The 14N(p,gamma)15O reaction studied with a composite germanium detector

TL;DR

This study provides new, precise cross section measurements for the 14N(p,gamma)15O reaction at astrophysical energies using advanced detection techniques, aiding in better modeling of stellar processes.

Contribution

It presents new experimental cross section data for key transitions in the 14N(p,gamma)15O reaction, utilizing a composite germanium detector to improve accuracy and reduce summing corrections.

Findings

Cross sections measured at 359, 380, and 399 keV beam energies.

Branching ratios for the 278 keV resonance decay remeasured.

Enhanced data quality for astrophysical extrapolations.

Abstract

The rate of the carbon-nitrogen-oxygen (CNO) cycle of hydrogen burning is controlled by the 14N(p,gamma)15O reaction. The reaction proceeds by capture to the ground states and several excited states in O-15. 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 14N(p,gamma)15O 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 O-15 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.