Projectile- z3 and -z4 corrections to basic Bethe-Bloch stopping power theory and mean excitation energies of Al, Si, Ni, Ge, Se, Y, Ag and Au

Abstract

Three independent sets of measurements of the stopping power of solid elemental targets for alpha particles were previously analyzed in terms of basic Bethe-Bloch theory with the low velocity projectile- z 3 correction term included. These data for Al, Si, Ni, Ge, Se, Y, Ag and Au have now been analyzed with the Bloch projectile- z 4 term and a revised projectile- z 3 term incorporated in the Bethe-Bloch formula, the projectile- z 3 revision having been effected by variation of the single free parameter of the projectile- z 3 effect formalism. The value of this parameter, fixed at 1.8 in previous studies, which counteracts inclusion of the projectile- z 4 term is 1.3 ± 0.1 for all target elements except Si.