Be-7 (n,p)Li-7 Reaction and the Cosmological Lithium Problem: Measurement of the Cross Section in a Wide Energy Range at n_TOF at CERN
Metadatos
Mostrar el registro completo del ítemEditorial
PHYSICAL REVIEW LETTERS
Materia
Neutron yields Simulation Elements
Fecha
2018-07-24Referencia bibliográfica
Damone, L., Barbagallo, M., Mastromarco, M., Mengoni, A., Cosentino, L., Maugeri, E., ... & Colonna, N. (2018). Be 7 (n, p) Li 7 Reaction and the Cosmological Lithium Problem: Measurement of the Cross Section in a Wide Energy Range at n_TOF at CERN. Physical review letters, 121(4), 042701.
Patrocinador
The European Atomic Energy Community (Euratom) Seventh Framework Programme No. FP7/2007-2011 under Project CHANDA (Grant No. 605203); Narodowe Centrum Nauki (NCN), under Grant No. UMO-2016/22/M/ST2/00183Resumen
We report on the measurement of the Be-7(n,p)Li-7 cross section from thermal to approximately 325 keV neutron energy, performed in the high-flux experimental area (EAR2) of the n_TOF facility at CERN. This reaction plays a key role in the lithium yield of the big bang nucleosynthesis (BBN) for standard cosmology. The only two previous time-of-flight measurements performed on this reaction did not cover the energy window of interest for BBN, and they showed a large discrepancy between each other. The measurement was performed with a Si telescope and a high-purity sample produced by implantation of a Be-7 ion beam at the ISOLDE facility at CERN. While a significantly higher cross section is found at low energy, relative to current evaluations, in the region of BBN interest, the present results are consistent with the values inferred from the time-reversal Li-7(p,n)Be-7 reaction, thus yielding only a relatively minor improvement on the so-called cosmological lithium problem. The relevance of these results on the near-threshold neutron production in the p + Li-7 reaction is also discussed.