Improvement of spatial resolution in phase-contrast X-ray computed tomography

Image quality of phase-contrast X-ray computed tomogram was evaluated by comparing tomograms obtained by using triple Lane-case X-ray interferometers with a thin or a thick crystal wafer. It was confirmed that the spatial resolution was improved when the wafer is thinned. A simulation study by means of the Takagi-Taupin equation was also carried out for theoretical understanding. According to the wavefront modulation transfer function calculated for Laue-case diffraction, it is suggested that using an interferometer with a thin wafer tends to improve image quality. However, a new problem is pointed out that the accuracy in quantitative measurement of high-frequency phase modulation is not secured even when the wafer is thinned.