A study of positronium formation in anodic alumina
| Autor: | Carlos Palacio, Corine Bas, N. Charvin, K Delendik, O Voitik, S. N. Gninenko, Nikolay Djourelov, G Drobychev, D Sillou, J. De Baerdemaeker |
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| Přispěvatelé: | Matériaux organiques à propriétés spécifiques (LMOPS), Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces (LEPMI ), Institut de Chimie du CNRS (INC)-Institut National Polytechnique de Grenoble (INPG)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut National Polytechnique de Grenoble (INPG)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2008 |
| Předmět: |
Physics
Annihilation Annealing (metallurgy) Analytical chemistry 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Amorphous solid Positronium Positron 0103 physical sciences [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] General Materials Science Crystallite Atomic physics 010306 general physics 0210 nano-technology Spectroscopy Doppler broadening |
| Zdroj: | Journal of Physics: Condensed Matter Journal of Physics: Condensed Matter, IOP Publishing, 2008, 20, pp.095206. ⟨10.1088/0953-8984/20/9/095206⟩ |
| ISSN: | 1361-648X 0953-8984 |
| DOI: | 10.1088/0953-8984/20/9/095206 |
| Popis: | Al_2O_3 samples grown with natural well-ordered channels (having sizes of 30–90 nm in diameter) perpendicular to the surface, one side closed, were measured by means of Doppler broadening (DB) by variable energy positron (VEP) beam and positron annihilation lifetime (PAL) spectroscopy. The samples annealed at 300 and 560 °C showed amorphous structure and no positronium (Ps) formation. The sample annealed at 850 °C showed gamma-phase polycrystalline structure and Ps formation. We were not able to prove from the PAL spectroscopy results themselves whether Ps is confined to the channels. We discuss the results of decomposition of the DB annihilation peak into four Gaussians. We conclude that the greater Ps fraction is confined to the channels. From the Compton-to-peak ratio analysis, the fraction of all the injected positrons which form o-Ps and in this form escape from the sample (for a VEP experiment, we have e+ injected from the open side of the channels) has been estimated as being ~20%. |
| Databáze: | OpenAIRE |
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