Observation of a mu s isomer in In-134(49)85: Proton-neutron coupling "southeast" of Sn-132(50)82

We report on the observation of a microsecond isomeric state in the single-proton-hole, three-neutron-particle nucleus ¹³⁴In. The nuclei of interest were produced by in-flight fission of a ²³⁸U beam at the Radioactive Isotope Beam Factory at RIKEN. The isomer depopulates through a γ ray of energy 56.7(1) keV and with a half-life of T1/2=3.5(4)μs. Based on the comparison with shell-model calculations, we interpret the isomer as the Iπ=5− member of the π0g−19/2⊗ν1f37/2 multiplet, decaying to the Iπ=7− ground state with a reduced-transition probability of B(E2;5−→7−)=0.53(6)W.u.Observation of this isomer, and lack of evidence in the current work for a Iπ=5− isomer decay in ¹³²In, provides a benchmark of the proton-neutron interaction in the region of the nuclear chart “southeast” of ¹³²Sn, where experimental information on excited states is sparse

Experimental study of the β decay of the very neutron-rich nucleus 85Ge

The β-decay properties of the very neutron-rich nucleus 85Ge, produced in the proton-induced fission of 238U, were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The level scheme of 8533As52 populated in 85Geβγ decay was reconstructed and compared to shell-model calculations. The investigation of the systematics of low-energy levels in N=52 isotones together with shell-model analysis allowed us to provide an estimate of the low-energy structure of the more exotic N=52 isotone 81Cu.status: publishe

beta and beta-n decay of the neutron-rich Ge-84 nucleus

The β-decay properties of the very neutron-rich 84Ge nucleus were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. Several new γ-transitions and levels were added to its decay scheme and the order of the two lowest-lying levels in the daughter 84As was corrected. For the first time γ radiation following β-delayed neutron emission was observed. The shell-model calculations and apparent β transition intensities were used to guide the spin assignment to the 84As levels, in particular for the low-energy part of the level scheme. The new spin-parity (2−) proposed for the ground state of 84As is supported also by the systematics of N=51 isotones.status: publishe