The {sup 13}C({alpha},n) reaction and its role as a neutron source for the s process
- Forschungszentrum Karlsruhe, Institut fuer Kernphysik, Postfach 3640, D-76021 Karlsruhe (Germany)
- University of Notre Dame, Department of Physics, Notre Dame, Indiana 46556 (United States)
The {sup 13}C({alpha},n){sup 16}O reaction constitutes the dominant neutron source for the main s process, which operates at a thermal energy of kT=8 keV. Since the cross section at stellar energies is very small, the reaction rate cannot be directly determined and has to be extrapolated from cross section results obtained at higher energies. To remove various discrepancies in the normalization of previous data sets and to subsequently improve the reliability of the extrapolation, we performed measurements of the {sup 13}C({alpha},n){sup 16}O reaction in the energy range E{sub c.m.}=320-700 keV. In addition, the double differential scattering cross section {sup 13}C({alpha},{alpha}){sup 13}C was measured in the energy range E{sub lab}=2.6-6.2 MeV for 28 angles. These data were used to constrain possible contributions from background resonances for a reliable extrapolation with the multichannel R-matrix code SAMMY. As a result, the uncertainties were significantly reduced, and a reaction rate of (4.6{+-}1.0)x10{sup -14} cm{sup 3}/moles at kT=8 keV (T=0.1x10{sup 9} K) was determined.
- OSTI ID:
- 21192155
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 78, Issue 2; Other Information: DOI: 10.1103/PhysRevC.78.025803; (c) 2008 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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