Electron paramagnetic resonance study of rare-earth related centres in K2YF5:Tb3+ thermoluminescence phosphors

► We studied Tb4+ centres in K2YF5:Tb3+ crystals by X-ray irradiation with EPR. ► The role of Tb4+ centres in the thermoluminescence of K2YF5:Tb3+ was verified. ► The EPR spectra of Er3+ and Yb3+ impurities in K2YF5 were identified.