Hannover 2003 – scientific programme
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A: Atomphysik
A 11: Postersitzung 1
A 11.24: Poster
Tuesday, March 25, 2003, 16:00–18:30, Poster
Exclusive production of the n=2 S-states in He-like uranium — •Dariusz Banas1,2, Thomas Stöhlker1,3, Heinrich F. Beyer1, Fritz Bosch1, Angela Bräuning-Demian1, Alexandre Gumberidze1,3,4, Siegbert Hagmann1, Christophor Kozhuharov1, Xinwen Ma1,5, Paul H. Mokler1, Rido Mann1, Andreas Orsic Muthig1,3, Dominik Sierpowski6, Zbigniew Stachura7, Uwe Spillmann1,3, Stanislav Tachenov1,3 und Andrzej Warczak6 — 1GSI-Darmstadt, Germany — 2Institute of Physics, Swietokrzyska Academy, Kielce, Poland — 3Institute für Kernphysik, University of Frankfurt, Germany — 4Tbilisi State University, Georgia — 5Institute of Modern Physics, Lanzhou, China — 6Jagiellonian University, Krakow, Poland — 7Institute of Nucler Physics, Cracow, Poland
In the presented experiment we concentrate on the process of K-shell ionization in 378 Mev/u U89+ —→ N2 collision. The obtained spectra are entirely governed by an intense single L —→ K transition and a broad continuum distribution. The broad continuum can be explained by the two-photon decay (2E1) of the [1s1/2, 2s1/2] 1S0 level. Consequently, the single Kalpha line observed arises exclusively from the M1 decay of the [1s1/2, 2s1/2] 3S1 state. To the best of our knowledge, no other process occurring in high-Z ion-atom collisions is known with such a high state selectivity. This also means that the 2S-electron stays passive during a collision leading to K-shell ionization because no decay from the neighboring excited P-states is observed. This effect gave us also the unique possibility to measure "not distorted" lines from decay of the n=2 S-states in He-like uranium.