Fig 1. Schematic depiction of the monochromatic SR system. A, Illustration of the experimental arrangement for SR microangiography at BL28B2. B, Photon mass attenuation coefficient of barium (blue line) and liquid water (red line). Monochromatic x-ray energy is adjusted to 37.5 keV, just above the barium K-edge energy to produce the highest contrast image.