Nuclear structure and β -decay schemes for Te nuclides beyond N=82

Abstract

We study for the first time the internal structure of Te produced by the -decay branch, the -delayed one-neutron and two-neutron emission branches were also established. By identifying the first 2 + and 4 + excited states of 140 Te, 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.

New nuclear structure data beyond 136Sn

“…Furthermore, the observation of three 1 + candidates in 140 I [18], support these assignments. According to the observed Iβ and logft values indeed the first and third (1 + ) levels are populated stronger than the second (1 + ) candidate state.…”

“…This points at the a different origin of the second 1 + state, similarly to 136 I. The population of allowed transitions is observed by the strong feeding of first and third 1 + states in both isotopes, which are suppressed in energy with the increase of N, consistent with [18].…”

“…The strategy in these complementary measurements is to find a common description of the entire region on orbital evolution and collectivity, while searching for single-particle and collective excitations and their persistence with the addition of particles. Here, we will give one example on the observation of high-energy low spin states for Z=53 nuclei, that we traced towards the end of the νf 7/2 shell at 140 I 87 [18] and at its beginning at 136 I 83 [17]. In the 140 I case, the states were populated in pure β-decay of Te projectiles, while for 136 I, they were populated in the prompt data of fission fragments, which accessed also βdecay states in the daughter nucleus, as well as in another β-decay experiment of Te→I nuclei.…”

First determination of β -delayed multiple neutron emission beyond A=100 through direct neutron measurement: The P2nCaballero-Folch1, Dillmann2, Agramunt3 et al. 2018Phys. Rev. C130140View full textAdd to dashboardCite

“…Some of them follow the main theoretical models describing the strength functions and some others are estimates and extrapolations like [52]. Concerning experimental measurements, there is a recent P 2n value reported for 140 Sb [56]. This value was determined through an indirect measurement based on relative intensities of γ-rays observed from transitions that were identified as belonging to 138 Te.…”

Evolution of Nuclear Shapes and Structure in Tellurium, Xenon, Barium and Cerium Isotopes

“…The mass region above the doubly closed 132 Sn towards the neutron drip-line represents a challenging subject for the both experimental and theoretical nuclear structure research. New experimental radioactive beam facilities at ORNL, RIKEN or GANIL together with highly efficient arrays of HPGe detectors at neutron beam facilities (EXILL campaign at ILL) made this region accessible for spectroscopic studies [1][2][3]. Chains of Te, Xe, Ba and Ce isotopes beyond N = 82 are of particular interest because they provide a natural laboratory to study shape and structural changes with gradually increasing number of nucleons outside doubly closed shells.…”