Stopping Cross-Sections of Rare Gases in Amorphous Silicon for MeV Energy Helium Ions

Using the Rutherford backscattering method, the stopping cross-sections of amorphous silicon doped with rare gases to a concentration of a few percent were measured for helium ions. The effective stopping cross-sections of the rare gases were deduced by assuming Bragg's rule and by using Ziegler's cross-section values for silicon. The results were systematically about 30 percent lower than Ziegler's values for the gaseous state, in the energy range near 1 MeV. The incident energies were 1.0–2.6 MeV for samples containing 8% argon, and 1.0–1.6 MeV for those containing 7% krypton or 4% xenon.