Zakopane 2026 Conference on Nuclear Physics

At the VITO beamline at ISOLDE, we use optical pumping to polarise nuclear spins of beams of different short-lived nuclei [1]. We then use the resulting anisotropic emission of beta radiation in a variety of fields, from nuclear structure, via material science, all the way to biology.
Recently, we have used $^{47,49,51}$K for a proof-of-principle experiment in decay spectroscopy of spin-polarized beams, in which we studied angular correlations between asymmetrically emitted beta particles and gamma-radiation or neutrons [2]. The aim is to use the measured beta-decay asymmetry factors to determine spins and parities of excited states in neutron-rich nuclei, especially beta-delayed neutron emitters relevant for the r process nucleosynthesis.
Furthermore, we use the spin-polarised beams for ultra-sensitive nuclear magnetic resonance detected via beta-decay asymmetry ($\beta$-NMR). By using liquid samples we have narrowed the linewidth of $\beta$-NMR resonances by two orders of magnitude, allowing to achieve ppm levels in the accuracy of magnetic moments of short-lived isotopes [3]. We have now combined this approach with nuclear DFT and atomic calculations to determine the so-called hyperfine anomaly in $^{47}$K [4], paving the way for studies of the composition and distribution of nuclear magnetisation in different short-lived nuclei [5].
This contribution will present the VITO experimental setups, followed by the results of the above-mentioned proof-of-principle studies, concluding with a layout of an rf-laser spectroscopy end station for precise hyperfine-anomaly studies.

1. M. Kowalska et al., J. Phys. G: Nucl. Part. Phys. 44 (2021) 084005
2. M. Piersa-Silkowska et al., CERN-INTC-2023-026/ INTC-P-662 (2023), and https://ep-news.web.cern.ch/content/isoldes-new-beta-decay-station-unlocks-advanced-decay-spectroscopy-experiments-laser (2025)
3. R. Harding et al., Phys. Rev. X 10 (2020) 041061, J. Croese et al, NIMB 1020 (2021), 165862, M. Jankowski et al JINST 21 (2026) P01003
4. M.L. Bissell et al, submitted, https://arxiv.org/abs/2603.20090
5. M.L. Bissell et al, CERN-INTC-2023-014 / INTC-P-655 (2023)