SAMOP 2023 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 51: Precision Measurements
Q 51.6: Vortrag
Donnerstag, 9. März 2023, 15:45–16:00, A320
Recent Developments towards the Lifetime Measurement of the 229mTh Nuclear Clock Isomer — •Kevin Scharl1, Daniel Moritz1, Mahmood Hussain1, Sandro Kraemer1,2, Lilli Löbell1, Florian Zacherl1, Shiqian Ding3, Benedict Seiferle1, and Peter G. Thirolf1 — 1LMU Munich — 2KU Leuven, Belgium — 3Tsinghua University, Beijing, China
The elusive thorium-229 isomer (229mTh) with its unusually low-lying first excited state (8.338 ± 0.024 eV) represents the so far only candidate for the realization of an optical nuclear clock. Possible applications of a nuclear clock are not limited to highly precise time keeping, but reach into many other fields from geodesy to fundamental physics studies as dark matter research. Considerable progress was achieved in the past few years to characterize 229mTh, from its first identification to recent observations of the long-searched radiative decay channel. While the determination of the nuclear resonance with laser-spectroscopic precision is still awaited, a measurement of the ionic lifetime of the isomer is being prepared by our group. There is experimental proof for the lifetime to last 103-104 s. To precisely target the quantity by hyperfine structure spectroscopy our experimental setup is based on a cryogenic Paul trap providing long enough storage of cooled 229mTh. The talk will present the status of the experimental setup and first tests to characterize the cryogenic confinement of 229mTh ions together with laser ablated 88Sr+ ions, their sympathetic Doppler cooling and the spectroscopic readout of the trapped ion states. This work was supported by the European Research Council (ERC): Grant agreement No. 856415.