Photon scattering experiments on the quasistable, odd-odd mass nucleus {sup 176}Lu

Journal Article · Thu Mar 15 04:00:00 EDT 2007 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.75.034301· OSTI ID:20995114

Walter, S; Stedile, F; Garrel, H von; Kneissl, U; Kohstall, C; Pitz, H H; Scheck, M ^[1]; Carroll, J J ^[2]; Fransen, C; Friessner, G; Hollmann, N; Jolie, J; Linnemann, A; Muecher, D; Scholl, C; Werner, V ^[3]; Karg, O; Neumann-Cosel, P von; Pietralla, N ^[4]; Kaeppeler, F ^[5]

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1. Institut fuer Strahlenphysik, Universitaet Stuttgart, D-70569 Stuttgart (Germany)
2. Department of Physics and Astronomy, Youngstown State University, Youngstown, Ohio 44555 (United States)
3. Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany)
4. Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)
5. 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, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 3 Vol. 75; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BREMSSTRAHLUNG
DIPOLES
DYNAMITRONS
EXCITATION
INTERMEDIATE STATE
KEV RANGE 100-1000
LUTETIUM 176
MASS
MEV RANGE 01-10
NUCLEAR STRUCTURE
ODD-EVEN NUCLEI
PHOTONS
SCATTERING