Y3+掺杂Ce:Li6Lu(BO3)3闪烁体的发光性能研究

针对Ce:Li₆Lu(BO₃)₃晶体有效原子序数(Z_eff)高的问题, 采用低原子序数的Y³⁺离子部分置换晶体中的Lu³⁺离子。通过固相合成法制备了Ce:Li₆Lu_1-xY_x(BO₃)₃(0≤x≤1)固溶体。X射线粉末衍射(XRD)分析表明, 该系列固溶体结构与Li₆Gd(BO₃)₃晶体相同, 空间群为P2_1/c。其X射线激发发射(XSL)的发光强度随着Y³⁺的含量增加而降低, 当x=0.5时, 固溶体的有效原子序数与Li₆Gd(BO₃)₃闪烁体相当, 但XSL发光强度是其1.4倍。Ce:Li₆Lu_0.5Y_0.5(BO₃)₃的XSL光谱和PL光谱都在400 nm附近出现Ce³⁺离子的特征峰, 可拟合出361和419 nm两个发光分量, 分别对应于Ce³⁺离子的激发态电子的⁵d₁→²F_5/2和⁵d₁→²F_7/2能级跃迁。Ce:Li₆Lu_0.5Y_0.5(BO₃)₃固溶体的衰减时间比Ce:Li₆Lu(BO₃)₃略长, 为19.6 ns。当x=0.50~0.70时, Ce:Li₆Lu_1-xY_x(BO₃)₃(0≤x≤1)闪烁体比较适合作为中子探测材料。

Luminescence Properties of High Y3+-doped Ce:Li6Lu(BO3)3 Scintillators

To decrease the high effective atomic number (Z_eff) of Ce:Li₆Lu(BO₃)₃ crystal, Y³⁺, which has a lower atomic number, is introduced to substitute Lu³⁺. The Ce:Li₆Lu_1-xY_x(BO₃)₃(0≤x≤1) solid solutions were prepared by the solid-state synthesis method. Based on the X-ray powder diffraction (XRD) analysis, Ce: Li₆Lu_1-xY_x(BO₃)₃ (0≤x≤1) solid solutions and Li₆Gd(BO₃)₃ crystal have the similar XRD patterns and belong to the space group P2_1/c. The luminescence intensity of X-ray stimulated luminescence (XSL) spectrum of Ce:Li₆Lu_1-xY_x(BO₃) (0≤x≤1) decreases with the increasing of the content of Y³⁺. In the case of x=0.5, the Z_eff of Ce:Li₆Lu_0.5Y_0.5(BO₃)₃ is similar to that of Ce:Li₆Gd(BO₃)₃, while the luminescence intensity of Ce:Li₆Lu_0.5Y_0.5(BO₃)₃ is as much as 1.4 times of Ce:Li₆Gd(BO₃)₃. The XSL and PL spectra of Ce:Li₆Lu_0.5Y_0.5(BO₃)₃ indicate that the emission band around 400?nm can be fitted into two peaks, 391 nm and 419 nm, which correspond to the electronic transition from 5d energy level to ²F_5/2 and ²F_7/2 of Ce³⁺ ions, respectively. The decaying time of Ce:Li₆Lu_0.5Y_0.5(BO₃)₃ is about 19.6 ns. When x=0.50-0.70, Ce:Li₆Lu_1-xY_x(BO₃)₃(0≤x≤1) is suitable for using as neutron detection material.