New attempt to combine scanning electron microscopy and small‐angle scattering in reciprocal space

• Published in: Journal of applied crystallography Vol. 52; no. 4; pp. 783 - 790
• Main Authors: Koizumi, Satoshi, Ueda, Satoru, Nishikawa, Yukihiro, Terao, Takeshi, Kubo, Norio
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.08.2019; Blackwell Publishing Ltd
• Subjects: Amplitudes; Electron emission; Fourier transforms; Fuel technology; Image detection; Neutrons; Noise reduction; Proton exchange membrane fuel cells; real space; reciprocal space; Scanning electron microscopy; Scattering amplitude; Silicon dioxide; small‐angle scattering; Structural analysis; Vacuum; Wavelengths
• ISSN: 1600-5767; 0021-8898; 1600-5767
• DOI: 10.1107/S1600576719009208

An attempt has been made to combine small‐angle scattering of X‐rays or neutrons with scanning electron microscopy in reciprocal space, in order to establish a structural analysis method covering a wide range of sizes from micro‐ to macro‐scales. A system with a binary contrast, in which scattering objects with a homogeneous density are dispersed in vacuum (or air), is considered. A topological surface image, detected by secondary electron emission, is converted by means of a Fourier transform into a two‐dimensional scattering amplitude in reciprocal space. The method was first tested by studying a dilute system of monodisperse SiO2 particles, with respect to calibrations for brightness inversion, noise reduction and two‐dimensional Fourier transform, to obtain a scattering amplitude that agrees well with the analytical amplitude for a spherical particle. Secondly, the microstructure of a carbon‐supported Pt catalyst for polymer electrolyte fuel cell applications was examined with the combined method, covering length scales from 10 µm down to nanometres. After two‐dimensional Fourier transformation, the secondary electron emission images with low magnification are able to overcome the limitation of the minimum wavenumber (qmin) detectable by ultra‐small‐angle scattering. An attempt has been made to combine small‐angle scattering of X‐rays or neutrons with scanning electron microscopy in reciprocal space, in order to establish a structural analysis method covering a wide range of sizes from micro‐ to macro‐scales.