Berlin 2008 – scientific programme

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VA: Fachverband Vakuumphysik und Vakuumtechnik

VA 4: NEPOMUC positron source and experiments

VA 4.1: Invited Talk

Monday, February 25, 2008, 15:00–15:40, H 0106

Surface and Bulk Investigations at the High Intensity Positron Beam Facility NEPOMUC — •Christoph Hugenschmidt^{1, 2}, Günther Dollinger³, Werner Egger³, Gottfried Kögel³, Benjamin Löwe¹, Jakob Mayer¹, Philip Pikart^{1, 2}, Christian Piochacz^{1, 2}, Klaus Schreckenbach^{1, 2}, Peter Sperr³, and Martin Stadlbauer^{1, 2} — ¹TU Munich, Department of Physics E21, James-Franck-Strasse, 85478 Garching — ²TU Munich, ZWE FRM II, Lichtenbergstrasse 1, 85748 Garching — ³UniBW Munich, LRT2, Werner-Heisenberg-Weg 39, 85577 Neubiberg

NEPOMUC – the NEutron induced POsitron source MUniCh – delivers a low-energy positron beam (E = 15 - 1000 eV) of high intensity in the range between 4·10⁷ and 5·10⁸ moderated positrons per second. At present four experimental facilities are in operation at NEPOMUC: A coincident Doppler-broadening spectrometer (CDBS), a positron annihilation induced Auger-electron spectrometer (PAES) and an apparatus for the production of the negatively charged positronium ion Ps⁻. Recently, the pulsed low-energy positron system (PLEPS) has been connected to the NEPOMUC beam line and first positron lifetime spectra were recorded within short measurement times. A positron remoderation unit, which is operated with a tungsten single crystal in back reflection geometry has been implemented in order to improve the beam brilliance. An overview of the status of the neutron induced positron source NEPOMUC at the research reactor FRM II and recent developments at the running spectrometers is given.