THERMAL ASSISTANCE AND THERMAL QUENCHING RELATED TO DEEP ELECTRON TRAPS IN ANNEALED SYNTHETIC QUARTZ

Abstract

Thermally assisted optically stimulated luminescence measured from annealed synthetic quartz using continuous-wave optical stimulation (CW-OSL) is reported. The samples were each annealed at 500,  900 and 1000 ^oC for 10 minutes before use. The sample annealed at  900 ^oC for 10 minutes was further annealed for 30 and 60 minutes to study features related to the duration of annealing. The samples were stimulated using 470 nm blue  LEDs at temperatures between 30  and 200 ^oC. Prior to optical stimulation, the sample was preheated to 500 ^oC. The integrated OSL intensity goes through a peak as a function of measurement temperature. The CW-OSL luminescence intensity increases from 30 ^oC to a maximum at 130 ^oC and thereafter decrease to 200 ^oC, the maximum temperature of the investigations. The increase in OSL intensity is explained in terms of thermal assistance and the decrease is ascribed to thermal quenching. The activation energy of thermal assistance and thermal quenching for sample anneaed at 500 ^oC for 10 minutes were evaluated as eV and  eV respectively. The annealing temperature and duration of annealing were found to affect the thermal assistance and thermal quenching parameters to some extent