Hannover 2010 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 21: Poster I
Q 21.78: Poster
Tuesday, March 9, 2010, 16:00–19:00, Lichthof
Laser spectroscopy of trapped Th+ ions: towards nuclear laser spectroscopy of Th-229 — •Kai Zimmermann, Oscar Andrey Herrera Sancho, Maxim Okhapkin, Christian Tamm, and Ekkehard Peik — Physikalisch-Technische Bundesanstalt, Braunschweig
We have built a linear Paul trap for laser spectroscopy of Th+ ions. The trap is loaded with up to 105 ions by ablation from a thorium metal target using a nitrogen laser. The ion cloud is cooled to room temperature by collisions with ≈ 10−3 mbar of helium buffer gas. An extended cavity diode laser is used to excite the strongest Th+ resonance line at 401.9 nm. Low-lying metastable levels are quenched by collisions with the buffer gas. This allows cyclic laser excitation and the observation of a fluorescence signal of more than 1 photon/s/ion.
This is a first step in a project towards laser excitation and detection of the nuclear excited state of Th-229 at 7.6 eV. We plan to perform multi-photon excitation of the electron shell and resonant transfer of the excitation to the nucleus, making use of the dense electronic level structure of Th+.