Stopping Cross Sections of Some Hydrocarbon Gases for 40-200-keV Helium Ions

The stopping cross sections of air, CH₄, C₂{H}₂$, ${C}₂H₄, C₃{H}₈$, ${(C{H}₂)}₃$, and ${C}₃H₆ have been measured for incident helium ions in the energy range 40 to 200 keV. The data are in good agreement with previous experiment work, and have standard deviations between 2 and 6%. They obey an energy dependence ε=βE1/2 in accord with the calculation of Lindhard and Scharff. It has been shown that while there is probably an effect due to chemical binding on the helium-ion stopping cross sections of hydrocarbons, this effect is small.