New halophosphor K3Ca2(SO4)3F activated by Eu and Ce has been synthesized by a co-precipitation method and characterized according to its thermoluminescence. The formation of traps in rare earth doped K3Ca2(SO4)3F and the effects of γ-radiation dose on the glow curve are discussed. The glow curve of K3Ca2(SO4)3F:Ce shows a prominent single peak at 150°C, whereas K3Ca2(SO4)3F:Eu and K3Ca2(SO4)3F:Ce,Eu at 142°C and 192°C, respectively. A single glow peak indicates that there is only one set of trap being activated within the particular temperature range. The presented phosphors are also studied because of its fading, reusability and trapping parameters. There was just 2% fading during a period of 10 days, indicating no serious fading problem. Trapping parameters such as order of kinetics (b), activation energy (E) and frequency factor (S) were calculated by using Chen's half-width method. The observations presented in this paper are good for lamp phosphors as well as solid-state dosimeter.