电子俘获材料Zn4B6O13:Dy3+的热释光特性研究

通过高温固相扩散反应合成了稀土元素镝掺杂的Zn4-xB6O13:xDy3+磷光体.测定了该化合物在高能60Co伽玛射线辐照下的热释发光曲线和三维热释光谱.三维热释光谱表明,位于大约480nm和580nm的发光谱带来自于Dy3+离子的f-f跃迁.基质中掺杂的Dy3+离子浓度的变化能够改变陷阱的相对分布,随着Dy3+浓度的增加,发光峰温向高温方向移动,这可提高剂量器的热稳定性.当辐照剂量增加时,发光峰温亦向高温方向移动,即陷阱加深.确定了Zn3.86B6O13:0.16Dy3+样品主峰的陷阱深度E=0.73eV,频率因子S=2.43×109s-1.在1～100Gy治疗级范围内,Zn3.86B6O13:0.16Dy3+对60Co伽玛射线辐照的热释光剂量响应呈良好的线性关系.实验结果表明,Zn3.86B6O13:0.16Dy3+是一个潜在的应用于临床医疗的伽玛射线电离辐射热释光剂量计材料.

Thermoluminescence Properties of Electron Trapping Material Zn4B6O13:Dy3+

The Dy 3+-doped Zn4-xB6O13:xDy3+ phosphors were prepared by solid-state reaction in air at high temperature. The thermoluminescence(TL) glow curves and three-dimensional(3D) spectrum after 60Co gamma ray irradiation were studied at 293 K. The emission bands at about 480 nm and 580 nm were observed in the three dimensional(3D) spectrum, which are attributed to the characteristic emission from f-f transitions of Dy 3+ ions. The distributions of traps produced by the irradiation of gamma ray can be altered greatly by the change of the concentrations of Dy 3+ ion doped in Zn4B6O13. The peak temperatures shift to higher temperature with the increasing of concentration of Dy 3+ ions in the studied range, this can enhance thermal stability of dosimeter. All glow peaks shift towards higher temperatures with the increase of irradiation dose, i.e. the thermal activation energy(E) is increased with the enhancement of irradiation dose in the studied range. The trap depth E of the main peak of Zn 3.86B6O13:0.16Dy 3+ phosphor is calculated as 0.73 eV, the frequency factor S=2.43×109 s-1. The TL dose-response curve to 60Co gamma-radiation for Zn 3.84B6O13:0.16Dy in the dose range from 1～100 Gy is linear. The experiment results showed that Zn 3.86B6O13:0.16Dy has potential use as the materials of gamma-ray thermoluminescence dosimeter(TLD) for clinical dosimeter.