Resonance strengths in the N14(p,$\gamma${})O15 and N15(p,$\alpha${}$\gamma${})C12 reactions

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Abstract
The N14(p,$\gamma${})O15 reaction is the slowest reaction of the carbon-nitrogen-oxygen cycle of hydrogen burning in stars. As a consequence, it determines the rate of the cycle. The N15(p,$\alpha${}$\gamma${})C12 reaction is frequently used in inverse kinematics for hydrogen depth profiling in materials. The N14(p,$\gamma${})O15 and N15(p,$\alpha${}$\gamma${})C12 reactions have been studied simultaneously, using titanium nitride targets of natural isotopic composition and a proton beam. The strengths of the resonances at Ep\,=\,1058 keV in N14(p,$\gamma${})O15 and at Ep\,=\,897 and 430 keV in N15(p,$\alpha${}$\gamma${})C12 have been determined with improved precision, relative to the well-known resonance at Ep\,=\,278 keV in N14(p,$\gamma${})O15. The new recommended values are $\omega${}$\gamma${}=0.353\ifmmode\pm\else\textpm\fi{}0.018, 362\ifmmode\pm\else\textpm\fi{}20, and 21.9\ifmmode\pm\else\textpm\fi{}1.0 eV for their respective strengths. In addition, the branching ratios for the decay of the Ep\,=\,1058 keV resonance in N14(p,$\gamma${})O15 have been redetermined. The data reported here should facilitate future studies of off-resonant capture in the N14(p,$\gamma${})O15 reaction that are needed for an improved R-matrix extrapolation of the cross section. In addition, the data on the 430 keV resonance in N15(p,$\alpha${}$\gamma${})C12 may be useful for hydrogen depth profiling.

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