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Title: Measurement of the Radiative Neutron Capture Cross Section of 206Pb and Its Astrophysical Implications

Authors:
 [1];  [2];  [3]
  1. Forschungszentrum Karlsruhe GmbH, Institute fur Kernphysik, Germany
  2. ORNL
  3. Collaboration affiliations
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
932097
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review C; Journal Volume: 76; Journal Issue: 4
Country of Publication:
United States
Language:
English

Citation Formats

Domingo-Pardo, C., Koehler, Paul Edward, and Collaboration, n_TOF. Measurement of the Radiative Neutron Capture Cross Section of 206Pb and Its Astrophysical Implications. United States: N. p., 2007. Web. doi:10.1103/PhysRevC.76.045805.
Domingo-Pardo, C., Koehler, Paul Edward, & Collaboration, n_TOF. Measurement of the Radiative Neutron Capture Cross Section of 206Pb and Its Astrophysical Implications. United States. doi:10.1103/PhysRevC.76.045805.
Domingo-Pardo, C., Koehler, Paul Edward, and Collaboration, n_TOF. Mon . "Measurement of the Radiative Neutron Capture Cross Section of 206Pb and Its Astrophysical Implications". United States. doi:10.1103/PhysRevC.76.045805.
@article{osti_932097,
title = {Measurement of the Radiative Neutron Capture Cross Section of 206Pb and Its Astrophysical Implications},
author = {Domingo-Pardo, C. and Koehler, Paul Edward and Collaboration, n_TOF},
abstractNote = {},
doi = {10.1103/PhysRevC.76.045805},
journal = {Physical Review C},
number = 4,
volume = 76,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • The (n,{gamma}) cross section of {sup 206}Pb has been measured at the CERN n{sub T}OF facility with high resolution in the energy range from 1 eV to 620 keV by using two optimized C{sub 6}D{sub 6} detectors. In the investigated energy interval about 130 resonances could be observed, from which 61 had enough statistics to be reliably analyzed via the R-matrix analysis code SAMMY. Experimental uncertainties were minimized, in particular with respect to (i) angular distribution effects of the prompt capture {gamma}-rays, and to (ii) the TOF-dependent background due to sample-scattered neutrons. Other background components were addressed by background measurementsmore » with an enriched {sup 208}Pb sample. The effect of the lower energy cutoff in the pulse height spectra of the C{sub 6}D{sub 6} detectors was carefully corrected via Monte Carlo simulations. Compared to previous {sup 206}Pb values, the Maxwellian averaged capture cross sections derived from these data are about 20% and 9% lower at thermal energies of 5 keV and 30 keV, respectively. These new results have a direct impact on the s-process abundance of {sup 206}Pb, which represents an important test for the interpretation of the cosmic clock based on the decay of {sup 238}U.« less
  • The neutron capture rate on {sup 18}O is of considerable interest in the interpretation of nucleosynthesis in inhomogeneous big bang scenarios and for stellar helium burning in massive red giant stars as well as AGB stars. We measured the reaction cross section of {sup 18}O({ital n},{gamma}){sup 19}O at the Forschungszentrum Karlsruhe with a fast cyclic neutron activation technique at laboratory neutron energies of 25, 129, 152, 250, and 370 keV. Direct capture and shell model calculations were performed to interpret the results as well as previous unpublished data. Contributions to the reaction cross section and to the new stellar reactionmore » rate will be discussed. {copyright} {ital 1996 The American Physical Society.}« less
  • The total cross section for the [sup 13]N([ital d],[ital n])[sup 14]O[sub g.s.] reaction has been measured with [sup 13]N radioactive beams at laboratory energies of 8.2, 12.0, 16.2, and 28.5 MeV. A spectroscopic factor of 0.9 is obtained from a distorted-wave Born approximation analysis of this transfer reaction. The astrophysical [ital S] factor for the [sup 13]N([ital p],[gamma])[sup 14]O reaction is calculated using the experimentally known resonance parameters for the resonant contribution and the direct-capture model with the experimental spectroscopic factor for the nonresonant contribution.
  • The neutron capture cross section of {sup 206}Pb has been measured at the CERN n/TOF spectrometer using a setup of two C{sub 6}D{sub 6} detectors. In the energy interval from 1 eV to 600 keV the cross section is dominated by resonances, which were analyzed via the R-matrix analysis code SAMMY. In the relevant energy ranges for stellar nucleosynthesis, i.e., at thermal energies of kT = 8 keV and kT = 23 keV, the present Maxwellian average cross section differs by 20% and 9% from the recommended values of Bao et al respectively. From the new cross section the s-abundancemore » of {sup 206}Pb could be reliably determined as 70(4)%. This result is of importance in order to test and constrain r-process abundance calculations in the actinide region, because the r-process portion of {sup 206}Pb is dominated by {alpha}-back decays of short-lived transbismuth isotopes.« less