Analysis of the¹⁹F(p, α₀)¹⁶O reaction at low energies and the spectroscopy of²⁰Ne

Abstract

The investigation of the 19 F(p, α 0 ) reaction at low bombarding energies allows the study of the spectroscopy of the 20 Ne compound nucleus in an energy region where the existence of quartet excitations has been suggested in the literature. Moreover, this reaction plays a major role in the fourth branch of the CNO cycle since it is relevant for the correct description of the hydrogen burning of fluorine in stars. For these reasons, we decided to investigate the 19 F(p, α 0 ) reaction in the E p 0.6-1 MeV energy range. The analysis of angular distributions and excitation functions allows one to improve the 20 Ne spectroscopy in an excitation energy region where some ambiguities concerning J π assignments exist in the literature. In particular, the present data suggest a J π = 0 + assignment to the E x = 13.642 MeV resonance. For this state, both partial and reduced widths for the α 0 channel have been deduced. The trend of the astrophysical factor has been obtained from the integrated cross section. A comparison of the present results with data reported in the literature is also discussed.

Indirect method to measure differential cross-sections for nuclear reaction analysis

“…Our data for h = 150°and 170°are in very good agreement with the data given by Paneta et al [12] even with respect to the absolute values. More recent measurements [11] of the differential cross-section at 150°in the proton energy range between 600 and 1000 keV also showed a very good agreement to the results presented in [6,7]. A direct comparison with our results is not possible because the data are not available and, furthermore, the fine structure of the excitation function in that energy range was not in the focus of our work.…”

“…Dieumegard et al [7] measured the cross-section for this reaction at 90°and 150°in great detail over a proton energy range of 300-2000 keV, by means of an automatic energy scanning system. More recently a detailed study for the energy range between 600 and 1000 keV and backscattering at 150°was performed by Lombardo et al [11]. Paneta et al [12] investigated a broad range of reactions including the one under consideration here but for high proton energies up to about 4 MeV.…”

The role of 13C excited states in α+9Be reaction and scattering cross sections

“…The main part of data that we included in the R-matrix analysis were obtained with an experiment done at the ttt3 tandem accelerator in Napoli [29]. Details concerning the experimental configuration are reported in Ref.…”

A proposed direct measurement of cross section at Gamow window for key reaction 19F(p,α) 16O in Asymptotic Giant Branch stars with a planned accelerator in CJPL

“…However, the energy resolution was not enough for achieving a good separation between resonances, thus preventing an accurate estimate of the their total widths as well as the reaction rate. Most recently, Lombardo et al reported new direct measurement data [34,35] on the 19 F(p,α 0 ) 16 O reaction at the energy region of E c.m. =0.18-1 MeV, and found the deduced astrophysical S -factor ≈1.5-2 times larger than currently recommended one.…”