Darmstadt 2008 – scientific programme
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A: Fachverband Atomphysik
A 15: Precision spectroscopy I
A 15.1: Invited Talk
Thursday, March 13, 2008, 08:30–09:00, 3C
Correlations and Quantum Electrodynamics effects in He-like uranium — •m. trassinelli1,2,3, a. kumar1, h.f. beyer1, c. brandau1, h. bräuning1, s. geyer1, a. gumberidze1, p. indelicato4, p. jagodzinski5, ch. kozhuharov1, s. hess1, r. märtin1, r. reuschl1, th. stöhlker1,3, s. trotsenko1, and g. weber1,3 — 1Gesellschaft für Schwerionenforschung, Darmstadt, Germany — 2Institut des Nanosciences de Paris, France — 3Physikalisches Institut, Heidelberg, Germany — 4Laboratoire Kastler Brossel, Paris, France — 5Akademia Swietokrzyska, Kielce, Poland
Electrons bound to a nucleus with a charge as high as Z=92 represent a unique probe of relativistic and Quantum Electrodynamics effects in the domain of strong fields. As compared to a one-electron and many-electron ions, heliumlike ions are the simplest multibody systems where the role electron-electron interaction in extreme conditions can be theoretically treated in a rigorous way. We present the first highly accurate measurement of the intra-shell transition 1s2p 3P2 → 1s2s 3S1 of He-like uranium performed via X-ray spectroscopy. The present experiment has been conducted at the gas-jet target of the ESR storage ring in GSI (Darmstadt, Germany) where a Bragg spectrometer, with a bent germanium crystal, was mounted. A high systematic accuracy has been achieved making use of a differential measurement between He- and Li-like ions. With this method, it was possible to measure the 1s2p 3P2 → 1s2s 3S1 He-like U transition energy, at 4510 eV, with respect to the 1s22p 2P3/2 → 1s22s 2S1/2 Li-like U transition energy, at 4460 eV, with an estimated uncertainty of about 0.5 eV.