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A: Atomphysik
A 10: Posters Wednesday (Cooling and Trapping, Electron Scattering and Recombination)
A 10.29: Poster
Mittwoch, 4. April 2001, 12:30–15:00, AT3
Accurate Determination of Dielectronic Recombination Resonance Energies in Lithium-like Kr — •Stojan Madzunkov, Eva Lindroth, Nils Eklöw, Andras Paál, and Reinhold Schuch — Department of Atomic Physics, Stockholm University, S-10405 Stockholm, Sweden
The 2s-2p splittings in Lithium-like ions provide a crucial test of Quantum Electrodynamical (QED) corrections to the many-body effects in atomic energies. In Kr33+ the QED correction to the splittings of ≈ 100eV is ≈ 2eV and is known to 19meV. We show here that the accurate determination of 2s-2p(nlj) dielectronic recombination (DR) resonances provides a two times smaller correction.
We performed the recombination measurements with Kr33+ at the heavy ion storage ring of Manne Siegbahn Laboratory equipped with cooler capable of producing an ultra cold electron beam. We investigated the energy range, which includes the first DR resonances i. e. 2p1/2(15l), 2p3/2(16l) and 2p3/2(11l) because these should provide the highest accuracy. The resonance spectrum was calibrated by a method, which eliminates the voltage measurement by taking the Schottky frequencies and the ion circulation length. The relative error in determining the energy position by this method is less than 0.2%, which gives an absolute error of 8 meV at the calibration point of 5.37 eV (2p1/215(l>3)). We point out that the main error in the experimental data was due to uncertainty of the ion circulating length and discuss ways to overcome this problem that can lead to a 3 times higher precision in the resonance positions.