Future reactor neutrino oscillation experiments at Krasnoyarsk

Recent studies of atmospheric neutrinos and the results from CHOOZ and Palo-Verde experiment call for new and more sensitive searches for neutrino oscillations at reactors. The main goal of the project considered here is to look for very small mixing angle oscillations of electron neutrinos in the atmospheric neutrino mass parameter region around Δm2 ∼ 3 x 10-3eV2 and to define the element Ue3 of the neutrino mixing matrix (Ue3 is the contribution of the mass-3 state to the electron neutrino flavor state). The practical goal of the project is to decrease, relative to the CHOOZ, the statistic and systematic errors as much as possible. To achieve this we plan to use two identical antineutrino detectors each with a ∼ 50-ton liquid scintillator target located at ∼1100 m and ∼250 m from the underground reactor (∼ 600 mwe). Much attention is given to the detector calibration and monitoring procedures. As a first step we consider two much smaller pilot detectors each of ∼ a 3 ton target mass stationed at ∼20 m and 35-60 m from the reactor. The goals of this first stage are: (i) to accumulate necessary experience and (ii) to investigate with electron neutrinos the LSND mass parameter region