Presentation of the possibilities of ultravacuum surface diffraction on the beamlines of the European Synchrotron Radiation Facility

After a brief introduction to the matter of X-rays diffraction at surfaces and interfaces we present in this paper an original and new equipment recently built at the ESRF (European Synchrotron Radiation Facility) on beamline D32(CRG-IF i.e. Collaborating Reseach Group - Interface). This goniometer is equipped with an ultrahigh vacuum chamber, a sample transfer and an introduction system. It allows one to study the growth via grazing incidence X rays diffraction of in situ prepared surfaces and interfaces. Without giving all technical details we also discuss the improvement we have made on this apparatus in regard to previous ones. First results are also presented.