X-ray Multimodal Intrinsic-Speckle-Tracking

TL;DR

The paper introduces MIST, a novel X-ray speckle-tracking technique that simultaneously recovers phase shift and SAXS signals from just two images, enhancing imaging efficiency and stability.

Contribution

MIST combines Fokker-Planck and optical-flow formalisms to enable rapid, stable, and dual-parameter X-ray imaging with minimal data acquisition.

Findings

Efficient recovery of phase and SAXS signals from two images.

Applicable to synchrotron data, demonstrating stability.

Faster and more stable than previous methods.

Abstract

We develop X-ray Multi-modal Intrinsic-Speckle-Tracking (MIST), a form of X-ray speckle-tracking that is able to recover both the position-dependent phase shift and the position-dependent small-angle X-ray scattering (SAXS) signal of a phase object. MIST is based on combining a Fokker-Planck description of paraxial X-ray optics, with an optical-flow formalism for X-ray speckle-tracking. Only two images need to be taken in the presence of the sample, corresponding to two different transverse positions of the speckle-generating membrane, in order to recover both the refractive and local-SAXS properties of the sample. Like the optical-flow X-ray phase-retrieval method which it generalises, the MIST method implicitly rather than explicitly tracks both the transverse motion and the diffusion of speckles that is induced by the presence of a sample. Application to X-ray synchrotron data shows the method to be efficient, rapid and stable.