Although the concept, first demonstration, and potential applications of X-ray transmission mirrors (XTMs) were initially described over 30 years ago, only a few implementations exist in the literature. This is attributed to the unsolved challenge of a thick frame supporting a thin, reflecting membrane which does not itself block the transmitted beam. Here, we introduce a novel approach to solve this problem by employing silicon microfabrication. A robust XTM frame has been fabricated by using a novel two-step etch process, which secures the thin-film membrane without blocking the transmitted beam. Specifically, we have fabricated delicate XTM optics with 90% yield, which consist of 280-nm-thick low-stress silicon nitride membrane windows that are 1.5 mm wide and 125 mm long on silicon substrates. The XTM optics have been demonstrated to be a more efficient high-pass X-ray filter; for example, when configured for 40% transmission of 11.3 keV photons, we measure the reduction of 8.4 keV photons by a factor of 56.

中文翻译：

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高效的高通滤波与实用的高产 X 射线透射镜光学元件

尽管 X 射线透射镜 (XTM) 的概念、首次演示和潜在应用最初在 30 多年前被描述，但文献中仅存在少数实现。这归因于厚框架支撑薄反射膜的未解决挑战，该膜本身不会阻挡透射光束。在这里，我们介绍了一种通过采用硅微细加工来解决这个问题的新方法。通过使用新颖的两步蚀刻工艺制造了坚固的 XTM 框架，该工艺可以固定薄膜膜而不阻挡透射光束。具体来说，我们制造了具有 90% 良率的精密 XTM 光学器件，它由 280 nm 厚的低应力氮化硅薄膜窗口组成，在硅衬底上宽 1.5 mm，长 125 mm。XTM 光学器件已被证明是一种更有效的高通 X 射线滤光片；例如，当配置为 11.3 keV 光子的 40% 透射率时，我们测量到 8.4 keV 光子减少了 56 倍。