Lithium antineutrino source in the tandem scheme of the accelerator and neutron producting tungsten target

Abstract

The antineutrinos of the neutron rich 8Li isotope is characterized by hard and good defined spectrum - averaged energy is 6.5 MeV and maximal - up to 13 MeV. An intensive antineutrino source with such parameters can be unique instrument for neutrino investigations and especially for search of sterile neutrinos. The 8Li can be produced by (n,gamma)-activation of 7Li isotope. The proposed scheme of the antineutrino source is based on the lithium blanket around the accelerator neutron producting target. We propose to use heavy water solution of the lithium hydroxide instead of lithium in metallic state. Such solution for lithium blanket substance ensure the large perspectives in real steps for creation of this installation. An analyses of neutron fields in the blanket and distribution of 8Li creation allows to propose the next principal steps in the construction of the lithium blanket. We propose to enclose the blanket volume isolating it's central part with more high 8Li production. This solution allows to decrease the necessary mass of very pure 7Li isotope (with admixture of 6Li - 0.0001) up to 120-130 kg (i.e., to decrease in ~ 150 times compare to variant of lithium blanket in metallic state). The source become more compact - the linear dimension is decreased in 2.5 times (up to 1.3 m) and this is very essential for sterile neutrino search taking in mind the indication on difference ~1 eV2 between squared mass of sterile and active neutrinos.