Baikal neutrino project: history and prospects

By the present time, a huge volume of knowledge of the history of the development and structure of the Universe has been accumulated using optical, microvave, x-ray, and gamma-radiation telescopes. In the last few years, neutrino astronomy has become a new “window” into the Universe. Many astrophysical objects from typical stars like our Sun to active galactic centers are high-power sources of neutrinos with energies changing in a wide range. In the last decades, a number of underground facilities have been created (for example, see [1–4]) to investigate the energy spectrum of solar neutrinos (their characteristic energies are 0.2–15 MeV) and of other neutrino sources. As a result of these investigations, a model of thermonuclear fusion inside the Sun has experimentally been checked, a neutrino signal from a supernew explosion has been registered for the first time [3], and neutrino oscillations have been discovered that unambiguously indicate a nonzero neutrino mass [4]. The largest underground Super-Kamiokande facility [4] has a volume of 52000 m