CHARGE-EXCHANGE OF LOW-ENERGY PARTICLES PASSING THROUGH THIN CARBON FOILS - DEPENDENCE ON FOIL THICKNESS AND CHARGE-STATE YIELDS OF MG, CA,TI, CR AND NI

We experimentally investigate charge exchange of ions passing through thin carbon foils of 1.1-10 mu g/cm(2) thickness at incident energies from 0.5 to 5 keV/u. At such low energies usually only the charge exch ange processes occurring at the back surface determine the final charg e state of the emerging projectiles. However, for some elements we obs erve a significant foil thickness dependence which cannot be explained by current theoretical models. Possible reasons for this thickness de pendence are discussed in this paper. We further present new data on c harge state yields for Mg, Ca, Ti, Cr and Ni.