The Role of 14-MeV Neutrons in Light Element Nucleosynthesis

The 14-MeV neutron-induced nuclear reactions which might contribute to better understanding of the so-called “cosmological lithium problem” have been discussed. The big bang nucleosynthesis theory predicted <sup>7</sup>Li overestimated value could be lowered by <sup>2</sup>n-induced reactions on Li isotopes and/or <sup>7</sup>Be destruction via resonance in the d + <sup>7</sup>Be → <sup>9</sup>B process. Proposals for <sup>6</sup>Li + <sup>2</sup>n and <sup>7</sup>Li + <sup>2</sup>n reactions’ cross section evaluations and measurements are discussed in some details. In addition, we discuss also a preliminary measurements of n–n coincidences from the <sup>10</sup>B(n,2n) <sup>9</sup>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 tried to deduce the neutron energies and calculate the <sup>9</sup>B missing mass spectrum. Improvements for better measurements are suggested.

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