A structural configuration and parameters of a modernized source of electrons and gamma quanta with energy of 4–10 MeV are presented. The source is designed on the basis of electron linac LUE-8-5 RV (INR RAS) and can be used for detector calibration and other practical applications.

In this article, we describe an experimental verification of the correctness of registration of delayed neutrons from 238U photofission at a maximum energy of 10 MeV of bremsstrahlung γ quanta on a pulsed linear electron accelerator LUE-8-5 in an interval of (1–5) ms after each beam pulse at times ≳7 min from the onset of irradiation. The measurements have been carried out using the scintillation spectrometer of fast neutrons based on a single stilbene crystal with pulse shape discrimination of γ quanta and fast neutrons. The temporal dependence of the counting rate of delayed neutrons in 238U photofission has been measured at a repetition rate of 300 s–1 in a time interval of (1.25–3.30) ms after the beam pulse.

A procedure for measuring the rhenium content in radioactive ore rocks is tested. Samples of rhenium-containing rocks are irradiated with neutrons from a photoneutron source. Analysis of activation gamma spectra shows that rhenium can be identified against a background of accompanying elements, making neutron activation analysis an effective way of determining rhenium content.

The feasibility of monitoring maximum energy of neutrons $$E_{{\text{n}}}^{{\max }}$$ in the neutron flux from a source by analyzing pulse-height spectra from a 10B detector is investigated. Ionization losses of 4He and 7Li nuclei in two detector gaps are modeled. The clear experimental dependence of the position of the maximum and the shape of these spectra on $$E_{{\text{n}}}^{{{\text{max}}}}$$ and calculations in agreement with this dependence can be used to monitor the maximum energy of neutrons.

An experiment to study total nuclear photoabsorption cross sections at the linear electron accelerator LUE-8-5 (INR, RAS) in the photon energy region of 5–10 MeV called the pygmy resonance is simulated. The motivation for the experiment is new experimental data on photoexcitation of spin isomers of medium-heavy nuclei, which indirectly indicate a change in multipolarity of near-threshold photoabsorption of nuclei. The experiment implies direct investigation of the observed effects by measuring total photoabsorption cross sections in the photon beam. The simulation is performed using the GEANT-4 code. The parameters of the facility are optimized, and the choice of the detectors for the measurements is substantiated.

A two-coordinate 10B detector is used to study the spatial distribution of a neutron flux with maximum energies $$E_{{\text{n}}}^{{{\text{max}}}}$$ = 3.3–5.1 MeV from the outlet channel of a photoneutron source. The maximum of neutron flux intensity measured along the horizontal axis is found to shift backward, relative to the direction of the primary electron beam upon an increase in maximum neutron energy $$E_{{\text{n}}}^{{{\text{max}}}}$$ .

Distributions of thermal neutron flux density are measured with respect to the center of a W–Be photoneutron source and the axis of an output neutron channel. The measurements are made using activation detectors. The distributions are approximated by simple functions with parameters that depend on the detectors’ coordinates. The spatial distribution is obtained for thermal neutrons in the horizontal plane relative to the axis of the photoneutron source’s output channel.

Experiments on measuring the energy spectra and time distributions of delayed neutrons are described. The neutrons are produced in 238 U photofission under the action of bremsstrahlung photons in the LUE-8-5 pulsed electron accelerator at the Russian Academy of Sciences’ Institute for Nuclear Research. The kinetic energy of incident electrons is ≈10 MeV. Measurements are made in the intervals between beam pulses. Fast neutrons are registered by a scintillation spectrometer, with identification of background γ quanta according to the shape of the scintillation pulses.

Разработан четырехслойный газовый детектор для определения интенсивности и энергии электронов и других заряженных частиц. Представлены результаты измерений с использованием разработанного детектора, показывающие возможность определения энергии заряженных частиц.