TL, PL and energy transfer in K2Ca2(SO4)3:Eu2+,Ce3+

The effects of Ce co-doping on the thermoluminescence (TL) and photoluminescence (PL) of K2Ca2(SO4)3:Eu phosphor are studied. The TL glow curve of K2Ca2(SO4)3:Eu,Ce sample shows a prominent peak at 420 K along with small shoulder at around 434 K. The TL sensitivity of the codoped sample is nearly 1.7 and 7 times higher than those of K2Ca2(SO4)3:Eu, and CaSO4:Dy phosphors, respectively. PL studies of K2Ca2(SO4)3:Eu phosphor show a well-known single broad band at 436 nm, which could be attributed to Eu2+ emission, while in case of the Ce codoped sample, in addition, other bands of lesser intensities are observed at around 322, 336, 361 and 377 nm, which could be assigned to Ce3+ emissions. The enhancement in TL and PL emissions suggest that Ce3+ ion is playing a positive role in these phenomena and probably energy transfer mechanism is the cause for the improvements. TL response to γ-rays of Cs137 and fading characteristics of the new phosphor are also studied. The phosphor is found to be very sensitive to ionizing radiation and thus might be used as a highly sensitive TLD phosphor.