Descripción
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The kinetics of amorphization in crystalline SiO2 (a-quartz) under irradiation with swift heavy ions (O+1 at 4 MeV, O+4 at 13 MeV, F+2 at 5 MeV, F+4 at 15 MeV, Cl+3 at 10 MeV, Cl+4 at 20 MeV, Br+5 at 15 and 25 MeV and Br+8 at 40 MeV) has been analyzed in this work with an Avrami-type law and also with a recently developed cumulative approach (track-overlap model). This latter model assumes a track morphology consisting of an amorphous core (area r) and a surrounding defective halo (area h), both being axially symmetric. The parameters of the two approaches which provide the best fit to the experimental data have been obtained as a function of the electronic stopping power Se. The extrapolation of the r(Se) dependence yields a threshold value for amorphization, Sth ? 2.1 keV/nm; a second threshold is also observed around 4.1 keV/nm. We believe that this double-threshold effect could be related to the appearance of discontinuous tracks in the region between 2.1 and 4.1 keV/nm. For stopping power values around or below the lower threshold, where the ratio h/r is large, the track-overlap model provides a much better fit than the Avrami function. Therefore, the data show that a right modeling of the amorphization kinetics needs to take into account the contribution of the defective track halo. Finally, a short comparative discussion with the kinetic laws obtained for elastic collision damage is given | |
Internacional
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Si |
JCR del ISI
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Si |
Título de la revista
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Journal of Nuclear Materials |
ISSN
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0022-3115 |
Factor de impacto JCR
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Información de impacto
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Volumen
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430 |
DOI
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Número de revista
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Desde la página
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125 |
Hasta la página
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131 |
Mes
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SIN MES |
Ranking
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