LARGE-ANGLE AND SMALL-ANGLE ION-SCATTERING SPECTROSCOPY FOR STUDYING COLD, CLEAN AND GAS-COVERED METAL-SURFACES

New possibilities of the large-angle and small-angle ion scattering sp ectroscopy are demonstrated. If the target material consists of two or more isotope components it was found that the ratio of isotope parts of the quasi-single-scattering peak reaches a maximum at some incidenc e angle. The maximum is attributed to the fact that the ions doubly sc attered from the atoms with smaller masses can have the same energy an d exit angle as the ions singly scattered from the atoms with larger m asses. Based on the atomic pair model (shadowing atom plus scattering atom) the mean distance between two atoms of the topmost atomic layer can be found. In the range of small scattering angles the substrate qu asi-single-scattering peak as well as the recoil peak show a fine stru cture if the cold metal surface is covered by a thin film of condensed gases. It is postulated that such effect is connected with a multiple scattering of projectiles and recoils inside the condensed film. Mult iple scattering direct the ions to the detector after single scatterin g from the substrate atom over the angles larger Or smaller that the d etection angle. This effect can be used for determination of a cleanli ness of the target surface or parameters of the condensed layer (thick ness or density).