Numerical investigation of a non-interferometric grating-based X-ray imaging system

Grating-based X-ray imaging can be classified into two categories: interferometric and non-interferometric. Interferometric setup, i.e. Talbot-Lau interferometer, has been intensively investigated in the recent past. To increase the angular sensitivity and maintain a reasonable system length, gratings with very small period are preferred, while the fabrication of such gratings remains challenging. Another obstacle for the interferometric setup is the degradation of visibility when using broadband X-ray sources, especially when operated at high Talbot orders. Non-interferometric setup uses a geometrical projection relation, thus has a more flexible system geometry. In this paper, we investigate the impact of several factors including grating period, intergrating distance and X-ray spectrum on the performance of the system using wave-optical simulations. In particular, we focus on the visibility of the phase stepping curve. Based on the simulation results, we discuss the design aspects and limitations of the non-interferometric setup.