Stability of multilayers for synchrotron optics

The temperature stability of metal (W, WRe, Co, Cr)-carbon multilayers has been studied using x-ray diffraction (θ–2θ and Debye–Scherrer) and electron microscopy. The results show that in all cases a crystallization occurs in the temperature range 650–750 °C. As a consequence of this crystallization, the layered structure is destroyed, the surface of the film becomes rough, and the x-ray reflectivity is considerably reduced. These results imply that efficient cooling or new multilayer structures will have to be developed for use at high temperatures or under high x-ray incident flux.