The15N(p,? 0)12C reaction at stellar energies

Abstract

The ~SN(p, %)lzC reaction has been investigated in the energy range of Ep(lab)=78-810keV. The measurement of the excitation functions and s-particle angular distributions involved solid targets as well as a quasi-point supersonic jet gas target. The determination of absolute cross sections has been carried out with the gas target. The observed energy dependence of the total cross sections can be described in terms of two-level Breit-Wigner shapes including the resonances at Ep(J~)=335(1 -) and 1,028(1-) keV. The data lead to a zero-energy intercept of the astrophysical S(E) factor of S(0)=65_+4 MeV-b. The angular distributions are asymmetric around 90 ~ and require an additional amplitude in the reaction mechanism, which interferes predominantly with the 335 keV resonance. The origin of this background amplitude is discussed. ENuclear Reaction: 15N(p, c%)~2C, Ev(lab)=78-810keV; measured c~(E, 0). Deduced astrophysical S-factor. Enriched 15N solid target and supersonic jet gas target,

R-matrix analysis of16O compound nucleus reactions

“…[31] where the R-matrix fit always overestimates the data points. This is in contrast to the low energy data of Ref.…”

“…[49,50] to estimate the low energy S-factor using the data of Refs. [30,31,34] which are all available in tabulated form. In these analyses, a two level R-matrix approach has been used which considers the 1 − levels at E x = 12.45 and 13.09 MeV.…”

“…Addition data considered in this reaction channel include the angular distributions of Refs. [29,31], the higher energy differential cross section measurements of Refs. [18,20,21] and the yield ratio data of Ref.…”

“…Included in this analysis are the angle integrated cross sections from Table 1 of Ref. [31], those digitized from Fig. 3 of Ref.…”

“…[19] (data from Fig. 3 [31], [26], and [34] (labeled a) through c) respectively). Laboratory proton energy is given on the top horizontal axis, excitation energy on the bottom horizontal axis of each plot.…”