[Bubble] Cross section measurement of the 17O(p, gamma)18F reaction

[Jay Benesch]

https://arxiv.org/abs/1703.03184

Gy. Gyürky, A. Ornelas, Zs. Fülöp, Z. Halász, G.G. Kiss, T. Szücs, R. 
Huszánk, I. Hornyák, I. Rajta, I. Vajda
(Submitted on 9 Mar 2017)

     The 17O(p,g)18F reaction plays an important role in hydrogen 
burning processes in different stages of stellar evolution. The rate of 
this reaction must therefore be known with high accuracy in order to 
provide the necessary input for astrophysical models.
     The cross section of 17O(p,g)18F is characterized by a complicated 
resonance structure at low energies. Experimental data, however, is 
scarce in a wide energy range which increases the uncertainty of the low 
energy extrapolations. The purpose of the present work is therefore to 
provide consistent and precise cross section values in a wide energy range.
     The cross section is measured using the activation method which 
provides directly the total cross section. With this technique some 
typical systematic uncertainties encountered in in-beam 
gamma-spectroscopy experiments can be avoided.
     The cross section was measured between 500 keV and 1.8 MeV proton 
energies with a total uncertainty of typically 10%. The results are 
compared with earlier measurements and it is found that the gross 
features of the 17O(p,g)18F excitation function is relatively well 
reproduced by the present data. Deviation of roughly a factor of 1.5 is 
found in the case of the total cross section when compared with the only 
one high energy dataset. At the lowest measured energy our result is in 
agreement with two recent datasets within one standard deviation and 
deviates by roughly two standard deviations from a third one. An 
R-matrix analysis of the present and previous data strengthen the 
reliability of the extrapolated zero energy astrophysical S-factor.
     Using an independent experimental technique, the literature cross 
section data of 17O(p,g)18F is confirmed in the energy region of the 
resonances while lower direct capture cross section is recommended at 
higher energies. The present dataset provides a constraint for the 
theoretical cross sections.

Comments: 	Accepted for publication in Phys. Rev. C. Abstract shortened 
in order to comply with arxiv rules