Une radiothérapie efficace nécessite un dépôt de dose localisé à la tumeur, et donc un contraste entre le tissu tumoral et les tissus sains environnants. Une irradiation de basse énergie monochromatique au synchrotron d'une tumeur chargée en éléments lourds permet de maximiser l'interaction photoélectrique dans la tumeur et d'épargner les tissus sains, car les photoélectrons et les électrons Auger produits ont un TEL très élevé et déposent leur énergie autour des éléments lourds, augmentant fortement le dépôt de dose. Ils peuvent induire des dommages à l'ADN (cassures double brin) fortement létaux. Un autre phénomène permet également de promouvoir l'émission d'électrons Auger et d'augmenter ainsi la dose, l'effet Mössbauer. Cette interaction résonante et sans recul spécifique à certains isotopes dont le 57Fe présente une section efficace 450 fois plus importante que celle de l'effet photoélectrique. Ce travail de doctorat a évalué l'utilisation in vitro de nanoparticules de magnétite combinées à ces deux effets physiques. Les nanoparticules présentent une internalisation et une distribution dans les cellules F98 qui sont très propices à la radiosensibilisation : de grandes concentrations proches du noyau des cellules, et peu de toxicité ont été obtenues. Ceci a permis d'obtenir par photoactivation des NPFe un facteur d'augmentation de 3 ce qui est considérable. Ce travail multidisciplinaire rassemble des expériences de physique, de biologie et de chimie, pour évaluer les applications de nanoparticules de fer à la radiothérapie. / An efficient radiotherapy needs a localized dose to the tumour, which means a high contrast between tumorous and healthy tissues. A synchrotron low energy monochromatic irradiation of a tumour charged in high-Z elements allows maximizing photoelectric interactions in the tumour and spare the healthy tissues. Photoelectrons and high LET Auger electrons thus produced deposit their energy locally, enhancing radiation dose to tumor cells. Another interaction allows to enhance the dose by Auger electrons: the Mössbauer effect. This resonant and recoilless interaction specific to some isotopes like 57Fe has a cross section 450 times bigger than photoelectric effect. This thesis evaluates the in vitro use of magnetite nanoparticles combined with those 2 types of interactions. The nanoparticles evaluated present a high internalisation and a perinuclear distribution inside F98 cells. A dose-enhancement factor of 3 was obtained by photo activation of the iron Nps, this represents a huge increase. This multidisciplinary work encompasses experiments in chemistry, physics and biology in order to evaluate the applications of magnetite nanoparticles to radiotherapy.

Orientador: Jose Augusto Chinellato / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-10T12:36:27Z (GMT). No. of bitstreams: 1 Muller_MarcioAparecido_D.pdf: 7258738 bytes, checksum: 730b20e67024246249997d646e724bed (MD5) Previous issue date: 2007 / Resumo: Este projeto contribui para a caracterização do sinal da passagem da frente de um Chuveiro Atmosferico Extenso no Detector de Superficie do Observatório Pierre Auger. Usando uma simulação do módulo básico do Detector de Superfície, que é um tanque Cherenkov, foi realizado um estudo do sinal depositado para cada tipo de partícula da frente do Chuveiro Atmosférico Extenso, individualmente, e depois da razão entre os sinais provenientes da componente hadrônica e das componentes comumente consideradas (componente eletromagnética + componente muônica) para alguns casos. Foram injetadas no tanque, individualmente, as partículas que ocorrem num Chuveiro Atmosférico Extenso, com valores discretos de energia no intervalo de eV até 10 TeV . Com isso, obtivemos "curvas resposta" do detector para cada partícula - essas curvas são equivalentes a distribuições de probabilidade para o número de fótons coletados (fótons que efetivamente geraram sinal nas fotomultiplicadoras) no tanque Cherenkov. Do conjunto de valores discretos de "curvas resposta", obtivemos, por interpolação, expressões gerais cobrindo toda a faixa de energia acima citada, ou seja, obtivemos uma parametrização geral do sinal (ainda preliminar, com pequenas melhorias numéricas a serem feitas), para qualquer partícula e a qualquer energia. Segundo testes já feitos, tal parametrização deve implicar em economia de tempo de processamento da ordem de milhares de vezes, o que será útil para futuros cálculos no projeto Auger. Partindo de chuveiros simulados na atmosfera através do software Corsika e usando a parametrização geral acima citada, obtivemos a razão da contribuição dos hádrons com relação 'as demais componentes da frente do chuveiro, nas condições do Observatório, ou seja, nas faixas de energia acima de 10 18 eV , para diferentes primários e na geometria típica do Observatório Pierre Auger. Conhecendo tais fatores, poderemos contribuir para uma calibração do sinal, de modo a poder corrigir a estimativa da energia do primário do chuveiro, que entra no cálculo do uxo de raios cósmicos primários. Esse é um item de bastante interesse na área. Nos cálculos deste trabalho, adicionamos ao tratamento tradicional das interações hadrônicas, o regime de baixas energias do Geant4. No nosso caso, merecem atenção especial as interações de nêutrons, principalmente porque o alvo considerado além dos tanques Cherenkov do Observatório inclui uma camada de solo abaixo deles, onde os nêutrons podem dar contribuição significativa. Dado que o sinal dos tanques é usado em várias condições de "trigger" para a determinação da energia do primário, teremos condições de computar a contribuição dos hádrons (principalmente nêutrons), com seu sinal e suas flutuações, para as incertezas nessa energia. Estamos contribuindo para um objetivo básico do Observatório Pierre Auger, que é estimar a energia do raio cósmico primário no topo da atmosfera / Abstract: This project contributes to the effort of characterizing the passage of Extensive Air Shower fronts through the Surface Detector of the Pierre Auger Observatory. Using a Geant4 simulation of the Cherenkov tank that is basic module of the SD, we performed a study on the electronic signal for each kind of shower particle individually at first, and then on the signal ratio between hadronic and electromagnetic + muonic component, for some cases. The particles that occur in a Extensive Air Shower were injected into the tank individually, with discrete energy values in the range eV up to 10 TeV , with randomly distributed coordinates. Thus we obtain, for each particle "response curves" which works equivalent as a the probability distribution for the number of collected photons (these photons generated a signal in the photo-multipliers). From the set of discrete samples of "response curves", we obtain, by interpolation, general expressions that cover the entire range of energies - i.e., we obtain sets of parameters of the signal (still preliminary, with small numerical improvements to be made), for any particle, at any energy in the above mentioned range. According to tests, this parametrization results in a remarkable improvement to the CPU time - the simulation turns out to be some thousand times faster than the extensive calculation. This will be usefull for future calculations in the Auger project. Starting from Corsika simulated air showers, using the parametrization above mentioned, we obtain the mentioned ratio of the signal (hadronic to eletromagnetic + muonic component), range energy above 10 18 eV , for different primaries. Since the contribution of hadrons (signal plus uctuations) is, in general not taken into account in shower reconstruction, this study can contribute to a better characterization of the signal in the tank and thus to the estimate of shower primary energy. In our calculations, we added to the commonly used treatment of hadronic interactions, the low energy regime of Geant4. In particular, neutrons deserve special treatment, mainly because in addition to the Cherenkov tank itself, we considered another target, which is a soil layer under the tank - where neutrons can make significant contribution to the signal. Including the hadron contribution (signal and uctuations) to the whole tank signal, under different trigger conditions, we will be able to contribute to a better estimation of primary energy, mainly for its uctuations. We are contributing to a basic goal of the Observatory, which is to estimate the energy of the primary cosmic ray at the top of the atmosphere and thus the primary ux / Doutorado / Física das Particulas Elementares e Campos / Doutor em Ciências

Orientador: Carola Dobrigkeit Chinellato / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-17T01:52:06Z (GMT). No. of bitstreams: 1 Souto_BrunoFontes_M.pdf: 1947654 bytes, checksum: a1d7f70ebf2510a975c39b16829bf94a (MD5) Previous issue date: 2010 / Resumo: O objetivo deste trabalho é aplicar umteste que visa determinar se as direções de chegada dos raios cósmicos de energias mais altas (> 1019 eV) observados pelo Observatório Pierre Auger seguem uma distribuição isotrópica. Sua principal vantagem é dispensar o uso de catálogos de objetos astrofísicos. Igualmente, procura-se uma correlação das direções de chegada com a região conhecida como Plano Supergaláctico. Dá-se ênfase na motivação, interpretação e na visão geral sobre anisotropia de raios cósmicos surgida nos últimos anos. O resultado obtido com os dados atuais neste trabalho é que de fato existe uma anisotropia nas direções de chegada, embora esta ainda seja difícil de caracterizar / Abstract: In this work, we apply a test designed to answer the question of whether the arrival directions of the highest energy (> 1019 eV) events observed by the Pierre Auger Observatory are consistent with being drawn from an isotropic distribution. Its main advantage is that the method does not rely on any catalogue of astrophysical objects. Furthermore, a correlation of the arrival directions with the region known as Supergalactic Plane is investigated. Emphasis is put on motivation, interpretation and on the global picture of cosmic ray anisotropy that has emerged during the last years. The result found so far from the current data in this work is that an anisotropy in the arrival directions indeed exists, even so it is still difficult to characterize / Mestrado / Raios Cósmicos / Mestre em Física

Orientador: Anderson Campos Fauth / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-13T19:51:37Z (GMT). No. of bitstreams: 1 Consalter_DanielMartelozo_M.pdf: 4699027 bytes, checksum: 410a5e77c9dca5e205ac6f413844f032 (MD5) Previous issue date: 2009 / Resumo: Os raios cósmicos de mais altas energias são hoje foco da atenção de muitos físicos ao redor do mundo.Estas partículas chegam a atingir energias acima 10 18 V,o equivalente a uma bola de baseball a 300 km/h,mas mecanismos de aceleração, propagação assim como a região onde são produzidos ainda são desconhecidos pela comunidade científica. Isso ocorre devido a dificuldade na detecção destas partículas, pois seu fluxo é baixíssimo: uma região com 1 km 2 de área é atingida por uma partícula por sr por ano. Este baixo fluxo obriga a construção de gigantescos experimentos como é o caso do Observatório Pierre Auger (OPA). Construído nos pampas argentinos, o OPA conta com 4 conjuntos de telescópios detectores de fluorecência atmosférica 1600 tanques detectores de radiação Cherenkov na água. A união das duas técnicas torna o Observatório Pierre Auger um detector híbrido. Este trabalho pode ser dividido em duas partes principais,sendo que a primeira consistiu no estudo do tanque Cherenkov instalado no Laboratório de Léptons da Universidade Estadual de Campinas, idêntico aos instalados no site do hemisfério Sul do Observatório Pierre Auger. Primeiramente finalizamos a instalação do detector, na qual instalamos novos componentes eletrônicos, escrevemos o software de aquisição de dados resolvemos o problema de umidade interna do ar que danificava os componentes eletrônicos instalados no tanque. Após a instalação completa, realizamos a caracterização do detector para múons atmosféricos individuais, selecionados a partir de um telescópio de múons formado por dois detectores cintiladores. Foi medido o tempo morto do sistema de aquisição de dados,determinadas as tensões de trabalho de cada uma das três fotomultiplicadora (PMT)e medida a carga do sinal produzido pelo múon passando verticalmente no centro do tanque,o VEM,obtendo 100 pC para o valor do pico do espectro de carga. Ao medirmos a resposta do sinal em função da distância entre a PMT a posição de passagem do múon vertical no tanque, pudemos observar uma dependência da carga média do tempo de atraso do sinal em função desta distância, na qual a soma da carga nas 3 PMTs manteve-se constante. Além disso, observamos que, nas medidas as quais o múon passa pela fotomultiplicadora, existe um pico duplo no espectro de tempo, sendo o primeiro pico produzido pelo sinal proveniente da interação do múon com o fotocátodo da PMT o segundo pelo sinal produzido pela passagem do múon na água. Finalizamos com a medida da resposta do sinal para múons selecionados inclinados na qual pode-se observar da linearidade da proporção entre a carga média do sinal e a quantidade de luz produzida pela passagem da partícula. A segunda parte do trabalho consistiu em analisar os dados detectados pelos detectores de superfície do Observatório Pierre Auger, no qual primeiramente, instalamos os softwares necessários para a realização da análise de dados através do ADST-OFFLINE. Foram analisados os raios cósmicos detectados desde 01 de janeiro de 2004 até 31 de dezembro de 2008 com energia acima de 3x1018 e V ângulos zenitais de direção de chegada entre 0 o e 60o. A partir destes dados construímos espectros diferenciais de fluxo de raios cósmicos para cada ano integrados a cada ano. A partir da análise destes gráficos pudemos confirmar que a partir de 2007 os número de eventos é suficiente para confirmar a supressão do fluxo de partículas com energia acima de 4x1019 e V devido ao efeito GZK. Confirmamos também que o espectro de raios cósmicos de altas energias é bem representado pela função F µ E -g ,cujo valor obtido para g do espectro construído a partir dos dados ntr 01 de janeiro de 2004 até 31 de dezembro de 2008 foi 2,69 ± 0,04 para o intervalo de energia entre 4x10 18 e V e 4x1018 e V e 3,5 ± 0,5 para energias acima de 4x1019 e V. / Abstract: The high energy cosmic rays actually are the center of attention of many physics around the world.These particle have energy above, equivalent a baseball with 300km/h, but the mechanism of acceleration, propagation even like the region that they are originated still unknown for the scientific community, fact that occurs due the difficult of detection from thes particles, because their flux is very low: a surface of 1 km 2 area is reached for one high energy particle per sr per year. This low flux obligates the build of giants experiments like Pierre Auger Observatory (PAO).Built in Malargue, Argentina,the PAO has 4 atmospheric fluorescence detectors and 1600 water Cherenkov tanks .The union of these two techniques made PAO a hybrid detector. This work can be divided in two principal parts, being the first a study of the water Cherenkov tank install d at Campinas that is identical of the tanks from South site of the Pi rre Auger Observatory. Firstly, we made a complete installation of the detector, in which was installed new electronic components, the data acquisition software was written and the internal humidity problem, that damages the electronic components, was solved. After the installation, we made a detector characterization using atmospheric muons selected by a muon telescope (2 scintillator detectors). We measured the dead time , working high voltage of each photomultiplier (PMT) and the medium charge produced by the vertical muon crossing the tank center (VEM), which value found was 100 pC. Measuring the signal dependence with the distance between the PMT and the position of the vertical muon, we could observe a decrease of the charge and increases of the time delay when this distance increase. But the sum of the charges in the 3 PMT kept constant. In addiction, we observed that, in the measure that the muons cross the photomultiplier there is a double peak in the time spectrum, being the first peak due the muon interaction with the photocathode and the second one by the Cherenkov light produced by the muon crossing the water. We completed the charact rization with the measurement of signal provided by inclined muon selected by the same telescope. These measurements show us the proportionality between the charge of the signal and the quantity of produced light by the particle. The second part of the work was the data analysis of the Pierre Auger surface detectors, in which firstly, we installed the software necessary to data analysis by ADST-OFFLINE. It was analyzed cosmic rays detected since 01 January 2004 until 31 December 2008 with energies above 3x1018 e V and zenith angle between 0o e 60o. From these data, we built differential cosmic rays spectra for each year and integrated yearly. This analysis shows that from 2007 the number of events is enough to confirm the flux suppression above 4x1019 e V due GZK effect. We also confirm that the high energy cosmic rays spectrum is well represented by the function F ¥ E,-g ,which g value measured for the spectrum with data acquired between 01 January 2004 and 31 December 2008 was 2,69 ± 0,04 in the energy range from 4x1018 e V until 4x1019 e V and 3,5 ± 0,5 for energy above 4x1019 e V. / Mestrado / Física das Particulas Elementares e Campos / Mestre em Física

Orientador: Ernesto Kemp / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-14T11:18:31Z (GMT). No. of bitstreams: 1 Almeida_RogerioMenezesde_D.pdf: 29880310 bytes, checksum: a6d709505699fa646136930c8822d569 (MD5) Previous issue date: 2009 / Resumo: Quase um século após o descobrimento da radiação cósmica, sua origem, composilção, mecanismos de aceleração e propagação pelo universo são ainda desconhecidos para a faixa de energia ultra-alta (E >~ 10 18 eV). O mistério torna-se ainda maior devido à supressão (corte GZK) no uxo dos raios cósmicos com energias E >~ 6 × 10 19 eV, devido à interação destas partículas com a radiação cósmica de fundo, previsto há cerca de 40 anos. Assim, espera-se que os raios cósmicos com energia acima deste limiar sejam provenientes de fontes distantes em até ~ 200 Mpc. Uma vez que nosso universo local é bastante heterogêneo e a rigidez magnética destas partículas é bastante elevada, espera-se que a distribuição das direções de chegada dos raios cósmicos de energia ultra-alta possa ser correlacionada com as direções de suas fontes, refletindo a anisotropia do universo local. Neste sentido, estudos de anisotropias nas direções de chegadas de tais partículas desempenham papel crucial na investigação da radiação cósmica e compreensão do universo. Este trabalho dedica-se ao estudo de anisotropias de pequena e larga escalas. No primeiro caso, procuramos UHECR¿s correlacionados com o surto gigante de radiação gama emitido pelo SGR 1806-20 em dezembro de 2004. Outro caso estudado é a análise de direções da esfera celeste com excessos de raios gama com significâncias estatísticas maiores que 4s, não associadas a fontes conhecidas, reportadas pela Colaboração JANZOS. Ainda com relação a anisotropias de pequena escala, são estudadas aplicações de filtros de wavelets para detecção de fontes pontuais. No contexto de anisotropias de larga escala, relacionadas a grandes distribuições de matéria, desenvolvemos um método de identificação de anisotropias independente de catálogos de objetos celestes, chamado MIIE. Testamos sua eficiência através de testes de hipóteses e o aplicamos a conjunto de eventos com energia extrema obtidos de dados do Observatório Pierre Auger / Abstract: Almost a century after the discovery of cosmic radiation, their origin, composition, acceleration and propagation mechanisms in the universe is still unknown for the ultra-high energy component ( > ~ 1018 eV). The mystery grows due to the suppression (GZK cutoff) in the ux of cosmic rays with energies E >~ 6 × 10 19 eV, caused by the interaction of these particles and the cosmic microwave background, predicted ~ 40 years ago. Thus, it is expected that cosmic rays with energy above this threshold are produced in sources within ~ 200 Mpc. Since our local universe is very inhomogeneous and the magnetic rigidity of these particles is very high, it is expected that the distribution of the arrival directions of ultra-high energy cosmic rays can be correlated with the directions of their sources, reflecting the anisotropy of our local universe. In this way, anisotropy studies play crucial role in the research of cosmic radiation and understanding of the universe. In this work, small-scale anisotropy, related to the study of point sources, are studied searching for UHECR¿s correlated with the giant are from SGR 1806-20 in December 2004. We have also analized directions with an excess of gamma rays with statistical significance S > 4s, not associated with any known sources, reported by the JANZOS Collaboration. Also, in this thesis wavelets are applied in the detection of point sources. In the context of anisotropy related to large distributions of matter, called large scale anisotropy, we propose a new anisotropy identification method independent of catalogs, so-called MIIE. We test its efficiency through hipothesis tests and apply it to events set obtained from the Pierre Auger data / Doutorado / Física das Particulas Elementares e Campos / Doutor em Ciências

L’origine et la composition des rayons cosmiques demeurent, presque un siècle après leur découverte, une question ouverte, certains résultats des expériences de détection des rayons cosmiques se contredisant même, aux énergies supérieures à 10¹⁸ eV. A ces énergies, le flux reçu sur Terre est si faible qu’une détection directe est impossible sur une échelle de temps raisonnable. La collaboration Pierre Auger a ainsi construit dans la Pampa argentine, un observatoire couvrant une surface de 3000 km² afin de déterminer les énergies, les masses et les directions d’arrivée des rayons cosmiques. Les techniques de détection déployées font de l’Observatoire Pierre Auger une référence dans le domaine des Ultra-Hautes Énergies. Durant les trois années de mon doctorat, il m’a été donné l’opportunité d’étudier les méthodes de détection déployées par cette expérience et de m’intéresser spécialement à son détecteur de surface dont l’extraction du signal jusqu’à la reconstruction des directions d’arrivée et des énergies des rayons cosmiques sont présentées dans ce manuscrit avec les optimisations développées, permettant l’établissement du spectre des rayons cosmiques. L’étude de ce spectre, combinée à celle des observables de composition, obtenues par le détecteur de fluorescence, permet son interprétation en terme de masse afin de contraindre les modèles d’accélération et de propagation dans le milieu Galactique ou extragalactique. / The origin and the composition of the cosmic rays, almost one century after their discovery, remain an open question. Results of some experiments dedicated to their detection are even contradicting themselves at energies above 10¹⁸ eV. At these energies, the flux of the cosmic rays reaching the Earth is so low that direct detection is unthinkable in a reasonable time scale. The collaboration Pierre Auger has thus built, in the Argentine Pampa, an observatory covering an area of 3000 km² to determine the energies, masses and arrival directions of cosmic rays. Deployed detection techniques make the Pierre Auger Observatory a reference in the field of Ultra-High Energy. During the three years of my thesis, I had the chance to study the detection methods deployed by this experiment, focusing on its surface detector from the extraction of its signal to the reconstruction of the arrival direction and energy of the cosmic ray, which are presented in this manuscript along with the optimizations developed. The energy spectrum of cosmic rays is then reconstructed. The study of this spectrum, combined with the observables of composition, deduced from the fluorescence detector, allows its interpretation in term of mass. Acceleration and propagation models in Galactic or extragalactic environment can then be constrained by this combined study.

Envenimée sous la Restauration, la querelle des classiques et des romantiques se joue en clair-obscur. Fils de la Révolution, le romantisme français se fait d’abord ombre du classicisme qui, sûr de sa splendeur, pourtant s’éteint. La décennie 1820 s’impose comme une période de transition au cours de laquelle l’obscure « nouvelle école » va détrôner la tradition classique pour conquérir sa part de lumière. Ce récit de l’exploit romantique, jusqu’ici, l’histoire littéraire n’en rend compte que par la seule voix des vainqueurs de la bataille. Cependant, lumière et ombre vont de pair, l’histoire du romantisme appelle une autre version pour en compléter la compréhension, version racontée par les défenseurs de la doctrine classique. Partant de cette hypothèse, la présente étude, consacrée à la période 1824-1834, se propose de revisiter ¬quelques grands moments de controverse sur le romantisme dans toutes ses problématiques. On verra ainsi Deschamps réagir à la condamnation académique d’Auger, le duel entre Hoffman et Hugo se poursuivre autour de la question poétique ou encore Janin et Nisard s’affronter sur la condition littéraire après 1830. Les tenants du romantisme ont tort de croire qu’ils l’ont inventé tout seuls ; cette nouvelle pensée esthétique, au contraire, s’est forgée à coups de conflits d’intérêts politiques et littéraires. Dans cette perspective, reconstituer l’enchevêtrement du classicisme et du romantisme permettra de mieux comprendre comment ces deux courants littéraires ont chacun pu construire l’image de soi en même temps que celle de l’autre. / The literary controversy between Classicism and Romanticism represents itself as a drama of light and shadow. Romanticism in the beginning was a shadow of the Classicism that, although proud of its past glory, began to decline. The decade 1820-1830 can be defined as a transition period, during which the obscure “newcomer” dethrones the “old champ”. French literary history has so far recounted this glorious story of the Romantics by referring exclusively to what they told. In other words, little has been done to examine the literary controversy seen by its losers. However, light and shadow go together; so to understand the history of Romanticism as a whole, it is necessary to complete it with another version told by the defenders of classical doctrine. With this in mind, this study attempts to revisit the decade 1824-1834 and to examine some historical controversies covering a wide range of subjects related to French Romanticism: thus we will be concerned with the anti-romantic speech of the academician Louis-Simon Auger that raised objections from Romantics such as Émile Deschamps, the debate between François-Benoît Hoffman and Victor Hugo about the poetic use of “image” or that of Désiré Nisard and Jules Janin about the condition of literature after the July Revolution of 1830. Romantics are wrong to consider Romanticism as their own creation. On the contrary, this new esthetic movement has been established through various conflicts between classical and romantic schools. From this point of view, analyzing their controversies will make it possible to understand how these two literary movements have created their own image as well as that of their opponent.

published_or_final_version / abstract / toc / Physics / Master / Master of Philosophy

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Les mécanismes de formation et de croissance des films d'oxydes à la surface des bronzes Cu-Sn sont encore peu connus. Dans ce contexte, cette étude a pour objectif de lever l'ambiguïté concernant la nature, la structure et la localisation des produits de corrosion formés à la surface des bronzes. Pour cela des électrodes de bronze ont été élaborées, mises en forme, puis oxydées par immersion et par polarisation anodique en milieu sulfate à 10 2 mol.L-1. Les espèces ainsi formées en surface sont ensuite réduites en mode galvanostatique. Les courbes font apparaître des paliers caractéristiques des réactions électroniques qui opèrent à l'électrode. Les valeurs de potentiel correspondant aux différents paliers sont comparées à celles obtenues sur des composés modèles. Cette étude comparative permet d'attribuer certains paliers à certains composés mais pas tous.Pour compléter l'identification, la diffraction des rayons X, la spectroscopie Mössbauer et la micro-spectrométrie Raman ont été mises en œuvre afin d'observer la présence d'oxyde d'étain (+ IV) en plus des composés du cuivre. La spectroscopie d'électrons Auger et la spectroscopie de photoélectrons X (XPS-AES) ont permis une analyse en profondeur des films par érosion progressive de la surface, qui a révélé qu'en premier lieu un film d'oxyde d'étain se forme à la surface de l'alliage Cu-Sn et, qu'ensuite, une couche d'oxyde de cuivre croit à l'interface oxyde/électrolyte. Les observations effectuées par microscopie électronique en transmission (MET) confirment ces résultats. Dans un second temps, les techniques électrochimiques conventionnelles, et plus particulièrement la spectroscopie d'impédance électrochimique, ont été utilisées afin d'identifier la structure des couches ainsi que les processus mis en jeu lors de l'oxydation. Elles ont permis d'en déduire un mécanisme réactionnel d'oxydation possible / Formation and growth mechanisms of oxides films on monophased copper-tin bronzes are still in discussion. In the literature two different patterns of corrosion are exposed. The first one claims that the bronze corrosion is similar to that of copper whereas the second one asserts that the copper-tin alloys oxidation lead to a double layer structure. The inner layer is enriched in tin consequently to copper selective dissolution. The outer layer is essentially composed of copper oxides.To The present study deals with the chemical-physical and electrochemical characterisations of artificial patinas, thin layer of corrosion products electrochemically formed at the surface of copper-tin alloys. A bronze containing 7 wt% of tin is oxidised in a 10-2 mol.L-1 desaerated sulphate solution, buffered at pH = 6.8. The synthesised species are cathodically reduced. The successive steps of the potential vs time curves, characteristic of the electrochemical reactions occurring at the electrode surface, are successfully calibrated with reference oxides.In order to complete the previous results, X-Ray Photoelectron Spectroscopy (XPS) depth profiles are carried out by abrading progressively the oxidised surface. The deconvoluted XPS and Auger Electron Spectroscopy (AES) spectra speak in favour of an “alloy/SnO2/Cu2O” layered structure similar to that reported in the literature. Analyses carried out on the oxidised samples by Transmission Electron Microscopy (TEM) confirm this pattern.The characterisation techniques carried out on archeological artefacts produce conclusions that are compared to those obtained on the electrochemical samples. This multi analytical study gives crucial piece of information. The reactional sequence that will be deduced is an essential tool for the good preservation of the world cultural heritage