Nuclear structure of 140Te with N = 88: Structural symmetry and asymmetry in Te isotopes with respect to the double-shell closure Z = 50 and N = 82

TL;DR

This study investigates the nuclear structure of the neutron-rich isotope 140Te through beta-delayed gamma-ray spectroscopy, revealing vibrational behavior and valence neutron symmetry and asymmetry relative to the N=82 shell closure.

Contribution

First experimental observation of 140Sb's properties and its decay to 140Te, providing new insights into the structure of Te isotopes near the N=82 shell closure.

Findings

140Sb half-life: 124(30) ms

Identified first 2+ and 4+ states of 140Te

Te isotopes exhibit vibrational character with E(4+)/E(2+) ≈ 2

Abstract

We study for the first time the internal structure of 140Te through the beta-delayed gamma-ray spectroscopy of 140Sb. The very neutron-rich 140Sb, Z = 51 and N = 89, ions were produced by the in-flight fission of 238U beam on a 9Be target at 345 MeV per nucleon at the Radioactive Ion Beam Factory, RIKEN. The half-life and spin-parity of 140Sb are reported as 124(30) ms and (4-), respectively. In addition to the excited states of 140Te produced by the beta-decay branch, the beta-delayed one-neutron and two-neutron emission branches were also established. By identifying the first 2+ and 4+ excited states of 140Te, we found that Te isotopes persist their vibrator character with E(4+)/E(2+) = 2. We discuss the distinctive features manifest in this region, such as valence neutron symmetry and asymmetry, revealed in pairs of isotopes with the same neutron holes and particles with respect to N = 82.