X-ray dark-field imaging with a single absorption grating

X-ray dark-field imaging is usually performed with a Talbot-Lau interferometer, but the quality of its analyser grating is limited by the fabrication process. This makes it difficult to achieve a large area and high aspect ratio. In this study, the analyser grating is abandoned and dark-field imaging is realized using only one absorption grating. The optimal grating position is derived theoretically in the single absorption grating x-ray dark-field imaging, and the conclusion is partially verified by the experiment. Meanwhile, the optimal object position for dark-field imaging has also been obtained from both the theory and experiment. In the process of comparing x-ray dark-field imaging with x-ray refraction imaging, it is found that both of them can be explained by geometric optics, showing the intrinsic relationship between them.