This thesis presents a set of measurements of spin asymmetries from the heavy atoms krypton and rubidium. These investigations allow examination of the spin orbit interaction for electron scattering from the target atoms. These measurements utilise spin polarized electrons in a crossed beam experiment to measure the Sherman function from krypton and the A2 parameter from the 52P state of rubidium. The measurements utilise a new spin polarized electron energy spectrometer which is designed to operate in the 20-200 eV range. The apparatus consists of a standard gallium arsenide polarized electron source, a 180 degrees hemispherical electron analyser to detect scattered electrons and a Mott detector to measure electron polarization. A series of measurements of the elastic Sherman function were performed on krypton at incident electron energies of 20, 50, 60, 65, 100, 150 and 200 eV. Scattered electrons are measured over an angular range of 30-130 degrees. These measurements are compared with calculations of the Sherman function which are obtained by solution of the Dirac-Fock equations. These calculations include potentials to account for dynamic polarization and loss of flux into inelastic channels. At the energies 50, 60 and 65 eV, experimental agreement with theory is seen to be extremely dependent on the theoretical model used. Measurement of the A2 parameter from the combined 52P1/2,3/2 state of rubidium are performed at an incident energy of 20 eV. The scattered electrons are measured over an angular range of 30-110 degrees. This measurement represents the first such measurement of this parameter for rubidium. Agreement with preliminary calculations performed using the R-matrix technique are good and are expected to improve with further theoretical development.

The past decade has witnessed dramatic changes in the oil and gas industry with the drilling and production extending into progressively deeper waters and higher operating pressures, therefore making it essential to gain a better understanding of the behaviour of gas hydrate at high pressure conditions. New experimental 3-phase H−LW−V (Hydrate−Liquid Water−Vapour) equilibrium data for nitrogen and H−LW−V (Hydrate−Liquid Water−Vapour) and H−LW−LHC (Hydrate−Liquid Water−Liquid Hydrocarbon) data for ethane and propane simple clathrate hydrates were generated by a reliable fixed-volume, isochoric, step-heating technique. The accuracy and reliability of the experimental measurements are demonstrated by comparing measurements with reliable literature data from different researchers. Additional experimental data up to high pressure (200 MPa when available) for CH4, C2H6, C3H8, i-C4H10, N2, Ar, Kr, Xe, H2S, O2, CO and CO2 clathrates have been gathered from literature. The Valderrama modification of the Patel-Teja (VPT) equation of state combined with non-density-dependent (NDD) mixing rules is used to model the fluid phases with previously reported binary interaction parameters. The hydrate-forming conditions are modelled by the solid solution theory of van der Waals and Platteeuw. Langmuir constants have been calculated by both Kihara potential as well as direct techniques. Model predictions are validated against independent experimental data and a good agreement between predictions and experimental data is observed, supporting the reliability of the developed model.

The field of noble gas mass spectrometry is a rapidly developing one. There is a sustained requirement for continuous development of instrumentation in order to allow researchers to answer critical questions facing their respective fields. Within planetary science, the question of whether our solar system is 'typical', has been a driving force behind many lines of research. This project sought to build upon the strong instrumental base of the Isotope Geochemistry and Cosmochemistry group of the University of Manchester, in order to develop the Resonance Ionisation Mass Spectrometer for Krypton Isotopes. From that basis, it then sought to develop techniques and protocols for the analysis of extra-terrestrial samples, particularly those of very low mass. The thesis is broken down into three studies. The first involved the development of the mechanisms used to fill the Xe-Ar four-wave mixing cell. This section covers the development, implementation, and characterisation of the newly installed mass flow controllers. The additional control over the mixing ratio granted allowed an eightfold increase to the sensitivity of the instrument. The reproducibility of the gas ratio is consistently shown throughout, and has ultimately reduced the tuning time of the instrument from a number of weeks to a day. The second section details the required procedures involved in data reduction, and the development of protocols and software for the RIMSKI instrument. A range of approaches are assessed, including a novel approach to cosmic ray exposure age calculations. The methods are discussed and implemented on extra-terrestrial samples, the Stannern eucrite and the Bereba eucrite. Finally, the analytical limits of the RIMSKI instrument are expanded via the measurement of the krypton systems of individual calcium-aluminium-rich inclusions. It is observed that Allende CAIs show a trapped component, Br-derived Kr, as well as an anomalous 'heavy Kr' component (one that is enriched in 86Kr). It is additionally noted that there is a lack of cosmogenic krypton to be found in all but one of the measured inclusions. The implications of these findings are discussed.

This thesis focuses on the analysis of heavy noble gases (argon, krypton and xenon) and halogens (chlorine, bromine and iodine) in Martian meteorites. In the absence of a sample-return mission, Martian meteorite analysis is essential for establishing evidence for an active fluid system, evaluating the potential for life and understanding the formation and evolution of Mars. Noble gas analysis has multiple applications for Martian meteorite study, as described in this thesis. The noble gas isotopic signatures of Earth’s atmosphere, Martian atmosphere and Martian interior are sufficiently different that they can be distinguished through noble gas analysis. Analysis of bulk and mineral separates of shergottites showed that Martian atmospheric Xe was distributed evenly amongst samples, whilst terrestrially weathered samples contained elevated concentrations of terrestrial atmospheric Xe. Both atmospheric components were introduced by weathering. Shock redistribution is responsible for the distribution of Martian atmosphere into more retentive sites. Crustal contamination may be responsible for the presence or absence of detectable 129Xe from the Martian atmosphere. Halogen abundances can be determined as an extension of the Ar-Ar dating technique. As the halogen system on Earth acts as a tracer for important fluid related processes, Martian halogen abundances in meteorites may provide a tracer for the Martian fluid system. Analysis of bulk and mineral separates of nakhlites showed that halogens are distributed amongst minor phases and clear variation of Br/Cl and I/Cl ratios was observed amongst samples. Elevated I concentrations in low temperature releases of finds NWA 998 and MIL 03346 are consistent with terrestrial contamination. Analysis of Nakhla, (a meteorite fall), showed a trend of elevated Br/Cl and I/Cl ratios in crush and low temperature releases, consistent with Br/Cl ratios observed in Martian rocks, soils and weathering products. In contrast, high temperature releases had lower I/Cl and Br/Cl ratios, which are broadly comparable to the terrestrial mantle. This trend may represent mixing of hydrothermal fluids (low Br/Cl and I/Cl) and surface brines (high Br/Cl and I/Cl). An impact-induced hydrothermal system may provide a mechanism for mixing of both fluid types. The crystallisation ages of nakhlite meteorites were determined using the Ar-Ar dating technique. The apparent ages measured were similar to previous Ar-Ar analysis, and older than reported for other chronometers. Previously unrecognised components were observed, including evidence for a trapped hydrous fluid. This Cl-rich component showed strong correlation with 40Ar and had 40Ar/36Ar and 40Ar/129XeXS ratios consistent with Martian atmosphere. As this component was released during crush and low temperature analysis, fluid inclusions formed by percolation of brines from the Martian surface are likely hosts. Both finds showed clear evidence of a trapped component with 40Ar/36Ar ratios similar to either terrestrial atmosphere or the Martian interior. A further component observed in olivine phases had low 40Ar/36Ar ratios, and likely formed by the release of 36Ar formed by cosmic-ray spallation reactions on iron.

Abstract In this thesis electronic structure of atomic chromium, rubidium and bromine are studied experimentally and theoretically through transitions and decay processes originating from selected M-shell hole states. The experiments are conducted with traditional methods of electron spectroscopy as well as more recent multicoincidence methods using pulsed synchrotron radiation and a magnetic bottle spectrometer. The observed electronic transitions are theoretically simulated with multiconfiguration Dirac-Fock method. Finally, the calculations are used to interpret the measured spectra to investigate the energy level structure and electron dynamics of the studied elements. / Original papers Original papers are not included in the electronically distributed version of the thesis. Keskinen, J., Huttula, S.-M., Mäkinen, A., Patanen, M., & Huttula, M. (2015). Experimental and theoretical study of 3p photoionization and subsequent Auger decay in atomic chromium. Radiation Physics and Chemistry, 117, 209–216. https://doi.org/10.1016/j.radphyschem.2015.08.018 Keskinen, J., Lablanquie, P., Penent, F., Palaudoux, J., Andric, L., Cubaynes, D., … Jänkälä, K. (2017). Initial-state-selected MNN Auger spectroscopy of atomic rubidium. Physical Review A, 95(4). https://doi.org/10.1103/physreva.95.043402 http://jultika.oulu.fi/Record/nbnfi-fe201706207380 Keskinen, J., Jänkälä, K., Huttula, S.-M., Kaneyasu, T., Hikosaka, Y., Shigemasa, E., … Lablanquie, P. (2019). Auger decay of the 3d hole in the isoelectronic series of Br*, Kr⁺ and Rb²⁺. Manuscript in preparation.

Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2017-05-02T11:34:44Z No. of bitstreams: 0 / Made available in DSpace on 2017-05-02T11:34:44Z (GMT). No. of bitstreams: 0 / Dentre as diversas aplicações dos radioisótopos, a utilização dos radiotraçadores é considerada uma das mais importantes, no diagnóstico de funcionamento dos equipamentos de processos, em plantas de indústrias químicas e petroquímicas. Os radiotraçadores são utilizados em procedimentos analíticos para obtenção de dados qualitativos e quantitativos de sistemas, em estudos de transferências físicas e físico-químicas. Na produção de radioisótopos gasosos utilizados como traçadores em processos industriais, destacam-se o 41Ar e 79Kr, gases nobres (inertes) que possuem baixa reatividade com os demais elementos químicos. O 41Ar é um emissor gama de alta energia (1,29 MeV) e apresenta elevada porcentagem de transformações com essa energia, o que resulta em quantidades relativamente pequenas necessárias em relação a outras para uma detecção eficaz, mesmo em componentes com grandes espessuras. Atualmente, a produção de radioisótopos gasosos em reatores nucleares de pesquisa é realizada em pequenas quantidades (bateladas), por meio de ampolas de quartzo contendo o gás natural 40Ar ou 78Kr. Nesse sentido, o objetivo desse estudo é desenvolver um sistema de irradiação capaz de produzir em escala contínua, o radioisótopo gasoso 41Ar, dentre outros, com atividade de 7,4x1011 Bq (20 Ci) por ciclo de irradiação, por meio do Reator IEA-R1 de 4,5 MW, fluxo de nêutrons térmicos médio de 4,71 x 1013 ncm-2s-1, para suprir uma demanda existente em empresas de END e inspeções, e pelo próprio Centro de Tecnologia das Radiações, no IPEN/CNEN-SP. O sistema de irradiação (SI) é constituído por uma cápsula de irradiação em alumínio, linhas de transferência, válvulas agulhas, conexões anilhadas, conectores rápidos, manovacuômetro, sistema de vácuo, dewar de liquefação, blindagem em chumbo, cilindros de armazenamento e transporte (CAT), dentre outros. O SI foi aprovado nos testes de estanqueidade e estabilidade (testes de formação de bolhas, pressurização, evacuação e com equipamento leak detector SPECTRON 600 T). Na produção experimental para obtenção de 1,07x1011 Bq (2,9 Ci) de 41Ar, distribuíram-se dosímetros de alanina em diversos componentes e dispositivos do SI. Além disso, determinaram-se as taxas de exposição na parede da blindagem em chumbo, ao concentrar o gás radioativo liquefeito e no CAT, após a transferência do 41Ar, pelo medidor de radiação portátil Teletector ® Probe 6150 AD-t/H. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

The structural properties of the very neutron deficient systems around N~Z~40 have been studied in two experiments performed at the GANIL and Legnaro laboratories. The fragmentation of a 60 MeV/u92 Mo beam on a natural nickel target at the GANIL Laboratory, France, produced exotic nuclei along the proton drip line in the mass 80 region. Isomeric decays have been observed for the first time in the N=Z+2 systems 74 36Kr, 80 39Y and 84 41Nb. The isomer in 74 Kr is interpreted as the hindered decay from an excited 0+ state, supporting the long-standing prediction of prolate/oblate shape coexistence in this nucleus. Transitions from states below an isomer in the N=Z nucleus 86 43Tc have also been tentatively identified, making this the heaviest N=Z system for which gamma-ray decays from excited states have been observed. Conclusive evidence for the existence of the Z=N+1 isotopes 77 39Y, 79 40Zr and 83 42Mo has also been obtained together with upper limits on the particle decay lifetimes of the odd-proton systems 81 41 Nb and 85 43Tc. The reported instability of the lighter odd-Z, Tz = -1/2 systems 69Br and 73Rb makes the observed existence for 77 39Y particularly interesting. A possible explanation for the relative particle stability of 77 39Y is given in terms of the shape polarising effect of the N=Z=38 prolate shell gap on the nuclear mean field and the increased centrifugal barrier associated with the occupation of a g9/2 proton orbital. The second experiment was performed to further investigate the oblate nature of the isomeric state in 74Kr. The reaction 40Ca(40Ca, alpha2p)74Kr was used at a beam energy of 135 MeV obtained from the Tandem XTU accelerator. The EUROBALL gamma-ray array was used in conjunction with the ISIS charged particle silicon ball to study the states above and below the isomer. The ISIS ball was used to highlight channel selection of non-yrast states by particle gating. No evidence for the 0+2 isomer in 74Kr was observed in this work.

<p>Atoms, molecules and clusters all constitute building blocks of macroscopic matter. Therefore, understanding the electronic and geometrical properties of such systems is the key to understanding the properties of solid state objects.</p><p>In this thesis, some atomic, molecular and cluster systems (clusters of O₂, CH₃Br, Ar/O₂, Ar/Xe and Ar/Kr; dimers of Na; Na and K atoms) have been investigated using synchrotron radiation, and in the two last instances, laser light. We have performed x-ray photoelectron spectroscopy (XPS) on all of these systems. We have also applied ultraviolet photoelectron spectroscopy (UPS), resonant Auger spectroscopy (RAS) and near-edge x-ray absorption spectroscopy (NEXAFS) to study many of the systems. Calculations using <i>ab initio</i> methods, namely density functional theory (DFT) and Møller-Plesset perturbation theory (MP), were employed for electronic structure calculations. The geometrical structure was studied using a combination of <i>ab initio</i> and molecular dynamics (MD) methods.</p><p>Results on the dissociation behavior of CH₃Br and O₂ molecules in clusters are presented. The dissociation of the Na₂ molecule has been characterized and the molecular field splitting of the Na 2<i>p</i> level in the dimer has been measured. The molecular field splitting of the CH₃Br 3<i>d</i> level has been measured and the structure of CH₃Br clusters has been determined to be similar to the structure of the bulk solid. The diffusion behavior of O₂, Kr and Xe on large Ar clusters, as a function of doping rate, has been investigated. The shake-down process has been observed from excited states of Na and K. Laser excited Na atoms have been shown to be magnetically aligned. The shake-down process was used to characterize the origin of various final states that can be observed in the spectrum of ground-state K.</p>

Atoms, molecules and clusters all constitute building blocks of macroscopic matter. Therefore, understanding the electronic and geometrical properties of such systems is the key to understanding the properties of solid state objects. In this thesis, some atomic, molecular and cluster systems (clusters of O2, CH3Br, Ar/O2, Ar/Xe and Ar/Kr; dimers of Na; Na and K atoms) have been investigated using synchrotron radiation, and in the two last instances, laser light. We have performed x-ray photoelectron spectroscopy (XPS) on all of these systems. We have also applied ultraviolet photoelectron spectroscopy (UPS), resonant Auger spectroscopy (RAS) and near-edge x-ray absorption spectroscopy (NEXAFS) to study many of the systems. Calculations using ab initio methods, namely density functional theory (DFT) and Møller-Plesset perturbation theory (MP), were employed for electronic structure calculations. The geometrical structure was studied using a combination of ab initio and molecular dynamics (MD) methods. Results on the dissociation behavior of CH3Br and O2 molecules in clusters are presented. The dissociation of the Na2 molecule has been characterized and the molecular field splitting of the Na 2p level in the dimer has been measured. The molecular field splitting of the CH3Br 3d level has been measured and the structure of CH3Br clusters has been determined to be similar to the structure of the bulk solid. The diffusion behavior of O2, Kr and Xe on large Ar clusters, as a function of doping rate, has been investigated. The shake-down process has been observed from excited states of Na and K. Laser excited Na atoms have been shown to be magnetically aligned. The shake-down process was used to characterize the origin of various final states that can be observed in the spectrum of ground-state K.

Les molécules possédant des atomes identiques en positions interchangeables existent sous différentes formes appelées " configurations de spin nucléaire " identifiées par la symétrie de la fonction d'onde rovibrationnelle et la valeur de leur spin nucléaire total. Dans le cas des molécules hydrogénées présentes dans les milieux interstellaires et cométaires, la mesure des rapports entre populations de configuration de spin différentes montre que ces dernières ne sont pas à l'équilibre thermodynamique attendu dans les conditions de température du milieu. L'origine de ce déséquilibre reste en débat, et des études plus poussées concernant la conversion de spin nucléaire (CSN) dans la phase solide et à l'interface avec la phase gazeuse à basse température sont nécessaires pour mieux comprendre les observations. Ce travail de thèse expérimental est dédié à l'étude de la CSN du CH4 dans des matrices d'argon et de krypton. La molécule de méthane présente trois configurations de spin qui peuvent être distinguées par spectroscopie d'absorption infrarouge à transformée de Fourier. Dans un premier temps, le travail a consisté en l'étude de la spectroscopie du méthane dans ces matrices (attributions, influence de l'environnement cristallin...). Dans un deuxième temps, nous avons étudié la dynamique de CSN par retour à l'équilibre de matrices préalablement enrichies en une espèce de spin donnée. L'influence de (i) la nature, (ii) la concentration en CH4 et (iii) la température (4.2 K - 10 K) des matrices sur les temps de conversion mesurés ont permis de mettre en évidence les différents mécanismes (inter et intramoléculaires) responsables de la modification des espèces de spin nucléaire de CH4. Ces travaux suggèrent que, pour des glaces astrophysiques, l'équilibre des populations relatives entre les configurations de spin devrait être obtenu en phase solide, ce qui remet en cause l'hypothèse de la conservation des rapports otho/para dans les glaces cométaires et interstellaires.