X-ray coherent diffraction imaging with an objective lens: towards 3D mapping of thick polycrystals

TL;DR

This paper introduces a novel x-ray imaging technique that combines coherent diffraction imaging with dark field microscopy and an objective lens to achieve high-resolution 3D mapping of thick polycrystals, overcoming previous resolution limitations.

Contribution

The method integrates an x-ray objective with iterative reconstruction and Fourier synthesis to enhance resolution and enable detailed 3D mapping of polycrystalline grains.

Findings

Achieved 13 nm spatial resolution in experiments.

Demonstrated effective grain mapping in thick polycrystals.

Lens aberrations are not critical for the method's success.

Abstract

We report on a new x-ray imaging method, which combines the high spatial resolution of coherent diffraction imaging with the ability of dark field microscopy to map grains within thick polycrystalline specimens. An x-ray objective serves to isolate a grain and avoid overlap of diffraction spots. Iterative oversampling routines are used to reconstruct the shape and strain field within the grain from the far field intensity pattern. The limitation on resolution caused by the finite numerical aperture of the objective is overcome by the Fourier synthesis of several diffraction patterns. We demonstrate the method by an experimental study of a ~500 nm Pt grain for the two cases of a real and a virtual image plane. In the latter case the spatial resolution is 13 nm rms. Our results confirm that no information on the pupil function of the lens is required and that lens aberrations are not critical.