0000000000335941
AUTHOR
J. Honzátko
Nuclear structure of 131Te studied with (n,γ) and reactions
Abstract The structure of 131 Te has been investigated with the 130 Te( n , γγ ) 131 Te reaction using thermal neutrons and with the 130 Te( d , p ) 131 Te reaction using polarized deuterons with energy E d =18 MeV. About 290 levels were identified in most cases including spin, parity and γ -decay. The γ -decay scheme after neutron capture is essentially complete containing about 100% of the decay of the capture state and about 100% of the population of the 11/2 − isomer and of the ground state. The scheme includes 42 primary transitions with energies between 750 keV and 2500 keV. The experimental level scheme is compared with predictions of the Interacting Boson–Fermion model (IBFM) and of…
Low-spin mixed particle–hole structures in 185W
Abstract The level structure of 185W has been studied using the prompt and delayed gamma–gamma coincidences from thermal neutron capture in 184W accompanied with the one-nucleon transfer reactions ( d , p ) and ( d , t ) with polarized beams. From these data and those of previous studies a total of 183 levels has been established for energies below 3 MeV. Many of these states have been grouped into rotational bands built on 28 intrinsic states of quasiparticle and quasiparticle-plus-phonon character. Although the DWBA analysis permitted definite spin–parity assignments for most of states a large number of particle transitions have ‘anomalous’ angular and asymmetry shapes with respect to the…
Nuclear structure of 187W studied with (n,γ) and (d,p) reactions
Abstract The level structure of 187 W has been studied using prompt and delayed gamma–gamma coincidences from thermal neutron capture in 186 W and also measuring the ( d , p ) reaction. From these data and those of previous studies a total of 170 levels (121 connected by γ transitions) have been established for energies below 2.35 MeV. Some of these levels have been grouped into rotational bands built on 14 intrinsic states of quasi-particle and quasi-particle plus phonon character. Of particular interest has been the identification of “quasi bands” with inverse spin sequence based on the newly established isomeric 11 / 2 + state at 410.1 keV. Although the DWBA analysis permitted definite s…
Nuclear structure of 127Te studied with (n,γ) and (d→,p) reactions and interpreted with IBFM and QPM
Abstract The nuclear structure of 127Te has been investigated with the Te 126 ( n , γ γ ) Te 127 reaction using thermal neutrons and with the Te 126 ( d → , p ) Te 127 reaction at E d = 20 MeV . About 190 levels were identified in a region to 4.1 MeV excitation energy, in most cases including spin, parity and γ-decay. The γ-decay scheme after neutron capture is essentially complete containing about 100% of the population of the 11 / 2 − isomer and of the ground state. The thermal neutron capture cross section and isomer production of the 11 / 2 − state at 88.3 keV were determined to be 0.44(6) b and 0.069(10) b, respectively. The neutron binding energy was determined to be 6287.6(1) keV. A …
Nuclear levels of 183W studied with and reactions
Abstract The level structure of 183 W has been studied using gamma–gamma coincidences from thermal neutron capture in 182 W accompanied with the reaction ( d → , p ) . From these data and those of previous studies a total of 76 levels and about 490 connecting γ -transitions have been established for energies below 2.4 MeV. An analysis based on the standard distorted-wave Born approximation (DWBA) provides the lj -angular momentum transfers and spectroscopic factors for 36 levels up to 2.2 MeV excitation energy. A large number of particle transitions indicate an influence of strong mixing between particle and probably hole states. The extra exchange of phonons across the Fermi surface leads …
Interplay of quasiparticle and phonon excitations in 181Hf observed through (n,γ) and reactions
Abstract Nuclear levels of 181 Hf were investigated in the range up to 3 MeV excitation energy by (n, γ ) and (d,p) reactions. Over 170 levels and about 390 γ -transitions were established most of them for the first time. 25 rotational bands were identified. Comparison of the results of the two reactions yields information on the fine structure in the fragmentation of Nilsson strength. The states below 2 MeV with the most complete spectroscopic information were interpreted in terms of the Quasiparticle Phonon Model (QPM). Excitation energies, electromagnetic transition rates, γ -branchings and spectroscopic factors are discussed in connection with their possible structure.
Nuclear structure of 157Gd
Abstract The energy levels of 157 Gd have been investigated using the (n, γ ) and (n, n′ γ ) reactions. As a result of the analysis of the γ -ray spectra from 16 isolated neutron resonances, a level scheme with a complete set of levels with spins J =1/2, 3/2 has been established up to 1.86 MeV excitation energy. A part of the level scheme is interpreted in more detail on the basis of Coriolis and Δ N =2 coupled Nilsson configurations. Slightly different sets of shape parameters are deduced for negative- and positive-parity levels. A large excess of unassigned 1/2 and 3/2 levels evidently requires an explanation in terms of inclusion of new additional degrees of freedom.