Positron Differential Elastic-Scattering Cross-Section Measurements for Argon

Relative elastic differential cross sections are measured for 100- to 300-eV positrons and electrons scattering at 30^∘{} to 135^∘{} angles from argon atoms in the first crossed-beam experiment to be performed with a positron beam. Good agreement is found with prior electron work and the few available calculations for positrons. The shapes of the positron and electron differential cross-section curves at 100 eV are quite different, but appear to become more similar at 300 eV.