[en] A comparison of mechanical neutron collimating and associated α-particle timing method is made in the experiments on the (n,xγ) reaction cross-section investigation. A 1.5 neutron collimator using Ge(Li) detector is described. For obtaining pure spectra of prompt γ-beams, the experiment must be carried out in the (nγ) coincidence regime. The device scheme, permitting to fix neutron flux in collimator direction by means of registration of α-particles accompanying neutrons is presented. The experimental data analysis shows that application of the regime of α-γ coincidences significantly supresses the background γ-radiation from the radioactive nucleus decay, and also permits to conduct background measurements by means of registration of the false coincidence spectra