Photon scattering experiments on the quasistable, odd-odd mass nucleus {sup 176}Lu
- Institut fuer Strahlenphysik, Universitaet Stuttgart, D-70569 Stuttgart (Germany)
- Department of Physics and Astronomy, Youngstown State University, Youngstown, Ohio 44555 (United States)
- Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany)
- Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)
- Institut fuer Kernphysik, Forschungszentrum Karlsruhe, D-76021 Karlsruhe (Germany)
The quasistable odd-odd-mass nucleus {sup 176}Lu is of special interest in nuclear structure physics and, above all, in nuclear astrophysics. Systematic photon scattering experiments have been performed at the bremsstrahlung facility of the 4.3-MV Stuttgart Dynamitron accelerator with bremsstrahlung end-point energies of 2.3 and 3.1 MeV to determine the low-energy dipole strength distribution in the s-only isotope {sup 176}Lu. The main goal was to pin down possible intermediate states (IS) for the photoactivation of the short-lived 123-keV isomer, which is the key process determining the effective lifetime of {sup 176}Lu in a stellar photon bath and hence for the use of this isotope as a stellar chronometer. Using an enriched sample, 29 transitions ascribed to {sup 176}Lu were detected below 2.9-MeV excitation energy. The corresponding excitation strengths were determined. For the previously proposed lowest IS at 839 keV, an upper limit for the excitation strength corresponding to a lifetime of {tau}{>=} 1.5 ps can be given. Astrophysical consequences, also in view of new Stuttgart photoactivation experiments, are discussed. The fragmentation of the dipole strength is compared to those in neighboring even-even and odd-even nuclei.
- OSTI ID:
- 20995114
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 75, Issue 3; Other Information: DOI: 10.1103/PhysRevC.75.034301; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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