Energy straggling of 5.486-MeV alpha particles in Al

Abstract

Energy straggling of 5.486-MeV $\alpha$ particles in Al foils has been measured as a function of energy loss using foil thicknesses corresponding to the range $0.01<\mathrm{}\frac{\Delta E}{E}<0.1\mathrm{}$. The thickness uniformity of the foils has been investigated by proton backscattering, electron microscopy, and by mechanical surface profiling. The estimated effect of foil nonuniformity on the straggling results is small. The results are in excellent agreement with the Bethe-Livingston theory.