Damage characteristics of platinum/carbon multilayers under X-ray free-electron laser irradiation

We evaluated the irradiation damage induced to platinum/carbon multilayers induced by hard X-ray free-electron lasers (XFELs). In this study, in order to test the use of the platinum/carbon multilayers for future XFEL focusing applications, we evaluated the structures in almost exactly the condition in which they would actually be used. The X-ray reflectivity of the multilayers was measured by using XFELs, and a cross-section of the multilayer that was irradiated by an XFEL was observed by transmission electron microscopy. We used a non-monochromatic beam at a photon energy of 10 keV. We confirmed that the intensity of the conditions under which the multilayers are to be used is sufficiently lower than the breakdown threshold of platinum/carbon multilayers.