Abstract We present a theoretical and experimental study of the subshell resolved L-shell ionization of relativistic targets such as 73Ta, 78Pt,90Th, and 92U. The measurements of x-ray production cross sections by (84–140 MeV) Si+q ions (q = 8; 12), were held at the Inter-University Accelerator Centre of New Delhi. Multiple-hole fluorescence and Coster-Kronig yields were used to obtain the Li(i = 1–3)ionization cross sections from the measured x-ray production cross sections of Ll, Lα, and Lβ, Lη, and Lγ lines. The experimental results are compared with ab initio theoretical calculations by means of the shell-wise local plasma approximation (SLPA). This model uses the quantum dielectric formalism to obtain the total ionization cross sections from an initial ground state. The wave functions and binding energies of the different targets were obtained by solving the fully-relativistic Dirac equation using the HULLAC code package. These calculations are based on first-order perturbation theory with a central field, including Breit interaction and quantum electrodynamics corrections. The present SLPA ionization cross sections of the L-shell are found to be independent of the charge state of the Si ions. The experimental observations display also quite similar character if the correct mean projectile charge state inside the target is used for including the multiple ionization effect during ion-solid collisions. A general good agreement between the experimental measurements and full theoretical calculations supports the reliability of present results. The comparison also includes the well-known ECPSSR and ECUSAR semi empirical approximations. We noted that the ECUSAR results agree well with the SLPA, while the ECPSSR cross sections are rather low.

中文翻译：

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硅离子撞击重原子的 L 壳层电离截面的实验和理论

摘要 我们提出了亚壳层分辨 L 壳层电离相对论目标如 73Ta、78Pt、90Th 和 92U 的理论和实验研究。(84–140 MeV) Si+q 离子 (q = 8; 12) 的 X 射线产生截面测量在新德里大学间加速器中心进行。使用多孔荧光和 Coster-Kronig 产率从测量的 Ll、Lα 和 Lβ、Lη 和 Lγ 线的 X 射线产生横截面获得 Li(i = 1–3) 电离横截面。通过壳层局部等离子体近似（SLPA）将实验结果与从头算理论计算进行比较。该模型使用量子介电形式从初始基态获得总电离截面。不同目标的波函数和结合能是通过使用 HULLAC 代码包求解完全相对论狄拉克方程获得的。这些计算基于具有中心场的一阶微扰理论，包括 Breit 相互作用和量子电动力学校正。发现 L 壳层的当前 SLPA 电离截面与 Si 离子的电荷状态无关。如果目标内部正确的平均弹丸电荷状态用于包括离子-固体碰撞期间的多重电离效应，则实验观察也显示出非常相似的特征。实验测量和完整理论计算之间的普遍良好一致性支持了当前结果的可靠性。比较还包括著名的 ECPSSR 和 ECUSAR 半经验近似。我们注意到 ECUSAR 结果与 SLPA 非常吻合，而 ECPSSR 横截面相当低。