AN ULTRAHIGH-VACUUM CHAMBER FOR SURFACE X-RAY-DIFFRACTION

An ultrahigh-vacuum environmental chamber for surface X-ray diffractio n on Station 9.4 at the Synchrotron Radiation Source, Daresbury Labora tory, is described. Film growth can be monitored by simultaneously rec ording the Auger signal and the X-ray intensity at a particular point in reciprocal space. Such in situ measurements are essential for under standing the dynamic processes that occur during adsorption. An exampl e is given in which the specularly reflected X-ray signal is correlate d with Auger plots, during growth of TI on Cu(001). In addition, the d iffractometer and chamber combination allow large reconstructions to b e investigated as shown by the in-plane structural analysis of the c(4 x4) InSb surface. A study of the layer structure of Cr on Ag(001), in which an extended out-of-plane detector assembly was used, is also pre sented.