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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Study and selection of scintillating crystals for the bolometric search for neutrinoless double beta decay / Etude et sélection de cristaux scintillants pour la recherche de la double désintégration bêta sans neutrino avec des bolomètres scintillants

Zolotarova, Anastasiia 24 September 2018 (has links)
L'observation de la désintégration double bêta sans émission de neutrino (0ν2β) fournirait des informations essentielles sur la nature du neutrino et son échelle de masse absolue. Ce processus consiste en la transformation simultanée de deux protons en deux neutrons avec l'émission de deux électrons et aucun neutrino. Cette transition n'est possible que si les neutrinos sont égaux aux antineutrinos (nature Majorana du neutrino). Les recherches pour une désintégration à ce point rare représentent un défi technique complexe, car les expériences de prochaine génération visent des sensibilités de l'ordre de 10^27-10^28 ans afin d'avoir un potentiel de découverte élevé. Cette thèse est focalisée sur les projets LUMINEU et CUPID-Mo, développant la technique des bolomètres scintillants pour la recherche de désintégration 0ν2β avec le radio-isotope 100Mo.Les bolomètres sont des détecteurs cryogéniques mesurant l'énergie des particules déposées via un changement de température dans l'absorbeur. Si des cristaux scintillants sont utilisés comme absorbeurs, les signaux lumineux peuvent être enregistrés avec un bolomètre auxiliaire, sensible à l'énergie totale déposée par les photons de scintillation. Une telle configuration permet de séparer les particules α des γ/β, en rejetant le fond le plus difficile. La technologie des bolomètres scintillants est décrite en détail comme une option pour une future expérience cryogénique à l'échelle d'une tonne, appelée CUPID, qui peut couvrir complètement la région de masses de neutrinos dans la hiérarchie inversée. / Neutrinoless double beta (0ν2β) decay is a process of great interest for neutrino physics: its observation would provide essential information on neutrino nature and its absolute mass scale. This process consists of the simultaneous transformation of two protons into two neutrons with the emission of two electrons and no neutrino, implying the violation of the total lepton number. Such transition is possible only if neutrinos are equal to antineutrinos (Majorana particles). The searches for such a rare decay are becoming a complicated technical challenge, as next generation of 0ν2β experiments aim at sensitivities of the order of half-life at 10^27-10^28 yr. This thesis is focused on LUMINEU and CUPID-Mo projects, developing the scintillating bolometers technique for 0ν2β decay search with 100Mo with Li2MoO4 crystals. Bolometers are cryogenic detectors measuring the deposited particle energy as a change of temperature in the absorber. The use of scintillating crystals allows to perform discrimination of α particles from γ/β ones due to different light output of these two particle types, rejecting the most challenging background. The scintillating bolometers technology is described in details as an option for a future ton-scale cryogenic experiment, named CUPID, which can completely cover the inverted hierarchy region of neutrino masses.
12

Studies on Performance Enhancement of Infrared and Terahertz Detectors for Space Applications

Sumesh, M A January 2016 (has links) (PDF)
Currently, the concept of multipurpose spacecrafts is being transformed into many small spacecrafts each of them performing specific tasks and thus leading to the realization of pico and nano satellites. No matter what is the application or size, demand for more number of IR channels for earth observation is ever increasing which necessitates significant reduction in the mass, power requirement and cost of the IR detectors. In this scenario, several order of magnitude mass and power savings associated with uncooled IR arrays are advantageous compared to cooled photon detectors. However the poor speed of response of uncooled microbolometer array devices obstruct the total replacement of cooled detectors in thermal imaging applications. This is especially true when the mission requires 50 m to 100 m ground resolution, in which even the "fastest" micro bolometer arrays turns "too slow" to follow the ground trace when looked from low earth orbit (LEO). Hence there is a great and unfulfilled requirement of faster uncooled detector arrays for meeting the demand for future micro and mini satellite projects for advanced missions. The present thesis describes the systematic studies carried out in development of high performance IR and THz detectors for space applications. Ge-Si-O thin films are prepared by ion beam sputtering technique with argon (Ar) alone and argon and oxygen as sputtering species, using sputtering targets of different compositions of Ge and SiO2. The deposited thin films are amorphous in nature and have chemical compositions close to that of the target. The study of electrical properties has shown that the activation energy and hence the thermistor constant (β) and electrical resistivity (ρ) are sensitive to oxygen flow rate, and they are the least for thin films prepared with Ar alone as the sputtering species. Different thermal isolation structures (TIS), consisting of silicon nitride (Si3N4) membrane of different thicknesses, Ge-Si-O thin film and, chromium coating on the rear side of the membrane, are prepared by bulk micro-machining technique, whose thermal conductance (Gth) properties are evaluated from the experimentally determined current-voltage (I-V) characteristics. Gth shows non-linear dependence with respect to raise in temperature of thin film thermistor due to Joule heating. The infrared micro-bolometer detectors, fabricated using one of the TIS structures have shown responsivity (<v) close to 115 V W−1 at a bias voltage of 1.5 V and chopping frequency of 10 Hz, thermal time constant (τth) of 2.5 ms and noise voltage of 255 nV Hz−1⁄2 against the corresponding thermal properties of Gth and thermal capacitance Cth equal to 9.0 × 10−5 W K−1 and 1.95 × 10−7 J K−1 respectively. The detectors are found to have uniform spectral response in the infrared region from 2 µm to 20 µm, and NEDT in the range from 108 mK to 574 mK when used with an F/1 optical system. The detector, in an infrared earth sensor system, is tested before an extended black body which simulates the earth disc in the laboratory and the results are discussed. As an extension of the single element detector to array device, design of a microbolometer array for earth sensor dispensing of scanning mechanisms is presented. It makes use of four microbolometer arrays with in-line staggered configuration that stare at the earth horizons, perceiving IR radiation in the spectral band of 14 µm to 16 µm. Design of the microbolometer has been carried out keeping in mind low power, lightweight, without compromising on the performance. An array configuration of 16 × 2 pixels is designed and developed for this purpose. Finite elemental analysis is carried out for design optimization to yield best thermal properties and thus high performance of the detectors. Suitable optical design configuration was arrived to image the earth horizon on to array. Using this optimum design, prototype arrays have been fabricated, packaged and tested in front of the black body radiation source and found to have Responsivity, NEP, and D∗ of 120 V W−1, 5.0 W Hz−1⁄2, 1.10 × 107 cm Hz1⁄2 W−1 respectively. The pixels show a uniform response within a spread of ±6 % and the pixel resistances are within a range of ±5 %. Optically Immersed Bolometer IR detectors are fabricated using electron beam evaporated Vanadium Oxide as the sensing material. Spin coated polyimide is used as medium to optically immerse the sensing element to the flat surface of a hemispherical germanium lens. This optical immersion layer also serves as the thermal impedance control layer and decides the performance of the devices in terms of responsivity and noise parameters. The devices have been packaged in suitable electro-optical packages and the detector parameters are studied in detail. Thermal time constant varies from 0.57 ms to 6.1 ms and responsivity from 75VW−1 to 757VW−1 corresponding to polyimide thickness in the range 2.0 μm to 70 μm for a detector bias of 9V. Highest D obtained was 1.28 × 108 cm Hz1⁄2W−1. Noise Equivalent Temperature Difference (NETD) of 20mK is achieved for devices with polyimide thickness of 32 μm, whereas the NETD × th product is the lowest for devices with moderate thickness of thermal impedance layer. Bolometric THz detectors were fabricated using V2O5 as sensing element immersed onto germanium hemispherical lens using polyimide as immersion media. These detectors were characterized for their efficiency in detection of THz radiation in the range 10 THz to 35 THz emitted by a black body radiator. The responsivity of the devices determined in four different frequency bands covering the spectrum of interest and a maximum responsivity of 398VW−1 was observed. A variation in the responsivity is observed which is due to the characteristics absorption of polyimide in the THz region of interest and can be avoided by replacing with HDPE which has less attenuation. NEP of 6.8 × 10−10WHz−1⁄2 was observed which is very close to the state of art in the case of uncooled detectors which entitles the detectors for spectroscopic applications. Specific Detectivity D* was observed to be much higher than the conventional detectors thanks to the benefits of immersion. NETD of 26mK was observed which is advantageous of application of these detectors in imaging applications These studies have lead to development of a new technology for fabrication of high performance IR and THz detectors which can be used for spectroscopic and imaging applications. Further, this technology can be scaled for development of linear and area arrays finding applications where the speed of respnose as well as sensitivity are of equal importance. from 0.57 ms to 6.1 ms and responsivity from 75 V W−1 to 757 V W−1 corresponding to polyimide thickness in the range 2.0 µm to 70 µm for a detector bias of 9 V. Highest D∗ obtained was 1.28 × 108 cm Hz1⁄2 W−1. Noise Equivalent Temperature Difference (NETD) of 20 mK is achieved for devices with polyimide thickness of 32 µm, whereas the NETD × τth product is the lowest for devices with moderate thickness of thermal impedance layer. Bolometric THz detectors were fabricated using V2O5 as sensing element immersed onto germanium hemispherical lens using polyimide as immersion media. These detectors were characterized for their efficiency in detection of THz radiation in the range 10 THz to 35 THz emitted by a black body radiator. The responsivity of the devices determined in four different frequency bands covering the spectrum of interest and a maximum responsivity of 398 V W−1 was observed. A variation in the responsivity is observed which is due to the characteristics absorption of polyimide in the THz region of interest and can be avoided by replacing with HDPE which has less attenuation. NEP of 6.8 × 10−10 W Hz−1⁄2 was observed which is very close to the state of art in the case of uncooled detectors which entitles the detectors for spectroscopic applications. Specific Detectivity D* was observed to be much higher than the conventional detectors thanks to the benefits of immersion. NETD of 26 mK was observed which is advantageous of application of these detectors in imaging applications These studies have lead to development of a new technology for fabrication of high performance IR and THz detectors which can be used for spectroscopic and imaging applications. Further, this technology can be scaled for development of linear and area arrays finding applications where the speed of respnose as well as sensitivity are of equal importance.
13

III-V semiconducting hopping bolometers for detecting nonequilibrium phonons and astroparticles

Taele, Benedict Molibeli January 2000 (has links)
No description available.
14

Fotometria e imageamento THz de fontes termicas e não-termicas / THz imaging and photometry of thermal and non-thermal sources

Melo, Arline Maria 11 July 2007 (has links)
Orientador: Jose Alexandre Diniz / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-11T06:36:37Z (GMT). No. of bitstreams: 1 Melo_ArlineMaria_D.pdf: 17701586 bytes, checksum: b5160ad894463745fdeea0dae1f71065 (MD5) Previous issue date: 2007 / Resumo: Este trabalho apresenta importantes informações sobre tecnologia THz, atualmente considerada um desafio tecnológico e estado da arte em diversas áreas de desenvolvimento. Com o objetivo de formar um sistema imageador THz, ainda indisponível comercialmente, foram dispensados esforços em diferentes frentes. Câmeras para o infravermelho médio (8 ¿ 14 µm) foram adquiridas, caracterizadas e testadas, com resultados relevantes e inéditos em Física Solar, aplicação considerada para este trabalho. Filtros de malha ressonante para diversas bandas na região THz (centrados em 0,4, 0,67, 0,85, 2, 4 e 8,5 THz) foram projetados, fabricados e testados exibindo excepcional resposta. E finalmente um primeiro protótipo imageador foi montado acoplando os filtros de malha ressonante a câmera IV sem sua óptica original de germânio. As primeiras imagens THz de uma resistência aquecida é apresentada, provando a funcionalidade do conceito original. Os desenvolvimentos e estudos aqui apresentados estarão contribuindo para dois experimentos espaciais recentemente propostos, DESIR ( Detection of Solar eruptive Infrared Radiation) e SIRA (Submillimeter-wave to InfraRed solar Activity emissions), prevendo a utilização de sistemas THz em observações de transientes em plasmas ativos solares em diferentes freqüências, a partir do solo e no espaço / Abstract: This work presents important information on THz technology, currently considered a technological challenge and state of the art in different areas of development. To form a THz imaging system, still unavailable commercially, efforts in different fronts had been excused. Cameras for medium IR (8 - 14 µm) had been acquired, characterized and tested, with excellent and unknown results in Solar Physics, application considered for this work. Filters of resonant metal mesh for diverse bands in the THz region (centered in 0,4, 0,67, 0,85, 2, 4 and 8,5 THz) had been projected, manufactured and tested showing excellent results. Finally a first imaging system was mounted connecting the filters of resonant mesh to the IR camera without its original optics of germanium. The first THz images of a warm resistance are presented, proving the functionality of the original concept. The developments and studies presented here will contribute for two space experiments recently considered, DESIR ( Solar Detection of eruptive Infrared Radiation) and SIRA ( Submillimeter-wave you the solar InfraRed Activity emissions), requiring the use of THz systems for observations of transient in solar active plasmas in different frequencies, from the ground and in the space / Doutorado / Eletrônica, Microeletrônica e Optoeletrônica / Doutor em Engenharia Elétrica
15

Développement de matériaux thermistors pour applications bolométriques / Development of thermistors for bolometric applications.

Bourgeois, Florian 28 October 2011 (has links)
La technologie des microbolomètres est à ce jour la plus avancée pour l'imagerie IR non refroidie. Le LETI développe une technologie basée sur l'utilisation du silicium amorphe comme matériau thermistor. L'introduction d'un matériau alternatif doit permettre de poursuivre l'amélioration des performances. Cette étude considère une solution alternative à base de films minces d'oxydes nanocristallins. Deux procédés sont envisagés : le dépôt IBS et le dépôt MOCVD. L'étude des procédés ainsi que la caractérisation des matériaux ont permis la maîtrise et la compréhension des évolutions structurales et fonctionnelles mises en jeux. Des caractérisations électriques (résistivité, TCR, bruit en 1/f) sur dispositifs ont permis de débattre de l'intérêt de ces nouveaux matériaux. Une réflexion a été menée sur les relations microstructure-propriétés. / Microbolometers FPAs are nowadays the most advanced technology for uncooled IR imaging. Developments at CEA-LETI are based on the use of amorphous silicon as thermistor material. Introduction of an alternative material is necessary to keep on improving detectors performances. This study considersnanocrystalline oxides thin films as an alternative material. Two deposition techniques have been studied : IBS and MOCVD. Process studies as well as materials characterizations allowed us to control and understand the involved micro-structural evolutions. Electrical characterizations (resistivity, TCR, 1/f noise) on integrated devices were achievedin order to estimate the potential of these new materials. Microstructure-property relationships are also discussed.
16

Development of luminescent bolometers and light detectors for neutrinoless double beta decay search / Développement de bolomètres luminescents et détecteurs de lumière pour la recherche de la double désintégration bêta sans émission de neutrinos

Tenconi, Margherita 28 September 2015 (has links)
L'étude de la double désintégration bêta sans neutrinos joue un rôle important dans plusieurs questions en physique des particules et cosmologie. Ce processus nucléaire hypothétique viole la conservation du nombre leptonique par deux unités et jusqu'à présent il est le seule moyen pratique pour dévoiler la nature du neutrino : sa détection implique forcement que neutrino et antineutrino sont la même particule. En outre, le taux de décroissance est sensible à la masse efficace de Majorana du neutrino, du coup à l'échelle absolue des valeurs propres de la masse et leur hiérarchie. La marque expérimentale de la DDB0ν est un pic monochromatique dans le spectre énergétique de la somme des deux électrons émis. Le but des expériences de prochaine génération est une sensibilité sur la masse efficace du neutrino de l'ordre de dizaines de meV, c'est-à-dire demi-vies de l'ordre de 10²⁷-10²⁸ années : en pratique, il s'agit de construire des sources de quelques centaines de kg d'isotope candidat, au moins, et les sonder par des détecteurs très efficients, tout en gardant le bruit de fond dans la région énergétique d'intérêt au niveau d'un coup/tonne/an. Les bolomètres luminescents sont une technique prometteuse vu leur excellentes résolutions énergétiques, haute efficacité de détection, ample choix pour les matériaux et extensibilité modulaire à grande échelle; de plus, grâce à la détection simultanée de chaleur et lumière produites par l'interaction des particules, il est possible de discriminer les contaminations α, dangereuse source de bruit aux énergies d'intérêt pour plusieurs noyaux candidats à la DDB0ν. Cette thèse a été effectuée dans le contexte de l'expérience LUMINEU : une expérience pilote qui a pour but la construction d'une expérience de prochaine génération basée sur les bolomètres scintillants en molybdate de zinc, pour l'étude de l'isotope candidat ¹⁰⁰Mo. En vue de la construction d'une expérience à grande échelle, il est nécessaire d'effectuer des caractérisations systématiques pour s'assurer des performances et de la reproductibilité des détecteurs et leurs composantes. La disponibilité d'installations expérimentales en surface, facilement accessibles, est souhaitable pour des tests routiniers : j'ai mené la plupart des expériences au CSNSM, où j'ai aussi travaillé à l'installation d'un nouvel cryostat à dilution basé sur la technologie du Pulse-Tube. Une partie de ma thèse a concerné l'étude de détecteurs bolométriques de lumière aux absorbeurs en germanium et thermomètres NTD (thermistors Neutron Transmutation Doped) : une structure standard pour LUMINEU a été établie et on a mesuré les performances des bolomètres telles que sensibilité, résolution énergétique, bruit de base et reproductibilité. Les résultats sont satisfaisants en vue d'un emploi dans une expérience avec bolomètres scintillants, bien que la configuration soit très sensible à la microphonie. En outre, j'ai testé avec succès des détecteurs bolométriques de lumière exploitants l'effet Neganov-Luke, qui augmente le rapport signal-bruit au niveau compatible avec la détection de la lumière Cherenkov pour la discrimination des événements. Une autre partie a vu la caractérisation des bolomètres scintillants en molybdate de zinc avec masse allant jusqu'à environ 300 g : couplés aux capteurs de lumière susmentionnés et lus par thermistors NTD, ils ont été refroidis en surface au CSNSM et en endroit souterrain à Modane, dans l'installation de l'expérience EDELWEISS pour la Matière Noire. Grâce à la détection simultanée de lumière et chaleur, les interactions des particules β/γ sont séparées des contaminations α. Les résultats démontrent que la caractérisation de bolomètres massifs, presque la taille cible des détecteurs finaux, est possible même en surface, en dépit du rayonnement cosmique. En outre, ces tests ont permis d'optimiser la compatibilité de l'installation de Modane avec les exigences des bolomètres scintillants pour la recherche de la DDB0ν. / Neutrinoless Double Beta Decay (0νDBD) is regarded as an important key in the decryption of some hot astroparticle and cosmological enigmas: it violates lepton number by two units and it is currently the only known practical way to shed light on the neutrino nature, being possible only in case of a Majorana neutrino, identical to its antiparticle. Moreover, the 0νDBD rate is sensitive to the effective neutrino mass, so it would be useful to define the absolute neutrino mass scale and hierarchy. The experimental footprint of 0νDBD is a monochromatic peak in the sum energy spectrum of the two emitted electrons. Next-generation experiments aim at reaching a sensitivity on the effective neutrino mass of the order of ten meV, corresponding to half lives in the range 10²⁷-10²⁸ years: this means to be able to gather, at least, a few hundred kilograms of 0νDBD candidate isotope source and to efficiently scrutinize it with very sensitive detectors. Meanwhile, background levels in the energy region of interest of the 0νDBD signal should be lowered to less than one count/ton/y. Cryogenic luminescent bolometers are a promising technique for 0νDBD search, as they feature excellent energy resolutions, high detection efficiency, flexibility in the material choice and easy scalability to large modular experiments; furthermore, the simultaneous read-out of heat and light signals produced by particle interactions provides an active discrimination method against the dangerous α contaminations, populating the 0νDBD energy region of several interesting candidate isotopes. The work presented in this dissertation was carried out in the context of the LUMINEU project: a pilot experiment focused on zinc molybdate scintillating bolometers, to define the strategies for the construction of a next-generation experiment based on the 0νDBD candidate ¹⁰⁰Mo. In view of the construction of a large 0νDBD experiment, involving hundreds of modules, systematic cryogenic measurements have to be performed to ensure good performance and reproducibility of the detectors and their components. Aboveground facilities are preferred for routinary tests because of their easier accessibility: most of the tests were carried out at CSNSM, where I also worked on the setup of a new cryogenic apparatus, based on the Pulse-Tube technology. One part of my thesis work saw the study of bolometric light detectors based on germanium absorbers and Neutron Transmutation Doped (NTD) thermometers: a proper design was developed in view of LUMINEU and the devices were characterized in terms of sensitivity, energy resolution, baseline noise and reproducibility. The results are compatible with a 0νDBD search final experiment, though this detector configuration is very sensitive to vibrational noise. In addition, the feasibility of bolometric light detectors based on NTD thermometers and Neganov-Luke amplification was investigated, demonstrating that this technique can actually boost the signal-to-noise gain to a level compatible with event discrimination based on Cherenkov light detection. Another part of my work dealt with the test of scintillating zinc molybdate bolometers of mass up to ~300 g, coupled to the aforementioned light detectors and operated both in the aboveground facilities at CSNSM and underground at Modane, in the cryostat of the EDELWEISS Dark Matter search experiment. Good event discrimination capability was achieved: thanks to double read-out of heat and light, it is possible to identify α particles, the threatening background for 0νDBD interests, against β/γ interactions. The results proved the possibility to pre-characterize aboveground detectors of mass close to the one of a final experiment module, despite the high cosmic rays rates. Besides, the measurements opened the way to the mutual compatibility of the underground setup, conceived for another kind of experiment, and LUMINEU 0νDBD search detectors.
17

Nouveaux concepts pour les matrices de bolomètres destinées à l’exploration de l’Univers dans le domaine millimétrique / New concepts for bolometer arrays for exploring the Universe at millimeter wavelengths

Rigaut, Olivier 06 May 2014 (has links)
Depuis sa découverte en 1964, l’étude du Fond Diffus Cosmologique dans le domaine des longueurs d’ondes millimétriques est devenue un enjeu majeur de la recherche expérimentale dans le domaine de la cosmologie. En particulier, ses anisotropies en température, mesurées pour la première fois par le satellite COBE puis plus finement par l’expérience WMAP et le satellite PLANCK. L’existence prédite d’anisotropies de polarisation du Fond Diffus Cosmologique est fait actuellement parti du champ d’expérimentation privilégié de l’étude du CMB. En effet, la preuve d’existence des modes B de polarisation, signature unique des ondes gravitationnelles primordiales, fait actuellement l’objet d’une recherche expérimentale intensive par le biais notamment de l’instrument BICEP2 qui aurait détecté sa signature en 2014 dans des valeurs du rapport tenseur sur scalaire r = 0,2. Le projet QUBIC fait parti de ces expériences destinées à révéler les modes B de polarisation grâce à son instrument basé sur la technique des interféromètres et sur le développement de matrice de bolomètres, demandant un champ d’investigation poussé englobant, entre autre, la physique des solides, la physique des basses températures et la cosmologie. La thèse présentée ici se situe dans ce cadre, avec pour objectif l’élaboration d’une matrice de bolomètres dont la performance et l’optimisation devrait permettre d’acquérir la sensibilité nécessaire à l’observation des modes B de polarisation. Les différentes techniques expérimentales acquises au CSNSM d’Orsay permettent en effet d’envisager l’optimisation des éléments clé de la matrice de bolomètre en s’appuyant notamment sur l’alliage amorphe de NbxSi1-x pour l’élaboration d’un senseur thermique optimisé, et sur un matériau novateur, l’alliage de titane-vanadium, pour la mise au point d’un absorbeur de rayonnement supraconducteur efficace, dont la faible chaleur spécifique doit permettre d’atteindre un temps de réponse du détecteur de l’ordre de la dizaine de milliseconde, valeur du temps de réponse nécessaire à une lecture efficace du signal du Fond Diffus Cosmologique. Le manuscrit de thèse ici présent a pour ambition de développer les principes physiques nécessaires au champ d’investigation du travail à accomplir. Ainsi, cette étude propose d’élaborer les différents éléments d’un bolomètre, réunissant un senseur thermique optimisé ainsi qu’un absorbeur de rayonnement de faible chaleur spécifique, permettant d’envisager la mise au point d’une matrice de bolomètres optimisée dans le cadre du projet QUBIC dont la campagne d’observation est prévue courant 2015 au dôme C du pôle Sud. / Since its discovery in 1964, the study of the Cosmic Microwave Background (CMB) in the field as of millimetre-length wavelengths became a major stake of experimental research in the field of cosmology. In particular, its anisotropies in temperature, measured for the first time by satellite COBE then more finely by the experiment WMAP and the PLANCK satellite. The predicted existence of anisotropies of polarization of the Cosmic Microwave Background is currently been part of the privileged field of experimentation of the study of the CMB. Indeed, the proof of exists modes B of polarization, single signature of the paramount gravitational waves, currently is the object of an intensive experimental research by the means in particular of the instrument BICEP2 which would have detected its signature in 2014 in values of the tensor report on scalar R = 0.2. Project QUBIC makes party of these experiments intended to reveal the modes B of polarization thanks to its instrument based on the technique of the interferometers and the development of bolometers array, asking for a thorough field of investigation including, amongst other things, the solid state physics, the physics of the low temperatures and cosmology. The thesis presented here is within this framework, with for objective making of a bolometers array whose performance and optimization should make it possible to acquire the necessary sensitivity to the observation of the B-mode polarization. The various experimental techniques acquired with the CSNSM of Orsay indeed make it possible to consider the optimization of the key elements of the bolometers array while being pressed in particular on amorphous alloy of NbxSi1-x for making of an optimized thermal sensor, and on an innovative material, titanium-vanadium alloy, for the clarification of an effective superconducting absorber of radiation, whose low specific heat must make it possible to reach a response time of the detector about ten millisecond, value of the response time necessary to an effective reading of the signal of the Cosmic Microwave Background. The manuscript of thesis here present has as an ambition to develop the physical principles necessary to the field of investigation of work to be achieved. Thus, this study proposes to work out the various elements of a bolometer, joining together a thermal sensor optimized as well as an absorber of radiation of low specific heat, making it possible to consider the clarification of a bolometers array optimized within the framework of the project QUBIC whose observation campaign is envisaged during 2015 with the dome C of the south pole.
18

Využití termovizní kamery pro měření teploty elektrických strojů / Utilization of infrared camera for temperature measurement of electrical machines

Líbal, Jan January 2009 (has links)
The master‘s thesis deals with utilization of infrared camera for temperature measurement of electrical machines. The first part describes non-contact temperature measuring, the second part describes principle of sensors that evaluate quantity of incident infrared radiation. In the next part there is termovision camera SAT-HY 6800 presented and the instructional manual for SAT Report computer programme created. This computer programme is used for analyzing of termovision pictures from the SAT-HY 6800 termovison camera. The chapter 7 describes temperature measuring of one-phase asynchronous motor type J22TO484. The chapter 8 describes temperature measuring of semiconductor components of EC motor G6 series. Both of these motors are produced by ATAS elektromotory Náchod a.s. The last part of the thesis describes creation of animation of one-phase asynchronous motor type J22TO455. The animation was created in 3ds Max computer programme.

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