Positron Scattering
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Changes in the crystalline degree in neutron irradiated EPDM viewed through infrared spectroscopy and inelastic neutron scattering
ABSTRACT The changes in the degree of crystallinity in commercial Ethylene Propylene Diene rubber-type M (EPDM) irradiated with neutrons at different doses has been studied by means of inelastic neutron scattering and infrared absorption spectroscopy experiments. EPDM samples were taken from the housing of non-ceramic electrical insulators which are used in
Matéria (Rio J.). Publicado em: 19/07/2018
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2. Variational calculation of low-energy positron life time in Xe atoms
The least-squares variational method (LSVM) is used for determining trial wavefunctions representing low-energy positron-xenon elastic scattering, which are used to determine the positron lifetime. The trial function is taken to depend on several adjustable parameters, and is improved iteratively by increasing the number of terms. The bound state wavefunctio
Brazilian Journal of Physics. Publicado em: 2010-03
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3. Applications of the Schwinger multichannel method to electron and positron scattering by molecules / Aplicaçôes do metodo multicanal de Schwinger ao espalhamento de eletrons e positrons por moleculas
O Método Multicanal de Schwinger (SMC) foi utilizado para estudar o espalhamento de elétrons e pósitrons de baixa energia por moléculas de pirrol (C4H4NH) e propanol (C3H7OH), para o primeiro caso, e acetileno (C2H2) e monóxido de carbono (CO), para o último caso. Seções de choque elásticas integrais e diferenciais foram calculadas para todos os sis
Publicado em: 2010
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4. Espalhamento de Férmions sob Influencia da Violação de Lorentz no Setor Fotônico / Scattering of Fermions under Influence of Violation Lorentz Sector Photonic
The standard model extension is a theoretical framework which includes the possibility of Lorentz symmetry violation in the Standard Model of elementary interactions. In electrodynamics, this possibility is represented by the term, KμFμF, that violates Lorentz symmetry without jeopardizing CPT symmetry, and the term "μvAμ@A, which violate
Publicado em: 2010
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5. The improvement of the Schwinger multichannel method for positron-atom/molecule scattering / O aprimoramento do metodo multicanal de Schwinger para o espalhamento de positrons por atomos/moleculas
Neste trabalho são apresentadas três modificações realizadas no Método Multicanal de Schwinger (SMC) para o espalhamento de pósitrons por moléculas (átomos): a inclusão de um potencial complexo para simular a absorção de partículas, a inclusão de um potencial delta real, proveniente de correções relativísticas, e a exibilização da base com
Publicado em: 2008
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6. Differential ionization studies for positron impact
Recent studies of differential ionization by positron impact being performed at the University of Missouri-Rolla are described. Recoil ion-scattered positron and recoil ion-scattered positron-ejected electron coincidences are measured to provide doubly and triply differential ionization data (DDCS and TDCS) for e+ - Ar collisions. The DDCS and TDCS studies a
Brazilian Journal of Physics. Publicado em: 2006-06
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7. Comparative study of vibracional excitation of hydrogen molecules by electron and positron impact / Estudo comparativo das seções de choque de excitações vibracionais de moleculas de hidrogenio por impacto de positrons e eletrons
Here we report a comparative calculation of both integral and differential vibrational excitation cross sections of low energy positron and electron scattering against Hydrogen molecules (H2). For these calculations we have used the Schwinger Multichannel (SMC) Method [1] for positron collision [2] and electron collision [3]. Using a set of SMC scattering am
Publicado em: 2006
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8. Vibrational excitations mediated by a electronic Feshbach resonance 2Eg+ in electron scattering by hydrogen molecules / Excitações vibracionais medidas pela ressonancia de Feshbach eletronica 2Eg+ no espalhamento de eletrons por moleculas de hidrogenio
The relationship between Feshbach resonances and electronic excitation is well known in electron scattering by Hydrogen molecules, but still little exploited in the positron scattering case, making interesting, a comparative study. However, before thinking about comparisons, we have to address the question if, in fact, a Feshbach resonance manifests itself i
Publicado em: 2006
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9. Dinamica de aniquilação de positrons em gases moleculares
We present applications of the Schwinger Multichannel Method adapted for low energy positron scattering, comparing two isoelectronic molecular systems: acetylene and nitrogen molecules. These systems awake great interest because they present different behavior for the Zeff parameter. Although with small number of electrons ( Z = 14), they present values diff
Publicado em: 2000
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10. Source theory analysis of electron-positron annihilation experiments
The phenomenological viewpoint already applied to deep inelastic scattering is extended to the discussion of electron-positron annihilation experiments. Some heuristic arguments lead to simple forms for the pion differential cross section that are in reasonable accord with the published experimental data in the energy interval 3-4.8 Gev.
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11. Applications of synchrotron radiation to protein crystallography: preliminary results.
X-ray diffraction photographs of protein single crystals have been obtained using synchrotron radiation produced by an electron-positron storage ring. The diffracted intensities observed with this unconventional source are a factor of at least 60 greater than those obtained with a sealed x-ray tube using the same crystal and instrumental parameters. Diffract