Thermoluminescence mechanism of dysprosium-doped β-tricalcium phosphate phosphor

β-Tricalcium phosphate (β-Ca3(PO4)2, β-TCP) and dysprosium-doped β-tricalcium phosphate (β-Ca3(PO4)2:Dy, β-TCP:Dy) phosphor were synthesized. Powder X-ray diffraction, electron spin resonance (ESR), photoluminescence (PL), and thermoluminescence (TL) were measured. Although no PL and TL could be identified for undoped β-TCP, PL and TL were observed for β-TCP:Dy phosphor. The TL emission peaks are assigned to the f–f transitions of the Dy3+ ion which were found to be the same as those of the PL of β-TCP:Dy phosphor. A detailed analysis of the TL peak shape can give information on the trap depth (activation energy image), indicating the trap depth of image from Hoogenstraatenʹs method. We succeeded in detecting the stable trapped hydrogen atom in the X-ray-irradiated β-TCP:Dy phosphor at room temperature for several months using ESR. The TL phenomenon of β-TCP:Dy phosphor is related with these trapped hydrogen atoms.