Thickness uniformity study on the ESRF multilayer deposition system

The ESRF Multilayers Laboratory provides reflective optics in the X-ray domain using a deposition system where silicon substrates are coated with a well-defined multilayers stack. The multilayers period is used to tune the photon energy of the reflected X-ray beam. In some applications, the variation of the thickness profiles of the deposited materials must not exceed 0.1%. The aim of the study is to quantify the thickness uniformity of 1.2 m long single layer coatings with a spatial resolution of 10 mm or better. Results have been analyzed to identify potential sources of thickness variations. Investigations of long multilayers coatings complement this work.