Papers by Author: Gottfried Kögel

Abstract: Brightness enhancement by re-moderation of highly intense slow positron sources at nuclear reactors or large electron accelerators is an inevitable requirement for most positron experiments. We demonstrate the feasibility of a new layout for re-moderation combining for the first time the high reliability of magnetic beam guiding, the high efficiency of reflection re-moderation, correction of spherical aberrations in the primary focussing lens and loss-free extraction of the re-moderated beam by an E x B-filter. In the case of the intense positron source NEPOMUC at the research reactor FRM II in Munich, up to 10-fold intensity and 100-fold brightness are predicted for the re-moderated positron beam, compared to the current situation.