Nearly diffraction-limited hard X-ray line focusing with hybrid adaptive X-ray mirror based on mechanical and piezo-driven deformation.

ABSTRACT

We have developed the new hybrid adaptive X-ray mirror based on mechanical and piezo-driven deformation to realize precise shape controllability on a long-length mirror. The mechanical bender approximately provides the required ellipse, while the piezoelectric actuators attached to the mirror correct very small residual errors to satisfy the diffraction-limited condition. The mechanical bender significantly reduces the role of the piezoelectric actuator, resulting in the suppression of accuracy degradation due to the drift and/or junction effect of the piezoelectric actuators. In addition, line focusing was demonstrated with two different numerical apertures at SPring-8, and the obtained beam sizes were 127 and 253 nm (FWHM), which agree well with the diffraction-limited sizes.