A positron beam based on absorption of high-energy prompt γ-rays from thermal neutron capture in 113Cd was installed at a neutron guide of the High Flux Reactor at the ILL in Grenoble. The positron source consists of platinum foils acting as γ-e+e -converter and positron moderator. After acceleration to 3keV by electrical lenses the positrons were magnetically guided through the beamline. Measurements were performed for various source geometries. The beam diameter and moderation characteristics... »