Powerful Hard-Spectrum Neutrino Source Based on Lithium Converter of Reactor Neutrons to Antineutrinos

The possibility of constructing an intense hard-spectrum neutrino source based on the β‾ decay of ⁸Li (T_1/2 = 0.8 s) is studied. Applications of such a source are considered in neutrino investigations. The source can be developed on the basis of a neutron-to-antineutrino lithium converter through (n, γ) activation of 7Li isotopes irradiated by neutrons from the active zone of a reactor. The physical parameters of the lithium converter are compared with those of other neutrino sources. Different geometries for a converter using heavy water are considered. The converter efficiency is calculated as a function of the purity of the ⁷Li isotope and the expected tritium activity values. The cross section of the neutrino-deuteron reaction increases rapidly in both the neutral ( + d → n + p + ) and the charged ( + d→ n + n + e⁺) channels as the converter efficiency is improved. The real efficiency is 9%, and the cross sections are enhanced by factors of 2.5 and 5 in the respective channels.