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

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