Selecting Materials for Short-Period Multilayer X-Ray Mirrors : Comparison Between Peak and Integrated Reflectivity

Based on our simulations, we have developed a systematic approach to identifying suitable materials for short-period multilayer mirrors operating at 30 keV. We tested many materials and evaluated the performance of each possible combination, focusing on two key figures of merit: integrated reflectivity and peak reflectivity. While it is typical to optimize a multilayer structure to maximize the peak reflectance, we found that this approach can lead to bias. Instead, we propose using integrated reflectivity as a more robust criterion for material selection. Our results demonstrate the effectiveness of this approach in identifying high-performance multilayer mirrors for X-ray applications.