Isomeric and β-decay spectroscopy of 173,174Ho

Abstract

β-decay spectroscopy of 173,174Ho (Z =67, N =106,107) was conducted at Radioactive Isotope Beam Factory at RIKEN by using in-flight fission of a 345-MeV/u 238U primary beam. A previously unreported isomeric state at 405 keV with half-life of 3.7(12) μs and a spin and parity of (3/2+) is identified in 173 Ho. Moreover, a new state with a spin and parity of 9− was discovered in 174 Er. The experimental log ft values of 5.84(20) and 5.25(18) suggest an allowed-hindered β decay from the ground state of 174Ho to the Kπ=8−isomeric state in 174Er. Configuration-constrained potential energy surface (PES) calculations were performed and the predictions are in reasonable agreement with the experimental results.