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Pedroza M, M.; Melendrez, R.; Barboza F, M.; Castaneda, B.
Universidad Autonoma Metropolitana, Unidad Iztapalapa, Mexico D.F. (Mexico)2004
Universidad Autonoma Metropolitana, Unidad Iztapalapa, Mexico D.F. (Mexico)2004
AbstractAbstract
[en] The creation of defects in polluted alkaline halogenides with divalent impurities exposed to ionizing radiation is explained by means of the creation of auto trapped excitons (STE), which can be formed by means of the excitement of the halogen ion or through the trapping of electrons in centers VK taken place during the process of ionization of the halogen ion. The luminescent recombination of the exciton auto trapped produces a characteristic exciton luminescence and the recombination non radiative causes the formation of the Frenkel type defects, even of centers F - H. Experimentally has been demonstrated that the same type of glasses, exposed to radiation non ionizing of the type UV of around 230 nm, they produce defects similar Frenkel. The situation is interesting all time that photons of 230 nm (5.3 eV) they cannot create excitons directly since they are in an energy level of approximately 2.4 inferior eV to the necessary energy for the production of the same ones. In order to investigating the type of process of creation of defects with UV light energy below the energy of the band prohibited in polluted alkaline halogenides with Eu2+, mainly looking for experimental information that allows to explain the creation of defects taken place by the radiation non ionizing, one carries out the present work. It was found that, independently of the energy of the radiation used for the excitement, the emission comes from the transition 4f65d(t2g)-4f7(8S7/2) of the ion Eu2+ characterized by a wide band centered in 420 nm and an additional component in 460 nm of possibly intrinsic origin. It was determined that so much the F centers and Fz participate in the thermoluminescent processes and of optically stimulated luminescence, achieving to identify those peaks of Tl strictly associated to the F centers (peak in 470 K for the KCl: Eu2+) and Fz (peak in 370 K). Also, by means of a process of selective photo stimulation evidence was obtained that the F center (peak in 470 K) is directly involved in the process of optically stimulated luminescence. Finally, the results point out that the existence of an exciton type process is more feasible of being observed in materials where the quantum efficiency of the auto trapped exciton emission is significantly bigger to that of the materials studied. (Author)
Original Title
Procesos de formacion de defectos en halogenuros alcalinos contaminados con Eu2+ inducidos por radiacion no ionizante
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Secondary Subject
Source
2004; 8 p; 7. International Conference. 17 National Congress on Solid State Dosimetry; Puebla (Mexico); 8-10 Sep 2004; ISBN 970-773-023-4; 

Record Type
Miscellaneous
Literature Type
Conference; Numerical Data
Report Number
Country of publication
ARGON, CRYSTAL DEFECTS, CRYSTAL GROWTH, CRYSTALS, CZOCHRALSKI METHOD, DIAGRAMS, EMISSION SPECTRA, EUROPIUM IONS, EXCITONS, EXPERIMENTAL DATA, F CENTERS, FRENKEL DEFECTS, HALOGEN COMPOUNDS, HEAT TREATMENTS, IMPURITIES, IONIZING RADIATIONS, LUMINESCENCE, PEAKS, POTASSIUM BROMIDES, POTASSIUM CHLORIDES, TEMPERATURE DEPENDENCE, THERMOLUMINESCENCE, TIME DEPENDENCE, TRAPPING, ULTRAVIOLET RADIATION
ALKALI METAL COMPOUNDS, BROMIDES, BROMINE COMPOUNDS, CHARGED PARTICLES, CHLORIDES, CHLORINE COMPOUNDS, COLOR CENTERS, CRYSTAL DEFECTS, CRYSTAL GROWTH METHODS, CRYSTAL STRUCTURE, DATA, ELECTROMAGNETIC RADIATION, ELEMENTS, EMISSION, FLUIDS, GASES, HALIDES, HALOGEN COMPOUNDS, INFORMATION, IONS, LUMINESCENCE, NONMETALS, NUMERICAL DATA, PHOTON EMISSION, POINT DEFECTS, POTASSIUM COMPOUNDS, QUASI PARTICLES, RADIATIONS, RARE GASES, SPECTRA, VACANCIES
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