50-nm-resolution full-field X-ray microscope without chromatic aberration using total-reflection imaging mirrors

Abstract

X-ray spectromicroscopy with a full-field imaging technique is a powerful method for chemical analysis of heterogeneous complex materials with a nano-scale spatial resolution. For imaging optics, an X-ray reflective optical system has excellent capabilities with highly efficient, achromatic, and long-working-distance properties. An advanced Kirkpatrick–Baez geometry that combines four independent mirrors with elliptic and hyperbolic shapes in both horizontal and vertical directions was developed for this purpose, although the complexity of the system has a limited applicable range. Here, we present an optical system consisting of two monolithic imaging mirrors. Elliptic and hyperbolic shapes were formed on a single substrate to achieve both high resolution and sufficient stability. The mirrors were finished with a ~1-nm shape accuracy using elastic emission machining. The performance was tested at SPring-8 with a photon energy of approximately 10 keV. We could clearly resolve 50-nm features in a Siemens star without chromatic aberration and with high stability over 20 h. We applied this system to X-ray absorption fine structure spectromicroscopy and identified elements and chemical states in specimens of zinc and tungsten micron-size particles.

Operando XAFS Imaging of Distribution of Pt Cathode Catalysts in PEFC MEA

“…The spatial resolution is determined by the two‐dimensional focusing size of hard X‐ray beam. Around 10 keV, hard X‐ray beams can be focused to 50 nm in record . These scanning methods provide two‐dimensional images by simple setup but the application to three‐dimensional imaging is difficult.…”

X-ray Fourier ptychography

“…Fourier ptychography allows high-resolution optics to be replaced by more efficient elements, even if by themselves they were limited to lower NAs or subject to aberrations ( 1 , 21 ). The technique could become useful for in situ or in operando measurements that require large working distances between sample and objective lens.…”

“…X-ray optics can be classified in three categories: diffractive optics, such as Fresnel zone plates (FZPs), reflective optics, i.e., mirrors, and refractive optics, e.g., compound refractive lenses (CRLs). Despite recent progress reported in ( 1 , 2 ), mirrors and refractive optics often introduce distortions that render their use as objectives extremely challenging. Consequently, transmission x-ray microscopes (TXMs) most commonly use FZPs as objectives, which allow for high NAs and are less prone to aberrations but, at high x-ray energies in particular, are of limited efficiency only.…”

Synchrotron Radiation X-ray Diffraction Techniques Applied to Insect Flight Muscle

“…Another type of focusing device is a pair of bent planar mirrors called Kirkpatric-Baez (KB) mirrors (see Figure 1 B). An X-ray microscope using this device is free of chromatic aberration that is inherent in the zone plates [ 19 ]. The spatial resolution obtained with this X-ray microscope is 50 nm, and this also depends on the accuracy of fabrication of the mirrors.…”