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Q: Fachverband Quantenoptik und Photonik
Q 3: Precision spectroscopy of atoms and ions I (with A)
Q 3.7: Vortrag
Montag, 17. März 2014, 12:00–12:15, BEBEL E42
Determination of the level structure of Ir17+ featuring transitions extremely sensitive to a variation of the fine-structure constant — •Alexander Windberger1, Oscar O. Versolato2, Hendrik Bekker1, Victor Bock1, Sebastian Kaul1, Ruben Schupp1, Julian Stark1, Joachim Ullrich2, Zoltan Harman1, Natalia Oreshkina1, Christoph Keitel1, Piet O. Schmidt2,3, and José R. Crespo López-Urrutia1 — 1Max-Planck-Institut für Kernphysik, Heidelberg — 2Physikalisch-Technische Bundesanstalt, Braunschweig — 3Leibniz Universität, Hannover
The Ir17+ ion is an ideal system to detect a possible variation of the fine-structure constant and test it in the laboratory, such as the one claimed by Webb and coworkers based on their analysis of quasar absorption spectra at high redshifts. The required sensitivity at the level of 10−19 /year can be attained by comparing highly forbidden optical transitions in the Ir17+ ion in a clock setup. Since theory reaches only an accuracy of 10−1 for those frequencies, an exploration of its electronic structure is needed. We perform electron excitation spectroscopy on Ir17+ inside the Heidelberg electron beam ion trap (EBIT) in the optical and vacuum-ultraviolet (VUV) range with an accuracy of 5 ppm and 200 ppm, respectively. To assign transitions to their corresponding levels, different approaches are considered, such as Rydberg-Ritz combinations, determination of g-factors, and use of the characteristic energy scaling of M1 transitions as a function of the atomic number. VUV fluorescence spectroscopy with FLASH-EBIT at BESSY II will be used for improved investigations of key ground state transitions.