Single-exposure X-ray dark-field imaging via a dual-energy propagation-based setup

TL;DR

This paper introduces a novel single-exposure dark-field X-ray imaging technique using dual-energy propagation-based setup with a photon-counting detector, enabling dynamic and low-dose imaging without complex optics.

Contribution

The work demonstrates the first single-exposure dark-field imaging method exploiting harmonic content and energy discrimination, eliminating the need for multiple exposures or complex setups.

Findings

Validated by imaging time-varying samples.

Showed the advantage of dark-field contrast in dynamic analysis.

Measured and corrected for detector charge-sharing effects.

Abstract

X-ray dark-field imaging visualises scattering from sample microstructure, and has found application in medical and security contexts. While most X-ray dark-field imaging techniques rely on masks, gratings, or crystals, recent work on the Fokker--Planck model of diffusive imaging has enabled dark-field imaging in the propagation-based geometry. Images captured at multiple propagation distances or X-ray energies can be used to reconstruct dark-field from propagation-based images but have previously required multiple exposures. Here, we show single-exposure dark-field imaging by exploiting the harmonic content in a monochromatised synchrotron beam and utilising an energy-discriminating photon-counting detector to capture dual-energy propagation-based images. The method is validated by filming time-varying samples, showing the advantage of the dark-field contrast in analysing dynamic evolution. We measure and adjust for the impact of detector charge-sharing on the images. This work opens the way for low-dose and dynamic dark-field X-ray imaging without the need for a high-stability set-up and precision optics.