Nessa tese serão apresentadas medidas de anisotropia azimutal elíptica de elétrons de decaimentos de quarks pesados feitas no perimento de colisão de íons pesados ALICE (A Large Ion Collider Experiment, em inglês). As medidas foram obtidas em colisões de Pb-Pb com energia de centro de massa por par de nucleons (psNN) igual a 2.76 TeV com o colisor de hadrons LHC (Large Hadron Collider, em inglês). Colisões ultrarelativísticas de íons pesados podem alcançar temperaturas e/ou densidades de energia suficientemente altas para formar o Plasma de Quarks e Gluons (QGP, na sigla em inglês), o estado da matéria onde os partons estão desconfinados dos hadrons. O parâmetro de anisotropia azimutal elíptica é um dos observáveis mais importantes utilizados no estudo da formação do QGP. Esse parâmetro é quantificado pelo segundo harmônico, denominado v2, da distribuição do ângulo azimutal das partículas em relação ao ângulo do plano de reação, o qual é definido pela direção do parâmetro de impacto e pela direção do feixe de partículas. Medidas de anisotropia azimutal elíptica de quarks pesados (charm e beauty) são interessantes, pois os quarks pesados são sondas sensíveis às propriedades do QGP, visto que eles são predominantemente produzidos em processos iniciais de espalhamento duro e interagem com o meio desconfinado. Medidas de v2 de elétrons de decaimentos de quarks pesados em baixos valores de momento transversal indicam movimento coletivo de quarks pesados e possível termalização no QGP. Por outro lado, medidas de v2 de elétrons de decaimentos de quarks pesados em altos valores de momento transversal são interpretadas como uma dependência da geometria do meio por onde os quarks pesados atravessam e perdem energia. Serão mostrados resultados de v2 de elétrons de decaimentos de quarks pesados em função do momento transversal em colisões de Pb-Pb a psNN = 2.76 TeV em eventos com centralidades 20-40% e 30-50%. O resultado é comparado com previsões teóricas e medida obtida em colisões de Au-Au a psNN = 0.2 TeV no experimento RHIC. Resultados preliminares de v2 de elétrons de decaimentos de charm e beauty, separadamente, também serão mostrados em colisões de Pb-Pb a psNN = 2.76 TeV em eventos com centralidade 30-50%. / This thesis presents measurements of the elliptic azimuthal anisotropy of electrons from heavy-flavour decays with the A Large Ion Collider Experiment (ALICE). The measurement is performed for the first time in Pb-Pb collisions at center-of-mass energy per colliding nucleon pair psNN = 2.76 TeV at the Large Hadron Collider (LHC). In heavy-ion collisions at ultrarelativistic energies sufficiently high temperature and/or energy density can be achieved to form the Quark-Gluon Plasma (QGP), the state of matter predicted by Quantum Chromodynamics (QCD) in which quarks and gluons are deconfined from hadrons. One of the most important probes of the QGP formation is the elliptic azimuthal anisotropy, which is quantified by the second harmonic v2 of the particle azimuthal angle distribution with respect to the angle of the reaction plane, which is defined by the impact parameter direction and the beam direction. In addition, heavy quarks (charm and beauty) serve as a sensitive probe of the QGP properties since they are predominantly produced in initial hard scattering processes and interact with the deconfined medium. The transverse momentum dependence of the heavy-flavour decay electron v2 can be used to investigate the QGP properties. The measurement of v2 of electrons from heavy-flavour decays at low transverse momentum provides a way to test whether heavy quarks take part in the collective motion in the medium. Whereas, v2 of electrons from heavy-flavour decays at high transverse momentum is interpreted as a path length dependence of heavy-quark energy loss within the created dense medium. Results of the elliptic azimuthal anisotropy of electrons from heavy-flavour decays as a function of tranverse momentum obtained in 20-40% and 30-50% central Pb-Pb collisions at psNN = 2.76 TeV will be shown. The measurement is compared with theoretical predictions and previous measurement at the RHIC experiment. Preliminary measurements of the elliptic azimuthal anisotropy of electrons from charm and beauty as a function of tranverse momentum in 30-50% central Pb-Pb collisions at psNN = 2.76 TeV will be shown as well.

Neste trabalho são reportadas medidas realizadas no detector PHENIX do RHIC sobre J/Psi em colisões p+p e Au+Au a s^(1/2) = 200 GeV na região de rapidez central e Psi\' em colisões p+p nas mesmas condições. As medidas incluem a dependência com o momento transverso da produção de charmônio e o fator de modificação nuclear de J/Psis para vários regimes de centralidade de colisão. / This work reports measurements done by the PHENIX detector at RHIC about J/Psi in p+p and Au+Au collisions at s^(1/2) = 200 GeV in the mid-rapidity range and Psi\' in p+p collisions in the same conditions. The measurements include the transverse momentum dependence of charmonium production and J/Psi nuclear modification factor in different centrality regimes.

O advento dos colisores modernos tem proporcionado novas possibilidades de estudo em física de partículas como, por exemplo, a busca por nova física e o estudo de novos estados da matéria hadrônica. Em particular, em colisões de íons pesados em altas energias, acredita-se que um novo estado da matéria seja formado antes da colisão, o chamado condensado de vidros de cor. Tal estado seria a condição inicial de um plasma de quarks e glúons e é caracterizado por altas densidades de pártons (quarks e glúons). De fato, as equações de evolução da Cromodinâmica Quântica predizem que, para virtualidades moderadas e altas energias, os hádrons se tornam sistemas extremamente densos devido ao crescimento das distribuições de glúons nessas condições. Um crescimento indefinido das distribuições de glúons poderia levar à violação do vínculo de unitariedade. Para evitar essa violação, existe um mecanismo chamado de saturação de pártons o qual contém o crescimento das distribuições de quarks e glúons de forma a respeitar o vínculo de unitariedade. Teoricamente, no limite de altas energias, observa-se que os hádrons são populados especialmente por glúons. Experimentalmente, existem indícios da saturação em colisões ep, pp, pA e AA, contudo, isso ainda é uma questão em aberto. Portanto, no limite de altas densidades, espera- se que a física não linear, a qual leva em conta efeitos de recombinações de glúon, passe a se manifestar. Uma alternativa para o estudo da saturação em colisores hadrônicos são os processos foto-induzidos, os quais ocorrem em interações ultraperiféricas. Em uma colisão ultraperiférica entre dois hádrons, o parâmetro de impacto é maior do que a soma dos raios dos hádrons, de forma que interações fortes são suprimidas. Dessa forma os hádrons atuam como fontes de fótons (quase reais) podendo ocorrer interações fóton-hádron e fóton-fóton. Nesse trabalho estudamos a fotoprodução difrativa de mésons vetoriais em energias do LHC para colisões ultraperiféricas próton-próton, próton-núcleo e núcleo-núcleo e a produção dupla de mésons vetoriais em colisões fóton-fóton e devido ao mecanismo de duplo espalhamento fóton-p(A). Mostramos como esses processos podem ser usados para estudar a física de altas energias e os efeitos de saturação. Os efeitos de saturação em nossos cálculos são levados em conta através do formalismo de dipolo de cor, que é uma das ferramentas básicas usadas nessa tese. O tratamento de colisões ultraperiféricas hádron-hádron foi feito com a aproximação de fótons equivalentes que assim como o formalismo de dipolo, foi extensamente usada. Nossos resultados apontam que o estudo fenomenológico e experimental dos tipos de processos citados acima são factíveis e podem ser usados para vincular a dinâmica da QCD em altas energias. / The advent of the modern colliders has provided new possibilities of study in particle physics as, for example, the search for new physics and the study of new states of the hadronic matter. In particular, in high energy heavy ion collisions is expected that a new state can be formed before the collision, the so called Color Glass Condensate. This state would be the initial condition of the Quark Gluon Plasma and is characterized by high parton (quarks and gluons) densities. Indeed, the Quantum Chromodynamics evolution equations predict that, for moderate virtualities and high energies, the hadrons become extremely dense systems due to the growth of the parton distribution in these conditions. An indefinite growth of the parton distributions could lead to the violation of the unitarity bound. To avoid this violation, there is a mechanism called parton saturation which tames the growth of the parton distributions to satisfy the unitarity bound. Theoretically, in the high energy limit, one can see that the hadrons are populated mainly by gluons. Experimentally, there are indications of the saturation in ep, pp, pA and AA collisions, however, this is an open question. So, in the high density limit, we expect that the nonlinear physics, which takes into account gluon recombination effects start to manifest itself. An alternative for the study of the saturation at hadronic colliders are the photon-induced processes, which occurs in ultra-peripheral collisions. In a ultra-peripheral collision between two hadrons the impact parameter is greater than the sum of the radii of the hadrons, so the strong interaction is suppressed. Thus, the hadrons act as sources of (almost real) photons and may occur photon-hadron and photon-photon interactions. In this work we study the diffractive photoproduction of vector mesons at LHC and future colliders energies in ultra-peripheral proton-proton, proton-nucleus and nucleus-nucleus collisions and the double vector meson production in photon-photon collisions and due to the double photon-p(A) scattering mechanism. We show how these processes can be used to study the high energy physics and the saturation effects. These effects are considered in our calculations through the color dipole formalism, which is one of the basic tools used in this thesis. The treatment of the ultra-peripheral hadron-hadron collisions was done through the equivalent photon approximation that just as in the dipole formalism, was widely used. Our results point that the phenomenological and experimental studies of the processes cited above are feasible and can be used to constraint the QCD dynamics in high energies.

Philosophiae Doctor - PhD / Lying in a rapidly-changing transitional region between nuclei that may behave as spherical vibrators (N ≤ 88) or good rotors (N ≥ 92), the N = 90 isotones present a unique testing ground where new nuclear collective phenomena may be uncovered. As part of a general investigation of collective structures and the coupling of single-particle states to these structures, the 150Sm(12C,4nγγ) and 150Sm(13C,4nγγ) reactions at a beam energy of Elab = 65 MeV were used to study the low and medium spin structure of 158,159Er nuclei below spin 20~. The γ-γ coincidence events were detected in the nine escape-suppressed HPGe Clover detectors using the AFRODITE γ-ray spectrometer at the iThemba Laboratory for Accelerator Based Sciences. DCO ratios and γ-ray polarization measurements were used to establish the spins and parities of newly observed and confirm previously established rotational bands. The observed bands will be discussed in terms of both traditional quadrupole rotational-vibration models and recent predictions of octupole correlations in the N = 90 isotones and neighbouring nuclei. The data obtained will be compared with the spectroscopic systematics of neighbouring nuclei.

Philosophiae Doctor - PhD / The combination of ion track technology and chemical etching as a tool to enhance polymer gas properties such as permeability and selectivity is regarded as an avenue to establish technology commercialization and enhance applicability. Traditionally, permeability and selectivity of polymers have been major challenges especially for gas applications. However, it is important to understand the intrinsic polymer properties in order to be able to predict or identify their possible ion-polymer interactions thus facilitate the reorientation of existing polymer structural configurations. This in turn can enhance the gas permeability and selectivity properties of the polymers. Therefore, the choice of polymer is an important prerequisite. Polyethylene terephthalate (PET) belongs to the polyester group of polymers and has been extensively studied within the context of post-synthesis modification techniques using swift heavy ion irradiation and chemical treatment which is generally referred to as ‘track-etching’. The use of track-etched polymers in the form of symmetrical membranes structures to investigate gas permeability and selectivity properties has proved successful. However, the previous studies on track-etched polymers films have been mainly focused on the preparation of symmetrical membrane structure, especially in the case of polyesters such as PET polymer films. Also, polyolefins such as polymethyl pentene (PMP) have not been investigated using swift heavy ions and chemical etching procedures. In addition, the use of ‘shielded’ material on PET and PMP polymer films prior to swift heavy ion irradiation and chemical etching to prepare asymmetrical membrane structure have not been investigated. The gas permeability and selectivity of the asymmetrical membrane prepared from swift heavy ion irradiated etched 'shielded' PET and PMP polymer films have not been determined. These highlighted limitations will be addressed in this study. The overall objective of this study was to prepare asymmetric polymeric membranes with porous surface on dense layer from two classes of polymers; (PET and PMP) in order to improve their gas permeability and selectivity properties. The research approach in this study was to use a simple and novel method to prepare an asymmetric PET and PMP polymer membrane with porous surface and dense layer by mechanical attachment of ‘shielded’ material on the polymer film before swift heavy ion irradiation. This irradiation approach allowed for the control of swift heavy ion penetration depth into the PET and PMP polymer film during irradiation. The procedure used in this study is briefly described. Commercial PET and PMP polymer films were mechanically ‘shielded’ with aluminium and PET foils respectively. The ‘shielded’ PET polymer films were then irradiated with swift heavy ions of Xe source while ‘shielded’ PMP polymer films were irradiated with swift heavy ions Kr. The ion energy and fluence of Xe ions was 1.3 MeV and 106 respectively while the Kr ion energy was 3.57 MeV and ion fluence of 109. After swift heavy ion irradiation of ‘shielded’ PET and PMP polymer films, the attached ‘shielded’ materials were removed from PET and PMP polymer film and the irradiated PET and PMP polymer films were chemically etched in sodium hydroxide (NaOH) and acidified chromium trioxide (H2SO4 + CrO3) respectively. The chemical etching conditions of swift heavy ion irradiated ‘shielded’ PET was performed with 1 M NaOH at 80 ˚C under various etching times of 3, 6, 9 and 12 minutes. As for the swift heavy ion irradiated ‘shielded’ PMP polymer film, the chemical etching was performed with 7 M H2SO4 + 3 M CrO3 solution, etching temperature was varied between 40 ˚C and 80 ˚C while the etching time was between 40 minutes to 150 minutes. The SEM (surface and cross-section micrograph) morphology results of the swift heavy ion irradiated ‘shielded’ etched PET and PMP films showed that asymmetric membranes with a single-sided porous surface and dense layer was prepared and remained unchanged even after 12 minutes of etching with 1 M NaOH solution as in the case of PET and 2 hours 30 minutes of etching with 7 M H2SO4 + 3 M CrO3 as observed for PMP polymer film. Also, the swift heavy ion irradiated ‘shielded’ etched PET polymer film showed the presence of pores on the polymer film surface within 3 minutes of etching. After 12 minutes chemical etching with 1 M NaOH solution, the dense layer of swift heavy ion irradiated ‘shielded’ etched PET polymer film experienced significant reduction in thickness of about 40 % of the original thickness of as-received PET polymer film. The surface morphology of swift heavy ion irradiated ‘shielded’ etched PET polymer film by SEM analysis revealed finely distributed pores with spherical shapes for the swift heavy ion irradiated ‘shielded’ etched PET polymer film within 6 minutes of etching with 1 M NaOH solution. Also, after 9 minutes and 12 minutes of etching with 1 M NaOH solution of the swift heavy ion irradiated ‘shielded’ etched PET polymer film, the pore walls experienced complete collapse with intense surface roughness. Interestingly, the 12 minutes etched swift heavy ion ‘shielded’ irradiated PET did not lose its asymmetrical membrane structure despite the collapse of the pore walls. In the case of swift heavy ion irradiated ‘shielded’ etched PMP polymer film, SEM morphology analysis showed that the pores retained their shape with the presence of defined pores without intense surface roughness even after extended etching with 7 M H2SO4 + 3 M CrO3 for 2 hours 30 minutes. Also, the pores of swift heavy ion irradiated ‘shielded’ etched PMP polymer films were observed to be mono dispersed and not agglomerated or overlapped. The SEM cross-section morphology of the swift heavy ion irradiated ‘shielded’ etched PMP polymer film showed radially oriented pores with increased pore diameters in the PMP polymer film which indicated that etching was radial instead of lateral, and no through pores were observed showing that the dense asymmetrical structure was retained. The SEM results revealed that the pore morphology i.e. size and shape could be accurately controlled during chemical etching of swift heavy ion ‘shielded’ irradiated PET and PMP polymer films. The XRD results of swift heavy ion irradiated ‘shielded’ etched PET revealed a single diffraction peak for various times of chemical etching in 1 M NaOH solution at 3, 6, 9 and 12 minutes. The diffraction peak of swift heavy ion irradiated ‘shielded’ etched PET was observed to reduce in intensity and marginally shifted to lower angles from 25.95˚ 2 theta to 25.89˚ 2 theta and also became broad in shape. It was considered that the continuous broadening of diffraction peaks due to an increase in etching times could be attributed to disorderliness of the ordered region within the polymer matrix and thus decreases in crystallinity of the swift heavy ion irradiated ‘shielded’ etched PET polymer film. The XRD analysis of swift heavy ion irradiated ‘shielded’ etched PMP polymer films indicated the presence of the diffraction peak at 9.75˚ 2 theta with decrease in intensity while the diffraction peaks located at 13.34˚, 16.42˚, 18.54˚ and 21.46˚ 2 theta disappeared after chemical etching in acidified chromium trioxide (H2SO4 + CrO3) after 2 hours 30 minutes. The TGA thermal profile analysis of swift heavy ion irradiated ‘shielded’ etched PET did not show the evolution of volatile species or moisture at lower temperatures even after 12 minutes of etching in 1 M NaOH solution in comparison with commercial PET polymer film. Also, it was observed that the swift heavy ion irradiated layered’ etched PET polymer film started to undergo degradation at a higher temperature than untreated PET which resulted in an approximate increase of 50 ˚C in comparison with the commercial PET polymer film. The TGA results of swift heavy ion irradiated ‘shielded’ etched PMP polymer film revealed an improvement of about 50 ˚C in thermal stability before thermal degradation even after etching in acidified chromium trioxide for 2 hours 30 minutes at 80 ˚C. Spectroscopy (IR) analysis of the swift heavy ion irradiated ‘shielded’ etched PET and PMP polymer films showed the presence of characteristic functional groups associated with either PET or PMP structures. The variations of irradiation and chemical etching conditions revealed that the swift heavy ion ‘shielded’ irradiated etched PET polymer film experienced continuous degradation of available functional groups as a function of etching time and also with complete disappearance of some functional groups such as 1105 cm-1 and 1129 cm-1 compared with the as-received PET polymer film which are both associated with the para-substituted position of benzene rings. In the case of swift heavy ion irradiated ‘shielded’ etched PMP polymer film, spectroscopic (IR) analysis showed significant variations in the susceptibility of associated functional groups within the PMP polymer film with selective attack and emergence of some specific functional groups such as at 1478 cm-1, 1810 cm-1 and 2115 cm-1 which were assigned to methylene, CH3 (asymmetry deformation), CH3 and CH2 respectively Also, the IR results for swift heavy ion irradiated ‘shielded’ etched PMP polymer showed that unsaturated olefinic groups were the dominant functional groups that were being attacked by during etching with acidified chromium trioxide (H2SO4+CrO3) which is an aggressive chemical etchant. The gas permeability analysis of swift heavy ion irradiated ‘shielded’ etched PET and PMP polymer films showed that the gas permeability was improved in comparison with the as-received PET and as-received PMP polymer films. The gas permeability of swift heavy ion irradiated ‘shielded’ etched PET increased as a function of etching time and was found to be highest after 12 minutes of chemical etching in 1 M NaOH at 80 ˚C. In the case of swift heavy ion irradiated ‘shielded’ etched PMP, the gas permeability was observed to show the highest gas permeability after 2 hours 30 minutes of etching in H2SO4 + CrO3 solution. The gas permeability analysis for swift heavy ion irradiated ‘shielded’ PET and PMP polymer films was tested for He, CO2 and CH4 and the permeability results showed that helium was most permeable compared with CO2 and CH4 gases. In comparison, the selectivity analysis was performed for He/CO2 and CH4/He and the results showed that the selectivity decreased with increasing in etching time as expected. This study identified some important findings. Firstly, it was observed that the use of ‘shielded’ material on PET and PMP polymer films prior to swift heavy ion irradiation proved successful in the creation of asymmetrical polymer membrane structure. Also, it was also observed that the chemical etching of the ‘shielded’ swift heavy ion irradiated PET and PMP polymer films resulted in the presence of pores on the swift heavy ion irradiated side while the unirradiated sides of the PET and PMP polymer films were unaffected during chemical etching hence the pore depth could be controlled. In addition, the etching experiment showed that the pores geometry can be controlled as well as the gas permeability and selectivity properties of swift heavy ion ‘shielded’ irradiated etched PET and PMP polymer films. The process of polymer bulk and surface properties modification using ion-track technology i.e. swift heavy ion irradiation and subsequent chemical treatment of the irradiated polymer serves to reveal characteristic pore profiles unique to the prevailing ion-polymer interaction and ultimately results in alteration of the polymer characteristics.

L'oxyde de grille des composants peut subir un claquage suite au passage d'un ion lourd unique au travers d'un événement appelé « Single Event Gate Rupture » (SEGR). Dans certains cas, aucune dégradation apparente n'est observée après irradiation bien qu'une interaction ait eue lieu au sein de la couche d'oxyde. Nous parlons alors de la création de défauts latents au sein de la couche isolante. L'objet de cette thèse consiste à évaluer l'impact de ce type de défaut sur la dé-fiabilisation des systèmes de conversion d'énergie embarqués à bord des satellites. En Europe, les principaux maîtres d'œuvre dans la fabrication des satellites se trouvent aujourd'hui face au problème que pose la prise en compte de ces défauts latents. En effet, pour garantir la fiabilité du système de conversion d'énergie, les transistors MOS de puissance doivent suivre une procédure de qualification radiation basée sur la méthode de test militaire américaine MIL-STD-750E/1080. Cette méthode est identique en tout point au standard européen mais recommande en plus, d'effectuer un stress électrique post radiation (Post Gate Stress Test, PGST) afin de révéler la présence d'éventuels défauts latents créés pendant l'irradiation. L'objet de ce travail est d'amener des résultats scientifiques permettant de statuer sur la pertinence du PGST. / At present, space actors are highly concerned with heavy ion-induced power MOSFETs hard failures and in particular by oxide rupture after heavy ion irradiations. In order to guarantee the reliability of space systems, contractors have to follow qualification procedures. The US military standard for heavy ion testing, MIL-STD-750E method 1080, recommends performing a post irradiation test (Post Gate Stress Test PGST) in order to reveal latent defects sites that might have been created during irradiation. Unfortunately, this type of test can only be considered as a pass or fail test. With a too much restrictive approach, rare are the devices to be qualified. Even if the US test method is accurate on most of the points, the main issue is related to the Post-irradiation Gate Stress. What is lacking is that this part of the US Test Standard has neither been dedicated to real space missions nor adapted to space environment. The PGST has even no physical basis justifying performing it for space applications. Working from fundamental to applicative, we aim at drawing test standards dedicated to the engineer in charge of space applications. The qualification of power MOSFETs for space applications is one of the major challenges for European space actors. The goal of this thesis is first to focus on latent defects formation criteria and then, to show under which conditions the post irradiation gate stress test might be relevant or not.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23002号 / 理博第4679号 / 新制||理||1671(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 大西 明, 准教授 菅沼 秀夫, 教授 田中 貴浩 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

Title: Study of transverse flow of kaons in Au + Au collisions at 1.23A GeV Author: Lukáš Chlad Abstract: The production and propagation of strange hadrons at the threshold energy are important probes of the in-medium hadron's properties and stiffness of the equation of state of nuclear matter. In this thesis, the transverse kaon flow at Au + Au collisions with kinetic beam energy 1.23A GeV measured with the HADES spectrometer is discussed. The motivation for such an analysis and the theoretical introduction are described first, followed by the characterization of the the individual parts of HADES spectrometer. The procedure to identify detected particles from the measured signals is introduced. Finally, the flow analysis and its results are presented. The differential directed and elliptic flow of kaons in measured gold on gold collisions is compared with published data and with kinetic transport model predictions. Keywords: relativistic heavy-ion collisions, transverse flow, kaon flow 1

No description available.

Highly energetic jets are considered to be a direct probe of hot and dense QCD medium created in heavy ion collisions. Jet measurements performed both at the LHC and RHIC indicate a presence of the jet quenching phenomenon. This thesis summarizes ATLAS jet heavy ion measurements and it reports the first exploratory study of properties of the multi-jet production in heavy ion collisions presented in terms of yield of neighbouring jets. The work is expected to shed a light on the process of the parton energy loss. The measurement is performed using the Pb+Pb collision data collected by ATLAS detector during the 2011 LHC runs at the nucleon-nucleon center of mass energy of 2.76 TeV. 1