Measurement of the Total Cross Section for Symmetric Charge Exchange in Helium from 400-2000 eV

Abstract

The energy dependence of the total cross section for symmetric charge exchange in helium is measured in the range from 400-2000 eV. Beam-attenuation techniques are used, and all measurements are made on the forward-scattered ions and the high-energy neutrals resulting from the charge exchange. Cross-section values are given at 100-eV intervals, and the results show a cross section decreasing as the energy increases, with a value at 1000 eV of 1.04 × ${10}^{-15\mathrm{}}$ ${\mathrm{cm}}^2$. The absolute cross sections are accurate to ± 12%. Relative cross-section values accurate to ± 6% are reported.