Phototransferred thermoluminescence characteristics of microcline (KAlSi3O8) under 470 nm blue- and 870 nm infrared-light illumination

Abstract

We report phototransferred thermoluminescence (PTTL) induced in microcline by 470 nm blue- and 870 nm infrared-light. A conventional thermoluminescence (TL) glow curve measured from a sample irradiated to 40 Gy produces five composite TL glow peaks P1, P2, P3, P4 and P5 at 90, 123, 166, 298 and 391 °C respectively. The sample produces PTTL peaks also identified as P1, P2, P3 and P4 following illumination by blue or infrared light after irradiation to 40 Gy and preheating to 400 °C. Step-annealing suggests the presence of deep electron traps associated with a signal beyond 500 °C. However, preheating to 500 °C and exposure to blue or infrared light does not produce significant PTTL peaks. For doses between 40 Gy and 100 Gy, the maximum PTTL is emitted within 60 and 150 s of blue light illumination. On the other hand, the same feature under the infrared light illumination occurs within 100–200 s of illumination. PTTL peaks P1, P2, P3 and P4 reproduced under blue light illumination have a linear dose response between 10 Gy and 100 Gy and those reproduced under infrared light illumination have a superlinear dose response between 10 and 100 Gy. In contrast, donor peak P5 in both cases follows sublinear dose response within the same dose range. Fading of PTTL peaks P1, P2, P3 and P4 as well as the donor peak P5 are negligibly small under blue light illumination compared to that of infrared light illumination. PTTL glow curves are also found to be properly reproducible.