Superimposed wavefront imaging of diffraction-enhanced x-rays: A method to achieve higher resolution in crystal analyzer-based x-ray phase-contrast imaging

Abstract

In conventional phase-contrast imaging methods, an optimum distance that is essential for x-ray interference and wavefront separation must be maintained between the object and the x-ray detector. This distance determines the apparent focal size of the x-ray source and affects spatial resolution of the system. To improve the spatial resolution, we proposed a phase-contrast imaging method that eliminates the distance required for x-ray interference and wavefront separation by placing a scintillator in close contact with a Laue angle analyzer (LAA). We mathematically described the image formed by superposition of diffracted beams in two directions of LAA and introduced a method to reconstruct tomographic sections from multiple projections captured by this setup. We experimentally demonstrated the validity and the usefulness of the proposed method. Using a physical phantom, we showed that the proposed method provides higher spatial resolution than conventional x-ray dark-field imaging. The proposed method may be useful for studying and elucidating the fine 3D microanatomy and histopathology of various biological specimens.