Investigating Shape Coexistence in ¹⁰⁰Zr

Shape coexistence can be found in many regions of the nuclear chart and is often associated with the presence of low-lying 0⁺ states. In the Zr isotopes with neutron number near N=60, there is also a rapid onset of deformation of the ground state band as the neutron number is increased from ⁹⁸Zr to ¹⁰⁰Zr. In addition, multiple shapes are predicted via Monte-Carlo shell-model calculations. The spherical configuration that forms the ground state in ⁹⁸Zr is predicted to migrate upwards in energy to become the 0₄⁺ state in ¹⁰⁰Zr, while the configuration forming the deformed 0₂⁺ state in ⁹⁸Zr descends in energy to become the ground state in ¹⁰⁰Zr. In order to probe the nature of the excitations, a β decay experiment has been performed using the GRIFFIN γ ray spectrometer at the TRIUMF-ISAC facility. States populated by the decay of ¹⁰⁰Y were investigated through γ ray spectroscopy, which includes γ-γ angular correlations to establish level spins and transition multipole mixing ratios. Lifetimes of states and conversion electron intensities were also measured using LaBr₃(Ce) and Si(Li) detectors, respectively. The current status of the analysis, and the implications of the results on the structure will be discussed.