Angular distribution studies are made for L₃ sub-shell X-rays of high Z elements; W, Pt, Hg, Pb, and U in the angular span 0°–180° at incident photon energies; near L₃ edge, where considerable anisotropy is anticipated and at 60 keV, the energy of experimental interest from standard laboratory source Am-241. Angular distribution of X-rays originating from L₃ sub-shell vacancies for each element is derived from theoretical alignment parameter already evaluated under non-relativistic dipole approximation (NDA) in a point Coulomb potential (A₂₀) and in a screened Coulomb potential (A₂₀*) that accommodates the effect of screened nuclear drag on electron wave function, and analytical perturbation theory (A₂₀**). The normalized ${\text{L}}_{\ell }$ and L_α intensity distributions show more anisotropy at L₃ threshold than at 60 keV for all the elements and under all theoretical models. Besides this, the anisotropy for ${\text{L}}_{\ell }$ is larger than L_α which comprises the unresolved L_α1 and L_α2 lines with opposite anisotropy. The angular distribution trends are almost similar for all the elements. The anisotropy values at L₃ threshold energy are assuredly greater than the reported experimental uncertainties (5–8 %) of X-ray intensities. Anisotropy magnitude is found sensitive to the theoretical models. The present anisotropy trends resemble the results of Zhang et al (Journal of Quantitative Spectroscopy and Radiative Transfer, 244 (2020) 106844), however, the values are not quite same.

对高Z元素的L ₃亚壳X射线进行了角分布研究；W，Pt，Hg，Pb和U在入射光子能量下的角度范围为0°–180°；接近L ₃边缘（预计会有很大的各向异性），并且在60 keV时，实验兴趣的能量来自标准实验室来源Am-241。对于每个元素，源自L ₃个子壳空位的X射线的角度分布是从已经在非相对论偶极近似（NDA）下在库仑势（A ₂₀）和屏蔽库仑势（甲₂₀ *），其容纳在电子波函数筛选核阻力，和分析微扰理论的效果（A₂₀ **）。归一化${\text{大号}}_{\ell }$和L _α强度分布表现出更多的各向异性为L ₃阈值比在60千电子伏为所有元件和下所有的理论模型。除此之外，各向异性${\text{大号}}_{\ell }$大于_Lα，后者包括具有相反各向异性的未_{分解的Lα1}和_Lα2线。所有元素的角度分布趋势几乎相似。确保在L ₃阈值能量处的各向异性值大于报告的X射线强度实验不确定性（5-8％）。发现各向异性大小对理论模型敏感。当前的各向异性趋势类似于Zhang等人（Journal of Quantitative Spectroscopy and Radiative Transfer，244（2020）106844）的结果，但是，这些值并不完全相同。