Bonn 2025 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 35: Precision Spectroscopy of Atoms and Ions III (joint session A/Q)
Q 35.6: Vortrag
Mittwoch, 12. März 2025, 12:30–12:45, HS PC
Towards a Precision Measurement of the 229mTh Isomeric Lifetime via Hyperfine Structure Laser Spectroscopy — •Kevin Scharl, Markus Wiesinger, Georg Holthoff, Tamila Teschler, Mahmood I. Hussain, and Peter G. Thirolf — Ludwig-Maximilians-Universität München
The development of a nuclear clock based on the unusually low-lying isomeric transition in 229Th at 8.355733554021(8) eV [Zhang et al., Nature 633, 63-70 (2024)] is of high interest for several research fields from precision metrology over geodesy to dark matter research.
In the recent past, several milestones towards the nuclear clock were reached via VUV spectroscopic measurements of 229Th in a solid state environment. In contrast to that, the LMU thorium nuclear clock setup uses 229(m)Th ions confined in a cryogenic Paul trap and sympathetically Doppler cooled with co-trapped 88Sr+ ions. This approach allows for an alternative and more precise measurement of the vacuum ionic half-life of the isomeric state which so far is reported to be 1400−400+600s [Yamaguchi et al., Nature 629, 26-66 (2024)].
In this talk on the LMU experimental setup, we focus on the electronic hyperfine structure spectroscopy of 229(m)Th3+ ions as an efficient way to distinguish between the two nuclear states. Moreover, the scheme for the isomeric state readout necessary for the realization of a nuclear clock and the measurement of the isomeric lifetime is presented.
This work was supported by the European Research Council (ERC) (Grant agreement No. 856415) and BaCaTec (7-2019-2).
Keywords: Thorium Nuclear Clock; Isomeric Lifetime; Hyperfine Structure Spectroscopy