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Project

Exploring the magical tenacity of doubly closed-core nuclei with gallium and francium isotopes.

This thesis presents nuclear spins, electromagnetic moments, and changes in the mean-square charge radii for radioactive gallium isotopes, and the latter two for the francium isotope 214Fr with additional α-decay spectroscopy.  Measurements were made using the CRIS technique at the ISOLDE facility in CERN, facilitating some of the most sensitive nuclear structure studies on exotic nuclei to date.  Where applicable, experimental results are compared to empirical, and LSSM calculations.  The amalgamated data set has presented the opportunity of probing the magical influences of three doubly-magic nuclei: 56Ni, 78Ni, and 208Pb.

Electromagnetic moment analysis of 65,67,69Ga corresponds to an albeit rather soft magic core for 56Ni.  Comparisons with shell model calculations not only confirm increased mixtures of π1p3/2/π0f5/2 configurations and the presence of neutron correlations towards N = 28, but they also highlight systematic trends with respect to the neighbouring odd-Z isotope chains.  Analyses of neutron-rich species up to 82Ga reveal a rich collection of nuclear structure effects: a gradual proton migration from π1p3/2 → π0f5/2 for the odd-A species which culminates in a ground-state spin reversal involving those spins at 81Ga, isomeric presence in 80Ga at N = 49, and a kink in the change in the mean-square charge radii for 82Ga at N = 51.  Overall, this adds further evidence for a robustly magical 78Ni core.

The measurement of 214Fr with t1/2 = 5 ms represents the shortest-lived isotope to have been measured with laser spectroscopy techniques at an online facility, in which the ISOL production mechanism is the limiting factor.  With its g factor suggesting a relatively pure configuration for Iπ = 1- and a kink in its change in the mean-square charge radii, the magical effects of 208Pb can be observed five protons away.

Date:30 Sep 2015 →  30 Sep 2019
Keywords:Laser spectroscopy
Disciplines:Instructional sciences, Condensed matter physics and nanophysics, Nuclear physics, Applied mathematics in specific fields, Elementary particle and high energy physics, Quantum physics, Classical physics, Other physical sciences
Project type:PhD project