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

Abstract

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.

Authors:
; ; ; ; ; ;  [1];  [2]; ; ; ; ; ; ; ;  [3]; ; ;  [4];  [5]
  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) (and others)
Publication Date:
OSTI Identifier:
20995114
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.75.034301; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
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

Citation Formats

Walter, S., Stedile, F., Garrel, H. von, Kneissl, U., Kohstall, C., Pitz, H. H., Scheck, M., Carroll, J. J., Fransen, C., Friessner, G., Hollmann, N., Jolie, J., Linnemann, A., Muecher, D., Scholl, C., Werner, V., Karg, O., Neumann-Cosel, P. von, Pietralla, N., and Kaeppeler, F. Photon scattering experiments on the quasistable, odd-odd mass nucleus {sup 176}Lu. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.034301.
Walter, S., Stedile, F., Garrel, H. von, Kneissl, U., Kohstall, C., Pitz, H. H., Scheck, M., Carroll, J. J., Fransen, C., Friessner, G., Hollmann, N., Jolie, J., Linnemann, A., Muecher, D., Scholl, C., Werner, V., Karg, O., Neumann-Cosel, P. von, Pietralla, N., & Kaeppeler, F. Photon scattering experiments on the quasistable, odd-odd mass nucleus {sup 176}Lu. United States. doi:10.1103/PHYSREVC.75.034301.
Walter, S., Stedile, F., Garrel, H. von, Kneissl, U., Kohstall, C., Pitz, H. H., Scheck, M., Carroll, J. J., Fransen, C., Friessner, G., Hollmann, N., Jolie, J., Linnemann, A., Muecher, D., Scholl, C., Werner, V., Karg, O., Neumann-Cosel, P. von, Pietralla, N., and Kaeppeler, F. Thu . "Photon scattering experiments on the quasistable, odd-odd mass nucleus {sup 176}Lu". United States. doi:10.1103/PHYSREVC.75.034301.
@article{osti_20995114,
title = {Photon scattering experiments on the quasistable, odd-odd mass nucleus {sup 176}Lu},
author = {Walter, S. and Stedile, F. and Garrel, H. von and Kneissl, U. and Kohstall, C. and Pitz, H. H. and Scheck, M. and Carroll, J. J. and Fransen, C. and Friessner, G. and Hollmann, N. and Jolie, J. and Linnemann, A. and Muecher, D. and Scholl, C. and Werner, V. and Karg, O. and Neumann-Cosel, P. von and Pietralla, N. and Kaeppeler, F.},
abstractNote = {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.},
doi = {10.1103/PHYSREVC.75.034301},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}