Design of ultrashort Kirkpatrick-Baez mirror for soft x-ray nanofocusing
Design of ultrashort Kirkpatrick-Baez mirror for soft x-ray nanofocusing
复制标题
用于软X射线纳米聚焦的超短柯克帕特里克-贝兹镜设计
DOI：
10.1117/12.2569845
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
and Hidekazu Mimura
中科院分区：
文献类型：
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作者：
Takenori Shimamura;Yoko Takeo;Takashi Kimura;Hirokazu Hashizume;Yasunori Senba;Hikaru Kishimoto;Haruhiko Ohashi;and Hidekazu Mimura
x射线聚焦光学对于获得高质量的x射线显微镜图像是必不可少的。菲涅耳带板（FZPs）通常用于通过衍射聚焦软x射线。使用Kirkpatrick-Baez （KB）反射镜在软x射线区域进行纳米聚焦是有限的，因为KB反射镜是一种反射x射线聚焦光学，它有一对垂直的反射镜，在掠入射配置中，由于焦距长，降低了数值孔径。提出了一种短焦距的KB反射镜用于硬x射线聚焦。本文设计了一种用于软x射线聚焦的超短KB反射镜，该反射镜通过减小反射镜长度来实现极短的焦距。此外，利用大掠掠角实现全反射聚焦。提出了一种超短KB反射镜，用于日本SPring-8光束线BL25SU-A的试点研究。射线跟踪模拟器用于确定KB几何结构中每个反射镜的滚转和偏航偏差公差。在此基础上，设计了反射镜机械手和其他设备来精确定位反射镜。虽然这种策略通常用于FZPs，导致工作距离短，光束接受度小，但我们相信它可以应用于消色差和强退放大的x射线显微镜应用的超短KB反射镜。
X-ray focusing optics are essential for acquiring high-quality X-ray microscopy images. Fresnel zone plates (FZPs) are conventionally used to focus soft X-rays via diffraction. The use of Kirkpatrick-Baez (KB) mirrors for nanofocusing in the soft X-ray region is limited because a KB mirror is a reflective X-ray focusing optic that has a pair of perpendicular mirrors in a grazing-incidence configuration, which lowers the numerical aperture due to the long focal length. KB mirrors with a short focal length have been proposed for hard X-ray focusing. This paper presents the design of an ultrashort KB mirror for soft X-ray focusing that has an extremely short focal length, which is achieved by reducing its mirror length. Moreover, a large grazing angle is employed to utilize total-reflection-based focusing. An ultrashort KB mirror is proposed for pilot studies at beamline BL25SU-A, SPring-8, Japan. A ray-tracing simulator is used to determine the misalignment tolerance in terms of roll and yaw for each mirror in the KB geometry. Based on the results, a mirror manipulator and other equipment are designed to precisely position the mirrors. Although this strategy, commonly used for FZPs, leads to a short working distance and a small beam acceptance, we believe that it can be applied to ultrashort KB mirrors for X-ray microscopy applications with achromaticity and strong demagnification.