Hannover 2016 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 30: Precision spectroscopy of atoms and ions (with Q)
A 30.11: Poster
Mittwoch, 2. März 2016, 16:30–19:00, Empore Lichthof
Search for optical excitation of the low-energy nuclear isomer of 229Th — •Johannes Thielking, David-Marcel Meier, Maxim V. Okhapkin, and Ekkehard Peik — Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany
Direct optical excitation of the nuclear transition between ground state and the 7.8 eV isomer in 229Th is the missing link towards a study of this system as a precise nuclear clock. To excite the nuclear isomer via electronic bridge [1]/NEET processes, we use two-photon laser excitation of high-lying electronic levels in Th+ within the energy range from 7.3 to 8.3 eV [2,3]. We investigate the hyperfine structure of electronic levels of Th+ as means for detection of the isomeric state and to examine its nuclear structure. We also study a possible two-photon excitation scheme in Th2+ for energies higher than 8.3 eV, since this range is hardly accessible in Th+ because of resonantly enhanced three-photon ionisation in our experiment.
[1] S. G. Porsev et al., Phys. Rev. Lett. 105, 182501 (2010)
[2] O. A. Herrera-Sancho et al., Phys. Rev. A 85, 033402 (2012)
[3] O. A. Herrera-Sancho et al., Phys. Rev. A 88, 012512 (2013)