Quick atomic-scale structure imaging by synchrotron x-rays: a new tool for probing realistic inhomogeneous systems

摘要

The present paper describes a new imaging method for obtaining information on the atomic-scale structure around specific elements covering quite a wide area of up to several cm~2 in a reasonable measuring time. Although the x-ray absorption fine structure (XAFS) technique is a popular method for analysing 'average' atomic-scale structures, recent rapid progress in materials research demands more information on inhomogeneous systems. In order to obtain an image of the heterogeneity of the structure, scanning by means of a microbeam has been employed in a wide variety of fields. However, this method has become rather impractical from the standpoint of measuring time once the pixel count is increased in order to obtain a high-quality image. The present research proposes the use of a new instrument: an x-ray fluorescence (XRF) projection-type microscope, which is a powerful new tool recently developed for rapid imaging. XAFS imaging was earried out by repeating the exposure of XRF images during the energy scan of the primary x-rays. The present research demonstrated the feasibility of the new instrument with respect to the imaging of the chemical-state as well as the atomic-scale structure.