High-resolution grating interferometer for phase-contrast imaging at PETRA III

Abstract

Phase-contrast imaging has proven to be a valuable tool when investigating weak absorbing materials like soft tissue, due to its increased contrast compared to conventional absorption-contrast imaging. While propagation-based phase-contrast is an ideal tool to achieve highest resolution at a good contrast for almost not-absorbing material, it quickly comes to its limitations on applications demanding for a high dynamic range in contrast. For those applications grating-based phase-contrast is the tool of choice, although it lacks of spatial resolution compared to inline phase-contrast or attenuation-based microCT. To reduce this gap in spatial resolution we equipped the two PETRA III beamlines P05 and P07 with a customized set of mechanics to maximize the performance of the interferometer. After latest optimization steps our system allows for phase-contrast measurements in a continuous energy range between 10 keV and 80 keV . Dependent on investigated material and energy the setup is capable to achieve a spatial resolution of 5 μm on a field of view of 6.5 mm. We will present our implementation of grating-based phase-contrast computed tomography for fast and high-resolution measurements at the PETRA III along with its recent optimization, and demonstrate its performance based on different kinds of applications.