[en] There are much data on neutron cross sections over the chart of nuclides for stable isotopes and not as much for the radioactive ones. Double neutron capture experiments could be fruitful to provide more data. Time-integrated mean flux of slow neutrons reaches the value of 2.3-10¹² n/cm² s at the irradiation port near the active zone of the IBR-2 pulsed reactor of JINR. This is enough to detect the double neutron capture products by the activation method. A high capture cross section is obtained in the present experiment for intermediate radioactive ¹⁸²Ta and ¹⁹⁴Ir target nuclides. Together with the known data for ¹⁹⁸Au, these values may prove an essential role of double neutron capture process for nucleosynthesis of ¹⁸³W, ¹⁹⁵Pt and ¹⁹⁹Hg isotopes at stellar conditions. (paper)