Open Collections

Lykiardopoulou, Eleni Marina

University of British Columbia

Experimental investigations of nuclear structure provide a probe to study the strong nuclear force, many properties of which still remain unknown. One powerful way to experimentally investigate nuclear structure is through the mass of the atomic nucleus, as it reveals the binding energy of the nucleus. In this work, mass measurements of Mg and Na isotopes are carried out and the results indicate, for the first time, a gradual re-emergence of magicity or closed shell behavior for Z ≤ 11 nuclei at the N = 20 island of inversion. The results also discover a previously unknown low-lying isomer, hence a long-lived excited state in ³²Na. In addition, complementary work at higher mass numbers which combines mass measurements and decay energies allows us to trace the two-proton dripline between iridium and lead, thus determining the limits of existence for elements with proton numbers Z = 77−82 on the proton-rich side of the Segrè chart. Comparisons with some theoretical calculations for this work show agreement while others, such as ab initio theory calculations, are currently unable to reproduce effects of the N = 20 island of inversion, and will require further developments. Yet the mass measurements serve as important benchmarks. Beyond studies of nuclear structure via direct mass measurements, this thesis describes the technical developments and improvements to the Measurement Penning Trap (MPET). The Penning trap, an experimental apparatus that uses electric and magnetic fields to determine the atomic mass through the ion’s cyclotron frequency, has been upgraded to operate at cryogenic temperatures with the goal to reach storage times on the order of seconds for highly-charged Ions. The aim for this upgrade is an improvement of the achievable precision by an order of magnitude. In addition, simulations and further technical upgrades towards the implementation of the Phase-Imaging Ion-Cyclotron measurement technique are carried out. With its new capabilities, the TITAN MPET is now able to perform mass measurements of short-lived radioactive isotopes in singly and highly charged states with an unprecedented precision.

Text

2023-12-05

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/86762

Physics

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/