Multiple Electron Loss Cross Sections for Heavy Ions Incident on Various Atomic and Molecular Gases

Differential cross sections for charge change resulting from the scattering of 20 MeV 127I5+ and 20 MeV 35Cl4+ ions from thin gaseous targets have been measured. Total cross sections for multiple electron loss have been determined by integration of the differential charge state yields over angle. Cross sections will be presented for 127I5+ ions and 35Cl4+ ions on Xe, Ar, and N2. Impact parameter analyses of charge fraction data have been performed; these analyses depend on the assumed interatomic potential but not on any absolute measurements. The applicability of Bohr, Thomas-Fermi, and Lenz-Jensen potentials with the experimental total cross sections will be shown. A different method, using a magnetic quadrupole to focus individual charge states; was used to measure absolute charge state yields of 20 MeV Fe ions emerging within a large acceptance angle from a differentially pumped gas cell of length 9.4 cm.2 N2, Ar, Kr, Xe, and SF6 targets were investigated. From the low pressure yields total cross sections for single and multiple electron loss were obtained using an improved version of the initial growth method.