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A new spectrometer for studying ion surface interaction is described. This apparatus is built around a secondary electron and ion detector with a very large acceptance angle and made of 16 individual microchannel plate detectors located on a half sphere. A simultaneous detection of the scattered projectiles with an additional position sensitive detector allows measurements of the correlation between all these particles using a multicoincidence technique. With this spectrometer, a large variety of measurements are possible such as the energy spectra of the secondary electrons as well as the statistics of the number of ejected electrons, the scattering pattern of the reflected projectiles and their charge-state distribution, the analysis of the sputtered ions. Some examples are given concerning the impact of multiply charged ions on a LiF single crystal. The dependence of the secondary electron multiplicity as a function of the charge state, of the surface channeling condition, and of the scattering angle of the reflected ion, is given as a type of information provided by the analysis of the correlation.

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This paper describes some results obtained while studying anisotropic repulsive forces by the small angle differential scattering method. The results of an experimental and numerical study of the anisotropic scattering for atom-molecular He, At-CO, NO, N2, CO2 systems are presented.