Nucleosynthesis of ^16O Under Quiescent Helium Burning
The ^12C(alpha,gamma) ^16O radiative capture reaction is one of the most important reactions in nuclear astrophysics as its reaction rate determines the C/O ratio in the Universe. A better understanding of this reaction is what motivates the experiments presented in this thesis. In experiments performed at Ohio University angular distributions and branching ratios of the 7.12- and 6.92-MeV transitions in ^16O were measured. An upper limit was set on the 7.12 to 6.13-MeV transition in ^16O. These results will better constrain the alpha-reduced width of the 6.92-MeV state in ^16O which is important for the extrapolation to helium-burning energies of both the E2 transition and cascade through the 6.92-MeV state. At the DRAGON recoil separator at TRIUMF, Canada, the E to 6.05 MeV transition in ^12C(alpha,gamma) ^16O was measured over a wide range of energies. The result shows that the cascade through the 6.05-MeV state is the most important cascade in ^12C(alpha,gamma) ^16O with an extrapolated S-factor at 300 keV, S 6.05(300)=25±16 keV b. A new value for the total S-factor at 300 keV is proposed.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:branching ratios in 16o cascade transitions the 6 05 mev state
Date of Publication:01/01/2006