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A theoretical study of the direct radiative capture reaction 16O(p,[gamma])17F

University of British Columbia

The radiative capture reaction ¹⁶0(p,γ)¹⁷F has been studied theoretically using a two-body model to estimate the capture cross sections. The ¹⁶0(p,γ)¹⁷F reaction is a direct capture process at low energies, which is of astrophysieal interest•because of its role in the C-N-0 bi-cycle responsible for hydrogen burning in the larger main sequence stars. The analysis done in this thesis involves a de- tailed fitting of the ¹⁶0(p,p)¹⁶0 scattering data to search for the parameters of a Saxon Woods potential with an energy dependent central well depth, which best describes the ¹⁶0+p interaction. The best set of parameters obtained is used to generate the initial continuum and bound state wave functions. The matrix elements of the electromagnetic interaction hamiltonian are calculated and first order time dependent perturbation theory is used to- obtain the capture cross sections. The results are compared with recent experimental data, observed by T. Hall (1973), from 0.78 Mev to 2.3 Mev, which has a significantly higher accuracy than previous data that was available. The angular distributions predicted by the theory agree satisfactorily with Hall's data. The astrophysieal S-factor extrapolated to thermal energies has the value 8.53 kev-barn at 10 kev, with an uncertainty of at least 5%„ Some of the methods used in the ¹⁶0(p,γ)¹⁷F calculations are applied to a somewhat different capture reaction ⁶Li(p,γ)⁷Be, which involves interferences with resonance capture. This is included in an appendix; and because of the limited experimental data on this reaction, the results are much less conclusive.

Text

2011-03-02

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http://hdl.handle.net/2429/31926

Physics

University of British Columbia

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