Dissertation / PhD Thesis

GSI-2026-00675

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Pushing the limits: mass measurements of neutron deficient lanthanides at the proton drip line & ion trapping advancements using printed circuit boards

Fowler-Davis, T. ; Reiter, M. P. (Thesis advisor) ; Woods, P. (Thesis advisor) ; Lederer, C. (Thesis advisor) ; Davinson, T. (Thesis advisor)

2025
University of Edinburgh Edinburgh

Please use a persistent id in citations: doi:10.7488/ERA/6772

Abstract: Accurate mass measurements of proton-rich elements are essential for research in nuclear structure. In the context of the light lanthanide region, nuclear properties are significantly affected by substantial beta-decay Q-values, as well as low or negative proton separation energies, and the confining effects of the Coulomb barrier. Furthermore, precise mass measurements facilitate the calculation of important quantities, including proton and neutron separation energies, thereby providing valuable insights into phenomena such as proton radioactivity, two-proton radioactivity, and exotic pairing phenomena. Utilising high-resolution mass spectrometry at the GSI FRS-IC, 14 new isotopes have been identified along the proton drip line, accompanied by 7 newly refined mass uncertainties in the region spanning Barium (Ba) to Terbium (Tb) as observed during the measurement campaign documented in S482. Simultaneous measurements of over thirty-five nuclides were conducted, encompassing extensive areas of the nuclide chart with stopped or thermalised nuclides. These findings, along with the innovative technical methodologies employed, yield significant insights into nuclear structure and facilitate the tracking of the proton drip line between 100Sn and 150Lu. To further enhance the capabilities of high-resolution mass spectrometry, a novel approach entailing the utilisation of printed circuit boards (PCB-RFQ) has been developed, constructed, and characterised. The PCB-RFQ system possesses the ability to supplant multiple sections of experimental beam time due to its capacity to achieve unity transport efficiency and generate ion bunches for an MR-TOFMS, supplemented by a dedicated prototype for an injection trap system. This process is accomplished by generating ion bunches of 133Cs with a time duration of 2.6 (1) ns and a moderate energy spread of 20 eV, in contrast to typical spreads of approximately 9 ns. This study elucidates the design and construction of the PCB-RFQ system while also presenting investigations into its performance.

Keyword(s): Mass measurements ; Lanthanides ; Proton drip line ; High-resolution mass spectrometry ; Printed circuit boards (PCB-RFQ)

Note: "dc.rights.embargodate 2026-11-25"
Note: Dissertation, University of Edinburgh, 2025

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Contributing Institute(s):

1. FRS / SFRS Experimente (FRS)
2. Collaboration FAIR: SuperFRS Experiment Collaboration (SuperFRS-EC@FAIR)

Research Program(s):

1. 612 - Cosmic Matter in the Laboratory (POF4-612) (POF4-612)

Experiment(s):

1. S482: Mean range bunching for experiments with stopped beams (POF3-612; HFS)

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