La spectroscopie sans fente a longtemps été considérée comme une technique compliquée de part ses effets d’auto- et d’inter-contamination. Toutefois, depuis l’ère des instruments du Télescope Spatial Hubble qui offrent un bruit de fond faible et une bonne résolution spatiale, la spectroscopie sans fente est devenue un outil largement utilisé pour les sondages spatiaux astrophysiques et cosmologiques. Dans ce contexte, nous nous sommes intéresser à l’application de cette technique pour l’étude individuelle d’objets. Dans les sondages actuels, l’analyse de ces spectres s’effectue généralement à partir de méthodes inverses qui ne tiennent pas compte de l’effet d’auto-contamination et mé- langent donc les propriétés morphologiques et spectrales de la galaxie. Les objectifs de cette thèse sont tout d’abord de prendre en compte cet effet de contamination qui dégrade la résolution spec- trale effective en fonction de l’extension spatiale de la source, afin de mesurer plus précisément le redshift et autres propriétés spectrales intégrées. Nous explorons aussi la faisabilité de la mesure de quantitées spatialement résolues telle que la cinématique interne des galaxies. Nous construisons alors un modèle complet qui peut être quantitativement comparé aux observations actuelles dans une approche forward. Ce modèle est par la suite testé sur des données sélectionnées des relevés GLASS et 3D-HST, afin de contraindre en particulier le redshift et les paramètres cinématiques modélisant la courbe de rotation de la galaxie. Notre approche forward permet d’atténuer l’effet d’auto-contamination et donc d’améliorer la précision sur la mesure du redshift. Dans un sous-échantillon de galaxies spirales isolées et résolues, il est alors possible de contrainte assez significativement les paramètres cinématiques. Nous étudions également les systématiques liées aux hypothèses de notre modèle grâce à des simulations avec les données du relevé de spectroscopie à champ intégral MaNGA, qui tendent à montrer que la mesure de ces paramètres reste assez difficile pour la plupart des données récentes de spectroscopie sans fente. Néanmoins, ces simulations indiquent que le modèle forward contraint relativement bien le redshift. Enfin, ces travaux montrent des applications prometteuses pour les futures grands relevés spectroscopiques tel que Euclid / Slitless spectroscopy has long been considered as a complicated and confused technique because of its self- and cross-confusion effets. However, since the era of the Hubble Space Telescope (HST) instruments which offer a low background and fine spatial resolution, slitless spectroscopy has become an adopted cosmological survey tool to study galaxy evolution from space. Within this context, we investigate its application to single object studies. In recent surveys, the spectra analysis is usually done using backward extraction which mixes spatial and spectral properties and therefore does not take into account self-confusion effect. The goals of this PhD is firstly to include this effect which degrades the effective spectral resolution (which depends on the extent of the source), in order to make the redshift and other integrated spectral features measure- ments more accurate. We also explore the feasibility to measure spatially resolved quantities such as galaxy kinematics. We build a complete forward model to be quantitatively compared to actual slitless observations. The model is tested on selected observations from 3D-HST and GLASS surveys, to estimate redshift and kinematic parameters (modeling the galaxy rotation curve) on several galaxies mea- sured with one or more roll angles. Our forward approach allows to mitigate self-confusion effect, and therefore to increase the precision of redshift measurements. In a sub-sample of well-resolved spiral galaxies from HST surveys, it is possible to significantly constrain galaxy rotation curve pa- rameters. We also study the systematics effects induced by the hypothesis of our model by building slitless simulations with the data of the integral field spectrograph survey MaNGA. These simu- lations suggest that the precise measurement of the kinematics parameters is difficult for most of the current slitless observations. Nethertheless, they point out that this forward model contrains significantly well the redshift. Finally, this work is promising for future large slitless spectroscopic surveys such as Euclid

L'accélération de l'expansion de l'Univers est l'un des sujets majeurs de la cosmologie actuelle. Elle pourrait être due à une nouvelle composante, appelée énergie noire, qui représenterait 70% du bilan énergétique de l'Univers. Pour étudier sa nature à travers son équation d'état, on mesure une règle étalon fournie par les oscillations baryoniques acoustiques (BAO) à différentes valeurs de décalage vers le rouge. Cette technique a été utilisée avec succès pour la première fois en 2005 par le projet Sloan Digital Sky Survey (SDSS-II). Depuis, l'observation des BAO a été confirmée en 2012 par le projet BOSS (SDSS-III) puis eBOSS (SDSS-IV), à la fois avec des galaxies et des absorbeurs de la raie à 21 cm révélés dans des spectres de quasar. Notre groupe prépare la prochaine génération d'expériences BAO en participant à la construction du spectrographe du nouveau programme Dark Energy Spectroscopic Instrument (DESI). Ce projet va réaliser un sondage 3D de plusieurs dizaines de millions de galaxies et quasars avec le télescope Mayall de 4m en Arizona (USA). J'ai participé à la mise au point du spectrographe de DESI en collaboration avec notre partenaire industriel (WINLIGHT). J'étais aussi en charge de développer un banc optique dans le but de valider l'alignement des capteurs CCD montés dans les enceintes des cryostats. Des matrices de microlentilles sont utilisées pour projeter très précisément des grilles de spots sur les CCD. En fonction de la distortion observée des grilles, nous sommes capables de déterminer la position des CCD. En parallèle, j'ai développé des algorithmes pour la sélection des quasars cibles, les objets les plus distants qui seront observés par DESI, basée sur leurs propriétés photométriques en exploitant des techniques d'apprentissage supervisé. / The accelerating expansion of the universe is one of the main topics of modern cosmology. It may stem from a new component, so-called dark energy, which would make up 70% of the energy content of the universe. To study its nature through its equation of state, one can measure a standard ruler given by baryonic acoustic oscillations (BAO) at various redshifts or for different slices of the universe. This approach was used successfully for the first time in 2005 by the Sloan Digital Sky Survey (SDSS-II) project. Then, the BAO signal was confirmed in 2012 by the BOSS project (SDSS-III) and then by the eBOSS project (SDSS-IV), both with galaxies and HI absorbers revealed in quasar spectra. Our group is preparing the next generation of BAO experiments by taking part in building the spectrograph of the new Dark Energy Spectroscopic Instrument (DESI) program. This project will perform a 3D survey of several tens of millions of galaxies and quasars with the 4-meter Mayall telescope in Arizona (USA). I participated in the adjustments of the spectrograph of DESI in collaboration with our industrial partner (WINLIGHT). I was also in charge of developing an optical bench in order to check the alignment of the CCD sensors mounted within the crysotat vessels. Arrays of microlens are used to project very precisely grids of spots on the CCDs. We are able to infer the position of the CCDs according to the observed distortion of the grids of spots. In parallel, I developped algorithms for the selection of quasar candidates, the more distant objects that will be observed by DESI, based on their photometry properties by making use of machine learning tools.

Large area fiber array telescopes are a relatively modern development in the long history of telescope design and effectively create a single large equivalent aperture by combining many smaller unit telescopes at a fraction of the cost. In this study a spectrograph optical design is demonstrated that utilizes photonic lanterns in the input fiber feed for the Large Fiber Array Spectroscopic Telescope (LFAST) design concept, where photonic lanterns provide a simplified approach to the fiber feed originally proposed for LFAST. Conservation of etendue is applied to derive the relationship between slit size and photonic lantern ratio, and classical echelle spectrograph designs are explored. A high-resolution spectrograph for LFAST is shown to not be feasible due to the large number of input fibers that result in a large required cross-dispersion within the constraint of practical and cost-effective optical component sizes. An alternative approach of splitting the slit length and replicating spectrographs is explored, and an optimal choice of four spectrographs with a photonic lantern ration of four is determined. Even with this approach, detailed spectrograph component designs show that the spectrograph does not meet the resolution requirements and is fundamentally limited by design constraints imposed by component sizes. Alternative layouts and design decisions to improve optical performance are surveyed for future design research, and include white pupil optics, echelle grating design considerations, spectral arm splitting, and use of reflective and catadioptric systems with aspheric surfaces. While these show promise for improving the spectrograph performance, the design is demonstrated to still be challenging and will likely require innovative approaches to meet the high-resolution design goals.

No description available.

1. A two prism spectrograph has been designed and oonstruoted with which it is believed Raman spectra may be obtained. 2. Attempts have been made using the spectrograph to obtain Raman spectra. These attempts, are as yet unsuccessful. / M.S.

The GMT-Consortium Large Earth Finder (G-CLEF) is an echelle spectrograph with precision radial velocity (PRV) capability that will be a first light instrument for the Giant Magellan Telescope (GMT). G-CLEF has a PRV precision goal of 40 cm/sec (10 cm/s for multiple measurements) to enable detection of Earth-like exoplanets in the habitable zones of sun-like stars'. This precision is a primary driver of G-CLEF's structural design. Extreme stability is necessary to minimize image motions at the CCD detectors. Minute changes in temperature, pressure, and acceleration environments cause structural deformations, inducing image motions which degrade PRV precision. The instrument's structural design will ensure that the PRV goal is achieved under the environments G-CLEF will be subjected to as installed on the GMT azimuth platform, including: Millikelvin (0.001 K) thermal soaks and gradients 10 millibar changes in ambient pressure Changes in acceleration due to instrument tip/tilt and telescope slewing Carbon fiber/cyanate composite was selected for the optical bench structure in order to meet performance goals. Low coefficient of thermal expansion (C 1E) and high stiffness-to-weight are key features of the composite optical bench design. Manufacturability and serviceability of the instrument are also drivers of the design. In this paper, we discuss analyses leading to technical choices made to minimize G-CLEF's sensitivity to changing environments. Finite element analysis (FEA) and image motion sensitivity studies were conducted to determine PRV performance under operational environments. We discuss the design of the optical bench structure to optimize stiffness to -weight and minimize deformations due to inertial and pressure effects. We also discuss quasi-kinematic mounting of optical elements and assemblies, and optimization of these to ensure minimal image motion under thermal, pressure, and inertial loads expected during PRV observations.

<p>Mass spectrometry is widely considered to be the gold standard of elemental analysis techniques due to its ability to resolve atomic and molecular and biological species. Expanding the application space of mass spectrometry often requires the need for portable or hand-held systems for use in field work or harsh environments. While only requiring “sufficient” mass resolution to meet the needs of their application space, these miniaturized systems suffer from poor signal to background ratio which limits their sensitivity as well as their usefulness in field applications. </p><p>Spatial aperture coding techniques have been used in optical spectroscopy to achieve large increases in signal intensity without compromising system resolution. In this work similar computational methods are used in the application of these techniques to the field of magnetic sector mass spectrometry. Gains in signal intensity of 10x and 4x were achieved for 1D and 2D coding techniques (respectively) using a simple 90 degree magnetic sector test setup. Initial compatibility with a higher mass resolution double focusing Mattauch-Herzog mass spectrograph is demonstrated experimentally and with high fidelity particle tracing simulations. A novel electric sector lens system was designed to stigmate high order coded aperture patterned beam which shows simulated gains in signal intensity of 50x are achievable using these techniques.</p> / Dissertation

The viability of using a slicer based integral field spectrograph (IFS) for high contrast observations has been under scrutiny due to the belief that the one dimensional coherence that persists along the slice to the point of sampling at the detector will cause the creation of secondary speckles that will not have the same characteristics as normal speckles, thus stopping us from calibrating them out. It has also been previously assumed that a suitably low differential wavefront error when moving slice to slice was not guaranteed by design. It was for these reasons that slicer based IFSs were not selected for the current generation of planet finding instruments. As part of the EPICS (Exo Planet Imaging Camera and Spectrograph for the E-ELT) design study it was decided that slicers should be re-investigated due to results from on sky observations suggesting these limitations did not exist. The purpose of this thesis was to determine whether there was validity to the concerns mentioned above and therefore to answer the question; Would implementing a slicer based integral field spectrograph limit the achievable contrast of an instrument designed for the direct detection of exoplanets? Chapter 1 gives a brief introduction into the field of exoplanet research. Charpter 2 describes the noise limiting direct detection of exoplanets and the ways to get around it. Chapter 3 gives an overview of the two types of IFS under investigation by the EPICS consortium. Chapter 4 looks into details of the EPICS instrument and the IFS design study that came about. Chapter 5 shows simulations performed for the aim of achieving better contrasts via post processing methods and accurate data reduction as well as simulations of slicer based integral field spectrographs. Experimental tests using a slicer and a preoptics setup designed to simulate the limiting noise are described in Chapter 6. Chapter 7 looks at using SINFONI for high contrast observations and Chapter 8 details the conclusions drawn from the work presented in this thesis, as well as possible extensions to it. The work performed in this thesis dispels the concerns about the continued one dimensional coherence up to the detecter and suggests that slicer based integral field spectrographs do not inherently limit the contrast achievable; Results from experiments fit well with the requirements for EPICS to achieve its goals. Simulations also supported the idea that secondary speckle noise should not be an issue for the slicer based IFS. This means that a slicer based IFS is a viable option for the EPICS instrument.

A análise da Interferência Coulombiana-Nuclear (ICN) foi aplicada à distribuição angular experimental do espalhamento inelástico de 6Li de 28,0 MeV em 76Ge, na excitação do estado 2_1^+. Os dados foram adquiridos no sistema Pelletron-Espectrógrafo Magnético Enge do LAFN do IFUSP. Na detecção dos íons emergentes, no plano focal do imã, foi utilizado um detector sensível à posição (PSD) de barreira de superfície (área de detecção de 47 × 8 mm^2 e espessura útil de 500 m). No presente trabalho foi introduzida a técnica de processamento digital de pulsos (PDP) no sistema de aquisição. Foram medidos espectros associados a vinte e seis ângulos de espalhamento na região angular de interesse: 10^o_Lab 55^o. A análise foi realizada na aproximação de Born com ondas distorcidas (DWBA) utilizando o potencial nuclear de transição descrito pelo modelo do potencial óptico deformado (DOMP) e parâmetros ópticos globais. O ajuste das previsões sobre a distribuição angular experimental foi realizado pela minimização do ^2 através do método iterativo de Gauss. O ajuste permitiu a extração dos parâmetros correlacionados: _2^N, comprimento de deformação nuclear e C_2=(_2^C)(_2^N ), razão entre os comprimentos de deformação de carga e nuclear. Os valores dos parâmetros correlacionados obtidos neste trabalho foram C_2=1,101(20) e _2^N=1,08(21) fm. Testes estatísticos através da simulação de Monte Carlo de 5000 novos conjuntos de dados comprovaram a qualidade do método empregado no ajuste dos parâmetros correlacionados. A metodologia aplicada na análise da ICN, permitiu a extração da razão (B(E2))B(IS2) ,que é proporcional ao quadrado de C_2, com boa precisão devido ao cancelamento da incerteza no fator de escala, das seções de choque absolutas. Os resultados obtidos no presente trabalho são inéditos e permitiram análise da evolução da coletividade ao longo da cadeia de isótopos pares de germânio, em conjunto com os valores obtidos nos isótopos 70,72,74Ge estudados previamente. Os resultados ao longo da cadeia indicaram que, apesar de uma leve predominância da contribuição dos prótons em relação aos nêutrons na excitação dos primeiros estados quadrupolares dos 70,72,76Ge, a contribuição dos nêutrons é consideravelmente maior para o 74Ge. Este aumento sugere forte mistura de configurações na descrição do estado fundamental deste isótopo. / The inelastic scattering of 28,0 MeV 6Li on 76Ge in the excitation of the 2_1^+ state, has been studied with the Coulomb-Nuclear Interference (CNI) analysis. The data were measured at the Pelletron-Enge-Spectrograph facility at LAFN-IFUSP. A solid-state position sensitive silicon detector (PSD) (500 m thickness and 47 × 8 mm^2 area) was used to measure the data at the spectrometer focal plane. Digital pulse processing (DPP) was implemented in the acquisition system. Twenty-six spectra were measured at carefully chosen scattering angles in the range of 10^o_Lab 55^o to obtain an angular distribution. The analysis was performed with the Distorted Wave Born Approximation (DWBA) and applied for the nuclear transition potential, the Deformed Optical Potential Model (DOMP), under well-established global optical parameters. The fit of the predicted cross sections to the experimental data through ^2 minimization, using the iterative method of Gauss, allowed for the extraction of the correlated parameters, _2^N, the mass deformation length, and C_2=(_2^C)(_2^N ), the ratio between charge and mass deformation lengths. The correlated parameters obtained in the present work were C_2=1,101(20) and _2^N=1,08(21) fm. Statistical tests, through a Monte Carlo simulation of 5000 new data sets, validated the method employed in the correlated parameters fit. The methodology applied for the CNI analysis allowed the extraction of ratio(B(EL))(B(ISL)), which is proportional to the square of C_2, with a good precision due to the scale uncertainties cancellation of the absolute cross sections. The values of B(IS2) and of the ratios (B(E2))(B(IS2)) obtained in the present work have not been reported before and allow the study of the evolution of the collectivity throughout the even-A germanium chain together with former results obtained for the 70,72,74Ge isotopes. The results along the chain indicate that although the protons relative to the neutrons reveal a small predominant contribution in 70,72,76Ge to the first quadrupole excitation, the neutron role is strongly enhanced in 74Ge. This behaviour suggests a strong mixing configuration in the 74Ge ground state description

A análise da Interferência Coulombiana-Nuclear (ICN) foi aplicada à distribuição angular experimental do espalhamento inelástico de 6Li de 28,0 MeV em 76Ge, na excitação do estado 2_1^+. Os dados foram adquiridos no sistema Pelletron-Espectrógrafo Magnético Enge do LAFN do IFUSP. Na detecção dos íons emergentes, no plano focal do imã, foi utilizado um detector sensível à posição (PSD) de barreira de superfície (área de detecção de 47 × 8 mm^2 e espessura útil de 500 m). No presente trabalho foi introduzida a técnica de processamento digital de pulsos (PDP) no sistema de aquisição. Foram medidos espectros associados a vinte e seis ângulos de espalhamento na região angular de interesse: 10^o_Lab 55^o. A análise foi realizada na aproximação de Born com ondas distorcidas (DWBA) utilizando o potencial nuclear de transição descrito pelo modelo do potencial óptico deformado (DOMP) e parâmetros ópticos globais. O ajuste das previsões sobre a distribuição angular experimental foi realizado pela minimização do ^2 através do método iterativo de Gauss. O ajuste permitiu a extração dos parâmetros correlacionados: _2^N, comprimento de deformação nuclear e C_2=(_2^C)(_2^N ), razão entre os comprimentos de deformação de carga e nuclear. Os valores dos parâmetros correlacionados obtidos neste trabalho foram C_2=1,101(20) e _2^N=1,08(21) fm. Testes estatísticos através da simulação de Monte Carlo de 5000 novos conjuntos de dados comprovaram a qualidade do método empregado no ajuste dos parâmetros correlacionados. A metodologia aplicada na análise da ICN, permitiu a extração da razão (B(E2))B(IS2) ,que é proporcional ao quadrado de C_2, com boa precisão devido ao cancelamento da incerteza no fator de escala, das seções de choque absolutas. Os resultados obtidos no presente trabalho são inéditos e permitiram análise da evolução da coletividade ao longo da cadeia de isótopos pares de germânio, em conjunto com os valores obtidos nos isótopos 70,72,74Ge estudados previamente. Os resultados ao longo da cadeia indicaram que, apesar de uma leve predominância da contribuição dos prótons em relação aos nêutrons na excitação dos primeiros estados quadrupolares dos 70,72,76Ge, a contribuição dos nêutrons é consideravelmente maior para o 74Ge. Este aumento sugere forte mistura de configurações na descrição do estado fundamental deste isótopo. / The inelastic scattering of 28,0 MeV 6Li on 76Ge in the excitation of the 2_1^+ state, has been studied with the Coulomb-Nuclear Interference (CNI) analysis. The data were measured at the Pelletron-Enge-Spectrograph facility at LAFN-IFUSP. A solid-state position sensitive silicon detector (PSD) (500 m thickness and 47 × 8 mm^2 area) was used to measure the data at the spectrometer focal plane. Digital pulse processing (DPP) was implemented in the acquisition system. Twenty-six spectra were measured at carefully chosen scattering angles in the range of 10^o_Lab 55^o to obtain an angular distribution. The analysis was performed with the Distorted Wave Born Approximation (DWBA) and applied for the nuclear transition potential, the Deformed Optical Potential Model (DOMP), under well-established global optical parameters. The fit of the predicted cross sections to the experimental data through ^2 minimization, using the iterative method of Gauss, allowed for the extraction of the correlated parameters, _2^N, the mass deformation length, and C_2=(_2^C)(_2^N ), the ratio between charge and mass deformation lengths. The correlated parameters obtained in the present work were C_2=1,101(20) and _2^N=1,08(21) fm. Statistical tests, through a Monte Carlo simulation of 5000 new data sets, validated the method employed in the correlated parameters fit. The methodology applied for the CNI analysis allowed the extraction of ratio(B(EL))(B(ISL)), which is proportional to the square of C_2, with a good precision due to the scale uncertainties cancellation of the absolute cross sections. The values of B(IS2) and of the ratios (B(E2))(B(IS2)) obtained in the present work have not been reported before and allow the study of the evolution of the collectivity throughout the even-A germanium chain together with former results obtained for the 70,72,74Ge isotopes. The results along the chain indicate that although the protons relative to the neutrons reveal a small predominant contribution in 70,72,76Ge to the first quadrupole excitation, the neutron role is strongly enhanced in 74Ge. This behaviour suggests a strong mixing configuration in the 74Ge ground state description