Effect of co-activation on the thermoluminescence and photoluminescence properties of nano-crystalline K2Ca2(SO4)3:Eu,Cu

Abstract

The effect of co-doping and change in dopant concentration on thermoluminescence (TL) properties of K2Ca2(SO4)3:Eu,Cu has been studied by varying the concentration of the two dopants europium and copper (0.05, 0.10, 0.20, 0.30 and 0.40 mol% equally divided between Eu and Cu). Chemical co-precipitation technique was used to prepare the co-doped phosphor K2Ca2(SO4)3:Eu,Cu. Using Williamson-Hall plot in the X-ray diffraction pattern of the phosphor, the size of the crystallites was estimated to be around 51.3–73.6 nm. Maximum TL sensitivity was obtained for 0.2 mol% concentration (0.1 mol% Eu and 0.1 mol% Cu). The co-doped phosphor was compared for its TL sensitivity with that of the singly doped phosphors K2Ca2(SO4)3:Eu, and K2Ca2(SO4)3:Cu and the standard TL dosimeter LIF:Mg, Ti (TLD-100). Higher TL peak intensity of co-doped phosphor compared to the singly doped phosphors K2Ca2(SO4)3:Eu and K2Ca2(SO4)3:Cu has been explained on the basis of energy transfer between the dopants. Photoluminescence studies of the co-doped and the singly doped samples confirm a positive energy transfer from Cu2+ to Eu2+. A linear TL response curve over a wide range of doses (10 Gy to 1 kGy) is a key factor that makes the present phosphor quite capable for dosimetric purposes.