Diffraction-limited two-dimensional hard-x-ray focusing at the 100nm level using a Kirkpatrick-Baez mirror arrangement

The spatial resolution of scanning x-ray microscopy depends on the beam size of focused x rays. Recently, nearly diffraction-limited line focusing has been achieved using elliptical mirror optics at the 100nm level. To realize such focusing two-dimensionally in a Kirkpatrick-Baez system, the required accuracies of the mirror aligners in this system were estimated using optical simulators based on geometrical or wave-optical theories. A focusing unit fulfilling the required adjustment accuracies was constructed. The relationships between alignment errors and focused beam profiles were quantitatively examined at the 1km long beamline (BL29XUL) of SPring-8 to be in good agreement with the simulation results.