Multilayer Optics for Intense Synchrotron X-Ray Beams: Recent Results on Their Performance

Present-day synchrotron X-ray beams are very demanding in terms of thermal, mechanical, and radiation stability of any optical element to be inserted in the beam. A set of multilayers was recently exposed and could resist to an X-ray power density > 7.5 W/mm exp 2 , which is comparable to the one expected for the multilayers to be used at ESRF. Such a power density was obtained by setting the multilayers at a grazing angle of approx 2 deg in a focused wiggler beam of 4.6 keV critical energy. The specimen, W/B sub 4 C and W/Si multilayers, were cooled either at room temperature or down to liquid nitrogen temperature during an 8-16 h exposure time.