Exploring magicity around N = 32 & 34 in Z >= 20 isotopes via precision mass measurements and developments with the TITAN MR-TOF mass spectrometer

The Nuclear Shell Model provided the first coherent description of the nucleus which accounted for a wide range of nuclear properties. The model originated from observations of particularly stable isotopes with certain numbers, known as `magic numbers’, of protons and neutrons. At the time it was developed, in the 1960s, observations were limited to naturally occurring, and therefore stable, isotopes. With the advent of radioactive beam facilities, new studies indicate that the magic numbers seem to evolve and model corrections are required.

In this thesis, the TITAN Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS) was employed to study `new' magic numbers N=32,34 across a range of isotopic chains about the traditionally magic Z=20. This work includes a characterisation of the TITAN MR-TOF-MS and high-precision mass measurements of 54Ca, 54,55Sc, 54-56Ti, and 54-58V. Isotopes of neutron-rich Ca, Sc, Ti and V were produced at the TRIUMF-ISAC facility and transported to the TITAN facility for measurement.

The results show magicity at N=32 is at a maximum in 52Ca, and the effects decrease with increasing Z across the isotopes measured, the effects are slightly weaker in 53Sc, and cease between 54Ti and 55V. This evolution is dramatically different due to the new measurements of 54,55Sc. The precision on the masses of all isotopes measured in the study is improved in comparison to the AME2016, and results include the first ever direct mass measurement of 58V. The evolution of N=32,34 magicity is explored via these new high-precision mass measurements.