Diffraction-enhanced X-ray imaging under low-temperature conditions: Non-destructive observations of clathrate gas hydrates

Abstract

Diffraction-enhanced imaging (DEI) is a phase-contrast X-ray imaging technique suitable for visualizing light-element materials. The method also enables observations of sample-containing regions with large density gradients. In this study a cryogenic imaging technique was developed for DEI-enabled measurements at low temperature from 193 K up to room temperature with a deviation of 1 K. Structure-II air hydrate and structure-I carbon dioxide (CO2) hydrate were examined to assess the performance of this cryogenic DEI technique. It was shown that this DEI technique could image gas hydrate coexisting with ice and gas bubbles with a density resolution of about 0.01 g cm-3 and a wide dynamic density range of about 1.60 g cm-3. In addition, this method may be a way to make temperature-dependent measurements of physical properties such as density. © 2012 International Union of Crystallography Printed in Singapore-all rights reserved.