The stopping power of hydrogen and hydrocarbon vapours for alpha particles over the energy range 1 to 8 MeV

Range-energy relations have been determined experimentally for 8.78 MeV alpha particles in a number of hydrocarbon vapours and in hydrogen. Differential stopping powers at various energies have been determined and mean excitation potentials derived. There is evidence of charge exchange taking place at low energies, but significant deviations from the Bragg rule due to variations in molecular binding have not been observed.