High-spin structures of 124−131Te: Competition of proton- and neutron-pair breakings
Résumé
The 124−131Te nuclei have been produced as fission fragments in two fusion reactions induced
by heavy ions (12C+238U at 90MeV bombarding energy and 18O+208Pb at 85MeV) and studied with
the Euroball array. Their high-spin level schemes have been extended up to 6MeV (even-A) and 5MeV
(odd-A) excitation energies from the triple γ-ray coincidence data. The γ-γ angular correlations have been
analyzed in order to assign spin and parity values to most of the observed states. Moreover the half-lives
of isomeric states have been measured from the delayed coincidences between the fission-fragment detector
SAPhIR and Euroball, as well as from the timing information of the Ge detectors. The behaviors of the
yrast structures identified in the present work are first discussed in comparison with the general features
known in the mass region, particularly the breakings of neutron pairs occupying the νh11/2 orbit identified
in the neighboring Sn nuclei. The experimental level schemes are then compared to shell-model calculations
performed in this work. The analysis of the wave functions shows the effects of the proton-pair breaking
along the yrast lines of the heavy Te isotopes.