Surface diffraction beamline at ESRF

A brief description of the main components of the beamline is given. The source is a standard ESRF undulator. The first active optical element is a double‐crystal monochromator cryogenically cooled and sagittally focusing. The end station consists in a six‐circle diffractometer and in an ultra high vacuum system with a welded beryllium window that allows incidence and exit angles up to 45°. Preliminary measurements on a Ge(001) clean surface, show that the counting rates of reflections characteristic of the surface reconstruction are of the order of 105 s−1 for standard operating conditions.