Optical, spectral and thermal properties of natural pumice glass


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Correcher V., Gomez-Ros J. M. , Dogan T. , Garcia-Guinea J., TOPAKSU M.

RADIATION PHYSICS AND CHEMISTRY, cilt.130, ss.69-75, 2017 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

Pumice is a natural Si-rich material displaying a complex cathodo- (CL) and thermoluminescence (TL) glow curves. The UV-IR CL emission consists of (i) a UV waveband in the range of 340-420 nm,(ii) blue band at 450-480 nm and (iii) a broad emission in the green-red region (at 550-650 nm) that could be respectively linked to Non Bridging Oxygen Hole Centers (equivalent to Si-O center dot), self-trapped excitons and point defects (Mn2+ -0.03%- and Fe -1.15%-). Thermal treatments performed on the TL glow curves allowed us to determine that the trap system could be associated with a continuum in the trap distribution, since successive thermal pretreatments in the range of 200-310 degrees C induce an emission that shifts linearly to higher temperatures when the thermal pretreatment (T-stop) is increased, while the intensity of the maxima decreases similarly to the peak area. The evaluation of the Ea values, s value and the trap system calculated by VHR, IR and Glow curve fitting methods considering three possible distribution function for n(E): gaussian, exponential and uniform, has given matching values for the 280 degrees C TL peak. (C) 2016 Elsevier Ltd. All rights reserved.