β-delayed neutron spectroscopy of 133In

Abstract

The decay properties of 133In were studied in detail at the ISOLDE Decay Station. The implementation of the Resonance Ionization Laser Ion Source allowed separate measurements of its 9/2+ ground state (133g In) and 1/2− isomer (133mIn). With the use of β-delayed neutron and γ spectroscopy, the decay strengths above the neutron separation energy were quantified in this neutron-rich nucleus for the first time. The allowed Gamow-Teller transition 9/2+ → 7/2+ was located at 5.93 MeV in the 133g In decay with a log f t = 4.7(1). In addition, several neutron-unbound states were populated at lower excitation energies by the first-forbidden decays of 133g,mIn. We assigned spins and parities to those neutron-unbound states based on the β-decay selection rules, the log f t values, and systematics.