Аннотация:Several experimental anomalies in neutrino physics may be pointing to possible existence of one or more additional neutrino species that do not interact weakly, and the so-called sterile. The third phase of the Borexino experiment (SOX) is devoted to verification of this hypothesis. Within the first stage (CeSOX) one will measure the count rate of antineutrino events in the liquid scintillation detector from an artificial source of144Ce-144Pr placed in the special pit beneath the setup. The smaller antineutrino fluxwith respect to the original one would indicate the presence of oscillations into sterilestates. This article provides an overview of the CeSOX experiment, including a generaldescription, a characterization of the radioactive source and the specifics of its use, adescription of the method of data analysis and the expected results. Depending on thesignificance of the obtained scientific information the decision on carrying out the secondstage of the SOX experiment with a 51Cr source of electron neutrinos might be accepted.
