We report on the performance of a vector apodizing phase plate coronagraph that operates over a wavelength range of 2-5 mu m. and is installed in MagAO/Clio2 at the 6.5 m Magellan Clay telescope at Las Campanas Observatory, Chile. The coronagraph manipulates the phase in the pupil to produce three beams yielding two coronagraphic point-spread functions (PSFs) and one faint leakage PSF. The phase pattern is imposed through the inherently achromatic geometric phase, enabled by liquid crystal technology and polarization techniques. The coronagraphic optic is manufactured using a direct-write technique for precise control of the liquid crystal pattern. and multitwist retarders for achromatization. By integrating a linear phase ramp to the coronagraphic phase pattern, two separated coronagraphic PSFs are created with a single pupil-plane optic, which makes it robust and easy to install in existing telescopes. The two coronagraphic PSFs contain a 180 degrees dark hole on each side of a star, and these complementary copies of the star are used to correct the seeing halo close to the star. To characterize the coronagraph, we collected a data set of a bright (m(L) = 0-1) nearby star with similar to 1.5 hr of observing time. By rotating and optimally scaling one PSF. and subtracting it from the other PSF, we see a contrast improvement by 1.46 magnitudes at 3.5 lambda/D. With regular angular differential imaging at 3.9 mu m, the MagAO vector apodizing phase plate coronagraph delivers a 5 sigma Delta mag contrast of 8.3 (= 10(-3.3)) at 2 lambda/D and 12.2 (= 10(-4.8)) at 3.5 lambda/D.

In recent years y-y angular correlations have been very useful in confirming the spins of excited nuclear states. Angular correlation techniques have also been employed to study the electric and magnetic character of excited nuclear states. With these things in mind, it was decided to design, construct, and test a precision angular correlation table.

The LHCb experiment is a single-arm forward spectrometer situated at the Large Hadron Collider, CERN. LHCb is optimised for the precision study of beauty and charm flavoured hadrons and in 2011 collected 1 fb-1 of proton- proton collision data at a centre-of-mass energy of 7TeV. The aim of LHCb is to search for rare decays and make precise measurements of Charge-Parity (CP) violation in the beauty and charm sectors. In the Standard Model the decay B°→ ΦK*(892)° is described by a loop mediated process, providing a sensitive test for new physics. In this decay, signs of CP violation could indicate the presence of physics beyond the Standard Model. This thesis presents a study of the flavour eigenstate B° → Φ(→ K+K-)K*(892)°(→ K+π-) and its charge conjugate -B°-decay. The decay products form an admixture of CP-even and CP-odd eigenstates, which can have longitudinal or transverse polarisation. An angular analysis is performed to disentangle these different contributions and the polarisation amplitudes and strong phases are measured. No difference is observed between B0 and -B0 amplitudes, supporting the hypothesis that CP is conserved in this decay. In addition, the Triple Product Asymmetries (TPAs) are determined from the products of the polarisation amplitudes and strong phases. True TPAs are zero in the event that CP symmetry is conserved, while fake TPAs can arise due to final-state interactions. Although the measured true TPAs are consistent with zero, several significant fake TPAs are observed.

Este trabalho realiza uma investigação sobre técnicas experimentais para a determinação de Funções de Resposta em Freqüência (FRFs) angulares com aplicações em estruturas do tipo viga. Estas FRFs são definidas considerando-se como variável de saída o movimento angular (deslocamento, velocidade ou aceleração) exibido pela estrutura sob estudo quando a mesma é excitada por uma força linear ou um momento puro. Dada a grande dificuldade em se aplicar um momento puro à estrutura sob estudo, este trabalho utiliza como forma de excitação apenas esforços lineares que podem ser aplicados através de técnicas usuais de excitação em análise modal, tais como o excitador eletrodinâmico e o martelo impulsivo. Portanto as FRFs obtidas descrevem relações de saída e entrada do tipo Angular/Linear. Uma das técnicas utilizadas na determinação das FRFs angulares consiste na excitação de uma estrutura com um excitador eletrodinâmico e utilização de um corpo rígido na forma de um bloco T que é montado sobre a estrutura sob estudo. Dois acelerômetros lineares devem ser montados sobre o bloco T e a partir das duas acelerações lineares medidas buscam-se estimar um sinal proporcional à aceleração angular da estrutura no ponto de conexão. Outra técnica utiliza uma formulação via diferenças finitas, onde dois ou três acelerômetros (de acordo com a formulação de diferenças finitas utilizada) igualmente espaçados são montados diretamente sobre a estrutura sob estudo e são usados para se derivar à aceleração angular. Os resultados obtidos a partir destas técnicas são comparados com resultados obtidos a partir da utilização de um acelerômetro angular piezelétrico recentemente disponível no mercado. Também foram desenvolvidos modelos analíticos e computacionais via método dos elementos finitos a fim de se gerar subsídios adicionais para a análise dos resultados. Foram feitas várias constatações e dentre elas destacam-se resultados onde as FRFs angulares/lineares resultantes podem sofrer alterações significativas dependendo de como os dados experimentais são processados. / The present work aims to perform an investigation on experimental techniques for the determination of angular Frequency Response Functions (FRFs) in Modal Testing. Angular FRFs are those where the output variable is given by angular displacement, velocity or acceleration, whereas the input is given in terms of linear or angular quantities (a pure moment). Since the application of a pure moment as an excitation source still remains as a challenge, this work is focused in studying techniques to estimate angular/linear types of angular FRFs. One of these techniques consists of exciting the structure with a shaker and using a rigid T-block to measure the linear accelerations and then calculating the angular FRFs from these linear accelerations. Another technique employs finite differences formulations to get the angular motions. This technique uses the closely spaced accelerometers mounted directly to the structure under test, where at least two (according to the finite difference formula employed) accelerometers are used. The translational measurements are gathered and finite difference formulas are used to derive the necessary angular quantities. Additional tests are performed with an angular piezoelectric accelerometer recently available in the market in order to provide a comparison basis for the results obtained using the two techniques. The results are also compared whit theoretical models developed using analytical and Finite Element Formulations. Among all results obtained, it was understood that depending on the level of angular vibrations exhibited by the structure, and how the signals are processed, the resulting angular FRFs can suffer some significant changes

Most of the 500 extra-solar planets detected to date have been discovered either by radial velocity measurements or photometric transits but very few by direct techniques. Direct imaging of exoplanets, however, gives access to a wider variety of information on the planet, from its orbital position to its spectrum, but is a difficult task to achieve because of the small angular separation between the star and its planet and the large flux ratio between them. For these two reasons, direct imaging of exoplanets has up to now been limited to the most favorable cases of bright giant exoplanets orbiting at large distances from their host stars. %The present work aims at developing the high dynamic range capabilities of single- and multi-aperture imaging techniques for the detection and characterization of planetary systems. The first part of this work reports studies of adaptive optics-aided ground-based telescopes and their complementarity with space-based facilities for the detection of extra-solar planets. Results obtained with the Well-Corrected Subaperture at Palomar observatory on narrow multiple systems are then used to illustrate this study. The second part of this work is dedicated to stellar and nulling interferometry. We first present a new data reduction technique for interferometry using the statistical distributions of the noise sources to significantly improve the precision of interferometric measurements. This technique is then applied to the Palomar Fiber Nuller instrument at Palomar observatory to constrain the presence of dust and companions in the innermost regions of Vega's stellar environment and to derive stellar angular diameters with very high accuracies. Finally, we introduce an on-going survey that we are pursuing with the AMBER interferometric instrument at the Very Large Telescope (Cerro Paranal, Chile) aiming at detecting sub-stellar companions around young main sequence stars.

Graduation date: 1991

The LHC, with its center-of-mass energy of 7 TeV, offers the chance to investigate the fundamental constituents of matter at a higher energy scale than ever before. Using the data acquired by the ATLAS detector in the summer of 2010, two different measures of the angular distributions of dijet final states are studied and compared to Standard Model QCD expectations. Such a comparison is used to set new stringent limits on the existence of quark substructure.

The LHC, with its center-of-mass energy of 7 TeV, offers the chance to investigate the fundamental constituents of matter at a higher energy scale than ever before. Using the data acquired by the ATLAS detector in the summer of 2010, two different measures of the angular distributions of dijet final states are studied and compared to Standard Model QCD expectations. Such a comparison is used to set new stringent limits on the existence of quark substructure.

No description available.

In this thesis, particle- particle angular correlations for reactions in non-zero degree geometry and with non-zero spin nuclei are performed and found to be a valuable tool for spin determination, (d-α) angular correlations in the reaction process ¹⁴N(⁶Li,d)¹⁸F* (α)¹⁴N are measured for three high excited states in ¹⁸F with a ⁶Li beam of 36MeV. Spins and parities for two of the observed states are determined, and in agreement with theoretical predictions, these states are suggested as members of the K^π=1⁺ α-rotational band. The three analysed 9.58MeV 6⁺, 11.2MeV, 14.1MeV 8⁺ states are found to undergo a predominant α-particle decay to the ground state of ¹⁴N. Gamow unbound formalism is carried out for the state descriptions. Angular distributions are measured and analysed under Hauser Feshbach and exact finite range DWBA formalisms. Spectroscopic factors are extracted and compared to shell model predictions, showing a reasonable agreement. (³He-α) and (t-α) angular correlations for the reaction processes ¹⁴N(⁶Li,³He)¹⁷0* (α)¹³C and ¹⁴N(⁶Li,t)¹⁷F* (α)¹³N respectively are measured at 36MeV of ⁶Li. High selectivity is observed for the three particle transfer processes and percentages of the different particle decays for the high populated states are presented. Structureless angular correlations hinder definite spin and parity assignements, but the displacement of the preferred direction observed in the pattern decay gives some information on the range of plausible angular momenta. Shell model calculations are performed for comparison with the experimental data, and this allows tentative spin identifications. EFR EWEA calculations are carried out, providing some confirmation on the spin suggestions. Useful nuclear structure information is obtained for the mass 17 and 18 nuclear states. The particle-particle angular correlation expression for a process where a direct reaction mechanism is involved is reviewed, programmed and used for obtaining the theoretical predictions to be compared to the experimental results.