• Conventional X-ray imaging methods that rely on X-ray attenuation cannot generate clear contrast in the observation of low-density materials such as polymers consisting of low-Z elements. However, the sensitivity to the materials can be improved drastically by X-ray phase imaging that detects X-ray refraction caused by the materials. X-ray Talbot or Talbot-Lau interferometry consisting of X-ray transmission gratings is now constructed in laboratories for X-ray phase imaging. X-ray phase tomography is also realized, enabling high-sensitive three-dimensional observation.
• X-ray phase imaging can be utilized for X-ray non-destructive testing of industrial products and baggage that cannot be checked conventionally.

We aim at appending a phase-contrast mode to micro-CT apparatuses and developing screening apparatuses in production lines.

• We successfully realized millisecond-order X-ray phase tomography using a fringe-scanning method in grating-based X-ray interferometry. We obtained phase tomograms with a measurement time of 4.43 ms using a white synchrotron X-ray beam. The use of a fringe-scanning method enables us to achieve not only a higher spatial resolution but also a higher signal-to-noise ratio than that attained by the Fourier transform method. In addition, our approach can be applied to realize four-dimensional or high-throughput X-ray tomography for samples that can be rotated at a high speed.