Positron and electron backscattering from solids

We present new experimental results for the angle and energy resolved backscattering of positrons and electrons from Al and Au at oblique incident angles. For ${\mathit{e}}^{+}$ on Au, and both ${\mathit{e}}^{\mathrm{-}}$ and ${\mathit{e}}^{+}$ incident on Al, evidence for specular scattering is observed. For positrons we find excellent agreement between these data and Monte Carlo simulations based on the Penn dielectric function.