Measurements of Isomer Energies in Potential “Astromers” *

Beta-decay properties like half-lives, decay branching ratios and isomeric states are key inputs for astrophysical nucleosynthesis calculations, and the availability and accuracy of this nuclear data directly impact the quality of different model predictions. Nuclear isomers play a significant role in determining the abundances of the elements in the universe. Refined studies of the influence of the “astromers", the nuclear isomers that are populated in astrophysical environments, have recently demonstrated both that astromers can play a prominent role in nucleosynthesis, and that essential nuclear data is missing [Mis21a, Mis21b]. We proposed a measurement that uses radioactive beams produced at CARIBU to measure the energy difference between the ground state and isomeric states of several key astromers with the Canadian Penning Trap (CPT). Better measurements of the energy of these isomers will improve r-process nucleosynthesis calculations by helping to clarify transition rates, thermalization temperatures, and astromer populations as they freeze out in the rapidly cooling post-r-process environment.

[Mis21a] G. W. Misch et al., The Astroph. Journ. Supp. Series, 252:2 (17pp), (2021)

[Mis21b] G. W. Misch et al., The Astroph. Journ. Lett. 913 L2 (2021)