Degree

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

Document Type

Dissertation

Abstract

The ground-state decay of 134Sb is reported by the current evaluated nuclear data to be dominated by a 0-→0+ first-forbidden Gamow-Teller transition to the ground state of 134Te. In 2013, a recoil-ion time-of-flight (RI-TOF) spectroscopy measurement of 134Sb with the Beta-decay Paul Trap (BPT) indicated that the ground-state feeding of 134Te is weaker than reported. Simulation work of 134Sb ground-state decays replicated the RI-TOF results with the addition of a theorised 5-MeV state that was fed with ~17% of the total β-decay strength. To search for higher energy states and transitions that could account for this strength, decay spectroscopy work on 134Sb was carried out using the combined Scintillator and Tape Using Radioactive Nuclei (SATURN)/X-Array decay station with radioactive ion beams provided by the Californium Rare Isotope Breeder Upgrade (CARIBU) at Argonne National Laboratory (ANL). Unfortunately these efforts were hampered due to the presence of isobaric contaminants in the beam and a high rate of background radiation due to the proximity of the CARIBU fission source.

These issues were addressed with facility upgrades such as the installation of the Multi-Reflection Time-Of-Flight (MR-TOF) mass separator at CARIBU and the relocation of SATURN/X-Array to an experimental hall with a significantly reduced level of background radiation. In this thesis, the recent decay spectroscopy work using the SATURN/X-Array decay station to study 134g,mSb decay through β-γ and β-γ-γ coincidence methods is described. A total of 39 new γ-ray transitions were observed following the β decay of 134mSb and 3 new γ-ray transitions were observed for the case of the ground-state β decay. Finally, β feeding results for the ground-state decay are presented and their impact with regards to future work is discussed.

Date

5-16-2024

Committee Chair

Marley, Scott

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