Enhanced long-persistence of Ca^sub 2^Al^sub 2^SiO^sub 7^:Ce^sup 3+^ phosphors for mechanoluminescence and thermoluminescence dosimetry

Ca^sub 2^Al^sub 2^SiO^sub 7^ phosphors having various concentration of Ce^sup 3+^ were synthesized by combustion-assisted method at initiating temperature of 600 °C, using urea as a fuel and its XRD, SEM, TEM and EDX were studied. X-ray diffraction (XRD) pattern indicates that the crystal structure of Ca^sub 2^Al^sub 2^SiO^sub 7^ is mainly tetragonal and particle size of prepared phosphor was determined by TEM. Scanning electron microscope (SEM) image was recorded to observe the surface morphology. Mechanoluminescence (ML) and thermoluminescence (TL) properties of Ca^sub 2^Al^sub 2^SiO^sub 7^:Ce^sup 3+^ phosphors was also investigated. The TL intensity of Ca^sub 2^Al^sub 2^SiO^sub 7^:Ce^sup 3+^ was recorded for different exposure time of γ-irradiation and it was observed that TL intensity is maximum for γ dose of 1180 Gy. The increase in TL intensity indicates that the concentration of traps increases with γ exposure time. The peak of ML intensity versus time curve increases linearly with increasing impact velocity of the moving piston. The ML intensity increases by increasing γ irradiation time up to 1180 Gy. The ML and TL spectra of Ca^sub 2^Al^sub 2^SiO^sub 7^:Ce^sup 3+^ phosphor exhibits a sharp emission at 400 nm wavelength due to transition of Ce^sup 3+^ ions. Mechanism of TL and ML excitation and suitability of Ca^sub 2^Al^sub 2^SiO^sub 7^:Ce^sup 3+^ phosphor for radiation dosimetry have been discussed.