Refraction-angle resolution of diffraction enhanced imaging

As a new method, x-ray diffraction enhanced imaging (DEI) has extremely high sensitivity for weakly absorbing low-Z samples in medical and biological fields. Conventional performance parameters, such as spatial resolution and low-contrast resolution, are not enough to describe the characteristics of a DEI system. This paper focuses on refraction-angle resolution which describes the ability of a DEI system to differentiate the x-rays refracted by the sample. The analysis of refraction-angle resolution is composed of two parts: the analysis of the single DEI image measured in a certain position of the rocking curve and the analysis of the refraction-angle image calculated by extraction methods. A 2D computer simulation experiment is performed to prove the results of the analyses. The limitations and conclusions of refraction-angle resolution are described in the end