Nuclear physics for the Re/Os clock
Φόρτωση...
Ημερομηνία
Συγγραφείς
Mosconi, M.
Heil, M.
Kappeler, F.
Plag, R.
Mengoni, A.
Fujii, K.
Domingo-Pardo, C.
Aerts, G.
Terlizzi, R.
Gallino, R.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Journal of Physics G-Nuclear and Particle Physics
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
Dating the age of the universe by the beta-decay of (187)Re (t(1/2) = 41.2 Gyr) requires the accurate assessment of the s-process reaction flow. The daughter nucleus (187)Os as well as its immediate s-only neighbor (186)Os are shielded from the r-process. Therefore, the radiogenic contribution to (187)Os can be derived via the local approximation of the s-process, which is well justified in this mass region: (<sigma > N(s))(187) = (<sigma > N(s))(186). Accordingly, accurate Maxwellian-averaged (n,gamma) cross sections have to be known for (186)Os and (187)Os over the full range of s-process temperatures. Because (187)Os has low-lying excited states, which are significantly populated during the s-process, neutron captures on these excited states have to be properly taken into account. The input for the corresponding Hauser-Feshbach calculations can be constrained by deriving the strength functions from a detailed resonance analysis of the measured (n,gamma) cross sections as well as by an additional measurement of the inelastic scattering cross section for the first exited level, which dominates the competition between the capture and scattering channels. This contribution reports on measurements of the neutron capture cross sections of (186)Os, (187)Os and (188)Os from the eV region to 1MeV at the CERN/n_TOF facility and of the inelastic scattering cross section of (187)Os around 30 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Based on these results and on a detailed resonance analysis, improved Maxwellian-averaged cross sections were obtained for thermal energies between 5 keV and 100 keV. The implications of these results for the Re/Os clock are discussed.
Περιγραφή
Λέξεις-κλειδιά
neutron cross-sections, inelastic-scattering, nucleosynthesis, os-187, isotopes, stars, age
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://000252019800016
http://iopscience.iop.org/0954-3899/35/1/014015/pdf/0954-3899_35_1_014015.pdf
http://iopscience.iop.org/0954-3899/35/1/014015/pdf/0954-3899_35_1_014015.pdf
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών και Τεχνολογιών. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιών