https://doi.org/10.1140/epja/i2019-12801-8
Regular Article - Experimental Physics
The determination of the astrophysical S-factor of the direct 18O(p,
)19F capture by the ANC method
1
Nuclear Physics Institute of Czech Academy of Sciences, 250 68, Řež, Czech Republic
2
Cyclotron Institute, Texas A&M University, 77843, College Station, TX, USA
3
Dipartimento di Fisica ed Astronomia E. Majorana, Università di Catania and INFN Laboratori Nazionali del Sud, Catania, Italy
4
Università degli Studi di Enna “KORE”, Enna, Italy
* e-mail: burjan@ujf.cas.cz
Received:
28
February
2019
Accepted:
12
June
2019
Published online:
23
July
2019
The depletion of 18O via the capture competes with the
capture during the CNO cycles in AGB stars. Despite the fact that the
capture is dominant, the
can play an important role in mixing stages of the AGB star evolution. Here, we attempt to determine the astrophysical S-factor of the direct part of the 18O(p,
)19F capture by the indirect method of asymptotic normalization coefficients (ANC). We measure the differential cross section of the transfer reaction 18O(3He, d)19F at a 3He energy of 24.6 MeV. The measurement was performed on the cyclotron of the CANAM infrastructure of NPI in Řež, Czech Republic, with the gas target consisting of the high-purity 18O (99.9%). The reaction products were measured by eight
-E telescopes composed of thin and thick silicon surface-barrier detectors. The parameters of the optical model for the input channel were deduced by means of the code ECIS and the analysis of transfer reactions to 12 levels of the 19F nucleus up to 8.014 MeV was made by the code FRESCO. The deduced ANCs were then used to specify the direct contribution to the 18O(p,
)19F capture process and were compared with the mutually different results of two works.
© Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature, 2019