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

TL;DR

This paper demonstrates a high-resolution x-ray imaging system, MIXIM, using a coded aperture mask and the Talbot effect to achieve a compact design with significantly increased effective area.

Contribution

The study introduces a novel MIXIM system employing a multiple coded aperture mask and the Talbot effect, enhancing effective area while maintaining high resolution.

Findings

Achieved 0.2" angular resolution with MIXIM.

Increased effective area by approximately 25 times.

Validated Talbot effect with high open fraction coded masks.

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 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 to MIXIM 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 about 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.