Abstract
The low-lying isomeric state of provides unique opportunities for high-resolution laser spectroscopy of the atomic nucleus. We determine the energy of this isomeric state by taking the absolute energy difference between the excitation energy required to populate the 29.2-keV state from the ground state and the energy emitted in its decay to the isomeric excited state. A transition-edge sensor microcalorimeter was used to measure the absolute energy of the 29.2-keV ray. Together with the cross-band transition energy () and the branching ratio of the 29.2-keV state measured in a recent study, the isomer energy was determined to be . Our result is in agreement with the latest measurements based on different experimental techniques, which further confirms that the isomeric state of is in the laser-accessible vacuum ultraviolet range.
- Received 18 August 2019
- Revised 12 October 2019
DOI:https://doi.org/10.1103/PhysRevLett.123.222501
© 2019 American Physical Society