, kvanttrådar och kvantprickar, som alla är strukturer lämpliga för framställning i MBE processer. De fysikaliska effekterna och i viss mån de tekniska tillämpningarna för dessa strukturer har studerats.</p><p>Den experimentella delen består av MBE tillväxt av en Si/Ge kvantbrunn-struktur och karakterisering m.h.a. Auger Electron Spectroscopy (AES). Tillväxten av strukturen, som består av tre kvantbrunnar av Si0,8Ge0,2 separerade av tjockare Si-lager, utfördes på Linköpings Universitet (LiU) och karakteriseringen utfördes på Chalmers Tekniska Högskola (CTH). Resultatet av karakteriseringen var inte det förväntade då knappast något Ge innehåll kunde detekteras men en utökad undersökning skulle kanske ge ett annat resultat.</p><p>Sökord: Kisel, germanium, Molecular Beam Epitaxy, MBE, kvantbrunn</p>

The development of new materials with novel properties plays an important role in improving our lives and welfare. Research in Nanotechnology can provide e.g. cheaper and smarter materials in applications such as energy storage and sensors. In order for this development to proceed, we need to be able to characterize the material properties at the nano-, and even the atomic scale. The ultimate goal is to be able to tailor them according to our needs. One of the great challenges concerning the characterization of nano-sized objects is how to achieve the physical contact to them. This thesis is focused on the contacting of nanoobjects with the aim of electrically characterizing them and subsequently understanding their electrical properties. The analyzed nanoobjects are carbon nanosheets, nanotetrapods, nanoparticles and molecular systems. Two contacting strategies were employed in this thesis. The first strategy involved the development of a focused ion beam (FIB) based nanocontact platform. The platform consists of gold nanoelectrodes, having nanogaps of 10-30 nm, on top of an insulating substrate. Gold nanoparticles, double-stranded DNA and cadmium telluride nanotetrapods have been trapped in the gaps by using dielectrophoresis. In certain studies, the gold electrodes have also been coated with conducting or non-conducting molecules, prior to the trapping of gold nanoparticles, in order to form molecular junctions. These junctions were subsequently electrically characterized to evaluate the conduction properties of these molecular systems. For the purpose of better controlling the attachment of molecules to the nanoelectrodes, a novel route to synthesize alkanedithiol coated gold nanoparticles was developed. The second contacting strategy was based on the versatility of the FIB instrument as a platform for in-situ manipulation and electrical characterization of non-functionalized and functionalized carbon nanosheets, where it was found that the functionalized samples had an increased conductivity by more than one order of magnitude. Both contacting strategies proved to be valuable for building knowledge around contacting and electrical characterization of nanoobjects