Clustering in 18O is of great interest to the nuclear physics community, due to theoretical predictions of core +α and nuclear molecular structures. An experiment was performed in order to measure branching ratios for states in 18O, determining the tendency towards clustering based on the value of Γα/Γtot for each state, and the reduced widths compared to the Wigner limit. An experimental method that enables the measurement of branching ratios for almost all available decay modes, including γ decay, α decay, and n decay, was employed. The method is also sensitive to the population of excited states in daughter nuclei, allowing for more accurate determination of the α0 branch. The measurements represent, for several states, either the first branching ratio measurement or the first determination of Γα/Γtot. Based on these measurements, no evidence of consistent cluster structure is seen across any of the bands previously proposed, casting doubt on their existence. Despite this, some states displaying cluster structure are observed.
Bibliographical noteFunding Information:
The authors would like to thank A. Bergmaier for his help loaning equipment during the setup of the experiment, as well as the operators of the Van de Graaff Tandem accelerator at the Maier-Leibnitz Laboratory in Munich for providing and maintaining the beam. This work was funded by the UK Science and Technology Facilities Council (STFC) under Grant Nos. ST/L005751/1 and ST/P004199/1, and by the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 65F9744.
© 2020 American Physical Society.
ASJC Scopus subject areas
- Nuclear and High Energy Physics