Shedding light on the nuclear structure of neutron-rich Mn

Understanding the structure of nuclei with extreme neutron-to-proton ratios is an important challenge in modern nuclear physics research. The neutron-rich isotopes between Ni (Z = 28) and Ca (Z = 20) are particularly interesting because of the rapid onset of deformation observed towards N = 40. In this seminar the results of two collinear laser spectroscopy experiments on Mn (Z = 25) will be presented. Spins and magnetic moments of 51,53-64Mn were extracted along with the quadrupole moments of the odd-even 53-63Mn isotopes. These spins and moments are powerful probes to identify and understand modifications of the nuclear structure and can therefore provide insight into the development of deformation approaching N = 40. In a first campaign, the hyperfine spectra of 51,53-64Mn were measured using standard bunched-beam collinear laser spectroscopy on atomic manganese. Although the spins and magnetic moments could be extracted with high precision, the quadrupole moment sensitivity was low. In a follow-up experiment focused on the quadrupole moments, laser spectroscopy was therefore performed on a much more sensitive transition starting from a metastable ionic state. To efficiently enhance the population of this metastable state, optical pumping in the ISOLDE RFQ cooler-buncher needed to be developed. This technique was pioneered in Jyväskylä, but its successful implementation at ISOLDE opens the door to many interesting physics cases previously inaccessible.