REFLECTION HIGH-ENERGY POSITRON DIFFRACTION FROM A SI(111) SURFACE

This report details the first observation of reflection high energy po sitron diffraction. A 20 keV positron beam was irradiated onto a hydro gen-terminated Si(111) surface from the [1 (1) over bar 0] and [11 (2) over bar] directions. The zeroth Laue zone consisting of a specular a nd diffraction spots with a shadow edge was clearly observed using a m icrochannel plate at relatively high glancing angles (theta > 3.0 degr ees). The rocking curve of the specular spot showed the primary Bragg peak and the total reflection of positrons. [S0031-9007(98)07178-6].