The 14N(p,γ)15O reaction is the slowest process of the CN cycle, and thus it is of high astrophysical interest since it regulates the total rate of energy and neutrinos production through the cycle. The 14N+p ground state capture is strongly influenced by a sub-threshold resonance corresponding to the 6.79 MeV state in 15O. The width of this resonance is a major source of uncertainty in the extrapolation of the reaction cross section in the Gamow energy window. Preliminary results of a new Doppler Shift Attenuation measurement of the lifetime of the 6.79 MeV state in 15O are discussed. The level of interest was populated via the 2H(14N,n)15O reaction in inverse kinematics at 32 MeV beam energy. The gamma-rays emitted in the decay of the 6.79 MeV level to the ground state were detected with the AGATA Demonstrator array of high-purity germanium detectors. The sensitivity of the shape of the peak in the gamma-ray energy spectrum to the level lifetime is investigated comparing the experimental peaks with detailed Monte Carlo simulations of the reaction mechanisms and the gamma-ray emission and detection. Nuclear levels in 15N (also populated in the 14N+ 2H reaction) for which the lifetimes are known in the literature provided a test of the analysis technique. © 2012 American Institute of Physics.
Lifetime measurement of the 6.79 MeV state in 15O with the AGATA demonstrator / R. Depalo, C. Michelagnoli, R. Menegazzo, C.A. Ur, D. Bazzacco, D. Bemmerer, C. Broggini, A. Caciolli, M. Erhard, E. Farnea, Z. Fulop, A. Gottardo, N. Keeley, S. Lunardi, M. Marta, D. Mengoni, T. Mijatovic, F. Recchia, C. Rossi-Alvarez, T. Szucs, J.J. Valiente-Dobon (AIP CONFERENCE PROCEEDINGS). - In: Nuclear structure and dynamics 2012 / [a cura di] T. Nikšić, M. Milin, D. Vretenar, S. Szilner. - [s.l] : AMER INST PHYSICS, 2012. - ISBN 978-0-7354-1103-6. - pp. 319-323 (( convegno Carpathian Summer School of Physics 2012: Exotic Nuclei and Nuclear/Particle Astrophysics (IV). From Nuclei to Stars, CSSP 2012 tenutosi a Sinaia nel 2012 [10.1063/1.4768511].
Lifetime measurement of the 6.79 MeV state in 15O with the AGATA demonstrator
R. Depalo;
2012
Abstract
The 14N(p,γ)15O reaction is the slowest process of the CN cycle, and thus it is of high astrophysical interest since it regulates the total rate of energy and neutrinos production through the cycle. The 14N+p ground state capture is strongly influenced by a sub-threshold resonance corresponding to the 6.79 MeV state in 15O. The width of this resonance is a major source of uncertainty in the extrapolation of the reaction cross section in the Gamow energy window. Preliminary results of a new Doppler Shift Attenuation measurement of the lifetime of the 6.79 MeV state in 15O are discussed. The level of interest was populated via the 2H(14N,n)15O reaction in inverse kinematics at 32 MeV beam energy. The gamma-rays emitted in the decay of the 6.79 MeV level to the ground state were detected with the AGATA Demonstrator array of high-purity germanium detectors. The sensitivity of the shape of the peak in the gamma-ray energy spectrum to the level lifetime is investigated comparing the experimental peaks with detailed Monte Carlo simulations of the reaction mechanisms and the gamma-ray emission and detection. Nuclear levels in 15N (also populated in the 14N+ 2H reaction) for which the lifetimes are known in the literature provided a test of the analysis technique. © 2012 American Institute of Physics.
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