Sub-arcsecond x-ray imaging with multi-image x-ray interferometer module (MIXIM): introduction of a periodic coded-aperture mask

We have developed a novel X-ray interferometer, Multi-Image X-ray interferometer Module (MIXIM), comprised of a fine aperture mask and an X-ray detector. The angular resolution of this system can be improved with an increase of the distance between two components or a decrease of the aperture size. Although MIXIM has already achieved an angular resolution of less than 0.1" by applying the Talbot effect with a periodic multi-pinhole mask, there remains the issue that its low opening fraction of 1.3% decreases the effective area of the imaging system. Therefore, we newly introduced periodic coded aperture masks which have opening fractions of about 50% instead of the multi-pinhole mask. Conducting an experiment with a 12.4 keV parallel X-ray beam, we successfully demonstrated that the periodic coded aperture could form the self-image, and obtained the X-ray source profile with sub-arcsecond angular resolution by deciphering the coded pattern. The effective area increases about 25 times compared with the multi-pinhole mask by the introduction of the periodic coded aperture masks, which indicates that this novel method can be effective for addressing the problem.