Thermoluminescence and mechanoluminescence of gamma-ray-irradiated SrB4O7:Dy phosphors

Abstract

Undoped and Dy-doped SrB4O7 phosphors were synthesised by solid-state reaction technique. X-ray diffraction pattern of the sample was recorded to confirm the formation of the sample. Thermoluminescence (TL) and mechanoluminescence (ML) of the gamma-ray-irradiated samples have been studied. A band in the range 200–260°C was observed in the TL glow curve of the gamma-ray-irradiated phosphors. Occurrence of a band in the TL glow curve is probably due to the overlapping of two or more than two quasi-static TL peaks. ML was excited impulsively by dropping a piston of mass 0.6 kg onto the samples with various impact velocities. A single peak was observed in the ML intensity against time curve. ML peak intensity increases with increasing impact velocity (stress rate). To study the effect of deformation on the TL of the SrB4O7 phosphors, TL of the deformed samples was recorded. It was observed that TL intensity reduced drastically and it was also observed that TL intensity decreased with increasing the deformation rate and the shape of glow curve was also changed. Decrement in TL with deformation is probably due to the de-trapping of trapped charge carriers responsible for TL and de-trapping of charge carriers increases with increasing deformation rate. Post-irradiation deformation may cause the redistribution of traps; consequently, shape of the glow curve may change.