Y^(3+)掺杂Ce:Li_6Lu(BO_3)_3闪烁体的发光性能研究

Luminescence Properties of High Y^(3+)-doped Ce:Li_6Lu(BO_3)_3Scintillators

针对Ce:Li6Lu(BO3)3晶体有效原子序数(Zeff)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:Li6Lu1-x Yx(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P21/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:Li6Lu0.5Y0.5(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→2F5/2和5d1→2F7/2能级跃迁。Ce:Li6Lu0.5Y0.5(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:Li6Lu1-x Yx(BO3)3(0≤x≤1)闪烁体比较适合作为中子探测材料。

To decrease the high effective atomic number （Zeff） of Ce：Li6Lu（BO3）3 crystal, Y3＋, which has a lower atomic number, is introduced to substitute Lu3＋. The Ce：Li6Lu1-xYx（BO3）3（O≤x≤1） solid solutions were prepared by the solid-state synthesis method. Based on the X-ray powder diffraction （XRD） analysis, Ce： Li6Lu1-xYx（BO3）3 （0≤x≤ 1） solid solutions and Li6Gd（BO3）3 crystal have the similar XRD patterns and belong to the space group P21/e. The lumines- cence intensity of X-ray stimulated luminescence （XSL） spectrum of Ce：Li6Lu1-xYx（BO3） （0≤x≤ 1） decreases with the increasing of the content of y3＋. In the case of x=0.5, the Zeff of Ce：Li6Luo.sYo.5（BO3）3 is similar to that of Ce：Li6Gd（BO3）3, while the luminescence intensity of Ce：Li6Lu0.5Y0.5（BO3）3 is as much as 1.4 times of Ce：Li6Gd（BO3）3. The XSL and PL spectra of Ce：Li6Lu0.5Y0.5（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 2F5/2 and2F7/2 of Ce3＋ ions, respectively. The decaying time of Ce：Li6Luo.sYo.5（BO3）3 is about 19.6 ns. When x=0.50-0.70, Ce：Li6Lu1-xYx（BO3）3（0≤x≤ 1） is suitable for using as neutron detection material.