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Literatura académica sobre el tema "Imagerie et spectroscopie UV-EUV"
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Tesis sobre el tema "Imagerie et spectroscopie UV-EUV"
Handschin, Charles. "Spectroscopie EUV résolue temporellement à l'échelle femtoseconde par imagerie de vecteur vitesse et génération d'harmoniques d'ordres élevés". Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00944627.
Texto completoDolliou, Antoine. "L'impact de petits événements brillants UV-EUV sur le chauffage coronal du Soleil calme : analyse de données de Solar Orbiter et simulations hydrodynamiques de boucles magnétiques". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP112.
Texto completoThe Solar corona temperature is maintained at more than 1 MK. One of the main theories of the coronal formation (Parker, 1988) suggests that the magnetic energy is dissipated into the corona through a high number of impulsive, low energetic (1E24 ergs) heating events, called “nanoflares.” On 30 May 2020, during its first high temporal and spatial resolutions observations, 1463 small (400 - 4000 km) and short-lived (10-200 s) EUV brightenings, referred to as “events”, were detected in the Quiet Sun (QS) by the high-resolution UV imager HRIEUV (174 Angström), on board Solar Orbiter. I tested the possibility that they might be signatures of nanoflare heating.As HRIEUV is sensitive to continuous temperature coverage, in particular between 1 MK and 0.3 MK, my goal was to verify if these events do reach coronal temperatures and, thus, if they contribute directly to the coronal heating.For the 30 May 2020 dataset, only SDO/AIA data were available to perform temperature diagnostics. To do so, I applied the “time lags” method to the coronal channels of AIA. This method provides signatures on plasma cooling or heating above 1 MK, as most AIA channels have their sensitivity peak at these temperatures. I compared the statistics between the events and the rest of the QS and concluded that the events are characterized by short time lags below the AIA cadence of 12 s. These results were confirmed by extending the study to later datasets using a higher AIA cadence of 6s. I proposed two possible interpretations: (1) the events peak below 1 MK, where the AIA response functions behave similarly; (2) the events' cooling time scale is too short to be resolved by the AIA cadence. Spectroscopic observations are thus necessary to better constrain the temperature of these events.To complete this work, I used co-temporal 2022 and 2023 QS data from HRIEUV, AIA (imagers), from Solar Orbiter/SPICE and HINODE/EIS (spectroscopy). I first detected events in HRIEUV and identified them in SPICE or EIS and in AIA. Then, I extracted the light curves from spectral lines emitted in a wide range of temperatures and applied spectroscopic diagnostics to derive the density as a function of temperature. I concluded that the emission of these events mainly originates from plasma below 1 MK. As such, most of them hardly contribute directly to the coronal heating.In order to understand the physical properties driving these events, I reproduced their observational signatures using the HYDRAD 1D hydrodynamics code. To do so, I computed the synthetic light curves from different models of short loops submitted to impulsive heating by changing parameters such as the loop length or the heating strength. I looked for the models that best reproduce the observations, including the light curves co-temporal peak. The work compares the results for two different types of loops that have very distinct properties: “hot” (T > 1E5 K) and “cool” (T < 1E5 K) loops. The results showed that cool loops submitted to impulsive heating are good candidates to explain the origin of most of the events detected by HRIEUV.To conclude, most of these events are probably not the signature of coronal heating phenomena, unless their coronal emission is below the instrumental limitations. One consequence of this work would be to reconsider their role in heating the QS corona, as they might instead provide a major contribution to the heating of the cooler lower solar atmosphere
Denneval, Charline. "Design, synthèse et évaluation de contrastophores bimodaux pour l'imagerie par absorption à deux photons et par tomographie par émission de positons". Thesis, Rouen, INSA, 2014. http://www.theses.fr/2014ISAM0012/document.
Texto completoThe purpose of this subject has been the synthesis of a bimodal probe using TPA–PET techniques for a potential application in biological imaging.In this context, we have synthesized a new range of A–π –D fluorophores incorporating diazine (p-deficient heterocycle) as electron-withdrawing moiety, N,N-dimethylaniline as electron-donating part and fluorene as p-conjugated linker. In order to increase the conjugation along the scaffold, ethynyl and/or triazole bridges have been introduced on both sides of the fluorene. The UV/Vis and photoluminescence properties have been measured. Further to those results two-photon absorption cross-section of our fluorophores (dTPA) has been obtained. Following these promising results, hydrophilic compounds using PEG groups have been prepared and photoluminescence properties have been carried out. In order to use the boron center as a site for radiofluorination, the synthesis of "BODIPY-like" probes has been considered. A new series of pyrimidine and triazole ligand have been synthesized but the corresponding boron complexes haven’t been obtained
Blondel, Walter. "Spectro-imagerie optique UV-Visible : approche multimodale et caractérisation de tissus biologiques in vivo appliquées au photodiagnostic en cancérologie". Habilitation à diriger des recherches, Université Henri Poincaré - Nancy I, 2008. http://tel.archives-ouvertes.fr/tel-00347421.
Texto completoRuiz, de galarreta fanjul Claudia. "Conception et réalisation des performances d'un spectro-imageur à transformée de Fourier dans l'UV lointain (IFTSUV)". Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112051.
Texto completoThe origin and evolution of the different structures that inhabit beyond the Sun’s photosphere, as well as the processes involved in the dynamics and the heating of the corona remain quite unknown. The inextricable complexity of the physical phenomena that govern the solar outer atmosphere is accompanied by the lack of suitable data adapted to the scientific need. Indeed, the interpretation and the models of the mechanisms that connect the exchanges between the chromosphere and the corona depend on critical observational parameters. It is for example essential to measure broad bands of vertical temperature and density ranges that fit the multiple spatial and temporal scales that are characteristic of the different events that take place in the Sun. The understanding of the dynamics of the plasma must be also based on the Doppler analysis of the observed scene. That implies the ability to combine time resolved spectroscopic and imaging technologies. Moreover, space is the place to observe the far UV corona and that implies a real technical challenge. Despite excellent advances in technology and instrumentation, the study of the Sun in the far UV is a fairly recent. To date, no solar space mission could provide a combined and simultaneous diagnostic of both observable in the spectral range of interest. It is because of these expectations that the study of a new device called IFTSUV (the acronym of Imaging Fourier Transform Spectrometer working in the far UV) is presented in this research. Despite the lack of opportunity missions on the near horizon, these thesis works have been conducted thanks to the R&D funding R-S11/OT-0004-040 from the CNES, concerning either the definition of an imaging Fourier transform spectrometer in the far UV, or the realization of a laboratory metrology demonstrator that is the cornerstone of the instrument’s feasibility. Thus, starting from the definition of the scientific requirements that lead to the technical choice, the first objective of this study is to develop a preliminary instrumental model of the IFTSUV. The overall technical and design specifications are based in theoreticalcalculations that have been expressed in terms of spectral accuracy, image quality and signal to noise ratio. Throughout the identification of difficult points, the realization of a servo-metrology system dedicated to the sampling mirror appears naturally as an intrinsic need of proof of concept. Indeed, the wavenumbers from the raw spectra are set by the interferogram. That implies that acquisition must be rigorously constant and that the sampling steps must be known with high accuracy. The mockup of a metrological solution is therefore the second objective of this work. The optical breadboard architecture under test has been chosen to meet the needs of angular stability (< 2.5 μrad) and linear accuracy (< 8 nm). The results on the demonstrator validate the concept even if its performances are away from the theoretical predictions. The experimental performance evaluation is used to establish solutions to the instrumental problems encountered. That converge to the optimization and prototyping of a system that could be integrated in a space based application
Gouisset, Emmanuel. "Développement et étude de la réponse instrumentale d'un imageur hyperspectral large bande (UV-Visible-NIR) permettant la caractérisation physico-chimique de contaminants sur surfaces sensibles d’engins orbitaux". Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS139.
Texto completoIn the field of failure analysis and in particular molecular and particulate contamination, being able to detect any trace of contaminants during the integration of an orbital spacecraft is crucial. In this context, fluorescence allows not only to detect but also to discriminate contaminants. For this project, we have therefore developed a broadband hyperspectral instrument (UV-Vis-NIR) from 330 to 1000 nm to be able to detect a wide range of contaminants. It is a catoptric assembly that eliminates chromatic aberrations. The field of view is 3.5° for an angular resolution of 25 arc seconds. It was designed to be portable and its fixed mechanical assembly allows easy optical alignment and rapid creation of calibration files between two scenes. We measured a spectral resolution of 1 nm in the UV range, 2 to 3 nm in the visible range and 5 nm in the NIR range. This allowed us to study the fluorescence response of two epoxy glues, typical sources of orbital spacecraft contamination, and to compare it with a measurement obtained with a commercial instrument. These measurements allowed us to evaluate the performance of our instrument and identify prospects of improvement, especially in terms of sensitivity in UV range
Auguste, Thierry. "Étude de la dynamique d'un microcanal de plasma d'argon". Paris 11, 1989. http://www.theses.fr/1989PA112314.
Texto completoStudy of the dynamics of an argon microchannel plasma. We have experimentalty and numerically studied the dynamics of an argon microchannel plasma. It is created by an external radiation source and maintained by the discharge of a capacitor bank. The goal of the experiment is to create a dense and hot plasma. Two methods of preionization have been used: in the first one, plasma was photoionized by a x-uv source created by laser irradiation of a solid; in the second one a frequency quadrupled neodynium laser was directly focused in argon. We used this last method for the rest of the experiment in view of its efficiency. Electronic density was measured by interferometry. The expansion velocity of the channel was measured with a visible streak camera. Visible and infrared spectroscopy was used to determine the electronic temperature. This one was estimated by computing the reabsorption of infrared lines with a collisionnal-radiative madel. This experiment has shawn that the obtained plasma was dense but remained cold whatever be the initial conditions. Indeed, it is resistive only during the first nanoseconds. The increase of the current is then dominated by the inductance of the channel. This study is interesting for the development of ultra-short switches with very low jitter. Moreover, the high density, low temperature argon plasma is an interesting source for highly correlated plasmas
Le, Thanh Doanh. "Étude d'une décharge à barrière diélectrique établie dans un mélange de gaz rare halogène". Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1172/.
Texto completoThis work concerns the study of a dielectric barrier discharge established in a mixture rare-halogen gas (xenon and chlorine). At present, Ultraviolet sources (UV) find nowadays numerous applications in the industry (drying of ink, surface treatments, lithographs for semiconductors etc. ) and they are generally produced by discharges in the vapour of mercury. New sources are however in full development: it is a question of sources based on the excited emissions by dielectric barrier discharge. More effective than sources with mercury, they allow an emission that is very located in the spectre, centred on a wavelength depending on the gas (or the gas mixture) in which occurs the discharge. To reach our objectives, we developed first of all one physical model intended for a DBD excilamp for a mixture of xenon and chlorine. This model bases on the resolution of the equation system formed mainly by the equations of continuity of the considered species, and the equation of Poisson. The resolution of this model allows us to describe the spatial and temporal distribution of all the species considered in the volume of discharge. Afterward, thanks to the developed model, we realized a study of the influence of three different modes of power supplies (sinusoidal and pulsed voltage waveform, pulsed current waveform) on the production of UV by the excilamp xenon / chlorine. These obtained results were confronted with experimental results coming from the scientific literature. Finally, thanks to a platform of study of these discharges developed in Laplace (system of pumping of the gas or the gas mixture, bench of manufacturing of lamps, tools of diagnosis and power supplies), we have studied several experimental measures such as spectre of emission, time resolved spectroscopy and imaging of the discharge of excilamp xenon/chlorine. These measures allowed us to estimate the performance of various modes of supplies at the same time the efficiency of UV production of the discharge and also on the lifetime. On the bases of the results obtained in our experimental measures, we can choose a better power supply for an excilamp xenon / chlorine