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Dissertations / Theses on the topic 'Cryogenic measurement'
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TRINDADE, IRIS DA SILVA. "PROPOSITION OF METROLOGICAL CONTROL FOR MEASUREMENT OF CRYOGENIC LIQUIDS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4405@1.
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INSTITUTO NACIONAL DE METROLOGIA, QUALIDADE E TECNOLOGIALíquidos criogênicos são amplamente empregados em diversos segmentos da atuação humana, destacando-se a Medicina, Engenharia Genética, setor industrial e no desenvolvimento cientifico. Sendo assim, efetuar o controle metrológico sobre os dispositivos e sistemas utilizados na comercialização de tais materiais é fundamental. Nesta dissertação propomos a implementação do controle metrológico neste segmento como forma de estabelecer confiabilidade e garantir trocas cada vez mais justas, sem prejuízos as partes envolvidas. Para tal, a estrutura legal é amparada pela regulamentação vigente no âmbito brasileiro, a qual é abordada e confrontada com as diretrizes internacionais. Os diferentes sistemas de medição atualmente adotados são abordados, com o intuito de julgar a adequação dos mesmos e estabelecer requisitos mínimos. Diante da inexistência de uma regulamentação ampla, capaz de agregar aspectos não só inerentes às boas práticas, mas que contemplem a realidade do mercado nacional, são estabelecidas proposições e diretrizes a serem seguidas na implementação e efetivação do controle metrológico.
Cryogenic liquids are widely employed in several fields of human activity,such as in Medicine, Genetics Engineering, the industrial sector and for the scientific development. This way, applying the metrological controls in devices and systems used for the commercialization of cryogenic liquids is essential. In this dissertation we proposed the implementation of the metrological controls in this area, objectifying to establish the reliability and the guarantee of fair trade,without damages for the involved parts. Thus, the legal structure is supported by the valid regulamentation in the Brazilian case, that is mentioned and faced against international policies. The different measurement systems adopted nowadays are approached, for judging their adequacy and establishing minimum requests. Considering that there is not a broad regulamentaion, capable of aggregate aspects of the good practice and to heed the national reality, proposals and guidelines are presented for reaching the implementation of effective metrological controls.
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Langham, Conway David. "Cryogenic sapphire dielectric resonators as microwave frequency standards : development and performance." Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364164.
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Nofziger, Michael James. "REFRACTIVE INDEX MEASUREMENTS OF MAGNESIUM OXIDE, SAPPHIRE, AND AMTIR-1 AT CRYOGENIC TEMPERATURES." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/291228.
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Martin, Damien. "Development and remote controlled deployment of non-cryogenic equipment used in the measurement of non-methane hydrocarbons." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271849.
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Eichelhardt, Frank [Verfasser], and G. [Akademischer Betreuer] Drexlin. "Measurement of the Tritium Pumping Properties of a 4.2 K Argon Condensate for the Cryogenic Pumping Section of KATRIN / Frank Eichelhardt. Betreuer: G. Drexlin." Karlsruhe : KIT-Bibliothek, 2009. http://d-nb.info/1013695739/34.
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Rink, Ann-Kathrin [Verfasser]. "Mass and life-time measurement of the 1.7ms 215-Po isotope : a crucial test of the novel concept of the cryogenic ion catcher for the Super-FRS at GSI-FAIR / Ann-Kathrin Rink." Gießen : Universitätsbibliothek, 2017. http://d-nb.info/1139638823/34.
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Vitry, Youen. "Étude expérimentale des écoulements film mince sur plan incliné avec contrecourant gaz dans des conditions de similitude aux écoulements cryogéniques." Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0117.
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L’objectif est d’améliorer la connaissance des écoulements de films minces se développant au sein des colonnes servant à distiller les gaz de l’air sous conditions cryogéniques. Ce travail porte sur la caractérisation expérimentale de l’épaisseur du film liquide dans des conditions hydrodynamiques proches de celles rencontrées dans l’industrie. Tout d’abord, ce travail a permis de déterminer les conditions opératoires permettant la réalisation d’écoulement en similitude hydrodynamique avec les écoulements cryogéniques mais à température et pression proches de l’ambiant. Ensuite, un dispositif expérimental a ensuite été développé afin de permettre la réalisation d’écoulement de film liquide avec et sans contre-courant gaz sur plan incliné. Une métrologie optique utilisant un procédé de fluorescence a été développée et calibrée afin de mesurer des épaisseurs de films minces inférieures à 2 mm. Pour finir, l’étude expérimentale a permis de caractériser l’écoulement du film mince par l’étude statistique de son épaisseur, l’étude des régimes d’ondes de surface ainsi que son aire interfacialeThe aim of this study is to get a better knowledge of thin film flow inside column used to distil the gases of air under cryogenic conditions. Experimental characterisation of the liquid film thickness submitted to hydrodynamic conditions similar to those found in real processes is investigated in this work. First, operating conditions were defined that allow thin film flow in hydrodynamic similitude with cryogenic flows but under conditions close to standard temperature and pression. Then, an experimental setup was designed in order to realize liquid film flows down an inclined plate with and without counter-current air flow. An optical technique using fluorescence was built and calibrated in order to measure the thickness of liquid film up to 2 mm. Finally, thin liquid film flow characteristics were experimentally studied with special attention given to the statistical variation of film thickness, interfacial wave patterns and interfacial area
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Holcman, Vladimír. "Dielektrická relaxační spektroskopie kompozitních soustav." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-233414.
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The subject of this doctoral thesis is the study of dielectric properties of a binary composite made up of a polymer matrix and metallic filler. Properties of such composites have been extensively examined in the past and they turned out to depend on temperature, frequency and in particular on filler concentration. The objective of this work was first to experimentally establish and second to describe quantitatively the effect of the size of metallic particles on the properties of the composite concerned, yet at the same filler concentration. This study was carried out on the model system ethylene-vinylacetate copolymer – nickel. The acquisition of experimental results required extensive measurements in a wide frequency and temperature interval, as well as a manufacture and preparation of a large set of samples with different concentrations and Ni filler sizes. Measurements were in part carried out at the Centre for Electronic Correlations and Magnetism, Institute of Experimental Physics V of the University of Augsburg (Germany) and, after the installation of a new cryogenic system, at the Department of Physics at FEEC, BUT Brno. Measurements were performed on a number of meters (Alpha-Analyzer of Novocontrol, HP4284A and HP4285A of Hewlett Packard and E4991A of Agilent) in the frequency range 1 Hz – 1 MHz and in the temperature interval 10 K – 300 K. The nickel concentration in systems studied varied from 0 % to 75 % and nickel particles were of a spherical shape with diameters between 35 and 115 m. The measurement results have shown that in the above frequency and temperature window just a single relaxation and a single conductivity mechanism occur. It was also proved that the frequency dependence of complex permittivity is for different Ni particle sizes at the same concentration different. These results have been quantified and a simple mathematical formula based on the Lichtenecker mixture rule has been proposed for their description. The physical origin of the effect of particle size at the same total nickel concentration is sought in different surface areas of internal interfaces between nickel and polymer in the composite
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Liskevych, Olga. "Calor imposto líquido: um novo conceito para quantificação do aporte térmico em soldagem a arco." Universidade Federal de Uberlândia, 2014. https://repositorio.ufu.br/handle/123456789/14758.
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Fundação de Amparo a Pesquisa do Estado de Minas GeraisA more detailed and accurate study of the thermal phenomena involved in arc welding processes is of great importance for both simulation developers of metallurgical transformations and residual stresses generation and users in general, whom need to understand this phenomenology to take decisions. In terms of thermal phenomena, heat input and its derivatives (such as thermal efficiency and fusion efficiency are the most representative parameters in welding engineering. However, scientific and technical literatures are very divergent on heat input values. In addition, they do not discuss the actual heat flow inside the plate. Initial tests demonstrated that these inconsistencies are due to systematic and random errors that occur during heat input measurements. Thus, the major purpose of this work was to develop a methodological approach to determine the heat input due to a welding process, which would be more representative of the heat that actually diffuses inside the workpiece and free of the assessment method and parameter influence. Thus, this actual heat input could be generally used in calculations that require this welding parameter. As methodological base, a descriptive model of heat flow in the welding region was developed. Then, a methodology to determine a heat input value free of measurement errors (here called as net heat input) was proposed and applied to cryogenic calorimetry. This procedure was validated using several welding conditions. The results demonstrated the proper functioning of the proposed methodology, regardless the welding process and its variables. It is expected that, with the application of the net heat input values, the calculations and simulations involved in welding engineering turn into more robust, since the use of such imprecise parameter as thermal efficiency is dispensed.
O conhecimento mais detalhado e preciso dos fenômenos térmicos envolvidos no processo de soldagem é de grande importância, tanto para os que desenvolvem simulações de transformações metalúrgicas e geração de tensões térmicas, como para os usuários de forma geral, que precisam entender essa fenomenologia para tomar decisões. Em termos de fenômenos térmicos, os parâmetros mais representativos na engenharia de soldagem são o calor imposto e seus derivados (tais como rendimento térmico e rendimento de fusão). No entanto, as literaturas científica e técnica são muito divergentes quanto aos valores de calor imposto. Também não discutem o real fluxo de calor dentro da chapa. Testes iniciais demonstraram que estas inconsistências existem devido aos erros sistemáticos e aleatórios que ocorrem durante as medições do calor imposto. Assim, o objetivo maior deste trabalho foi desenvolver uma abordagem metodológica para determinação do calor imposto por um processo de soldagem, que seja mais representativo do calor que realmente difunde pela peça e isento da influência dos métodos e parâmetros de ensaio, de tal forma que possa ser usado genericamente em cálculos de soldagem que necessitem deste parâmetro. Para este fim, como base metodológica, foi desenvolvido um modelo descritivo de fluxo de calor na região de soldagem. Em seguida, foi proposta uma metodologia para determinação de um calor imposto isento dos erros de medição (chamado aqui de calor imposto líquido) aplicado à calorimetria criogênica. Esse procedimento foi validado para várias condições de soldagem. Os resultados obtidos demonstraram um adequado funcionamento da metodologia proposta, independentemente do processo de soldagem e suas variáveis. Espera-se que, com a aplicação do calor imposto líquido, os cálculos e simulações envolvidos na engenharia de soldagem sejam mais robustos, uma vez que se dispensa o uso de um parâmetro impreciso, como o rendimento térmico.
Doutor em Engenharia Mecânica
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Mohn, Thea Ragna Storesund. "Heat Capacity Measurements of Porous Materials at Cryogenic Temperatures." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18486.
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In the search for new technology, new materials are prerequisite for major breakthrough. One of these classes of functional materials is the metal-organic framework (MOF). The MOFs offer higher surface areas because of its porous structure and a potential for improved adsorption activity than other currently used materials. This makes it attractive for physical adsorption, which is a hydrogen storage technique. Adsorption type storage systems are alternatives that have the potential to reach the goals for handling hydrogen in on-board storage systems. However, the transient processes during charging and discharging of a storage system play an important role in the utilization of the hydrogen adsorption storage systems, and the heat distribution in the sorption material plays a major role during charging and discharging of a storage system. The specific heat capacity for activated carbon, Norit R0.8 (1), and three microporous MOFs, Cu-btc (2), Fe-btc (3), and MIL-100(Fe) (4), have been measured, both for inactivated and activated material. The compounds were measured using an MDSC method on a Q2000 differential scanning calorimeter with an appurtenant liquefied nitrogen cooler system (LNCS). The heat capacities were measured from -180°C to 150°C. The uncertainties for the different measurements were determined; it varied from 5% to 7%, depending on the assumed water content adsorbed. Further the measurement accuracy was found to depend very little on the inert gases present in the sample. In addition to measuring the porous material´s specific heat capacity, is it performed and presented a literature survey on theoretical models and published data for both gas adsorption and heat capacities in porous materials. The experimental results are compared with published data on reference materials where possible, and a complete uncertainty analysis on the experimental results presented. The inactivated sample curves showed a general trend, where the heat capacities for inactivated material normally were higher than the heat capacities for the respective activated material, which most probably was due to higher water content in the inactivated material. A considerable number of measurements on each material were performed, without obtaining the expected results for the activated samples. The principal reason was that an unexplainable transition around -150 °C was present on almost half of the obtained data. The exact reason behind this anomaly was not found. However, the most likely error was the activation of the samples, based on analysis and investigation of the results. This presumption was stated mainly because the heat capacities for the inactivated samples increased in a smooth and continuous matter with increasing temperature, without this sudden heat capacity change around -150 °C. The conclusion is due to the time perspective of this work an assumption based on observations and personal experience. Further investigation on the matter is recommended, especially to find out if there was a problem in the actual activation procedure or a chemical change in the investigated materials.
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Rosson, Joel Christopher. "Dynamic flow quality measurements in a transonic cryogenic wind tunnel." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/101463.
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Two instruments mounted in a piggyback arrangement were developed for time-resolved measurements of dynamic flow quality in a transonic cryogenic wind tunnel. The first one is a dual hot-wire aspirating probe for measurement of stagnation pressure and temperature. The second is a miniature high-frequency response angle probe consisting of surface mounted pressure sensors.
The aspirating probe was tested in the 0.3-m Transonic Cryogenic Tunnel (TCT) at NASA-Langley Research Center. Stagnation pressure and temperature measurements were taken in the free-stream of the settling chamber and test section. Data were also obtained in the unsteady wake shed from an airfoil oscillating at 5 Hz. The investigation revealed the presence of large stagnation pressure and temperature fluctuations in the settling chamber occurring at the blade passing frequency of the tunnel driving fan. The fluctuations in the test section are of a much more random nature and have amplitudes much lower than those in the test section. The overall results are consistent with previous tunnel disturbance measurements in the 0.3-m TCT. In the unsteady wake shed from the oscillating airfoil, stagnation temperature fluctuations as high as 42 K rms were observed.
The high-frequency angle probe is a four sensor, pyramid type probe capable of simultaneously measuring time resolved stagnation and static pressures and two orthogonal flow angles. Using measurements from both probes, all flow parameters of interest can be deduced. Aerodynamic behavior of a full size model of the probe was established in an open air jet of known conditions.M.S.
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Griffith, Dwaine O. "Turbulence measurements and noise generation in a transonic cryogenic wind tunnel." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/45979.
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A high-frequency combination probe was used to measure dynamic flow quality in the test section of the NASA Langley 0.3-m Transonic Cryogenic Tunnel. The probe measures fluctuating stagnation (total) temperature and pressure, static pressure, and flow angles in two orthogonal planes. Simultaneous unsteady temperature and pressure measurements were also made in the settling chamber of the tunnel. The data show that the stagnation temperature fluctuations remain constant, and the stagnation pressure fluctuations increase by a factor of two, as the flow accelerates from the settling chamber to the test section. In the test section, the maximum rms value of the normalized fluctuating velocity is 0.7 percent. Correlation coefficients l failed to show vortlcity, entropy, or sound as the dominant mode of turbulence in the tunnel.
At certain tunnel operating conditions, periodic disturbances are seen in the data taken in the test section. A possible cause for the disturbances is found to be acoustic coupling of the test section and plenum chamber via the perforated side walls in the tunnel. The experimental data agree well with the acoustic coupling theory.
Master of Science
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Rengnez, Florentin. "Développement de comparateur cryogénique de courants très faible bruit pour la métrologie électrique quantique." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLN009/document.
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Dans un contexte de besoin grandissant en précision dans la mesure des faibles courants pour les instituts nationaux de métrologie, l’industrie, les fabricants d’instruments et la physique fondamentale, l’étude des dispositifs à un électron (SET) capables de générer un courant continu directement proportionnel à une fréquence et la charge élémentaire, couplés à un amplificateur de courant très performant, le comparateur cryogénique de courant (CCC), devient pertinente pour réaliser un étalon quantique de courant. Dans ce contexte, les travaux ont été poursuivis au LNE sur l’étude de nouveaux dispositifs SET et le développement de nouveaux CCC. Durant cette thèse, un montage expérimental a été mis en place afin d’évaluer les performances d’un nouveau CCC, constitué d’une conception originale et de 30 000 tours. Les résultats expérimentaux obtenus sont satisfaisant par rapport aux objectifs fixés, que ce soit en termes de résolution en courant, d’erreurs, de stabilité des mesures et de reproductibilité. Le CCC développé durant la thèse peut donc être utilisé pour quantifier de manière métrologique les dispositifs à un électron. De plus, une modélisation réalisée à partir d’un schéma électrique équivalent a été mis en place afin de simuler le comportement réel du CCC en prenant en compte les aspects magnétiques et électriques mis en jeu. Cette simulation a permis la quantification de l’erreur due aux fuites de courants au travers des capacités parasites entourant les enroulements. Les résultats de la simulation indiquent que cette erreur atteint 10 10 à la fréquence de travail, ce qui est inférieure de deux ordres de grandeurs à l’erreur maximale tolérable : 10-8. Les résultats expérimentaux et de modélisation fournissent de nouveaux éléments d’amélioration de la conception de CCCs de grand gain. Enfin, la modélisation développée, une fois insérée dans une routine d’optimisation, pourra aussi être un outil de conception des CCCs très utileIn a context of growing need of precision in measuring low currents for national metrology institutes, industry, instrument manufacturers and fundamental physics, study of single-electron tunneling (SET) devices capable of generating a direct current directly proportional to the frequency and the elementary charge, coupled with a high performance current amplifier, the cryogenic current comparator (CCC), becomes relevant to realize a quantum current standard. In this framework, at LNE, study of new SET devices and the development of CCCs continues. In this thesis, an experimental setup was implemented to evaluate the performance of a new CCC, consisting of a new design and 30 000 turns. The experimental results fulfill our goals, whether in terms of current resolution, errors, measurement stability and reproducibility. The CCC developed during the thesis can thus be used to metrologically quantify SET devices. In addition, a model based on an equivalent circuit diagram has been developed to simulate the actual behavior of the CCC, taking into account the magnetic and electrical aspects involved. This simulation allows the quantification of the error due to currents leakage through parasitic capacitances surrounding the windings. Results of the simulation indicate that this error reaches 10 10, which is less, by two orders of magnitude, than the maximum tolerable error: 10 8. Results obtained experimentally and by simulation provide new improvement elements in the design of high ratio CCCs. The developed model, once inserted into an optimization routine, can also be a very useful design tool of CCCs
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Gebara, Edward. "Cryogenic on-wafer microwave load-pull power measurements and device performance analysis." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/19601.
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Lachenmyer, Nathan S. (Nathan Scott). "Measurements of electric field noise and light-induced charging in cryogenic surface electrode ion traps." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61210.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 85-89).
Ion traps provide an excellent tool for controlling and observing the state of a single trapped ion. For this reason, ion traps have been proposed as a possible system for large-scale quantum computation. However, many obstacles must be overcome before quantum computing can become a reality. In particular, perturbations in the electric field due to noise and electrode charging must be reduced to increase coherence of the motional quantum state. Gold has been a popular choice in the past due to its inert properties; however, it is undesirable due its incompatibility with CMOS technology. This has led to increased research into alternative CMOS-compatible materials, such as aluminum and copper. This thesis presents measurements of electric field noise and light-induced charging in aluminum, copper, and gold surface electrode traps. In addition, the effect of oxide growth on field noise and electrode charging is explored by controlling the thickness of aluminum oxide on several aluminum traps. The measurements show that electric field noise can be suppressed in aluminum traps to approximately 10-18 V2 cm-2 Hz-1, matching the noise exhibited in gold traps, and that copper traps exhibit noise within an order of magnitude of that in aluminum and gold. However, the natural oxide of aluminum poses many problems towards high-performance aluminum ion traps. The electric field noise is shown to be strongly dependent on the oxide thickness, increasing the noise by a factor of about 10 until saturation at a thickness of 13 nm. Charging of surface electrodes is shown to be highly dependent upon the material, but the model presented does not match the experimental data and is found to be incomplete. These results indicate that ion traps made out of CMOS-compatible materials can perform as well as more traditional traps fabricated from gold with respect to heating and charging as long as methods are developed for controlling oxide growth.
by Nathan S. Lachenmyer.
S.B.
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Pedurand, Richard. "Instrumentation for Thermal Noise Spectroscopy." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1356.
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La résolution des interféromètres gravitationnels est limitée par le mouvement Brownien - ou bruit thermique - de leurs miroirs dans la partie centrale de leur bande de détection, entre 10Hz et 1kHz. La répartition en fréquence de ce bruit thermique est dictée par les mécanismes de dissipation d'énergie mécanique à l'origine de cette vibration aléatoire, en accord avec le théorème fluctuation-dissipation. Cette dissipation provient principalement des revêtements optiques déposés sur les miroirs pour leur donner leur réflectivité. Dans le but de réduire le bruit thermique, une nouvelle génération de détecteurs d'ondes gravitationnelles employant des miroirs refroidis à température cryogénique a été proposée. Le développement de nouveaux matériaux optiques en couche mince à faible dissipation mécanique, opérant à la fois à température ambiante et température cryogénique, demande donc de nouveaux outils expérimentaux. L'objet principal de cette thèse est la construction d'un nouvel instrument, le CryoQPDI, qui consiste en l'association d'un interféromètre haute résolution et d'un cryostat basé sur un refroidisseur pulse tube. Il est capable de mesurer directement le mouvement Brownien d'un microlevier entre 300 K et 7 K. En combinant des mesures effectuées sur un microlevier avant et après le dépôt d'une couche mince, il est possible de caractériser la dissipation mécanique interne de cette couche mince. Cet instrument participera ainsi à l'optimisation des revêtements optiques des futurs interféromètres gravitationnels, dans le but de minimiser les nuisances dues au bruit thermiqueThe resolution limit of gravitational wave interferometers is set by their mirrors' Brownian motion – or thermal noise - in the central part of their detection band, from 10Hz to 1kHz. This thermal noise frequency distribution is given by the mechanical energy dissipation mechanisms it originates from, in agreement with the fluctuation-dissipation theorem. This dissipation mainly derives from the optical coatings deposited on the mirrors to give them their reflectivity. To reduce this thermal noise, a new generation of gravitational wave detectors employing mirrors cooled to cryogenic temperature has been suggested. The development of new optical thin-film materials with low mechanical dissipation, operating at both room and cryogenic temperatures, therefore requires new experimental tools. The main object of this thesis is the construction of a new instrument, the CryoQPDI, which is an association between a high-resolution interferometer and a cryostat based on a pulse tube cooler. It can directly measure the Brownian motion of a microcantilever between 300 K and 7 K. By combining measurements made on a microcantilever before and after the deposition of a thin film, it is possible to characterize the internal mechanical dissipation of this thin film. This instrument will eventually contribute to the optimisation of optical coatings of future gravitational wave detectors, aiming at minimizing the limitations due to thermal noise
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Park, Keunhan. "Thermal Characterization of Heated Microcantilevers and a Study on Near-Field Radiation." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14597.
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Recently, remarkable advances have been made in the understanding of micro/nanoscale energy transport, opening new opportunities in various areas such as thermal management, data storage, and energy conversion. This dissertation focuses on thermally-sensed nanotopography using a heated silicon microcantilever and near-field thermophotovoltaic (TPV) energy conversion system.
A heated microcantilever is a functionalized atomic force microscope (AFM) cantilever that has a small resistive heater integrated at the free end. Besides its capability of increasing the heater temperature over 1,000 K, the resistance of a heated cantilever is a very sensitive function of temperature, suggesting that the heated cantilever can be used as a highly sensitive thermal metrology tool. The first part of the dissertation discusses the thermal characterization of the heated microcantilever for its usage as a thermal sensor in various conditions. Particularly, the use of heated cantilevers for tapping-mode topography imaging will be presented, along with the recent experimental results on the thermal interaction between the cantilever and substrate.
In the second part of the dissertation, the so-called near-field TPV device is introduced. This new type of energy conversion system utilizes the significant enhancement of radiative energy transport due to photon tunneling and surface polaritons. Investigation of surface and bulk polaritons in a multilayered structure reveals that radiative properties are significantly affected by polariton excitations. The dissertation then addresses the rigorous performance analysis of the near-field TPV system and a novel design of a near-field TPV device.
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Kurian, Febin [Verfasser], Peter [Akademischer Betreuer] [Gutachter] Hülsmann, and Oliver [Gutachter] Kester. "Cryogenic current comparators for precise ion beam current measurements / Febin Kurian ; Gutachter: Peter Hülsmann, Oliver Kester ; Betreuer: Peter Hülsmann." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2015. http://d-nb.info/1125525681/34.
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Whitis, Thomas James. "Measurement of Time Projection Chamber Optical Properties and Xenon Circulation System Development for The LZ Experiment." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1543947238765113.
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Roubal, Zdeněk. "Nízkoúrovňová měření." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-234612.
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The doctoral thesis presents methods for low-level measurements, which are exemplified by the general measurement of air ion concentration. Within the first section, the author progressively identifies certain critical effects influencing the concentration of air ions, and these effects are to be considered in evaluating the uncertainty of the measured concentrations. Thus, the thesis aims to provide a systematic description of the procedures and requirements related to low-level measurements; the proposed description then involves a discussion of the process reliability requirements, namely the factors of repeatability, elimination of errors, and definition and describability of measurement uncertainties. Such methodology facilitates, among other activities, the long-term monitoring of air ion concentration in extreme environments, including caves or spaces characterized by high temperatures and humidity. The use of common methods for determining the air ion mobility spectrum is accompanied by a number of disturbing effects, such as spurious fluctuation in the concentration of air ions in time. The experimental section of the thesis describes the testing of different configurations of the measuring device (a collecting electrode and a polarization capacitor); at this stage, we seek the most advantageous distribution of the electrostatic field in the sensor – a Gerdien tube. The systematic suppression of the influence of spurious fluctuations in air ion concentration during the measurement of saturation characteristics is carried out with the least-squares numerical method (as a supporting element), a hybrid technique to describe and evaluate the experimental model. In the second part of the thesis, the methodology of low-level measurement is complemented with procedures for the measurement of freezing potential. This latter domain, as an overall experimental approach applicable during phase changes of the sample, has hitherto not been sufficiently characterized from the metrological perspective, in an up-to-date manner; several subregions of the said domain remain somewhat obscured and deserve significantly more attention. In the given context, this thesis systematically considers a problem where comparable measurement results produced by multiple authors are not available. The measuring methodology proposed herein was utilized in applied research to facilitate the fabrication of an apparatus for the experimental measurement of freezing potential in pre-defined samples; the obtained results then lead us to conclusions with respect to the evaluation of effects that cause differences in the measured data, and the results can be further compared with those obtained by other researchers investigating the given segment of the problem.
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Ramirez-garcia, Eloy. "Analyse expérimentale et modélisation du bruit haute fréquence des transistors bipolaires à hétérojonctions SiGe et InGaAs/InP pour les applications très hautes fréquences." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112082/document.
Full textAbstract:
Le développement des technologies de communication et de l’information nécessite des composants semi-conducteurs ultrarapides et à faible niveau de bruit. Les transistors bipolaires à hétérojonction (TBH) sont des dispositifs qui visent des applications à hautes fréquences et qui peuvent satisfaire ces conditions. L’objet de cette thèse est l’étude expérimentale et la modélisation du bruit haute fréquence des TBH Si/SiGe:C (technologie STMicroelectronics) et InP/InGaAs (III-V Lab Alcatel-Thales).Accompagné d’un état de l’art des performances dynamiques des différentes technologies de TBH, le chapitre I rappelle brièvement le fonctionnement et la caractérisation des TBH en régime statique et dynamique. La première partie du chapitre II donne la description des deux types de TBH, avec l’analyse des performances dynamiques et statiques en fonction des variations technologiques de ceux-ci (composition de la base du TBH SiGe:C, réduction des dimensions latérales du TBH InGaAs). Avec l’aide d’une modélisation hydrodynamique, la seconde partie montre l’avantage d’une composition en germanium de 15-25% dans la base du TBH SiGe pour atteindre les meilleurs performances dynamiques. Le chapitre III synthétise des analyses statiques et dynamiques réalisées à basse température permettant de déterminer le poids relatif des temps de transit et des temps de charge dans la limitation des performances des TBH. L’analyse expérimentale et la modélisation analytique du bruit haute fréquence des deux types de TBH sont présentées en chapitre IV. La modélisation permet de mettre en évidence l’influence de la défocalisation du courant, de l’auto-échauffement, de la nature de l’hétérojonction base-émetteur sur le bruit haute fréquence. Une estimation des performances en bruit à basse température des deux types de TBH est obtenues avec les modèles électriquesIn order to fulfil the roadmap for the development of telecommunication and information technologies (TIC), low noise level and very fast semiconductor devices are required. Heterojunction bipolar transistor has demonstrated excellent high frequency performances and becomes a candidate to address TIC roadmap. This work deals with experimental analysis and high frequency noise modelling of Si/SiGe:C HBT (STMicroelectronics tech.) and InP/InGaAs HBT (III-V Lab Alcatel-Thales).Chapter I introduces the basic concepts of HBTs operation and the characterization at high-frequency. This chapter summarizes the high frequency performances of many state-of-the-art HBT technologies. The first part of chapter II describes the two HBT sets, with paying attention on the impact of the base composition (SiGe:C) or the lateral reduction of the device (InGaAs) on static and dynamic performances. Based on TCAD modelling, the second part shows that a 15-25% germanium composition profile in the base is able to reach highest dynamic performances. Chapter III summarizes the static and dynamic results at low temperature, giving a separation of the intrinsic transit times and charging times involved into the performance limitation. Chapter IV presents noise measurements and the derivation of high frequency noise analytical models. These models highlight the impact of the current crowding and the self-heating effects, and the influence of the base-emitter heterojunction on the high frequency noise. According to these models the high frequency noise performances are estimated at low temperature for both HBT technologies
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Venkataraman, Sunitha. "Systematic Analysis of the Small-Signal and Broadband Noise Performance of Highly Scaled Silicon-Based Field-Effect Transistors." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16232.
Full textAbstract:
The objective of this work is to provide a comprehensive analysis of the small-signal and broadband noise performance of highly scaled silicon-based field-effect transistors (FETs), and develop high-frequency noise models for robust radio frequency (RF) circuit design. An analytical RF noise model is developed and implemented for scaled Si-CMOS devices, using a direct extraction procedure based on the linear two-port noise theory.
This research also focuses on investigating the applicability of modern CMOS technologies for extreme environment electronics. A thorough analysis of the DC, small-signal AC, and broadband noise performance of 0.18 um and 130 nm Si-CMOS devices operating at cryogenic temperatures is presented. The room temperature RF noise model is extended to model the high-frequency noise performance of scaled MOSFETs at temperatures down to 77 K and 10 K. Significant performance enhancement at cryogenic temperatures is demonstrated, indicating the suitability of scaled CMOS technologies for low temperature electronics. The hot-carrier reliability of MOSFETs at cryogenic temperatures is investigated and the worst-case gate voltage stress condition is determined. The degradation due to hot-carrier-induced interface-state creation is identified as the dominant degradation mechanism at room temperature down to 77 K. The effect of high-energy proton radiation on the DC, AC, and RF noise performance of 130 nm CMOS devices is studied. The performance degradation is investigated up to an equivalent total dose of 1 Mrad, which represents the worst case condition for many earth-orbiting and planetary missions.
The geometric scaling of MOSFETs has been augmented by the introduction of novel FET designs, such as the Si/SiGe MODFETs. A comprehensive characterization and modeling of the small-signal and high-frequency noise performance of highly scaled Si/SiGe n-MODFETs is presented. The effect of gate shot noise is incorporated in the broadband noise model. SiGe MODFETs offer the potential for high-speed and low-voltage operation at high frequencies and hence are attractive devices for future RF and mixed-signal applications.
This work advances the state-of-the-art in the understanding and analysis of the RF performance of highly scaled Si-CMOS devices as well as emerging technologies, such as Si/SiGe MODFETs. The key contribution of this dissertation is to provide a robust framework for the systematic characterization, analysis and modeling of the small-signal and RF noise performance of scaled Si-MOSFETs and Si/SiGe MODFETs both for mainstream and extreme-environment applications.
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Ganu, Hrishikesh Vidyadhar. "A Morphological Technique For Direct Drop Size Measurement Of Cryogenic Sprays." Thesis, 2005. http://etd.iisc.ernet.in/handle/2005/1481.
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Offner, Erik J. "The design and implementation of a cryogenic thermal conductivity measurement system." Thesis, 2003. http://hdl.handle.net/1957/30354.
Full textAbstract:
A steady state, axial flow thermal conductivity test apparatus was designed
and constructed to operate between room temperature and approximately 4 Kelvin,
and to be compatible with existing electronic instrumentation and a continuous
flow cryostat. The test design included a radiation shield that had its temperature
profile matched to that of the sample to minimize radiation heat transfer losses.
The cryostat was used to provide the controllable, low temperature test environment
in which the test apparatus would operate. A special wiring bundle was constructed
to ensure proper connection of the test device to the required electronic
instrumentation, which was controlled from a computer by custom written software.
Once assembled, the thermal conductivity of a high purity copper sample
was measured over the temperature range from 45 to 300 Kelvin and compared to
literature recommended values. The test was performed a second time to check repeatability
of the measurements over a range of temperature. Next, the thermal
conductivity of a high purity niobium sample was measured and compared to literature
recommended values. This test was also performed twice. When completed,
these tests had demonstrated the accuracy and repeatability of the measurement of
thermal conductivity by the test apparatus over the range of temperatures specified
and over a range of conductivities. Finally, the thermal conductivity of a sample of
the bulk metallic glass Vitreloy 1 was measured over the same temperature range.
As far as was known, this was the first time the thermal conductivity of this particular
material had been tested below 400 Kelvin.Graduation date: 2003
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Cheng, Chun, and 鄭鈞. "Cryogenic mechanical loss measurement system setup and annealing effect on the mechanical loss of the nano-layer coatings." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/99073680856566484755.
Full textAbstract:
碩士國立清華大學
光電工程研究所
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The Laser Interferometer Gravitational Wave Observatory (LIGO) detects gravitational waves with a large Michaelson interferometer and is used to observe astronomical phenomena. Signal of gravitational wave is weak, it is important that the noises should be reduced. The sensitivity of the Laser Interferometer Gravitational wave Observatory (LIGO) is mainly limited by coating Brownian noise at 100 Hz. This noise comes from the high reflective optical coating on the mirror. According to the fluctuation-dissipation theorem, noise of the film is proportional to mechanical loss, thus the level of thermal noise can be known from measuring the mechanical loss of the film. To measure mechanical loss, one can let an excited silicon cantilever ring down decay, while observing the decay time to obtain mechanical loss. Furthermore, from Fluctuation-dissipation theorem, it can also be known that system temperature is proportional to thermal noise, thus it is desirable to know the property of the film material under low temperature. To increase the system's sensitivity, thermal noise on the reflecting film must be minimized; therefore, we attempt to search for a material for the film that has low mechanical loss, and can be measured at low temperature. The first part of the paper describes a new cryogenic apparatus which allows the measurement of the mechanical Q-factor – as a measure of internal losses – in a temperature range from 5 K up to 300 K. This closed-loop cryogenic system is able to measure mechanical loss of the coatings on the cantilevers. And the whole measurement process is fully automatic without human attendance. The second part is crystallization following thermal annealing of thin film stacks consisting of alternating nm-layer(Titania/Silica) was investigated. Coatings of the mirror is composed of pairs of alternating high and low refractive index thin films with thickness of quarter-wavelength. Currently, the materials used in the coatings are silica and Titania in amorphous. It was found that thermal annealing also reduces coating mechanical losses, and thermal noise . However, excessive thermal annealing eventually leads to crystallization. Mechanical losses due to friction among crystallites, as well as scattering from the grain boundaries, make the coatings unsuitable. It was found that the Titania layers eventually crystallized forming the Anatase phase. However, progressively thinner layers exhibited progressively higher threshold temperatures for crystallization onset. Accordingly it can be expected that composites with thinner layers will be able to sustain higher annealing temperatures without crystallizing. In order to increase the annealing temperature, we use nano-multilayer film structure to replace the high reflector of the high refractive index layer. The structure of nano-layer has the same total optical thickness. Notice that nano-layer with more numbers of layers has thinner TiO2 layer thickness, which translates into tolerance for higher annealing temperature. Then, apply different thermal annealing processes to the structure of the 11,15,19 layer of the nano-layer and discuss how the annealing of each structure affects mechanical loss. Key word: mechanical loss, cantilever, closed-loop cryogenic system, low vibration noise, temperature gradient, clamping torque
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Risius, Steffen. "Development of a time-resolved quantitative surface-temperature measurement technique and its application in short-duration wind tunnel testing." Thesis, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E44D-A.
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Coppi, Chiara [Verfasser]. "Quenching-factor measurements for cryogenic dark matter detectors / Chiara Coppi." 2009. http://d-nb.info/996080392/34.
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(8999573), James R. Nakamura. "Electronic Fabry-Perot Interferometry of Quantum Hall Edge States." Thesis, 2020.
Find full textAbstract:
Two-dimensional electron systems in GaAs/AlGaAs heterostructures have provided a platform for investigating numerous phenomena in condensed matter physics. The quantum Hall effect is a particularly remarkable phenomenon due to its topological properties, including chiral edge states with quantized conductance. This report describes progress made in interference measurements of these edge states in electronic Fabry-Perot interferometers. Previous interference experiments in the quantum Hall regime have been stymied by Coulomb charging effects and poor quantum coherence. These Coulomb charging effects have been dramatically suppressed by the implementation of a novel GaAs/AlGaAs heterostructure which utilizes auxiliary screening wells in addition to the primary GaAs quantum well. Using this heterostructure, Aharonov-Bohm interference is measured in very small devices which have greatly improved coherence. Robust Aharonov-Bohm interference is reported at fractional quantum Hall states nu = 1/3 and nu = 2/3. Discrete jumps in phase at nu = 1/3 consistent with anyonic braiding statistics are observed. The report concludes with proposed future experiments, including extending these results to possible non-Abelian quantum Hall states.
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Ferrer, García Rafael [Verfasser]. "Mass measurements on neutron-deficient nuclides at SHIPTRAP and commissioning of a cryogenic narrow-band FT-ICR mass spectrometer / von Rafael Ferrer García." 2008. http://d-nb.info/987172379/34.
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Xavier, Mário David Grosso. "Development of a system for adsorption measurements in the 77 – 500 K and 1 – 100 bar range." Master's thesis, 2016. http://hdl.handle.net/10362/19411.
Full textAbstract:
Adsorption is a phenomenon present in various systems important to the field of
cryogenics, having a great deal of relevance in the development of vibration-free coolers:
these are crucial for the cooling of sensitive detectors, as they offer the possibility of
using a sorption compressor, do not have moving parts and do not induce unwanted
mechanical vibrations in the system, maintaining its sensibility and greatly minimizing
wear due to use.
In the context of an ESA-funded project for the development of such a cooler, a study
on adequate adsorption materials to use for the non-mechanical cryogenic compressor
present in the final system was required. Considering this, a system for measurement of
adsorption properties in the range of its operating pressures and temperatures was
needed and, independently, also useful in future adsorption studies the laboratory
decides to perform.
A brief historical and functional review of the adsorption phenomenon, its
applications in cryogenics, and available and various methods for its measurement is
made. The design and assembly of an adsorption measurement system, through the
volumetric (also known as manometric) method, for temperatures in the 77 K to 500 K
range and pressures up to 100 bar is detailed.
Proof pressure tests were made to validate the design of the vessel, with positive
results. Other pre-measurement tests, such as heating and cooling assays, void and dead
volume measurements, empty-vessel measurements, were all carried out with an
intention to validate and characterize the developed system. A LabVIEWTM interface for
the control and automatic acquisition of the system parameters was developed and
tested throughout the whole process.
Results were taken using a sample of HKUST-1 (also known as Cu3(BTC)2 or
BasoliteTM C300) and compared against the results from another group, as well as a
partner laboratory, from both their theoretical simulations and their commercial
gravimetric system.