Decay properties of two new isotopes of astatine, \ (^188\) At and \ (^190\) At, were studied in the Accelerator Laboratory of the University of Jyväskylä, Finland. The nuclei were produced in fusion–evaporation reactions, and those were separated from the primary beam and target-like products by employing the RITU (Recoil-Ion Transport Unit) recoil separator. Decay-spectroscopy studies were performed for the produced nuclei resulting in information about the decay properties of \ (^188\) At and \ (^190\) At. The \ (^188\) At isotope was found to be the heaviest proton emitter to date. Additionally, the \ (^190\) At isotope was observed to decay via \ (\) decay. The results were compared with the systematics and with non-adiabatic quasiparticle calculations. In \ (^188\) At, a deviation in the one-proton separation energy was observed, indicating the first possible sign of the Thomas–Ehrman shift in heavy nuclei. Abstract Published by the Jagiellonian University 2026 authors
Kokkonen et al. (2026) studied this question.