70 research outputs found
Thermal Equilibration of 176-Lu via K-Mixing
In astrophysical environments, the long-lived (\T_1/2 = 37.6 Gy) ground state
of 176-Lu can communicate with a short-lived (T_1/2 = 3.664 h) isomeric level
through thermal excitations. Thus, the lifetime of 176-Lu in an astrophysical
environment can be quite different than in the laboratory. We examine the
possibility that the rate of equilibration can be enhanced via K-mixing of two
levels near E_x = 725 keV and estimate the relevant gamma-decay rates. We use
this result to illustrate the effect of K-mixing on the effective stellar
half-life. We also present a network calculation that includes the
equilibrating transitions allowed by K-mixing. Even a small amount of K-mixing
will ensure that 176-Lu reaches at least a quasi-equilibrium during an
s-process triggered by the 22-Ne neutron source.Comment: 9 pages, 6 figure
Multiquasiparticle states in the neutron-rich nucleus 174 Tm
Deep inelastic and transfer reactions with an 820-MeV, 136Xe beam and various ytterbium and lutetium targets have been employed to study high-spin structures in the neutron-rich thulium isotopes beyond 171Tm. Results in the doubly odd nucleus, 174Tm, inc
Revised level structure of 120Te
The level scheme of the nucleus Te120, populated in the reaction Se80(Ca48,α4n), was reinvestigated using γ-ray coincidence data measured with the Gammasphere spectrometer. Previously, five high-spin rotational bands were discovered in this nucleus. Th
High-spin structure, K isomers, and state mixing in the neutron-rich isotopes 173 Tm and 175 Tm
High-spin states in the odd-proton thulium isotopes 173Tm and 175Tm have been studied using deep-inelastic reactions and γ-ray spectroscopy. In 173Tm, the low-lying structure has been confirmed and numerous new states have been identified, including a t
Anomalous isomeric decays in 174Lu as a probe of K-mixing and interactions in deformed nuclei
A KÏ€=13+, 280 ns four-quasiparticle isomer in the odd-odd nucleus 174Lu has been identified and characterized. The isomer decays to both KÏ€=7+ and KÏ€=0+ rotational bands obtained from the parallel and antiparallel coupling of the proton 7/2+[404] and neutron 7/2+[633] orbitals. K mixing caused by particle-rotation coupling explains the anomalously fast transition rates to the 7+ band but those to the 0+ band are caused by a chance degeneracy between the isomer and a collective state, allowing the mixing matrix element for a large K difference to be deduced
Shape evolution in 116,118 Ru: Triaxiality and transition between the O(6) and U(5) dynamical symmetries
116Ru and 118Ru have been studied via β-delayed γ-ray spectroscopy of nuclei produced in fragmentation reactions at the Radioactive Ion-Beam Factory (RIBF) facility. Level schemes with positive-parity states up to spin J=6 have been constructed. The re
Isomers and excitation modes in the gamma-soft nucleus 192 Os
New spectroscopic results for high-spin states in 192Os populated in deep-inelastic reactions include the identification of a 2-ns, 12+ isomeric state at 2865 keV and a 295-ns, 20+ state at 4580 keV and their associated δJ=2 sequences. The structures ar
Three-quasiparticle isomers and possible deformation in the transitional nuclide, 195 Au
Deep-inelastic reactions and γ-ray spectroscopy have been used to study excited states in 195Au. A three-quasiparticle isomer with a mean-life of 18.6(3) μs has been assigned at 2461+Δ keV, with decays into newly identified structures. Possible config
Long-lived three-quasiparticle isomers in 191Ir and 193Ir with triaxial deformation
Deep-inelastic reactions have been used to populate high-spin states in the iridium isotopes. New results include the identification of particularly long-lived three-quasiparticle isomers in 191Ir and 193Ir, with mean-lives of 8.2(7) s and 180(3) μs res
- …