Efecto de la radiación en las propiedades termoluminiscentes de lavas

Abstract

Blue thermoluminescence (TL) emission from different lavas of many places (Costa Rica, Canary Islands, Hawaii Islands, Iceland and Italy) corresponding to different eruptions has been studied to know its potential use in the field of dating and retrospective dosimetry. Due to the light emission is linked to the point defects of the crystalline lattice structure, X-ray diffraction analyses were performed to determine the components of this polymineral material that mostly are cristobalite, plagioclase and phyllosilicates. Exposures to different doses (in a range of 1-25 Gy) were given to each sample to determine the evolution of the TL signal with the irradiation under laboratory conditions. In all cases, a linear response could be observed and no saturation has been detected in this range of doses. Both natural (NTL) and induced (ITL) TL signal exhibit a complex glow curve structure associated to a continuous trap distribution over 100$^{\circ}$C that could be attributed to the formation-annihilation [AlO$_{4}$/alcali]$^{ + }$ and [AlO$_{4}$]$^{o}$ centres. In ITL signal a discrete electron trap distribution (at lower temperature $\sim $85$^{\circ}$C) could be detected, thus the coexistence of both trap structure could be appreciated in this material.