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Bing Guo China Institute of Atomic Energy Beijing Summer School, 2004

Determination of 11 C(p, g ) 12 N Astrophysical S-factor via Measurement of 11 C(d,n) 12 N Reaction. Bing Guo China Institute of Atomic Energy Beijing Summer School, 2004. Motivation. 3 a → 12 C process. Hot pp chains. CNO nuclei.

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Bing Guo China Institute of Atomic Energy Beijing Summer School, 2004

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  1. Determination of 11C(p,g)12N Astrophysical S-factor via Measurement of 11C(d,n)12N Reaction Bing Guo China Institute of Atomic Energy Beijing Summer School, 2004

  2. Motivation 3a→12C process Hot pp chains CNO nuclei ★ The proton- and a-capture reactions on proton-rich unstable nuclei of A≤13 involved in the hot pp chains are thought to be another alternative way to the 3a process for transforming material from the pp chains to the CNO nuclei in the peculiar astrophysical sites where the temperature and density are high enough so that the capture reaction becomes faster than the competing b decay or photodisintegration. ★11C(p,g)12N isone of the key reactions in the hot pp chains 3He(a,g)7Be(a,g)11C(p,g)12N(e+n)12C 3He(a,g)7Be(p,g)8B(a,p)11C(p,g)12N(e+n)12C.

  3. GIRAFFE---the secondary beam facility of the HI-13 tandem accelerator at China Institute of Atomic Energy, Beijing.

  4. Experimental setup

  5. Production of 11C secondary beam The 11C ions were produced via 1H(11B,11C)n reaction. After the magnetic separation and focus, the 63.4 MeV 11C secondary beam was delivered.

  6. The quality of11C beam

  7. 12N identification

  8. Background subtraction

  9. 11C(d,n)12N angular distribution

  10. Angular distribution →ANC

  11. S-factor

  12. The comparison with other works [1] N. K. Timofeyuk and S.B. Igamov, Nucl. Phys. A 713 (2003) 217. [2] Xiaodong Tang, A. Azhari, C. A. Gagliardi, A. M. Mukhamedzhanov, F. Pirlepesov, L. Trache, R. E. Tribble, V. Burjan, V. Kroha, and F. Carstoiu, Phys. Rev. C 67, 015804 (2003).

  13. Conclusion In contrast to the prediction in Ref. [3], our results show that the direct capture dominates 11C(p,g)12N in the wide energy range of astrophysical interest except the ranges corresponding to two resonances. W. Liu, Z. Li, X. Bai, B. Guo et al., Nucl. Phys. A. 728 (2003) 275. [3] P. Descouvemont, Nucl. Phys. A 646 (1999) 261.

  14. Thanks!

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