以Ｘ射线荧光光谱分析为手段，测试了用Ｂｒｉｄｇｍａｎ方法生长的ＰｂＦ２：Ｇｄ晶体中Ｇｄ离子沿生长方向的分布．发现该晶体在Ｘ射线激发下的发光强度与Ｇｄ在ＰｂＦ２晶体中的含量变化均从结晶开始端至结晶结束端逐渐降低，表明ＰｂＦ２：Ｇｄ晶体的发光是不均匀的，这种不均匀性源于Ｇｄ离子在ＰｂＦ２晶体中的分布不均匀性．通过在ＰｂＦ２：Ｇｄ晶体中掺入一定量的碱金属离子，可以比较有效地改善Ｇｄ离子在ＰｂＦ２晶体中的不均匀分布，使晶体的发光均匀性和透光率得到明显提高，其中以Ｎａ离子的均匀化效果为最好．推测Ｎａ离子的作用是消除了ＰｂＦ２：Ｇｄ晶体中因Ｇｄ离子的掺杂而造成的间隙Ｆ离子，从而使晶体中的缺陷浓度大大降低．
Gd doped lead fluoride crystals were grown by modified Bridgman methods. Under X-ray excitation, their emission intensities peaked at 278nm and 312nm increase
with the doping amount of Gd3+ ions, but decrease from the beginning part to the finishing end of the crystallization along the growth direction. The concentration
of Gd3+ ions in the PbF_2 crystal, analyzed by X-ray fluorescence spectrophotometer, also decreases in the same direction as emission intensity does. The correspondence
between Gd content and luminescence intensity of PbF2:Gd crystal demonstrates that the non-uniformity of luminescence intensity results from the in-homogeneous
distribution of Gd3+ ions in the crystal. It was found that by co-doping suitable amount of alkali metal ions, such as Na+ and K+, with Gd ion into
PbF2 crystal, the difference of luminescent intensities and Gd3+ concentration from the bottom to the top of the crystal become smaller and the transmittance
is higher than that of the single doping crystal. Especially, the uniformization effect of Na+ ions is better than that of K+ ions. It shows that the role of
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