[en] A detector for neutron radioactive capture and fission event detection is described. The invention is aimed at increase of effectiveness of event detection and accuracy of their identification. For this purpose a hydrogen-containing liquid scintillator with neutron absorbing substance - trimethylborate is placed in the detector between crystal scintillators and region of neutron passing. The scintillator is divided into light-insulated sections, each of them being optically connected with its photomultiplier. Technical merits of the described detector as compared with a basic one are as follows: 1) high efficiency of capture and fission event detection (efficiency of fission event detection makes up 95%) and absence of the error associated with ignorance of these efficiencies; 2) high accuracy of capture and fission event identification (degree of capture and fission event separation is approximately 2-3 times higher). It results in approximately 2-3-fold increase of measuring accuracy of capture cross section of basic fuel-raw materials, for example