Hou, Q. Chang, G.C. Ji, B. Li, M. Yue, S.P. JACoW Publishing Geneva, Switzerland 2673-5520 978-3-95450-250-9 10.18429/JACoW-MEDSI2023-WEPPP019 English 181-183 optics synchrotron synchrotron-radiation radiation photon Contribution to a conference proceedings 2024 2024-07 https://doi.org/10.18429/JACoW-MEDSI2023-WEPPP019 https://jacow.org/medsi2023/papers/weppp019.pdf Multilayer optics is widely used for the x-ray beam monochromatization, focusing, and collimation in synchrotron light source. However, the multilayer coatings might be damaged by the high heat loads, the poor film adhesion, the high internal stress, or the inadequate vacuum conditions. As a result, it is essential to develop a method to make the optical substrate reusable without compromising its quality. In our published work, we successfully prepared a W/B4C multilayer coating with a 2 nm Cr buffer layer on a small-sized Si wafer. The coating was stripped from the Si substrate by dissolving the Cr buffer layer using an etchant. After the etching process, the sample’s roughness was comparable to that of a brand-new substrate. We have since utilized this method to clean the multilayers on the surface of a 20 cm × 5 cm silicon-based mirror for High Energy Photon Source (HEPS). The surface roughness and shape were measured, and they reached the level of a brand-new mirror.