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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.
301

Mesure des neutrinos solaires de la raie du béryllium dans l'expérience Borexino

Beau, Tristan 18 October 2002 (has links) (PDF)
L'expérience Borexino (BX), collaboration impliquant neuf pays, est implantée dans le laboratoire souterrain du Gran Sasso en Italie. Elle vise la mesure du flux de neutrinos solaires de la raie du béryllium à 862 keV, première mesure en temps réel à si basse énergie. Cette expérience impose des contraintes très fortes en radiopureté. Sa faisabilité technique est testée dans le prototype Counting Test Facility (CTF).<br> Le groupe du Collège de France est chargé du système de numérisation rapide (FADC) sur BX. Ces FADC ont été conçus au laboratoire et nous les avons finalisés début 2002. Les cartes prototypes et les premiers modèles industriels ont été implantés sur CTF à titre de test, numérisant les signaux issus des photomultiplicateurs.<br> Nous avons développé les logiciels d'acquisition des FADC sur CTF et BX. Pour BX, nous utilisons un algorithme interne de réduction des données basé sur l'élimination en temps réel des événements à trop basse énergie tout en conservant les événements en coïncidence. Sur CTF, nous produisons des données depuis l'été 2000 et sur BX les premiers tests ont eu lieu sans scintillateur.<br> L'analyse de CTF porte sur les données issues des FADC seuls et des donnés conjointes entre les FADC et l'électronique standard mise en place par l'équipe italienne. Nous montrons que les FADC permettent de reconstruire l'énergie des événements et les coïncidences avec des précisions comparables à celles de l'électronique standard. La comparaison des données issues des deux systèmes montre l'apport du FADC, sans temps mort, pour la mesure de contaminations dans le détecteur, l'analyse des signaux tardifs issus des photomultiplicateurs et la discrimination entre événements de type alpha et bêta. Plusieurs méthodes de discrimination sont également étudiées par simulations pour BX.
302

O espectro de escalares do mecanismo seesaw triplo

Caetano, Wellington de Lima 06 May 2011 (has links)
Made available in DSpace on 2015-05-14T12:14:00Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1204809 bytes, checksum: 5976a34278e9533ed5bacae174865cb0 (MD5) Previous issue date: 2011-05-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this thesis we study some extensions of the Standard Model to accommodate mass for neutrinos. In order to explain the deficit of atmospheric and solar neutrinos observed on Earth, the phenomenon of flavor oscillation between families requires that neutrinos have physical mass eigenstates. For this, we constructed possible mass terms of Majorana or Dirac. We also develop type I-II seesaw mechanisms to generate neutrino masses. Analyzing the applicability of these seesaw mechanisms, we observe, for example, that the type I seesaw requires the existence of heavy right-handed neutrinos mass with the scale of grand unification. Next, we study the triple seesaw mechanism, where we show the possibility of generating neutrino mass using the TeV energy accelerators. We also examine the scalar sector of this mechanism, which is based on a Two Higgs Doublet Model, in addition to standard model content. Finally, we derive the mass spectrum of the scalar, obtaining a stable pseudoscalar with mass close to 10 GeV, as a possible cold dark matter candidate. / Nesta dissertação estudamos algumas extensões do Modelo Padrão que acomodam massa para neutrinos. Para a explicação do déficit de neutrinos solares e atmosféricos observados na Terra, o fenômeno da oscilação de sabores entre as famílias requer que neutrinos tenham autoestados físicos massivos. Para isso, construímos possíveis termos de massa de Dirac ou Majorana e desenvolvemos os mecanismos seesaw dos tipos I e II para geração de massa para neutrinos. Analisando as aplicabilidades destes mecanismos seesaw, observamos, por exemplo, que o seesaw do tipo I requer a existência de neutrinos pesados de mão-direita com massa na escala das teorias de grande unificação. Em seguida, estudamos o mecanismo seesaw Triplo, que tem como base um modelo com dois dubletos e um singleto de escalares, além do conteúdo padrão. Neste modelo, mostramos a possibilidade de geração de neutrinos massivos usando os aceleradores com energia na escala de TeV. Finalmente, analisamos o setor escalar do modelo que realiza este seesaw, onde derivamos o espectro de massa dos escalares, obtendo um pseudoescalar estável com massa próxima a 10 GeV, que é um possível candidato a matéria escura fria.
303

Detecção de neutrinos do Tau de altissimas energias em detetores de fluorescencia / Detection of ultra high energy Tau neutrinos in fuorescence detectors

Moura Junior, Celio Adrega de 10 May 2006 (has links)
Orientador: Marcelo Moraes Guzzo / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-07T11:07:30Z (GMT). No. of bitstreams: 1 MouraJunior_CelioAdregade_D.pdf: 3776986 bytes, checksum: 07c139c8c30b32426082bda432e718e0 (MD5) Previous issue date: 2006 / Resumo: Fazemos uma estimativa do número de Chuveiros Atmosféricos Extensos originados por neutrinos do tau em Detetores de Fluorescência como os do Observatório Pierre Auger. Consideramos modelos de produção de neutrinos do elétron e do múon de altíssimas energias em objetos extra galácticos e Defeitos Topológicos, assim como mudança de sabor na propagação dos neutrinos da fonte até a Terra. Para a seção de choque dos neutrinos utilizamos um modelo que extrapola os parâmetros do Modelo Padrão até energias da ordem de 1021 e V. Porém esses parâmetros foram comprovados até a ordem de 1012 e V. gerando incertezas nos números obtidos para altíssimas energias. Concluímos que, dependendo da relação entre fluxo e seção de choque, existe uma região restrita de energia dos neutrinos do tau que pode gerar eventos com chuveiros atmosféricos duplos detectáveis em Detetores de Fluorescência. A energia dos neutrinos do tau deve ser de aproximadamente 1018 e V e o número de eventos pode variar algumas ordens de magnitude em torno de um evento por ano, dependendo dos modelos propostos e das caracteristicas do detetor / Abstract: We calculate the possible number of Extensive Air Showers originated by tau neutrinos in Fluorescence Detectors like the ones of the Pierre Auger Observatory. We consider models of production of electron and muon neutrinos in extra galactic objects and Topological Defects, as well as the possibility of neutrino flavor change in the propagation of the neutrinos between the source and the Earth. The neutrino cross section was calculated by the extrapolation of the standard model parton distribution functions until energies of the order of 1021 e V. However, due to uncertainties in the extrapolation for energies higher than 1012 e V the results are not robust. We conclude that, depending on the relation between flux and cross section, there is a strict range of energy for the tau neutrinos to generate double extensive air showers detectable in Fluorescence Detectors. The tau neutrino energy must be approximately 1018 e V and the event rate can vary some orders of magnitude around one event per year , depending on the flux-cross section relation and detector characteristics / Doutorado / Física das Particulas Elementares e Campos / Doutor em Ciências
304

Soluções de grande comprimento de oscilação para o problema de neutrinos solares / Solutions of large length of oscillation for the solar neutrinos problem

Alberto Martin Gago Medina 27 March 2001 (has links)
Esta tese apresenta uma análise estatística detalhada dos dados de experimentos com neutrinos solares mais recentes, com duas diferentes soluções para oscilações de neutrinos, ambas caracterizadas por um grande comprimento de oscilação. A primeira baseada no mecanismo de oscilação padrão, ou seja, induzida por massa, sendo esta estudada nos casos de duas e três gerações e dentro do regime de quase-vácuo. E a segunda, uma exótica, que usa como mecanismo de oscilação uma possível violação do princípio de equivalência, que foi analisada somente para o caso de duas gerações, sendo este discutido para transições entre neutrinos ativos, e entre neutrinos ativos e estéreis. Nossos resultados mostraram que ambas soluções são consistentes com os dados de neutrinos solares e, também, no caso específico do quase-vácuo, observamos que a hipótese de três gerações ficou desfavorecida. / This thesis presents a well detailed statistical analysis using the recent data from solar neutrino experiments. This analysis was done in the framework of two different solutions of neutrino oscillations, both characterized by a long oscillation wavelength. The first was based on the standard mass induced oscillation mechanism, here we worked in the scheme of two and three neutrino generations within the quasivacuum regime. The second was an exotic mechanism, where the neutrino oscillation is due to a possible breakdown of the equivalence principle, this alternative was analyzed only for two neutrino generations, in the cases for the conversion among active neutrino and active to sterile neutrino. Our results show a good agreement between the solar neutrino data and both solutions, also in the specific case of quasivacuum, we found that the hypothesis for the three neutrino generation is disfavored.
305

Simulação da interação de partículas no detector central e dos sinais elétricos gerados pela eletrônica de leitura no Projeto Neutrinos Angra / Simulation of particles interaction in the central detector and electrical signal generation the readout electronics in the Neutrinos Angra Project

Alvarenga, Tiago Araujo 29 August 2013 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-03-31T11:02:02Z No. of bitstreams: 1 tiagoaraujoalvarenga.pdf: 1818159 bytes, checksum: 57d4c9e47aceef252cc9514841d2b15d (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T02:55:55Z (GMT) No. of bitstreams: 1 tiagoaraujoalvarenga.pdf: 1818159 bytes, checksum: 57d4c9e47aceef252cc9514841d2b15d (MD5) / Made available in DSpace on 2016-04-24T02:55:55Z (GMT). No. of bitstreams: 1 tiagoaraujoalvarenga.pdf: 1818159 bytes, checksum: 57d4c9e47aceef252cc9514841d2b15d (MD5) Previous issue date: 2013-08-29 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O Projeto Neutrinos Angra tem como objetivo o desenvolvimento de um detector compacto e de superfície, capaz de medir o fluxo de antineutrinos provenientes de reatores nucleares. Esta técnica possibilita o monitoramento da potência térmica instantânea dissipada de forma não invasiva e de maneira independente dos equipamentos de controle do reator. O projeto prevê a instalação deste detector a aproximadamente 25 m do núcleo do reator Angra II em Angra dos Reis - RJ, ao lado da cúpula externa do sistema de proteção, bem como de um laboratório de controle e aquisição do experimento. O detector foi projetado para capturar fótons produzidos nos processos de interação de partículas em seu interior, principalmente por efeito Cherenkov. Os fótons gerados são convertidos em sinais elétricos através de tubos fotomultiplicadores. Os fótons capturados pelos tubos fotomultiplicadores produzem sinais elétricos que são amplificados e modelados pelo circuito de front-end. Após passarem pelo módulo de front-end os sinais são amostrados e digitalizados pelo módulo de aquisição do experimento NDAQ. O sinal digitalizado será então entregue a uma FPGA, onde poderá ser processado e armazenado em computadores locais. Apresenta-se neste trabalho um programa que usa como técnica principal o Método de Monte Carlo para simular os principais processos de interação de partículas que ocorrerão no interior do detector alvo do Projeto Neutrinos Angra. Esta simulação cobre desde as interações de partícula com a matéria, até o processo de digitalização dos sinais elétricos produzidos e da conversor analógico digital. O simulador de interação de partículas e de sinais elétricos foram desenvolvidos com o intuito de ajudar na concepção e no entendimento do funcionamento do detector e dos resultados que serão obtidos, assim como na elaboração de algoritmos de estimação e de detecção dos eventos de antineutrinos eletrônico emitidos pelo reator nuclear. / The Neutrinos Angra Project aims to develop a compact detector capable of measuring the antineutrinos flux coming from nuclear reactors. The detector is intended to work on the surface, at sea level. This measurement makes it possible to monitor the reactor’s thermal power in a non-invasive way and independently of the reactor’s control system. The project intends to install the detector to a distance of about 25 meters from the nuclear reactor’s core. The detector and its acquisition and control systems will be placed just outside of the Angra II Reactor, located in the city of Angra dos Reis – RJ, Brazil, inside a container. The detector has been designed to capture photons produced by Cherenkov effect. The detector will be equipped with a total of 48 Photomultipliers used to convert photons to electrical signals. Those signals will be amplified and shaped by a front-end circuitry before they are sent to the acquisition system of the experiment where they will be digitalized to be sent to a group of FPGAs. Once acquired by the FPGAs, the incoming signals can be further processed before being recorded into local computers. This work presents a software which makes use of Monte Carlo Techniques to simulate the main interaction processes occurring inside the target detector of the experiment. The implemented simulation covers from the particles interaction with matter up to the digitalization process occurring just before delivering the electrical signals to FPGAs. This software has been developed to help on the design conception of the detector and on understanding its operational characteristics in detail. The data generated by this software will be available to be employed on the development of estimation and detection algorithms intended to select the antineutrinos events and to estimate their energy.
306

The IceCube Neutrino Observatory: search for extended sources of neutrinos and preliminary study of a communication protocol for its future upgrade

Pinat, Elisa 27 June 2017 (has links)
English Version: When humans started looking out at a starry night, astronomy was born. Photons emitted by stars travel up to sometimes billions of light years to reach our eyes, and by studying the properties of this photon flux we are able to infer properties of the star itself. Instead of photons, the IceCube Observatory, located at South Pole, aims at detecting neutrinos and hopes to shed some light on the still unsolved mystery of cosmic-ray acceleration and production mechanisms, and on the most energetic phenomena of the Universe. At the time of this writing, IceCube has proven the existence of an astrophysical neutrino flux with a significance exceeding seven sigmas. Nevertheless, the observed astrophysical neutrino flux shows no significant directional clustering nor a clear association with any known source class so far. Also the latest results given by IceCube’s point source analysis show no significant clustering as well. It is therefore important to widen the search to different source topologies to maximize the discovery potential. In the first part of this work we present an extended source analysis with seven years of IceCube data, adding three years of data to the previous published work and implementing a novel likelihood formulation. Since the extensions of any potential sources are not known a priori, five different extensions have been considered, from 1° to 5°. No significant clustering is observed in any of the maps. The ability of IceCube to establish neutrino astronomy by finding neutrino sources is limited by the number of cosmic neutrinos measured. Despite the aforementioned discovery of an astrophysical flux, detailed spectral studies and searches for specific source locations in this signal remain a challenge with the event sample sizes available from the IceCube instrument. Therefore, a considerable expansion of the current detector, IceCube Gen2, is promoted, which includes the instrumentation of a 10 km3 volume, able to deliver substantial increases in the astrophysical neutrino sample for all flavors. Not only the hardware will be upgraded, but many systems will undergo improvements, such as communications and timing infrastructures. A new communication system has been investigated and is presented in the second part of this document. Binary Phase Shift Keying (BPSK), the simplest digital modulation technique, has been studied as possible communication technique for IceCube Gen2. / French Version: Quand les humains ont commencé à regarder le ciel étoilé, l’astronomie est née. Les photons émis par les étoiles voyagent parfois des milliards d’années lumière avant d’atteindre nos yeux, et c’est grâce à l’étude de ce flux de photons que l’on peut déduire les propriétés des étoiles mêmes. Au lieu des photons, l’Observatoire IceCube, situé au Pôle Sud, a pour but de détecter des neutrinos :il espère éclairer le mystère encore non résolu de l’accéleration et des mécanismes de production des rayons cosmiques, ainsi que des phénomènes les plus énergétiques de l’Univers. Au moment où ce document a été rédigé, IceCube a démontré l’existence d’un flux de neutrinos astrophysiques avec une signification statistique excédant sept sigmas. Cependant, le flux de neutrinos astrophysiques observé ne montre aucun regroupement directionnel significatif ni une évidence d’association avec aucune source connue à l’heure actuelle. De plus, les derniers résultats fournis par les analyses de sources ponctuelles de la collaboration IceCube ne montrent non plus aucun regroupement. Il est donc important d’étendre ces recherches vers des typologies de sources différentes pour maximiser le potentiel de son découverte. Dans la première partie de ce travail nous présentons une analyse de source étendue basée sur sept années de données d’IceCube, ce qui rajoute trois ans de données au travail précédemment publié tout en mettant en oeuvre une nouvelle formulation de maximum de vraisem- blance. Comme les extensions de sources potentielles ne sont pas connues à priori, cinq extensions différentes ont été considérées, de 1° à 5°. Aucun regroupement significatif n’a été observé sur aucune des cartes. La capacité d’IceCube de consolider l’astronomie neutrino en découvrant des sources de neutrinos est limitée par le nombre de neutrinos cosmiques mesuré. Malgré la découverte susmentionnée d’un flux astrophysique, les études détaillées de spectre ainsi que les recherches de sources spécifiques pour ce type de signal demeurent un défi, à cause de la limitation de taille disponible des échantillons avec l’instrument IceCube. Par conséquent, une expansion considérable du détecteur actuel, IceCube Gen2, est promue :elle inclut l’instrumentation d’un volume de 10 km3, apte à fournir une augmentation importante des échantillons de neutrinos de toutes les saveurs. Non seulement le hardware sera mis à niveau, mais de nombreux autres systèmes subiront des améliorations, comme les infrastructures de communication et de timing. Un nouveau système de communication a été étudié et est présenté dans la deuxième partie de ce document. Le Binary Phase Shift Keying (BPSK), la technique de modulation numérique la plus simple, a été étudiée comme technique potentielle pour IceCube Gen2. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
307

A search for a prompt atmospheric muon neutrino flux in the northern hemisphere using data releases from IceCube

Haberland, Marcus January 2020 (has links)
The IceCube Neutrino Observatory is a cubic kilometre scale detector for high-energy neutrinos above hundreds of GeV produced in Earth’s atmosphere as well as outside our solar system whenever particles are accelerated to ultra-relativistic energies. The prompt atmospheric contribution is a result of the creation of heavy mesons with charm components in the atmosphere. Past studies from IceCube using a maximum likelihood estimation over the whole neutrino energy spectrum always reported a best-fit zero prompt contribution so far [1–5], contrary to theory [6, 7]. In this analysis we tried to measure this prompt atmospheric flux in muon neutrino event data from different IceCube releases. In contrast to past studies we performed a binned least-squares fit of the conventional atmospheric flux from data at low energies and subtracted this fit and an astrophysical flux reported by IceCube to measure a prompt contribution. Due to a lack of statistics and accessible information from data releases, our results are also compatible with a zero prompt contribution.
308

Recherche de neutrinos lourds avec l'expérience T2K / Search for heavy neutrinos with the T2K experiment

Lamoureux, Mathieu 26 June 2018 (has links)
La masse non-nulle des neutrinos rend nécessaire l'introduction de nouvelle physique pour expliquer celle-ci. Par exemple, l'ajout de neutrinos lourds avec une masse de l'ordre du GeV permettrait d'expliquer à la fois la masse des neutrinos et l'asymétrie matière-antimatière dans l'Univers, comme cela est proposé dans le modèle nuMSM.Un domaine de masse particulièrement intéressant pour ces nouvelles particules est celui entre 140 et 493 MeV/c^2, qui est accessible avec les expériences actuelles, en particulier avec le détecteur proche ND280 de l'expérience T2K, expérience d'oscillation des neutrinos située au Japon.L'analyse vise à isoler un échantillon de désintégrations de neutrinos lourds dans ND280, après leur production dans la désintégration de kaons chargés dans le faisceau de T2K. Le bruit de fond provenant d'interactions de neutrinos a été réduit à quelques événements dans l'ensemble des données de T2K (2010-2017), ce qui permet de contraindre l'espace des paramètres des neutrinos lourds de manière compétitive par rapport aux expériences dédiées comme PS191.Une des étapes importantes de l'analyse consiste à valider les algorithmes de reconstruction et les simulations du bruit de fond attendu, ce qui a nécessité d'étudier les interactions de neutrinos actifs dans les murs des TPCs; Cet échantillon a également pu être utilisé pour des études de physique.Un dernier travail effectué durant cette thèse concerne la mise à niveau du détecteur ND280, prévue d'ici 2021, dans le but d'augmenter la précision des mesures de section efficace d'interaction des neutrinos afin d'améliorer les analyses des oscillations. / Non-zero neutrino mass requires the introduction of new physic beyond the Standard Model. For instance, the nuMSM (Neutrino Minimal Standard Model) predicts the existence of new heavy neutrinos, with masses at GeV-scale, that would explain both neutrino masses and baryon asymmetry in the Universe.A particularly interesting mass domain is between 140 and 493 MeV/c^2, which is accessible to current experiments, in particular with the near detector ND280 of the T2K experiment, which is a long baseline neutrino oscillation experiment located in Japan.The analysis aims at the selection of a sample containing heavy neutrino decays, after they have been produced in kaon decays along the standard T2K neutrino beam. Background coming from standard neutrino interactions has been reduced to few events in the current dataset (2010-2017), which allow to constrain heavy neutrino parameter space quite well with respect to dedicated experiments such as PS191.An important step in the analysis consists in the validation of the reconstruction algorithms and of the expected background. It has been done with the study of active neutrino interactions in the walls of the TPCs. This sample is also interesting per se for physics.A last topic in this thesis concerns the upgrade of the near detector, that is scheduled for 2021. The goal is to improve neutrino cross-section measurements in order to get more precise determination of oscillation parameters.
309

Search for high energy neutrinos from the Galactic plane with the ANTARES neutrino telescope / Recherche de neutrinos de haute énergie provenant du plan galactique avec le télescope à neutrino ANTARES

Grégoire, Timothée 18 September 2018 (has links)
Deux analyses sont présentées dans cette thèse. Une première analyse exploite les données du télescope à neutrino ANTARES pour sonder la présence d'un flux de neutrino diffus galactique. Cette analyse se base sur un modèle récent de propagation des rayons cosmiques dans la galaxie, le modèle KRAγ. Ce modèle prédit un flux de neutrinos particulièrement élevé et proche de la sensibilité des télescopes à neutrinos actuels. Il existe deux versions de ce modèle correspondant à différentes coupures sur l'énergie des rayons cosmiques, à 5 et 50 PeV/nucléon. Une méthode de maximisation d'une fonction de vraisemblance est utilisée pour prendre en compte les caractéristiques du modèle, autant spatiales qu'en énergie. Cette analyse a également été combinée avec les données de l'expérience IceCube dans le but d'exploiter au mieux les données actuelles. Des limites ont été mises sur ce modèle rejetant la version avec une coupure à 50 PeV et limitant la version avec une coupure à 5 PeV à moins de 1,2 fois le flux prédit par le modèle. Une deuxième analyse de suivi du signal d'ondes gravitationnelles GW170817 par le télescope à neutrino ANTARES est également présentée. Le signal d'onde gravitationnelles GW170817 résulte de la coalescence d'une binaire d'étoiles à neutrons. Cette deuxième analyse a pour objectif de sonder la présence d'un flux de neutrinos provenant de cet événement en cherchant des neutrinos corrélés spatialement et temporellement. J'ai pris part à cette analyse en y ajoutant les événement de type cascade. Aucun événement n'a été détecté en corrélation, des limites ont été mises sur le flux de neutrino attendu. / Two analyses are detailed in this thesis. A first analysis exploit the data of the ANTARES neutrino telescope to probe the presence of a Galactic diffuse neutrino flux. This analysis is based on a recent model of cosmic ray propagation in the Galaxy, the KRAγ model. This model predict a neutrino flux particularly high and close to the sensitivity of the current neutrino telescopes. Two versions of this model exist corresponding to different cuts in the cosmic ray energy, one at 5 PeV/nucleon and an other one at 50 PeV/nucleon. A method of maximization of a likelihood function is used in order to account for the model characteristics in energy and space. The analysis has also been combined with the data of the IceCube experiment in order to exploit all the available data. Limits have been put on this model rejecting the version of the model with the 50 PeV cut and limiting the version with the 5 PeV cut to less than 1.2 times the predicted flux.A second analysis of gravitational wave signal follow-up by the ANTARES neutrino telescope is also presented in this work. The GW170817 gravitational wave signal results from the coalescence of a binary neutron star system. This second analysis aims at probing the presence of a neutrino flux coming from this event looking for neutrino events correlated in space and time. I took part to this analysis by adding the shower-like event sample. No event has been detected in correlation, limits have been put on the expected neutrino flux.
310

Measurement of proton and alpha-particle quenching in LAB based scintillators and determination of spectral sensitivities to supernova neutrinos in the SNO+ detector

von Krosigk, Belina 26 June 2015 (has links)
SNO+, the successor of the Sudbury Neutrino Observatory, is an upcoming low energy neutrino experiment, located in the 2 km deep laboratory SNOLAB, Canada. The spheric acrylic vessel in the detector center will contain 780 t of LAB. The main goal of SNO+ is the search for the neutrinoless double beta decay of 130Te, using a novel scintillator in which natural Te is bound with an initial loading of 0.3% via water and a surfactant. Within this thesis, the first measurement of the Alpha-particle and proton quenching parameters of loaded and unloaded LAB is described. These parameters are crucial for an efficient background suppression, necessary to reach a sensitivity above the current limit in 76Ge of T1/2(0v) > 2.1 x 10^(25) y (90% C.L.). For 0.3% Te-loading, the quenching parameter obtained is kB = (0.0070 +/- 0.0004) cm/MeV for Alpha-particles and kB = (0.0090 +/- 0.0003) cm/MeV for protons. Additionally, the spectral sensitivity of SNO+ to supernova electron anti-neutrinos and muon and tau (anti-)neutrinos is determined for the first time, using inverse beta decay and v-p elastic scattering with the measured quenching parameters. The obtained sensitivity to the mean energy of electron anti-neutrinos is E = 15.47^(+1.54)_(-2.43) MeV and of muon and tau (anti-)neutrinos is E = 17.81^(+3.49)_(-3.09) MeV. / SNO+, der Nachfolger des Sudbury Neutrino Observatorys, ist ein bevorstehendes Niederenergie-Neutrino-Experiment im 2 km tiefen Untergrundlabor SNOLAB in Kanada. Die Acryl-Kugel im Zentrum des Detektors wird mit 780 t LAB gefüllt werden. Das Hauptziel von SNO+ ist die Suche nach dem neutrinolosen Doppelbetazerfall von 130Te mit einem neuartigen Szintillator, in dem natürliches Te mit einer Anfangskonzentration von 0.3% über Wasser und ein Tensid gebunden wird. In dieser Arbeit wird erstmals die Messung der Alpha-Teilchen und Proton Quenching Parameter in diesem und in normalem LAB beschrieben. Die Parameter sind unverzichtbar für eine effiziente Untergrund Unterdrückung, die notwendig ist um auf das bestehende Limit in 76Ge von T1/2(0v) > 2.1 x 10^(25) y (90% C.L.) sensitiv zu sein. Der ermittelte Quenching Parameter bei 0.3% Te beträgt kB = (0.0070 +/- 0.0004) cm/MeV für Alpha-Teilchen und kB = (0.0090 +/- 0.0003) cm/MeV für Protonen. Zusätzlich wird erstmals die spektrale Sensitivität von SNO+ auf Supernova Elektron Anti-Neutrinos und Muon and Tau (Anti-)Neutrinos bestimmt über den inversen Betazerfall und die elastische v-p Streuung zusammen mit den gemessenen Quenching Parametern. Die ermittelte Sensitivität auf die mittlere Energie der Elektron Anti-Neutrinos ist E = 15.47^(+1.54)_(-2.43) MeV und der Muon und Tau (Anti-)Neutrinos ist E = 17.81^(+3.49)_(-3.09) MeV.

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