Stopping Cross Section of Low Atomic Number Materials for He+, 65–180 keV

Abstract

Stopping cross sections were measured for H₁⁺ in carbon and for He⁺ in carbon, aluminum, and chromium over the energy range of 65 to 180 keV. Layers of the stopping materials were evaporated in vacuo onto a gold‐plated quartz crystal and their areal densities were computed from the shift in the resonant frequency of the crystal. The energy lost by the ions in the stopping material was determined by measuring the energy of the scattered ions. Experimental results show a divergence from available theory above 80 keV.