The role of 14 MeV neutrons in light element nucleosynthesis

Abstract

Abstract-The 14 MeV neutron induced nuclear reactions which might contribute to better understanding of so-called "cosmological lithium problem" have been discussed. The BBN theory predicted 7 Li overestimated value could be lowered by 2 n induced reactions on Li-isotopes and/or 7 Be destruction via resonance in d+ 7 Be→ 9 B process. Proposals for 6 Li+ 2 n and 7 Li+ 2 n reactions cross section evaluations and measurements are discussed in some details.We discuss also a preliminary measurements of n-n coincidences from the 10 B(n,2n) 9 B reaction with two neutron detectors placed outside the cone of 14 MeV tagged neutron beam. From the time-of-flight measurements and known geometry we deduce the neutron energies and calculate the 9 B missing mass spectrum.