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The Global ETD Search service is a free service for researchers
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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.
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Showing 191 to 200 of 200 (0.009 seconds)| 191 |
Lepton production in ice by scattering of astrophysical neutrinos at high energies / Leptonenerzeugung im Eis durch Streuung astrophysikalischer Neutrinos bei hohen EnergienHettlage, Christian 23 September 2005 (has links)
No description available.
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Piezoelectric Mirrors for Adaptive Optics in Space TelescopesAlaluf, David 02 December 2016 (has links)
Future generations of space-based telescopes will require increasingly large primary reflectors, with very tight optical-quality tolerances. However, as their size grow, it becomes more and more difficult to meet the requirements, due to the manufacturing complexity and the associated costs. Chapters 2 and 3 propose two concepts of Adaptive Optics deformable mirrors, intended to be used as secondary corrector to compensate for manufacturing errors, gravity release and thermal distortion of large lightweight primary mirrors of space telescopes: (i) A scalable segmented bimorph mirror, based on independent PZT patches glued on Silicon wafers, providing a large number of degrees of freedom, a low mass while overcoming the problem of a low resonance mode; and (ii) A monolithic bimorph mirror, controlled by an array of independent electrodes, done by laser ablation on a single PZT patch. The modelling, the control strategy and the technological aspects are described. The performances of the manufactured prototypes are demonstrated experimentally. These prototypes have been developed in the framework of the ESA project, Bimorph Adaptive Large Optical Mirror Demonstrator (BIALOM). Chapter 4 introduces alternative designs, allowing to face the thermal distortion inherent to the bimorph architecture. They are compared in terms of stroke, voltage budget and first resonance frequency. These designs are required to be controlled in both directions using only positive voltages. Finally, the last chapter explores the feasibility of the shape control of a small size active thin shell reflector (with double curvature). The prototype is intended to be a technology demonstrator of a future large and very light active primary reflector. The behavior of the shell is studied through numerical simulations, and a preliminary design is proposed. This investigation is carried out in the framework of the ESA project: Multilayer Adaptive Thin Shell Reflectors (MATS). / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished
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Adaptive optics with segmented deformable bimorph mirrorsMendes da Costa Rodrigues, Gonçalo 25 February 2010 (has links)
The degradation of astronomical images caused by atmospheric turbulence will be much more severe in the next generation of terrestrial telescopes and its compensation will require deformable mirrors with up to tens-of-thousands of actuators.<p>Current designs for these correctors consist of scaling up the proven technologies of flexible optical plates deformed under the out-of-plane action of linear actuators. This approach will lead to an exponential growth of cost with the number of actuators, and in very complex mechanisms.<p><p>This thesis proposes a new concept of optical correction which is modular, robust, lightweight and low-cost and is based on the bimorph in-plane actuation.<p><p>The adaptive mirror consists of segmented identical hexagonal bimorph mirrors allowing to indefinitely increase the degree of correction while maintaining the first mechanical resonance at the level of a single segment and showing an increase in price only proportional to the number of segments.<p><p>Each bimorph segment can be mass-produced by simply screen-printing an array of thin piezoelectric patches onto a silicon wafer resulting in very compact and lightweight modules<p>and at a price essentially independent from the number of actuators.<p><p>The controlled deformation of a screen-printed bimorph mirror was experimentally achieved with meaningful optical shapes and appropriate amplitudes; its capability for compensating turbulence was evaluated numerically. The generation of continuous surfaces<p>by an assembly of these mirrors was numerically simulated and a demonstrator of concept consisting of 3 segments was constructed. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished
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Correction active des discontinuités pupillaires des télescopes à miroir segmenté pour l’imagerie haut contraste et la haute résolution angulaire / Active correction of pupil discontinuities on segmented telescopes for high contrast imaging and high angular resolutionJanin-Potiron, Pierre 19 October 2017 (has links)
La recherche de signes de vie extraterrestre par l'observation et la caractérisation d'exoplanètes est, entre autres, l'un des enjeux majeurs de l'astrophysique moderne. Cette quête se traduit de manière instrumentale par le développement de télescopes fournissant des résolutions angulaires supérieures à celles obtenues à l'heure actuelle. C'est pourquoi les projets de futurs très grands télescopes font usage de miroirs primaires dépassant les 30 mètres de diamètre. Leur conception est alors inévitablement basée, pour des raisons techniques et technologiques, sur une géométrie segmentée. De ce fait, la segmentation du miroir primaire implique une complexification des structures pupillaires du télescope. Dans le but d'atteindre les niveaux de qualité optique nécessaires aux applications scientifiques visées, la prise en compte et la correction des effets introduits par un mauvais alignement des segments est de prime importance puisque la résolution angulaire d'un télescope non cophasé serait équivalente à celle obtenue avec un segment individuel. Dans ce contexte, je développe dans cette thèse deux analyseurs de cophasage permettant de mesurer et de corriger les aberrations de piston, tip et tilt présentes sur une pupille segmentée. Le premier, nommé Self-Coherent Camera - Phasing Sensor (SCC-PS), est basé sur une analyse du signal en plan focal. Le second, nommé ZELDA - Phasing Sensor (ZELDA-PS), repose quant à lui sur une analyse du signal en plan pupille. Sont présentés dans ce manuscrit les résultats obtenus à l'aide de simulations numériques ainsi que ceux issus de l'implémentation de la SCC-PS sur un banc d'optique d'essai. / Searching for extraterrestrial life through the observation and characterization of exoplanets is, amongst others, one of the major goal of the modern astrophysics. This quest translate from an instrumental point of view to the development of telescope capable of reaching higher angular resolution that what is actually ongoing. That is why the future projects of extremely large telescopes are using primary mirrors exceeding the 30 meters in diameter. Their conception is consequently based, for technical and technological reasons, on a segmented geometry. The segmentation of the primary mirror therefore implies a growing complexity of the structure of its pupil. In order to reach the optical quality required by the sciences cases of interest, taking into account and correct for the effects introduced by a poor alignment of the segments is mandatory, as the angular resolution of a non-cophased telescope is equivalent to the one obtained with a single segment. In this context, I develop in this manuscript two cophasing sensors allowing to measure and correct for the aberrations of piston, tip and tilt present on a segmented pupil. The first one, the Self-Coherent Camera - Phasing Sensor (SCC-PS), is based on a focal plane analysis of the signal. The second one, the ZELDA - Phasing Sensor (ZELDA-PS), is based on a pupil plane analysis of the signal. The results obtained by means of numerical simulations and the first results coming from the implementation of the SCC-PS on an optical bench are presented in this manuscript.
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Caractérisation d’atmosphères d’exoplanètes à haute résolution à l’aide de l’instrument SPIRou et développement de méthodes d’extraction spectrophotométriques pour le télescope spatial James WebbDarveau-Bernier, Antoine 10 1900 (has links)
L'étude des exoplanètes et de leur atmosphère a connu une croissance fulgurante dans les deux dernières décennies. Les observations spectrophotométriques à partir d'observatoires spatiaux comme Hubble ont permis d'apporter certaines contraintes sur les phénomènes physiques et la composition de leur atmosphère, notamment grâce à la spectroscopie d'éclipse. Ces découvertes concernent généralement les planètes les plus favorables à cette technique, dont font partie les Jupiter chaudes. Cependant, les conclusions tirées à partir telles observations comportent leur lot de dégénérescences, causées par leur faible résolution spectrale, leur couverture restreinte en longueurs d'onde et leur précision photométrique limitée. Ces lacunes peuvent être corrigées en partie grâce à la complémentarité des spectrographes à haute résolution basés au sol ainsi qu'à l'aide du nouveau télescope spatial James Webb (JWST).
Cette thèse présente, en premier lieu, une des premières analyses combinées d'observations spectrophotométriques prises avec l'instrument Wide Field Camera 3 de Hubble et d'observations à haute résolution avec l'instrument SPIRou (SpectroPolarimètre InfraRouge) du télescope Canada-France-Hawaï. Cette analyse avait pour cible le côté jour de la Jupiter ultra chaude WASP-33b, la deuxième exoplanète la plus chaude connue à ce jour. Aux températures se retrouvant dans l'atmosphère de WASP-33b, avoisinant les 3000 K, des molécules comme l'eau ne peuvent demeurer stables. Cependant, le CO, beaucoup plus résistant à la dissociation thermique, reste observable. Les données de SPIRou ont donc permis de confirmer la détection des raies d'émission du CO, en accord avec deux précédentes études. La combinaison avec les données de Hubble a aussi mené à l'obtention d'un premier estimé de son abondance avec un rapport de mélange volumique de logCO = -4.07 (-0.60) (+1.51). De plus, cette analyse a pu améliorer les contraintes sur la structure verticale en température et confirmer la présence d'une stratosphère. Des limites supérieures sur d'autres molécules comme l'eau, le TiO et le VO ont aussi pu être établies.
En second lieu, un algorithme d'extraction spectrale intitulé ATOCA (Algorithme de Traitement d'Ordres ContAminés) est présenté. Celui-ci est dédié au mode d'observation SOSS (Single Object Slitless Spectroscopy) de l'instrument NIRISS (Near InfraRed Imager and Slitless Spectrograph), la contribution canadienne à JWST. Ce mode d'observation couvre une plage de longueurs d'onde allant de 0,6 à 2,8 um simultanément grâce à la présence des deux premiers ordres de diffraction sur le détecteur. La nécessité d'un nouvel algorithme provient du fait que ces deux ordres générés par le « grisme » du mode SOSS se chevauchent sur une petite portion du détecteur. En conséquence, la région de l'ordre 1 couvrant les plus grandes longueurs d'onde (1,6–2,8 um) est contaminée par l'ordre 2 couvrant l'intervalle entre 0,85 et 1,4 um. ATOCA permet donc de décontaminer chacun des ordres en construisant d'abord un modèle linéaire de chaque pixel individuel du détecteur, en fonction du flux incident. Ce flux peut ensuite être extrait simultanément pour les deux ordres en comparant le modèle aux observations et en solutionnant le système selon un principe de moindres carrés. Ces travaux ont pu montrer qu'il est possible de décontaminer en dessous de 10 ppm pour chaque spectre individuel. / In the last decades, the research on exoplanets and their atmosphere has grown phenomenally. Space based observatories with spectrophotometric capabilities like Hubble allowed
to put some constraints on the physical processes occuring in exoplanets’ atmosphere and
their chemical composition. These discoveries concern mainly the hotter and larger planets,
such as Hot Jupiters, which are the most favorable for atmospheric characterization. However, due to their low spectral resolution and their limited wavelength range and photometric
accuracy, the scientific conclusions based on these observations can be degenerate. Some of
these degeneracies can be lifted with the use of ground-based high-resolution spectrographs
or the new James Webb Space Telescope (JWST).
On the one hand, this thesis present one of the first analysis combining Hubble’s spectrosphometric data and high-resolution observations obtained with SPirou (SpectroPolarimètre
InfraRouge) at the Canada-France-Hawai telescope. This analysis targeted the dayside of
the Ultra Hot Jupiter WASP-33 b, the second-hottest exoplanet known to date. WASP-33 b
atmosphere can reach temperatures high enough (≥ 3000 K) to dissociate molecules such
as water. However, CO, which is much more resistant to thermal dissociation, remains observable. SPIRou’s observations allowed us to confirm the presence of CO emission lines in
WASP-33 b emission spectrum, in agreement with two previous studies. With the addition
of published Hubble data, we were able to push further and provide the first estimate CO
abundance, with a volume mixing ratio of log10 CO = ≠4.07+1.51 ≠0.60.
On the other hand, this thesis propose a new spectral extraction algorithm called ATOCA
(Algorithm to Treat Order ContAmination) specifically designed for the SOSS (Single Object Slitless Spectroscopy) mode of the NIRISS instrument (Near InfraRed Imager and Slitless
Spectrograph), the Canadian contribution to JWST. This observing mode covers the wavelength range spaning from 0.6 to 2.8 µm simultaneously, due to the presence of the two first
diraction orders on NIRISS detector. The need for a new algorithm arises from the fact
that these orders, originating from SOSS “grism”, overlap on a small portion of the detector. Consequently, the region of order 1 covering the longest wavelengths (1.6–2.8 µm) is
contaminated by the signal from order 2 between 0.85 and 1.4 µm. Hence, ATOCA allows
to decontaminate both orders by first building a linear model of each individual pixel of the detector, with the incident flux as an independant variable. This flux is then extracted
simultaneously for the two orders by comparing the model to the detector image and by
solving the system for the best least square fit. This work has shown that ATOCA can
reduce the contamination level below 10 ppm for each individual spectrum.
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Studies of active galactic nuclei with the MAGIC telescopesCaneva, Gessica De 30 March 2015 (has links)
Schwerpunkt dieser Arbeit ist die Emission von hochenergetischer Gammastrahlung aus Aktiven Galaxienkernen, anhand von Beobachtungen mit den MAGIC Teleskopen. Aktive Galaxien entstehen durch die Freisetzung von Gravitationsenergie der Stellarmaterie, die in das zentrale Schwarze Loch fällt. Zwei diametral entgegengesetzte Jets strömen aus dem Kern. Falls einer von diesen Jets zum Beobachter zeigt, wird der aktive Galaxienkern als Blazar bezeichnet. In dieser Doktorarbeit wird die Analyse der MAGIC Beobachtungen von drei Blazaren präsentiert: der bisher unbekannte hochenergetische Blazar 1ES 1727+502 und die bekannten Objekte 3C 279 und PKS 1510-089. Die Quelle 1ES 1727+502 gehört zu der Unterklasse der BL Lac Objekte, die die zahlenmässig größte Klasse an extragalaktischen hochenergetische Objekten ist. Diese Entdeckung beweist, wie wichtig es ist, mehrere und verschiedene Kriterien für die Auswahl von Objekten zu benutzen. Der Blazar 1ES 1727+502 wurde aus einem X-ray Katalog ausgesucht, die Datennahme war unabhängig von dem Aktivitätsstatus der anderen Energiebänder. Die Blazare 3C 279 und PKS 1510-089 gehören zu der Unterklasse des Flat Spectrum Radio Quasars. Es gibt nur drei bekannte Flat Spectrum Radio Quasare. Die Entdeckung von Flat Spectrum Radio Quasaren ist schwierig, weil im leisen Zustand der hochenergetische Fluss niedrig ist. Während eines Flares steigt der Fluss in sehr kurzer Zeit um mehrere Größenordnungen an, deswegen ist die Beobachtung eines Flares schwer zu realisieren aber physikalisch äußerst interessant. Die MAGIC Beobachtungen sind mit Messungen aus anderen Energiebändern kombiniert. Mögliche Interpretationen des beobachteten Verhaltens werden diskutiert. Die Ergebnisse werden erläutert und mit historischen Beobachtungen verglichen. Die offenen Fragen und Probleme, die Ziel zukünftiger Studien sein sollen, werden am Schluss hervorgehoben. / This PhD thesis addresses the problem of understanding the very high energy emission from active galactic nuclei as detected with the MAGIC telescopes. Active galactic nuclei are galaxies powered by the release of gravitational energy of stellar material falling into a black hole, located in their core. Two opposed jets extend from the central region outwards, if one of the them points towards the observer, the source is called a blazar. In this thesis the analysis of MAGIC observations of three different blazars is presented: the newly discovered very high energy blazar 1ES 1727+502, and the two known objects 3C 279 and PKS 1510-089. The source 1ES 1727+502 belongs to the subclass of BL Lac objects, the most numerous class of extragalactic very high energy emitters. This source was selected for observations from an X-ray catalogue and was observed even if no high activity states were reported at lower energies. For this reason, this discovery proves the importance of using several criteria for the selection of very high energy observation targets. The other two objects, 3C 279 and PKS 1510-089, belong to the subclass of flat spectrum radio quasars. We count only three representatives of this class in the very high energy domain. Their detection is critical because during quiescent states they have low flux levels at very high energies. During flaring states, flat spectrum radio quasars exhibit flux enhancements of orders of magnitudes and short time scales. Observations during such states, difficult to catch, are interesting because extreme processes are taking place. Very high energy observations of these three objects are complemented with measurements at lower energies and interpretations of the observed behaviours are discussed. The results are compared with historical observations, highlighting open questions and problems which should be addressed by future studies.
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Radiações e telescópios: uma proposta educacional para o ensino e aprendizagem de Física no ensino médio / Radiation and telescopes: an educational proposal for the teaching and learing of Physics in high schoolRodrigues, Jean Carlos 31 August 2016 (has links)
Acompanha: Radiações e telescópio: uma proposta para o ensino médio: caderno de sugestões de atividades educacionais / Este trabalho apresenta características e discussões pertinentes à pesquisa desenvolvida no Programa de Pós-Graduação em Formação Científica, Educacional e Tecnológica da Universidade Tecnológica Federal do Paraná – UTFPR – Campus Curitiba/PR. Esta pesquisa é constituída de elementos que permeiam a problematização do ensino de Física para o 3º ano do Ensino Médio das escolas públicas em geral e em particular do Colégio Estadual Paulina Pacífico Borsari, em Curitiba/PR. A referida pesquisa apresenta estratégias de ensino para abordar Radiações no Ensino Médio, tendo como objeto motivador os telescópios espaciais, dentro da perspectiva do agir comunicativo de Jürgen Habermas, do uso do discurso no âmbito explicativo com o intuito de atingir a estrutura cognitiva do aluno, para que este consiga relacionar os conceitos aprendidos com os demais âmbitos: objetivo, social e subjetivo. Ao fazer as relações nos três âmbitos citados, espera-se que aluno tenha conseguido estabelecer na sua estrutura cognitiva inter-relações entre os conhecimentos prévios e os novos conceitos. Esse processo envolve a assimilação e retenção de novos conhecimentos, de acordo com os modelos teóricos estabilizados, para aprendizagem significativa, de acordo com a Teoria da Aprendizagem Significativa de David Ausubel e colaboradores. Os dados desta pesquisa foram constituídos por meio de: registros escritos em diário de campo, elaborados pelo pesquisador; gravações em áudio das atividades educacionais desenvolvidas; mapas conceituais elaborados pelo professor e pelos alunos; questionários respondidos pelos discentes. Esses dados foram analisados por meio de Análise de Conteúdo. Entre os resultados, podem ser destacados indícios de assimilação de conceitos científicos para a ampliação de âmbito explicativo e estabelecimento de relações entre ciência e tecnologia em referência aos âmbitos objetivo, social e subjetivo. / This study presents characteristics and relevant discussions on research conducted at the Postgraduate Program in Scientific, Educational and Technological Formation in Federal University of Technology-Parana- UTFPR-Campus Curitiba / PR. This study consists of elements that permeate the questioning of the teaching of Physics for the 3rd year of high school in public schools in general and in particular the State College Paulina Pacific Borsari, in Curitiba / PR. This research presents teaching strategies to address radiation in high school, with the space telescopes as motivating objects, from the perspective of communicative action by Jürgen Habermas, considering the speech use in explanatory domain in order to achieve student cognitive structure, so that this learner can relate the learned concepts with other domains: objective, social and subjective. By making the relationships in the three mentioned domains, it is expected that the student has been able to establish interrelationships in their cognitive structure between prior knowledge and new concepts. This process involves the assimilation and retention of new knowledge, according to stabilized theoretical models, aiming a meaningful learning, according to Meaningful Learning Theory by David Ausubel and colleagues. Data from this study were constituted by: written records in field diary, made by the researcher; audio recordings of the developed educational activities; conceptual maps made by the teacher and students; questionnaires answered by students. These data were analyzed by means of Content Analysis. Among the results, it can be highlighted some evidence of assimilation of scientific concepts for the expansion of explanatory domain and of establishment of relations between science and technology in reference to objective, social and subjective domains.
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Radiações e telescópios: uma proposta educacional para o ensino e aprendizagem de Física no ensino médio / Radiation and telescopes: an educational proposal for the teaching and learing of Physics in high schoolRodrigues, Jean Carlos 31 August 2016 (has links)
Acompanha: Radiações e telescópio: uma proposta para o ensino médio: caderno de sugestões de atividades educacionais / Este trabalho apresenta características e discussões pertinentes à pesquisa desenvolvida no Programa de Pós-Graduação em Formação Científica, Educacional e Tecnológica da Universidade Tecnológica Federal do Paraná – UTFPR – Campus Curitiba/PR. Esta pesquisa é constituída de elementos que permeiam a problematização do ensino de Física para o 3º ano do Ensino Médio das escolas públicas em geral e em particular do Colégio Estadual Paulina Pacífico Borsari, em Curitiba/PR. A referida pesquisa apresenta estratégias de ensino para abordar Radiações no Ensino Médio, tendo como objeto motivador os telescópios espaciais, dentro da perspectiva do agir comunicativo de Jürgen Habermas, do uso do discurso no âmbito explicativo com o intuito de atingir a estrutura cognitiva do aluno, para que este consiga relacionar os conceitos aprendidos com os demais âmbitos: objetivo, social e subjetivo. Ao fazer as relações nos três âmbitos citados, espera-se que aluno tenha conseguido estabelecer na sua estrutura cognitiva inter-relações entre os conhecimentos prévios e os novos conceitos. Esse processo envolve a assimilação e retenção de novos conhecimentos, de acordo com os modelos teóricos estabilizados, para aprendizagem significativa, de acordo com a Teoria da Aprendizagem Significativa de David Ausubel e colaboradores. Os dados desta pesquisa foram constituídos por meio de: registros escritos em diário de campo, elaborados pelo pesquisador; gravações em áudio das atividades educacionais desenvolvidas; mapas conceituais elaborados pelo professor e pelos alunos; questionários respondidos pelos discentes. Esses dados foram analisados por meio de Análise de Conteúdo. Entre os resultados, podem ser destacados indícios de assimilação de conceitos científicos para a ampliação de âmbito explicativo e estabelecimento de relações entre ciência e tecnologia em referência aos âmbitos objetivo, social e subjetivo. / This study presents characteristics and relevant discussions on research conducted at the Postgraduate Program in Scientific, Educational and Technological Formation in Federal University of Technology-Parana- UTFPR-Campus Curitiba / PR. This study consists of elements that permeate the questioning of the teaching of Physics for the 3rd year of high school in public schools in general and in particular the State College Paulina Pacific Borsari, in Curitiba / PR. This research presents teaching strategies to address radiation in high school, with the space telescopes as motivating objects, from the perspective of communicative action by Jürgen Habermas, considering the speech use in explanatory domain in order to achieve student cognitive structure, so that this learner can relate the learned concepts with other domains: objective, social and subjective. By making the relationships in the three mentioned domains, it is expected that the student has been able to establish interrelationships in their cognitive structure between prior knowledge and new concepts. This process involves the assimilation and retention of new knowledge, according to stabilized theoretical models, aiming a meaningful learning, according to Meaningful Learning Theory by David Ausubel and colleagues. Data from this study were constituted by: written records in field diary, made by the researcher; audio recordings of the developed educational activities; conceptual maps made by the teacher and students; questionnaires answered by students. These data were analyzed by means of Content Analysis. Among the results, it can be highlighted some evidence of assimilation of scientific concepts for the expansion of explanatory domain and of establishment of relations between science and technology in reference to objective, social and subjective domains.
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Dark Matter Searches Towards the Sun with ANTARES and Positioning Studies for KM3NeTPoirè, Chiara 24 October 2022 (has links)
[ES] Los neutrinos de alta energía son partículas esquivas: no tienen carga, tienen una sección transversal de interacción muy pequeña con la materia ordinaria y su masa es extremadamente pequeña. Los neutrinos son una sonda importante en el estudio del origen de los rayos cósmicos, y también, siguiendo algunos modelos de la física más allá del modelo Stardard, pueden producirse a partir de la propagación de partículas del modelo estándar producidas por la aniquilación de la materia oscura.
En el último siglo, se han desarrollado muchos enfoques nuevos en la física de astropartículas, tratando de resolver los enigmas no resueltos del Universo, como el origen de los rayos cósmicos y la existencia de la materia oscura. Entre los diferentes experimentos destacan, sin duda, los telescopios de neutrinos. Los telescopios de neutrinos, consistentes en un gran volumen de un medio transparente monitorizado por sensores ópticos para detectar luz de Cherenkov, pueden detectar neutrinos de alta energía de fuentes galácticas o extragalácticas, y también pueden usarse para el estudio de las propiedades de los neutrinos.
ANTARES y su sucesor KM3NeT son dos telescopios de neutrinos ubicados en el mar Mediterráneo. El telescopio ANTARES empezó a estar operativo en 2007 y ha tomado datos de forma casi continua hasta principios de 2022. KM3NeT, aprovechando la experiencia de ANTARES, pretende ser el telescopio de neutrinos más sensible de la próxima generación de detectores.
Esta tesis presenta mis contribuciones en ambos detectores. En concreto, la parte técnica del trabajo se ha desarrollado en colaboración con KM3NeT. Está dedicado al estudio de los datos de los sensores de orientación instalados en los módulos de detección ópticos de KM3NeT: desde su calibración antes del despliegue en el mar hasta el análisis de sus datos in situ. Estos sensores permiten una monitorización de los movimientos de los elementos detectores en el mar. Por otro lado, en colaboración con ANTARES se ha desarrollado un análisis de física relacionado con la búsqueda de la aniquilación de la materia oscura en el Sol analizando trece años de datos. Se han obtenido nuevos límites superiores para los flujos de neutrinos y antineutrinos a partir de la aniquilación de materia oscura en el Sol, y a partir de estos, se han derivado límites superiores a la sección eficaz de dispersión de Materia Oscura - Nucleón. Estos resultados mejoran en un factor dos los resultados anteriores de ANTARES y son competitivos con respecto a otros experimentos. / [CA] Els neutrins d'alta energia són partícules esquives: no tenen càrrega, tenen una secció transversal d'interacció molt petita amb la matèria ordinària i la massa és extremadament petita. Els neutrins són una sonda important en l'estudi de l'origen dels raigs còsmics, i també, seguint alguns models de la física més enllà del Model Stardard, es poden produir a partir de la propagació de partícules del model estàndard produïdes per l'aniquilació de la matèria fosca. A l'últim segle, s'han desenvolupat molts enfocaments nous a la física d'astropartícules, tractant de resoldre els enigmes no resolts de l'Univers, com l'origen dels raigs còsmics i l'existència de la matèria fosca.
Entre els diferents experiments destaquen, sens dubte, els telescopis de neutrins. Els telescopis de neutrins, consistents en un gran volum d'un medi transparent monitoritzat per sensors òptics per detectar llum de Cherenkov, poden detectar neutrins d'alta energia de fonts galàctiques o extragalàctiques, i també es poden utilitzar per a l'estudi de les propietats dels neutrins. ANTARES i el seu successor KM3NeT són dos telescopis de neutrins ubicats al mar Mediterrani. El telescopi ANTARES va començar a estar operatiu el 2007 i ha pres dades de forma gairebé contínua fins a principis del 2022. KM3NeT, aprofitant l'experiència d'ANTARES, pretén ser el telescopi de neutrins més sensible de la propera generació de detectors. Aquesta tesi presenta les meves contribucions a tots dos detectors.
Concrètement, la part tècnica del treball s'ha desenvolupat en col·laboració amb KM3NeT. Està dedicat a l'estudi de les dades dels sensors d'orientació instal·lats als mòduls de detecció òptics de KM3NeT: des del calibratge abans del desplegament al mar fins a l'anàlisi de les seves dades in situ. Aquests sensors permeten una monitorització dels moviments dels elements detectors al mar. D'altra banda, en col·laboració amb ANTARES s'ha desenvolupat una anàlisi de física relacionada amb la recerca de l'aniquilació de la matèria fosca al Sol analitzant tretze anys de dades. S'han obtingut nous límits superiors per als fluxos de neutrins i antineutrins a partir de l'aniquilació de matèria fosca al Sol, i a partir d'aquests, s'han derivat límits superiors a la secció eficaç de dispersió de Materia Fosca - Nucleó. Aquests resultats milloren en un factor dos els resultats anteriors de ANTARES i són competitius respecte a altres experiments. / [EN] High energy Neutrinos are elusive particles: they are chargeless, have a very small cross section with ordinary matter and their mass is extremely small. Neutrinos are an important probe in the study of the origin of cosmic rays but also, following some models of physics Beyond the Standard Model, they can be produced from the decay of Standard Model particles produced by dark matter annihilation.
In the last century, many new approaches have been developed in astroparticle physics, trying to solve the unsolved puzzles of the Universe such as the origin of Cosmic Rays and the existence of Dark Matter. Among the many experiments, neutrino telescopes certainly stand out. Neutrinos telescopes, made of large volume of a transparent medium observed by optical sensors, can detect high energy neutrinos from galactic or extra-galactic sources, and they can also be used for the study of neutrino properties.
ANTARES and its successor KM3NeT are two neutrino telescopes located in the Mediterranean sea. ANTARES operations started in 2007 and it has taken data almost continuously until the beginning of 2022. KM3NeT, taking advantage from the experience of ANTARES, aims to be the most sensitive neutrino telescope in the next generation of detectors.
This thesis presents my contributions to both detectors. In particular, the technical part of the work has been developed in collaboration with KM3NeT. It is devoted to the the study of data from the compasses installed
in the KM3NeT detection elements: from their calibration before deployment to the analysis of their data in the sea. These compasses allow a tracking of the movements of the detector elements in the sea. In collaboration with ANTARES a physics analysis related to the search of dark matter annihilation in the Sun has been developed analyzing thirteen years of data. New upper limits for neutrino and antineutrino fluxes from dark matter annihilation in the Sun have been obtained, and from these upper limits on the Dark Matter - Nucleon scattering cross section have been obtained. These results improve previous ANTARES results by a factor of 2 and are competitive with those obtained by other experiments. / Poirè, C. (2022). Dark Matter Searches Towards the Sun with ANTARES and Positioning Studies for KM3NeT [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/188750
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Johann Friedrich von Uffenbach. Sammler – Stifter – Wissenschaftler / Johann Friedrich von Uffenbach. Collector - Donor - ScientistMeyerhöfer, Dietrich 28 January 2020 (has links)
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