Helium ion beam interactions with materials have important implications for magnetic confinement fusion, material modification, and helium ion microscopy. These interactions depend on the precise physics of how helium ions channel into the materials, which can vary greatly based on the local crystalline orientation. In this work, we performed a dedicated experiment to investigate helium ion channeling in a well-characterized tungsten single crystal. Time-of-flight impact-collision ion scattering spectroscopy was used to obtain multi-angle maps of the backscattering intensity for 3 keV He+ → W(111). We found that the backscattering intensity profile arising from helium ion channeling could be well described by a shadow cone analysis. This analysis revealed that subsurface W atoms as deep as the ninth monolayer contributed to the backscattering intensity profile. Binary collision approximation simulations were performed with MARLOWE to model the experimental maps with sufficient accuracy to allow for quantitative comparisons using reliability factors. These quantitative comparisons were applied to investigate how the W lattice structure and He-W interatomic potential affect the multi-angle maps.

中文翻译：

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用碰撞-碰撞离子散射光谱定量研究表面结构和原子间势

氦离子束与材料的相互作用对磁约束聚变、材料改性和氦离子显微镜具有重要意义。这些相互作用取决于氦离子如何进入材料的精确物理特性，这可能因局部晶体取向而有很大差异。在这项工作中，我们进行了一项专门的实验，以研究特征良好的钨单晶中的氦离子通道。飞行时间碰撞碰撞离子散射光谱用于获得 3 keV He+ → W(111) 的后向散射强度的多角度图。我们发现由氦离子通道引起的反向散射强度分布可以通过阴影锥分析很好地描述。该分析表明，深至第九单层的地下 W 原子对后向散射强度分布有贡献。使用 MARLOWE 进行二元碰撞近似模拟，以足够准确度对实验图进行建模，以允许使用可靠性因子进行定量比较。这些定量比较用于研究 W 晶格结构和 He-W 原子间势如何影响多角度图。