Charge state distributions of fast helium ions after transmission through a thin carbon foil coated with clean aluminum

Abstract Charge state distributions of fast helium ions with energies ranging from 5 to 650 keV are investigated after the transmission through a thin carbon foil. The rear surface of this foil is coated with an aluminum film produced in situ by a sputtering deposition technique under ultrahigh vacuum conditions and is inspected by means of Auger spectroscopy. We observe clear effects of the chemical composition of the foil surface on the charge state distributions, which indicates an important role of electron transfer processes taking place in the surface region.