No time to lose: Towards the creation of a thorium-based nuclear clock and a new era of ultra-high precision spectroscopy with radioactive isotopes.

A large international effort is ongoing to build the first nuclear clock [1]. The low excitation energy and expected long radiative lifetime make the first isomer in Th-229 the prime nuclear-clock candidate [2,3].The development of such a device is hindered by the experimental uncertainties on the measured nuclear properties of 229Th [3,4].My FWO project will address these knowledge gaps by performing high-precision studies of this isotope. The in-gas-jet laser spectroscopy technique developed in KU Leuven, in addition to experiments at radioactive ion beam facilities, are ideally suited for such studies[6,7,8].The radiative decay of 229mTh will be measured using VUV spectrometry after implanting different parent-nuclei of 229Th in CaF2 crystals or trapping of a pure ion beam of 229mTh in a Paul trap.The proposed upgrade to the experimental setup at KU Leuven making use of a Paul trap, will allow to present ultra-pure sources of the 229Th isomer for further studies and additionally opens up long-term perspectives of performing laser spectroscopy on radioactive isotopes with a precision up to 6 orders of magnitude better than current state-of-the-art.[1] Nuclock project, nuclock.eu[2] Bloom et al., Nature, 506 (2014) 71–75 [3] Seiferle et al., Nature 573 (2019) 243[4] VD Wense et al., Nature 533.7601 (2016) 47[6] Ferrer et al., Nature Commun. 8 14520 (2017)[7] Verlinde et al., Phys Phys Rev C 100 024315 (2019)[8] Zadvornaya et al., Phys Rev X 8 (2018) 041008

Keywords:Nuclear clock based on thorium, Laser spectroscopy on radioactive isotop, Ion manipulation in Paul traps

Disciplines:Atomic physics, Experimental aspects of nuclear physics, Lasers and quantum electronics