First trap-assisted decay spectroscopy of the 81Ge ground state

The beta-delayed gamma spectroscopy of As-81 has been performed using a purified beam of Ge-81 (9/2(+)) ground state at the Ion Guide Isotope Separator On-Line facility (IGISOL). The Ge-81(+) ions were produced using proton-induced fission of Th-232 and selected with the double Penning trap JYFLTRAP for the post-trap decay spectroscopy measurements. The low-spin (1/2(+)) isomeric-state ions Ge-81m(+) were not observed in the fission products. The intrinsic half-life of the Ge-81 ground state has been determined as T-1/2 = 6.4(2) s, which is significantly shorter than the literature value. A new level scheme of As-81 has been built and is compared to shell-model calculations.

Automated summary

The beta-delayed gamma spectroscopy of As-81 was performed using a purified beam of Ge-81 ground state. The intrinsic half-life of the Ge-81 ground state was determined to be significantly shorter than the literature value. A new level scheme of As-81 was built and compared to shell-model calculations.