The nuclear resonance parameters and the capture cross section of the neutron magic isotope 139La and of the radioactive isotope l5lSm have been measured relative to 197 Au in the energy range of O.6 eV-l MeV at neutron time-of-flight (n_TOF) facility at CERN. The description of the experimental apparata is followed by the indication of the data analysis procedures consisting in the efficiency correction by means of the Pulse Height Weighting Function technique, in the determination of different background components and in their subtraction. We extracted the resonance parameters and the related nuclear quantities such as the resonance integral, the average gamma width, the nuclear level densities and the neutron strength function. These results improve the accuracy of the existing data. The deduced values of the Maxwellian-¨averaged capture cross section, together with the most recent spectroscopic observations in low metallicity stars, provide key indications far modelling the nucleosynthesis and the chemical evolution of heavy nuclei in the Galaxy.
Astrophysical Implication of the 139La(n,gamma) and 151Sm(n,gamma) Section Measured at n_TOF
Ventura, A.;
2006-06-25
Abstract
The nuclear resonance parameters and the capture cross section of the neutron magic isotope 139La and of the radioactive isotope l5lSm have been measured relative to 197 Au in the energy range of O.6 eV-l MeV at neutron time-of-flight (n_TOF) facility at CERN. The description of the experimental apparata is followed by the indication of the data analysis procedures consisting in the efficiency correction by means of the Pulse Height Weighting Function technique, in the determination of different background components and in their subtraction. We extracted the resonance parameters and the related nuclear quantities such as the resonance integral, the average gamma width, the nuclear level densities and the neutron strength function. These results improve the accuracy of the existing data. The deduced values of the Maxwellian-¨averaged capture cross section, together with the most recent spectroscopic observations in low metallicity stars, provide key indications far modelling the nucleosynthesis and the chemical evolution of heavy nuclei in the Galaxy.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
