Development of a Scanning X-ray Fluorescence Microscope Using Size-Controllable Focused X-ray Beam from 50 to 1500nm

Abstract

In scanning X‐ray microscopy, focused beam intensity and size are very important from the viewpoints of improvements of various performances such as sensitivity and spatial resolution. The K‐B mirror optical system is considered to be the most promising method for hard X‐ray focusing, allowing highly efficient and energy‐tunable focusing. We developed focusing optical system using K‐B mirrors where the focused beam size is controllable within the range of 50 – 1500 nm. The focused beam size and beam intensity can be adjusted by changing the source size, although beam intensity and size are in a trade‐off relationship. This controllability provides convenience for microscopy application. Diffraction limited focal size is also achieved by setting the source size to 10 μm. Intracellular elemental mappings at the single‐cell level were performed to demonstrate the performance of the scanning X‐ray fluorescence microscope equipped with the optical system at the BL29XUL of SPring‐8. We will show magnified elemental images with spatial resolution of ∼70 nm.