Stopping powers of copper, silver and gold for protons and helium ions of low energy

Abstract

Protons and helium ions in the energy range 4-16 keV have impinged on free films of copper, silver and gold of thicknesses from 300 to 700 AA. The stopping powers have been determined by measuring the energy spectra of the ions transmitted within a cone of 3 degrees half-angle. As for the stopping power for helium ions, the nuclear stopping power is very small compared with the electronic stopping power in this method. The experimental results show that the dependence of the electronic stopping power on the ion velocity is almost in quantitative agreement with the Lindhard, Scharff and Schiott (LSS) theory.