Direct Laser Excitation of the Th-229 Nucleus in the CaF2 Crystal Environment Using a VUV Tunable Laser
ORAL
Abstract
We report on the resonant excitation of the low energy nuclear isomer state of the Th-229 using a tabletop tunable vacuum ultraviolet (VUV) laser system, and measured its long-lived fluorescence signal. To achieve this, we dope Th-229 nuclei as Th4+ ions into calcium fluoride (CaF2) crystals [1]. The solid-state approach allows for a high Thorium concentration (up to 1019 cm−3) resulting in a high signal yield. The isomer signal was observed in two different crystals with different doping concentrations but was absent in a control experiment with a Th-232 doped crystal. These results are significant because they pave the way for Th-229 nuclear laser spectroscopy with a hertz-level resolution, similar to what has been achieved in the most advanced optical atomic clocks. This brings us one step closer to the development of the first nuclear clock.
[1] Beeks, K. et al. Sci Rep 13, 3897 (2023).
[1] Beeks, K. et al. Sci Rep 13, 3897 (2023).
*This work has been funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 856415), the Deutsche Forschungsgemeinschaft (DFG) – SFB 1227 - Project-ID 274200144 (Project B04), and by the Max-Planck-RIKEN-PTB-Center for Time, Constants and Fundamental Symmetries. The research was further supported by the Austrian Science Fund (FWF) Projects: I5971 (REThorIC) and P33627 (NQRclock).
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Publication: Paper submitted
Presenters
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Fabian Schaden
- Technische Universität Wien - Atominstitut