Complete level scheme of 124Te up to 3 MeV

Abstract Excited states of 124 Te were measured with the transfer reactions 123 Te(d,p) 124 Te, 125 Te(d,t) 124 Te and 123 Sb( 3 He,d) 124 Te and with the inelastic scattering reaction 124 Te(p,p′) 124 Te at the Tandem Accelerator in Munich. Levels were obtained up to 3.5 MeV with energy resolutions of 3–6 keV. The 124 Te(γ,γ′) 124 Te reaction was studied at the S-DALINAC accelerator in Darmstadt for bremsstrahlung endpoint energies E 0 = 3.5 and 5 MeV. The 123 Te(n,γ) 124 Te reaction with thermal neutrons was investigated in Riga and in Dubna including γ-γ coincidences. In Dubna the special method of sum coincidences was applied, analyzing the γ-γ cascades to the ground state and the first 2 + level. Based on these experiments a level scheme was constructed with states up to 4.5 MeV which is assumed to the complete up to 3 MeV for angular momenta J h . A quasiparticle-phonon model calculation with a configuration space of up to three-phonon coupling permits a good description for many of the low-energy states. Transition probabilities, E2 M1 mixing ratios and branching ratios between these levels are generally well described. The quantitative reproduction indicates a two-phonon quadrupole-octupole coupled 1 − structure of the states most strongly excited in the (γ,γ′) reaction. The 2 − member of the 2 1 + ⊗ 2 1 + ⊗ 3 1 − septuplet is identified in the unusual decay cascade following thermal neutron capture. A candidate for a 2 + state with mixed symmetry structure is proposed.