A polycrystalline NaCl target has been bombarded with 20 keV 4He+, 20Ne+, 40Ar+, 84Kr+ and 132Xe+ ions (ion current densities up to 50 μA cm-2). The velocity spectra of sputtered Na atoms have been measured by resonance fluorescence with a Doppler Shift Laser Spectrometer (DSLS). The measured spectra indicate three different contributions to the sputtering process of NaCl. The energy spectra can be explained by the influence of random collision cascades, thermal spikes and thermal evaporation due to surface decomposition, respectively. The relative contributions of the three processes depend strongly on the mass of the projectile ion. The binding energy of Na to the NaCl target was found to be about 1.3 eV and the spike temperature about 2200 K. The surface temperature as deduced from the low energy part of the spectra was found to be about 300 K. © 1979.
