Multi-image X-ray interferometer module: II. Demonstration of high-resolution X-ray imaging with regular-interval coded apertures

Abstract. We have been developing an X-ray imaging system, multi-image X-ray interferometer module (MIXIM), to achieve a high angular resolution with a compact system size. MIXIM is comprised of a mask with equally spaced apertures and an X-ray detector. The aperture size and the mask-detector distance determine the system’s angular resolution. Although a smaller aperture gives a better resolution, the degree of improvement is limited by a diffraction effect. MIXIM circumvents this problem by utilizing the Talbot effect. Our experiment with the previous model equipped with a multi-pinhole mask obtained an angular resolution of 0.5″ with a mask-detector distance of 92 cm. A major downside of the multi-pinhole mask is, however, that it has a very low opening fraction, which results in a very low effective area. Here, we newly adopt a multiple coded aperture (MCA) mask, an array of coded aperture patterns. Our proof-of-concept experiment demonstrates that the Talbot effect works even for the MCA mask with a high opening fraction of ∼50% at 12.4 keV. Consequently, the new MIXIM realizes ∼25 times as large an effective area as that of the previous model while maintaining a high angular resolution of 0.2″ and a compact size of ∼1.5 m.