Constraining the 12C+12C astrophysical S-factors with the 12C+13C measurements at very low energies
oleh: N.T. Zhang, X.Y. Wang, D. Tudor, B. Bucher, I. Burducea, H. Chen, Z.J. Chen, D. Chesneanu, A.I. Chilug, L.R. Gasques, D.G. Ghita, C. Gomoiu, K. Hagino, S. Kubono, Y.J. Li, C.J. Lin, W.P. Lin, R. Margineanu, A. Pantelica, I.C. Stefanescu, M. Straticiuc, X.D. Tang, L. Trache, A.S. Umar, W.Y. Xin, S.W. Xu, Y. Xu
| Format: | Article |
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| Diterbitkan: | Elsevier 2020-02-01 |
Deskripsi
We use an underground counting lab with an extremely low background to perform an activity measurement for the C12+13C system with energies down to Ec.m.=2.323 MeV, at which the 12C(13C,p)24Na cross section is found to be 0.22(7) nb. The C12+13C fusion cross section is derived with a statistical model calibrated using experimental data. Our new result of the C12+13C fusion cross section is the first decisive evidence in the carbon isotope systems which rules out the existence of the astrophysical S-factor maximum predicted by the phenomenological hindrance model, while confirming the rising trend of the S-factor towards lower energies predicted by other models, such as CC-M3Y+Rep, DC-TDHF, KNS, SPP and ESW. After normalizing the model predictions with our data, a more reliable upper limit is established for the C12+12C fusion cross sections at stellar energies. Keywords: Fusion cross section, Astrophysical S-factor, Extrapolation models, Hindrance