[en] The cross section for the ²³⁹Pu (n, f) reaction has been measured on the Harwell 45 MeV linac using the time-of-flight method. The fission events have been recorded by detecting the prompt neutrons and the incident neutron spectrum has been measured with a detector calibrated against two standard detectors. The relative cross section has been normalised in the 10 to 30 keV energy interval to agree with the recent evaluation of Sowerby et al. and shows agreement with this evaluation to within 5% at energies above a few keV

[en] The results are presented on the production of intense neutron 2 and 24,3 keV beams on the SM-2 reactor. Measurements of ²³⁵U and ²³⁹Pu fission cross sections for these energies are carried out. The measurements have been made with respect to the cross sections of thermal neutron induced fission of ²³⁵U and ²³⁹Pu and resulted in simultaneous detection of fission fragments and neutrons in fluxes of thermal and 2 and 24,3 keV neutrons

[en] Ratios of the neutron induced fission cross sections of ²³⁸U and ²³⁹Pu relative to ²³⁵U have been measured with a gas scintillator in the 60 MeV Saclay linac up to 5 MeV. Below the fission threshold of ²³⁸U intermediate structures have been observed. Due to the good energy resolution some structures appear between 300 keV and 1200 keV for ²³⁸U and up to 1 MeV for ²³⁹Pu

[en] A method for retarded recording of fast neutron pulse radiation has been considered. This method is based on deceleration and diffusion phenomena in the media containing hydrogen with a consequent registration of thermal neutrons. Due to an exponent in an expression for a neutron flux the dynamic range of the method has been extended not less than in 10² times. Results for measurements of the counting speed are given for various types of detectors. It has been shown that the detector counting speed depends upon the effect of the scattered radiation generated due to neutron interaction with the environment and due to its own detector background. The use of the paraffin protection for the boron proportional counters with its basic noise less or equal to 0.02 pulses/s permits to extend its dynamic range in two-three orders. The all-wave boron detector with a constant efficiency of neutron recording from 0.025 through 14 MeV, which is used in the method of retarded recording permits to record pulse neutron radiation with fluxes on detector surfaces of 0.5 - 10⁶ neutron/sq.cm

[en] Fission cross-section for U²³⁵ with nominal resolution 3 ns/m has been measured using the IAE 60-MeV linac neutron spectrometer. Resonance and fission integrals in the energy range 0,01-10 keV are calculated. The results obtained are compared with data published previously

[en] An automated multi-level system designed for acquisition, accumulation, sorting and processing of information obtained in the course of an experiment is discussed. Intelligent terminals are established at each nuclear installation, which are interconnected with measuring equipment of the corresponding installation. The intelligent terminals operating in the interactive real-time mode permit to use through data links computing facilities and storage of the processing centre. On the top level of the automated system the third generation M4030 computer with 256 Kbyte internal memory is employed. The intelligent terminals are created on the basis of the Ryad-1010 and M-400 computers

[en] Radiative capture-to-fission (α) have been measured for ²³⁹Pu. Measurements have been made by a neutron lead slowing-down method. The method has the following essential features: 1) Neutron scattering does not change isotropic neutron field of the spectrometer. The consequence is a steady background of the detector. 2) Detection of capture and fission events in the sample is carried out by a proportional α-detector. Efficiency of the α-detector is proportional to the total energy of α-quanta, emitted on capture and fission and it does not depend on the spectral picture. 3) Screening for thermal neutrons in utilized samples is small and taken exactly into account. Measurements have been carried out on ''thin'' (anti n = 4,2x 10²⁰ at x cm^-2) and ''thick'' (anti n = 4,9x 10²¹ at x cm^-2) plutonium samples. The data obtained over α and fission cross section sigmasub(f), averaged over neutron energy levels are given in the table. Comparison is made and presented graphically between the obtained averaged values of α and the results of other authors

[en] Counting characteristics of multifilament spark detector (SD) for α-particles and fission fragments are presented. It has been found that irradiation of SD with γ-rays resulted in increasing the detection threshold for α-particles. A method is proposed for decreasing the dead time(tau m) for SD, that has been tested under real operation conditions in a reactor. It has been found that tausub(m) < or approximately 80 msec

[en] Two gas targets, one filled with deuterium and the other with tritium, are presented which have been designed for the production of fast neutrons from the D(d, n)³He and T(p, n)³He reactions. Cooling for the entrance window is achieved by circulation of the gas itself for the deuterium target and by helium circulation in a double window system for the tritium target. The performance of each target with regard to allowable beam current, neutron flux and neutron energy spread is discussed for neutron energies ranging from 2 to 15 MeV

[en] Two-zone nonbreeding systems are studied using a pulsed neutron source. It is theoretically and experimentally shown that the following neutron-physical parameters of such systems can be calculated with high accuracy: the average neutron albedo, macroscopic capture cross section, the neutron diffusion coefficient. The method is applicable to small samples. The two-zone system of media with a cylindrical interface simulates a typical boundless layer crossed by a well. It is shown that calculation of the thermal neutron capture cross section in a laminated medium in one-rate diffusion approximation is in satisfactory agreement with experimental data for models of a laminated medium with a water-filled well. The effective capture cross section decreases with growing layers