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A: Fachverband Atomphysik
A 6: Interaction of matter with ions
A 6.5: Talk
Tuesday, March 11, 2008, 09:30–09:45, 3D
Spectral shape of two-photon decay from 2s state in He-like Tin — •ajay kumar1, sergiy trotsenko1,2, andrei volotka3, dariusz banas4, heinrich beyer1, harald bräuning1, alexandre gumberidze1, siegbert hagmann1,2, sebastian hess1,2, christophor kozhuharov1, regina reuschl1,2, uwe spillmann1,2, martino trassinelli1,5, günter weber1,6, and thomas stöhlker1,6 — 1Atomic Physics Group, GSI, Darmstadt, Germany — 2University of Frankfurt, Germany — 3TU Dresden, Germany — 4Swietokrzyska Academy, Kielce, Poland — 5Institut des NanoSciences de Paris, France — 6Universität Heidelberg, Germany
The (1s2s) 21S0 state of He-like ions decays to the ground state via two-photon electric dipole (2E1) transitions. The study of the spectral shape of this 2E1 decay mode in He-like ions is of interest due to its sensitivity to electron-electron correlations and quantum electrodynamical effects. In the present investigation a novel experimental approach has been applied to study two-photon transitions in few-electron high-Z ions. Relativistic collisions of Li-like projectiles with a gaseous target were used to form the desired initial state, which allowed for a measurement of the undistorted two-photon spectral shape. The decay of the 21S0 state in He-like tin was measured, following a successful earlier experiment with He-like uranium. The continuum shape of the two-photon energy distribution was compared with fully relativistic calculations, which are Z-dependent. With the present technique we could, for the first time, observe Z-dependent effects in the spectral shape.