Measurement of the 14O(α ,p ) 17F cross section at Ec .m .≈2.1 -5.3 MeV
Abstract
Background: The 14O(α ,p ) 17F reaction plays an important role as the trigger reaction for the x-ray burst.
Purpose: The direct measurement of 14O(α ,p ) 17F was made for studying the resonant states in 18Ne and determining the reaction rate of 14O(α ,p ) 17F at astrophysical temperatures. Methods: The differential cross section of the 14O(α ,p ) 17F reaction was measured using a 2.5-MeV/u 14O radioactive beam and the thick target method in inverse kinematics. Three sets of Δ E -E Si telescopes were installed and coincidence measurements were performed. We analyzed single-proton decay events using the time-of-flight (TOF) information of the recoiling protons. Results: The excitation function of 14O(α ,p ) 17F was acquired for excitation energies between 7.2 and 10.4 MeV in 18Ne by considering the two channels which decay to the ground state and first excited state of 17F . Several new, as well as previously known, states in 18Ne were observed and their resonance parameters were extracted from R -matrix analysis. The contributions of four resonances over the excitation energy range, 7 <Ex<8.2 MeV , to the 14O(α ,p ) 17F reaction rate were calculated. Conclusions: We observed very strong single-proton decay events, but did not observe strong double-proton decay events as in a previous study by Fu et al. The reaction rates contributed by the 7.35-, 7.58-, and 7.72-MeV states were estimated to be dominant at temperatures T9>2 . Among these three states, the 7.35-MeV state was found to enhance the reaction rate by a factor of 10 greater than the other two resonance states.- Publication:
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Physical Review C
- Pub Date:
- September 2015
- DOI:
- 10.1103/PhysRevC.92.035801
- Bibcode:
- 2015PhRvC..92c5801K
- Keywords:
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- 25.55.-e;
- 26.30.-k;
- 27.20.+n;
- <sup>3</sup>H- <sup>3</sup>He- and <sup>4</sup>He-induced reactions;
- Nucleosynthesis in novae supernovae and other explosive environments;
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