Berlin 2005 – scientific programme

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VA: Vakuumphysik und Vakuumtechnik

VA 2: Quanten, Neutronen und Positronen

VA 2.6: Talk

Monday, March 7, 2005, 12:40–13:00, TU E20

First Positron Experiments at NEPOMUC — •Christoph Hugenschmidt, Klaus Schreckenbach, Martin Stadlbauer, and Benno Straßer — ZWE FRM II, Technische Universität München, 85747 Garching, Germany

In summer 2004 the in-pile positron source NEPOMUC (Neutron Induced Positron Source Munich) of the new Munich research reactor FRM-II was set into operation at the nominal reactor power of 20 MW. Intensity and positron beam profile measurements were preformed at 30 eV and 1 keV respectively. For this purpose, NaI-scintillators detect the 511 keV γ-radiation of positrons that annihilate at a removable target in the beam line. The beam profile is determined with a micro channel plate detector and a CCD-camera.

In the present arrangement of NEPOMUCs instrumentation the monoenergetic positron beam is magnetically guided to a coincident Doppler broadening (CDB) facility and to a PAES (positron induced Auger electron spectroscopy) analysis chamber. First experiments on alloys were performed in order to show the abilities of these new facilities. An overview of the positron beam facility is given and first experimental results are presented.