Multiple shape coexistence in <sup>100</sup>Zr
ORAL
Abstract
The ground states of nuclei with A ≈ 100 undergo a sudden shape transition, appearing sharply at N = 60. Equally dramatic changes are observed in the energy spectra, suggesting a possible shape-coexistence scenario. These unique features of Zr isotopes were successfully reproduced by large-scale Monte-Carlo shell model (MCSM) calculations. The coexistence of states with multiple different intrinsic shapes was predicted, accompanied by an inversion of configurations in 98Zr and 100Zr, appearing with small to no mixing due to type-II shell evolution.
A β-decay study of 100Y was performed at the TRIUMF-ISAC facility in November 2021. A radioactive ion beam mixture of 100Rb and 100Sr was used to populate the nucleus of interest in a series of β decays. The experimental setup consisted of 15 large-volume GRIFFIN HPGe detectors, coupled to seven LaBr3 detectors for fast-timing lifetime measurements.
Using the rich γ-ray coincidence data, the level scheme of 100Zr was largely extended. The spins of several key states were unambiguously assigned via γ-γ angular correlations, including several newly observed low-lying 0+ states. The lifetime of the 22+ state was measured for the first time, allowing to put on firm ground the shape-coexistence scenario.
Selected results will be presented and discussed in the context of the MCSM calculations. Structural similarities between 100Zr and 98Sr, for which shape coexistence has already been established, will be highlighted.
A β-decay study of 100Y was performed at the TRIUMF-ISAC facility in November 2021. A radioactive ion beam mixture of 100Rb and 100Sr was used to populate the nucleus of interest in a series of β decays. The experimental setup consisted of 15 large-volume GRIFFIN HPGe detectors, coupled to seven LaBr3 detectors for fast-timing lifetime measurements.
Using the rich γ-ray coincidence data, the level scheme of 100Zr was largely extended. The spins of several key states were unambiguously assigned via γ-γ angular correlations, including several newly observed low-lying 0+ states. The lifetime of the 22+ state was measured for the first time, allowing to put on firm ground the shape-coexistence scenario.
Selected results will be presented and discussed in the context of the MCSM calculations. Structural similarities between 100Zr and 98Sr, for which shape coexistence has already been established, will be highlighted.
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Publication: D. Kalaydjieva et al., "First Report of a Doublet 2209-keV State in 100Zr", vol. 16, article 4-A15, 2023
Presenters
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Desislava N Kalaydjieva
- University of Guelph