Recent Progress in X-ray and Neutron Phase Imaging with Gratings

Abstract

Under the JST-ERATO project in progress to develop X-ray and neutron phase-imaging methods together, recent achievements have been selected and reviewed after describing the merit and the principle of the phase imaging method. For X-ray phase imaging, recent developments of four-dimensional phase tomography and phase microscopy at SPring-8, Japan are mainly presented. For neutron phase imaging, an approach in combination with the time-of-flight method developed at J-PARC, Japan is described with the description of new Gd grating fabrication.

EUV and Hard X-ray Hartmann Wavefront Sensing for Optical Metrology, Alignment and Phase Imaging

“…Many of these experiments require an optimum or at least a properly defined beam wavefront (WF). Several X-rays WF sensing techniques have been proposed in the past: grating-based interferometry [ 1 ], speckle tracking [ 2 , 3 ], ptychography [ 4 , 5 , 6 ] and imaged-based wavefront sensing combined with machine learning [ 7 ]. Among these techniques, Hartmann WF sensing provides several advantages, such as achromaticity, very large dynamic range, real-time wavefront display and ease of use [ 8 , 9 , 10 , 11 ].…”

Towards spatially resolved magnetic small-angle scattering studies by polarized and polarization-analyzed neutron dark-field contrast imaging

“…The technique of grating interferometry has been introduced to neutron imaging in 2006 as a tool for phase contrast imaging and it has gained substantial impact with the establishment of the neutron dark-field contrast modality, enabling structural studies beyond direct spatial image resolution 1 – 5 . Dark-field contrast imaging (DFI) provides contrast based on local small-angle scattering (SAS) in bulk samples and thus enabled the visualization of local microstructural inhomogeneities 6 – 8 .…”

Phase-Contrast Tomography with X-ray Hartmann wavefront sensor

“…Many techniques have been implemented to perform X-ray Phase Contrast Tomography (XPCT) like Free-Space Propagation set-ups, 6,7 Talbot, 8 coded aperture 2 and interferometry. 9 For biological application measuring the density variations inside the tissues is an important parameter to differentiate morphological structures and their changes. Object densities are described by their index of refraction n(ω) = 1 − δ(ω) − iβ(ω), where ω is the wave pulsation , δ(ω) is proportional to the phase and β(ω) to the absorption.…”