Multiple scattering in scanning helium microscopy
Multiple scattering in scanning helium microscopy
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DOI：
10.1063/1.5143950
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发表时间：
2020-02-10
影响因子：
4
通讯作者：
Ward, D. J.
中科院分区：
文献类型：
--
作者：
Lambrick, S. M.;Vozdecky, L.;Ward, D. J.
使用原子束在真实空间中对样品的表面进行成像是一种新兴的技术，它可以从精致的样品中产生独特的对比度。在这里，我们探索由于氦原子的多次散射而产生的对比度，这是一个在扫描氦显微镜(SHEM)图像中形成地形对比度的重要过程。用离子束球磨的方法制备了由一系列不同深度的沟槽组成的试件。浅沟(深度/宽度1)的SHEM图像强度增强。利用蒙特卡罗射线追踪法对氦气散射信号进行了解析建模和数值模拟。这两种方法都与实验数据很好地吻合，并证实了增强是由于多次散射引起的散射氦原子的局域化。结果被用来解释具有深孔结构的生物技术相关样品的SHEM图像，突出了多重散射在SHEM图像解释中的相关性。(C)2020年作者(S)。
Using atom beams to image the surface of samples in real space is an emerging technique that delivers unique contrast from delicate samples. Here, we explore the contrast that arises from multiple scattering of helium atoms, a specific process that plays an important role in forming topographic contrast in scanning helium microscopy (SHeM) images. A test sample consisting of a series of trenches of varying depths was prepared by ion beam milling. SHeM images of shallow trenches (depth/width 1) exhibited an enhanced intensity. The scattered helium signal was modeled analytically and simulated numerically using Monte Carlo ray tracing. Both approaches gave excellent agreement with the experimental data and confirmed that the enhancement was due to localization of scattered helium atoms due to multiple scattering. The results were used to interpret SHeM images of a bio-technologically relevant sample with a deep porous structure, highlighting the relevance of multiple scattering in SHeM image interpretation. (C) 2020 Author(s).