The study of radioactive isotopes remains a frontier of nuclear physics research. This project studies the properties of refractory elements, which are difficult to produce due to their chemical properties, using beyond state-of-the-art laser spectroscopy and ion manipulation techniques. Laser spectroscopy methods are versatile tools to measure a set of nuclear properties, nuclear electromagnetic moments, spins and charge radii, and can do so in a nuclear model-independent way. These observables provide information on the size and shape of nuclei, and can be used to probe the nuclear wavefunction. By unambiguously measuring the nuclear spins, key information on the ordering of nuclear shell model orbits can be deduced while anchor points can be provided for nuclear decay studies. The nuclear charge radius provides important insight into shell and subshell effects , correlations and mixing, and can be related to nuclear deformation and related topics. The radioactive refractory isotopes of Fe-Ni, Tc-Pd and W-Os have eluded study with optical methods for many decades, a problem which has been identified as the next major challenge for laser spectroscopy. This lack of data leaves large gaps in our understanding of ground-state properties and nuclear structure in these regions. This project seeks to finally address the experimental deficiencies that have so far prevented measurements on many refractory species, and thus makes a significant and unique contribution to the field. It furthermore aims at a closer integration of the laser spectroscopy and ion trapping programmes present in the IGISOL laboratory in Jyväskylä, Finland.
This project enhances the capabilities of the laser spectroscopy programme at the IGISOL facility, and is divided into two main objectives.
1. The design, construction and commissioning of a new beam line tailored to enhance the CRIS method,
2. The measurement of the spins, electromagnetic moments and changes in mean-squared charge radii of 108-120Pd.
This project couples of a CRIS beamline to the existing double-Penning trap. This will provide significant advantages to both the CRIS and the Penning trap measurements.
• The Penning traps can be used as a powerful tool for beam purification , removing all remaining collisional or non-resonantly laser-ionized background from the measurements. Furthermore, the traps can be used to disentangle ground- and isomeric state contributions to the observed hyperfine structure spectra.
• Conversely, selective laser-ionization can be used to create isomerically pure beams, which allows the Penning traps to e.g. measure low-lying isomeric states without hindrance of the (potentially much more intense) beam of ground-state nuclides or other contaminants.
The novel RAPTOR (RIS And Purification Traps for Optimised spectRoscopy) concept thus represents a considerable expansion of the capabilities of the IGISOL laboratory, and opens up research avenues for the long-term future in Jyväskylä and elsewhere.
