钛宝石中子辐照色心的研究

研究了中子辐照下钛宝石单晶体缺陷的形成及光学性能的变化。对温度梯度法(TGT)生长的钛宝石晶体进行中子辐照。中子能量为1．5MeV，剂量为4．32×10^18 neutrons／cm^2。辐照后194nm吸收峰强度增加,268nm吸收峰强度则降低。荧光谱检测中发现辐照使得420nm荧光峰强度明显降低，荧光峰位置也蓝移至414nm处。分析表明辐照使得钛宝石晶体内形成F^+缺陷，同时Ti^4+离子则转化成Ti^3+离子。辐照后的钛宝石在247C处有热释光TL出现，通过初始上升法计算出其陷阱深度为0．63eV。

Neutron-irradiation induced optical properties changes and defects formation in Ti-doped sapphire crystals were studied. Temperature gradient technique (TGT) grown Ti-doped sapphire crystals were irradiated by 1.5 MeV neutrons with a dose of 4.32×1016 neutrons/cm2. Absorption, emission and excitation spectra were presented. The 194-nm absorption band intensity enhanced and the 268-nm band weakened after irradiation. And the 420-nm luminescence band weakened and blue shifted to 414-nm. The results indicated that F+-type centers formed and the valence state of titanium switched from quadrivalent to trivalent during irradiation. Thermoluminescence (TL) was observed at 247℃ and assigned to irradiation-induced color centers. The thermoluminescence trap depth is 0.63 eV calculated with initial elevation method, and the lower thermoluminescence intensity is ascribed to the quenching effect of Ti ions.