Hannover 2010 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 23: Poster II
A 23.20: Poster
Donnerstag, 11. März 2010, 16:30–19:00, Lichthof
Absolute determination of X-ray transition energies in H-like and He-like ions — •Katharina Kubiček, Hjalmar Bruhns, Johannes Braun, José R. Crespo López-Urrutia, and Joachim Ullrich — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
We present high-precision wavelength measurements for H- and He-like ions performed with the Flash-EBIT using a flat crystal x-ray spectrometer applying a collimation-free technique [Rev. Sci. Instrum. 76 (2005), S. 073105] which allows to determine absolute Bragg angles without the need of reference lines. We have reduced further the already small leading experimental uncertainty by installing the spectrometer coaxially to the electron beam, thus viewing the ion cloud as a point source. This setup reveals a minute curvature of the x-ray lines on the detector plane which hitherto had to be estimated. Results for the Lyman-α1 and “w” (1s2p 1P1→1s2 1S0) transition wavelengths in H-like and He-like argon, sulfur and iron ions with experimental uncertainties of esimated Δ E < 8 meV are sensitive to the far larger QED contributions of 1 eV.