The loss in reflectivity due to the slope corresponding to a defect edge. Outside the sloped region, the surface is assumed flat, giving the full reflectivity of the multilayer (angle of incidence is 6 degrees). Within the sloped region, the tilt results in incident light at the wrong angle of incidence, which reduces the multilayer reflectivity as the light deviates further from normal incidence. The reference data for multilayer reflectivity vs. angle of incidence was obtained at the CXRO web site. The multilayer consists of 40 6.9 nm periods containing Si (60%) on Mo (40%) on an SiO2 substrate.