Regensburg 2007 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 20: Poster session
MM 20.7: Poster
Dienstag, 27. März 2007, 14:45–18:00, Poster C
Depth-resolution measurement of CDB of layered Al-Sn-Sample — •Philip Pikart1,2, Christoph Hugenschmidt1,2, Jakob Mayer1,2, Martin Stadlbauer1,2, and Klaus Schreckenbach1,2 — 1Physikdepartment E21, James-Frank-Straße, 85748 Garching — 2ZWE FRM-II, Lichtenbergstr. 1, 85748 Garching
At the new positron source NEPOMUC at the FRM-II in Munich a moderated positron beam with an intensity of ≥ 108 positrons per second is available. After linear acceleration up to 30 keV at the entrance of the analysis chamber, coincident doppler broadening (CDB) measurements can be performed.
The implantation depth of the positrons can be varied using different beam energies, and scanning of the positron beam enables lateral resolved analysis of the sample. In this experiment, the minimal visible thickness of the tin-layer is determined by DB measurements and by CDB with improved elemental sensitivity.
For this reason, samples were prepared, which are containing a wedge-shaped layer of tin with a thickness in the range of 1-200nm, on an aluminum substrate and covered by an aluminum layer of constant thickness of ≥ 100 nm. The samples were grown out of high purity materials in a MBE-chamber.
The results of the DB-measurements were then compared to CDB-measurements on the same sample with same conditions in order to determine a sensitivity threshold for DB and CDB respectively.