Access Restriction

Author Kiss, G.g. ♦ Lamia, L. ♦ Puglia, S.m.r. ♦ Spitaleri, C. ♦ Koshchiy, E. ♦ Kuchera, A. ♦ Santiago, D. ♦ Avila, M. ♦ La, Cognata M. ♦ Romano, S. ♦ Mukhamedzhanov, A.m. ♦ Spartà, R. ♦ Trippella, O. ♦ Guardo, G.l. ♦ Rogachev, G.v.
Source Directory of Open Access Journals (DOAJ)
Content type Text
Publisher EDP Sciences
File Format PDF
Date Created 2015-02-05
Copyright Year ©2015
Language English
Subject Domain (in LCC) QC1-999
Subject Keyword Science ♦ Physics
Abstract The 13C(α, n)16O reaction is the neutron source for the main component of the s-process. It is is active inside the helium-burning shell of asymptotic giant branch stars, at temperatures ≲ 108 K. In this temperature region, corresponding to an energy interval of 140 − 230 keV, the 13C(α, n)16O cross section is dominated by the −3 keV sub-threshold resonance due to the 6.356 MeV level in 17O. Direct measurements could not establish its contribution owing to the Coulomb barrier between interacting nuclei, strongly reducing the cross section at astrophysical energies. Similarly, indirect measurements and extrapolations yielded inconsistent results, calling for further investigations. The Trojan Horse Method was applied to the 13C(6Li, n16O)d quasi-free reaction to access the low as well as the negative energy region of the 13C(α, n)16O reaction. By using the generalized R-matrix approach, the asymptotic normalization coefficient (C̃17O(1/2+)α13C)2 of the 6.356 MeV level was deduced. For the first time, the Trojan Horse Method and the asymptotic normalization coefficient were used in synergy. Our indirect approach lead to (C̃17O(1/2+)α13C)2 = 7.7−1.5+1.6 fm−1, slightly larger than the values in the literature, determining a 13C(α, n)16O reaction rate slightly larger than the one in the literature at temperatures lower than 108 K, with enhanced accuracy.
ISSN 2100014X
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG ♦ Career/Technical Study
Learning Resource Type Article
Publisher Date 2015-01-01
e-ISSN 2100014X
Journal EPJ Web of Conferences
Volume Number 86
Starting Page 00023

Source: Directory of Open Access Journals (DOAJ)