Thermoluminescence of quartz optical fibres with different contents of OH-groups

Full text: The thermo-luminescence or afterglow (AG) of quartz optical fibres (OF) of FVP-300 marks with contents of 1000 ppm OH groups and FIL with 10 ppm OH-group was studied after gamma γ-irradiations at 77 K to different doses in the temperature interval of 77-300 K. In the both OF types the AG was detected at 77K with the intensity decreasing while keeping at 77K and completely disappeared in 2-3 hours. The AG curves of both types FL contain peaks with maxima at 90, 95, 110, 130, 170 and 220 K. Besides, in FL with low contents OH-groups there is also a broad band at 260K. The intensities of peaks at 170, 220 and 260 K in OF with low contents of OH-groups are much higher than those for a large OH group contents. It means that higher contents of OH group suppresses the formation of these AG peaks. The comparative analysis of AG peaks of these OF types with literary data has shown their full coincidence with the data of work [1] on study of thermal luminescence of quartz crystal activated simultaneously by germanium and aluminum. We explained the studied radiation-stimulated changes in both OF types by analogy with the case of crystalline quartz with Ge and Al admixtures by Mackey model though it does not reflect completely all the processes of creation and annealing the centres. The essence of Mackey model is the following: during γ-irradiation of silicon dioxide at 77K [GeO4]- +[Ale+O4]+M+ centers are formed. Either heating up to 300K or long ageing at 77K (as in our case of OF) leads to the formation of [GeO4]-M+ +[Ale+O4]+hν type centres. References: 1. Tcinober L.I. Proceedings of the conference of All-union Scientific Research Institution of piezo-optic mineral crude, M., 1960, vol. 3, No 2, p. 95. (authors)