The N14(p,γ)O15 reaction studied with a composite germanium detector

The rate of the carbon-nitrogen-oxygen (CNO) cycle of hydrogen burning is controlled by the {sup 14}N(p,{gamma}){sup 15}O reaction. The reaction proceeds by capture to the ground states and several excited states in {sup 15}O. In order to obtain a reliable extrapolation of the excitation curve to astrophysical energy, fits in the R-matrix framework are needed. In an energy range that sensitively tests such fits, new cross-section data are reported here for the four major transitions in the {sup 14}N(p,{gamma}){sup 15}O reaction. The experiment has been performed at the Laboratory for Underground Nuclear Astrophysics (LUNA) 400-kV accelerator placed deep underground in the Gran Sasso facility in Italy. Using a composite germanium detector, summing corrections have been considerably reduced with respect to previous studies. The cross sections for capture to the ground state and to the 5181, 6172, and 6792 keV excited states in {sup 15}O have been determined at 359, 380, and 399 keV beam energy. In addition, the branching ratios for the decay of the 278-keV resonance have been remeasured.