PROTON AND HELIUM STOPPING CROSS-SECTIONS IN H-2, HE, N2, O2, NE, AR, KR, XE, CH4 AND CO2

Proton and helium stopping cross sections were measured for the noble gases helium, neon, argon, krypton and xenon, the diatomic gases hydrogen, nitrogen and oxygen and for the molecules carbon dioxide and methane in the energy ranges 700 keV-2.1 MeV and 1.0-3.0 MeV, respectively. The statistical and systematical errors are between 1.0 and 1.5% each. Optimum parameters for the Andersen-Ziegler semi-empirical formula were deduced for all data sets by means of the least-squares method. From the stopping cross sections of protons and 4He-ions at same velocity higher order Z1 corrections (Barkas-correction) for the noble gases He, Ne, Ar, Kr and Xe and the diatomic gases H2, N2 and O2 were calculated, using theoretical values for the Bloch-correction approximated by Bichsel and Porter. The experimental Z13-corrections were compared with the different theoretical predictions of Ashley, Ritchi and Brandt, Jackson and McCarthy and Lindhard and Esbensen. © 1990.