Optics metrology and at-wavelength wavefront characterization by a microfocus X-ray grating interferometer.

Abstract

A microfocus X-ray grating interferometer (MFXGI) is proposed to measure the profile of the X-ray wavefront and slope error of X-ray optical elements. This device consists of a phase grating G1 to modulate the incoming wavefront and an absorption grating G2 as a transmission mask for the position-sensitive detector. The wavefront distortions caused by the deformable mirror were analyzed under operating conditions for in situ investigation of X-ray optical elements. The MFXGI can obtain direct and reflected beams in one recorded image at the same time through a microfocus X-ray source. The direct beam can be used to calculate the parameter errors and spherical shape for error compensation and retrieve the aspherical shape of the height profile. This instrument is expected to be a valuable tool for further technical progress in X-ray adaptive optics and X-ray mirror manufacturing and mounting.