Experimental study of the reaction at high and low energies

The 14 N ( p , γ ) 15 O reaction controls the rate of the carbon–nitrogen–oxygen (CNO) cycle of stellar hydrogen burning. The reaction proceeds by capture to the ground state and several excited states in 15 O . Several studies of this reaction have recently been performed in the low energy range 150 < E p < 500  keV and only one set of data from an experiment performed in 1987 extends up to 3 MeV. In order to obtain a reliable extrapolation of the excitation curve to astrophysical energy, R-matrix fits need data covering the widest possible range of energy. In a first phase, the experimental investigation has been performed at the Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator in an energy range that sensitively tests such fits, placed deep underground in the Gran Sasso facility in Italy, using a composite germanium detector. In a second phase, the reaction has been studied at the high-current FZD Tandetron in Dresden (Germany), in the energy region from 0.6 to 2.5 MeV. The astrophysical motivation, setup, and data analysis are presented.