Thermoluminescence characteristics of BaB4O7:Dy phosphor

The polycrystalline powder samples of dysprosium-doped BaB4O7:Dy phosphor were prepared by a solid-state reaction in air at high temperature and the thermoluminescence (TL) glow curves and three-dimensional (3D) TL emission spectrum after Co-60 gamma-ray irradiation was studied in the 20-130 kGy dose range at 293 K. The emission bands about at 480, 575, 660 and 750 nm were observed in the three-dimensional (313) emission spectrum. The 3D TL emission spectrum of the BaB4O7:Dy is attributed to the characteristic emission from transitions of Dy3+ ion. That no emission spectrum is observed for Dy2+ ions is probably due to the emission wavelengths lying outside the measurement range. The distributions of traps produced by the irradiation of gamma-ray can be altered greatly by the change of the concentrations of Dy3+ ion doped in BaB4O7 and peaks temperatures shift to higher temperature, this will be favorable for TL output. The depth of trap E of the main peak of BaB4O7:Dy is calculated as 1.38 eV. The influence of the Co-60 gamma-ray irradiation doses on thermoluminescence of BaB4O7:Dy phosphor and the order of kinetics of TL glow peaks were also discussed. The TL-dose response of the BaB4O7:Dy polycrystalline powder sample to gamma-ray radiation in the range from 1 to 100 Gy for clinical dose levels is almost linearity. The experiment results showed that BaB4O7:Dy potential use as the materials of gamma-ray thermoluminescence dosimeter (TLD) for clinical dosimetry. (C) 2004 Elsevier B.V. All rights reserved.