Theoretical analysis on x-ray cylindrical grating interferometer

TL;DR

This paper provides a rigorous theoretical analysis of cylindrical x-ray grating interferometers using Rayleigh-Sommerfeld diffraction, supported by numerical simulations demonstrating the self-imaging phenomenon and potential advantages over flat gratings.

Contribution

It introduces a detailed theoretical framework for curved grating interferometers, expanding understanding beyond flat gratings and highlighting their benefits.

Findings

Theoretical analysis aligns with numerical simulations.

Cylindrical gratings exhibit self-imaging phenomena.

Curved gratings offer larger field of view and higher visibility.

Abstract

Grating interferometer is a state of art x-ray imaging approach, which can simultaneously acquire information of x-ray attenuation, phase shift, and small angle scattering. This approach is very sensitive to micro-structural variation and offers superior contrast resolution for biological soft tissues. The present grating interferometer often uses flat gratings, with serious limitations in the field of view and the flux of photons. The use of curved gratings allows perpendicular incidence of x-rays on the gratings, and gives higher visibility over a larger field of view than a conventional interferometer with flat gratings. In the study, we present a rigorous theoretical analysis of the self-imaging of curved transmission gratings based on Rayleigh-Sommerfeld diffraction. Numerical simulations have demonstrated the self-imaging phenomenon of cylindrical grating interferometer. The theoretical results are in agreement with the results of numerical simulations.