Compound-Nucleus and Doorway-State Decays of β-Delayed Neutron Emitters ^{51,52,53}K.

We investigated decays of ^{51,52,53}K at the ISOLDE Decay Station at CERN in order to understand the mechanism of the β-delayed neutron-emission (βn) process. The experiment quantified neutron and γ-ray emission paths for each precursor. We used this information to test the hypothesis, first formulated by Bohr in 1939, that neutrons in the βn process originate from the structureless "compound nucleus.

Half-life determination of At and Ra with high-purity radioactive ion beams.

At CERN-ISOLDE, high-purity radioactive ion beams of Fr and RaF were investigated with α-decay spectroscopy at the CRIS and ASET experiments in the course of three different experimental campaigns. The half-life of At, α-decay daughter of Fr, is measured to be 36.3(3)[9]μs, and that of Ra was determined to be 26.

Production of Xe and Xe via neutron activation of Xe and Xe at ILL-RHF and NCBJ-MARIA high-flux reactors.

The long-lived xenon isomers Xe and Xe are of interest for the GAMMA-MRI project, which aims at developing a novel imaging modality based on magnetic resonance of polarized unstable tracers. Here, we present the steps leading to and following the production of these two isomers via neutron irradiation of highly-enriched Xe and Xe gas samples at two high-flux reactors, the High-Flux Reactor (Réacteur à haut flux, RHF) at the Institut Laue-Langevin (ILL) and the MARIA reactor at the National Centre for Nuclear Research (NCBJ). We describe the experimental setups and procedures used to prepare the stable xenon samples, to open the irradiated samples, and to transfer xenon isomers into reusable transport vials.

^{133}In: A Rosetta Stone for Decays of r-Process Nuclei.

The β decays from both the ground state and a long-lived isomer of ^{133}In were studied at the ISOLDE Decay Station (IDS). With a hybrid detection system sensitive to β, γ, and neutron spectroscopy, the comparative partial half-lives (logft) have been measured for all their dominant β-decay channels for the first time, including a low-energy Gamow-Teller transition and several first-forbidden (FF) transitions. Uniquely for such a heavy neutron-rich nucleus, their β decays selectively populate only a few isolated neutron unbound states in ^{133}Sn.

Observation of the radiative decay of the Th nuclear clock isomer.

The radionuclide thorium-229 features an isomer with an exceptionally low excitation energy that enables direct laser manipulation of nuclear states. It constitutes one of the leading candidates for use in next-generation optical clocks. This nuclear clock will be a unique tool for precise tests of fundamental physics.