Berlin 2015 – scientific programme

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MI: Fachverband Mikrosonden

MI 9: Positron Annihilation Studies of Condensed Matter

MI 9.1: Invited Talk

Wednesday, March 18, 2015, 11:45–12:30, EMH 225

Experiments with the intense and brightness enhanced positron beam at NEPOMUC — •Christian Piochacz, Thomas Gigl, Niklas Grill, Markus Reiner, Samantha Zimnik, and Christoph Hugenschmidt — Heinz Maier-Leibnitz Zentrum (MLZ) and Physik Department E21, Technische Universität München, Lichtenbergstr. 1, 85748 Garching, Germany

At the intense positron source NEPOMUC at the Heinz Maier-Leibnitz Zentrum (MLZ), four different spectrometers are installed permanently and one beam port is open for positron experiments provided by external users. The NEPOMUC remoderator enhances the brightness of the primary beam due to stochastic cooling of the positrons in a W(110) single crystal. Although the beam intensity is reduced to about 6 % the remoderation is a uniquely efficient technique to reduce the beam diameter and the energy spread considerably. Therefore, it is crucial for experiments with high lateral resolution and exceptional time resolution. However, there are also some experiments which are not as sensitive onto the beam quality but need as many positrons as possible. To meet the different demands of current and future experiments, the approved NEPOMUC positron remoderator was relocated and two novel beam switches were installed in order to provide the primary, high intensity beam or the remoderated, high brightness beam within short switching times. Within this contribution the NEPOMUC positron beam facility and some selected experiments are presented. Special attention is set to emphasize the benefit of the high intensity and high brightness beam, respectively.