Options for using ordered 3D arrays of photonic crystals for the generation of gigahertz, optical, and neutron radiation upon interaction with a beam of high-energy electrons are considered. The optical emission spectra of photonic crystals produced in the interaction with a beam of relativistic electrons are presented. Experiments were carried out to obtain 2D images of objects in gamma and neutron fluxes generated in the interaction of an electron beam with a photonic crystal material. Various neutron generating targets are considered, for which the corresponding neutron yields were calculated. The characteristics of electromagnetic and neutron fields obtained in the experiment are also presented.

As part of the commissioning work at the linear electron accelerator LINAC-200 (JINR), we conducted experiments to study the characteristics of a pulsed neutron source obtained by irradiating a converter target with a 140 MeV electron beam. To estimate neutron source parameters and neutron energy spectra in lead and tungsten targets with different sizes numerical simulations were performed. Additionally, we have conducted experiments to measure the energy spectra of neutrons and gamma rays using high-resolution time-of-flight method. It has been found that the ratio of integral estimates between the calculated and average measured neutron yields (for tungsten and lead targets) did not exceed 30%. The fluence of resonant and thermal neutrons in the target is estimated at 2.8x1013 x 10 13 neutrons per second, which corresponds to the requirements for modern pulsed neutron sources.

Beam characteristics of a terahertz/subterahertz radiation obtained by collimation of coherent diffraction radiation (DR) emitted by ultrarelativistic electrons are considered. To achieve the maximum intensity on the beam axis of such radiation, it is proposed to use a semi-parabolic target with a focal length equal to the distance between the target and the collimator aperture. It is shown that for the proposed geometry, the DR distribution on the aperture plane has a maximum along the beam axis, in contrast to the previously used coherent transition radiation mechanism, which is characterized by a “funnel-shaped” structure with a minimum along the beam axis.

Relative yields have been measured in the 40-130 MeV bremsstrahlung induced reactions of 59Co. The experiments have been performed with the beam from the electron linear accelerator LINAC-200 using the activation and off-line γ-ray spectrometric technique. The bremsstrahlung photon flux has been calculated with the Geant4 program. The cross sections were calculated by using computer code TALYS-1.96 with different models and are found to be in good agreement with the experimental data.

ITMO-JINR multidisciplinary project: development of the source of relativistic vortex electrons (carrying orbital angular momentum - OAM) based on the LINAC-200 electron accelerator in JINR. First stage: testbench with RF-gun based acceleration yielding vortex electrons with energies up to 5 MeV. Concept: generating vortex electrons via photoemission process with OAM transfer from photons to electrons.

This paper is devoted to researching the resonant structure of the accelerating sections of the LINAC-200 accelerator in the CST Studio software. A simulation has been carried out for different operating conditions of the structure, i.e., at room temperature (T = 20°C) and using a thermal stabilization system (T = 45°C). These results will be needed when setting the temperature regime for accelerator sections.

The LINAK-200 linear accelerator at the JINR Nuclear Power Plant is being built to provide electronic test beams with an energy of up to 200 MeV for research and development in the field of particle detectors, to study advanced methods for diagnosing electron beams and to work as an irradiation unit for applied research. Although the LINAK-200 uses MEA accelerator equipment (NIKHEF), the vacuum system has been significantly upgraded. This paper presents the design and condition of the new vacuum system.

The results of analytical estimates of the change in the efficiency of the accelerating structure and the accelerating system as a whole with a shift in the operating frequency of the microwave system of a linear electron accelerator with a traveling wave in the 10-cm range are presented. In order to verify the estimates, the energy characteristics of the electron beam are measured when the frequency of the master oscillator at the microwave power source is changed and the natural frequencies of the SLED system resonators of the LUE-200 accelerator are selected (IREN facility of the Joint Institute for Nuclear Research, Dubna).

Results of experimental and theoretical investigation of coherent transition radiation from a finite-size target in the prewave zone are presented. The measurements were conducted in sub-terahertz frequency range on the 100-MeV electron beam extracted from LINAC-200 (JINR). A formula for the spectral-angular density of coherent transition radiation is obtained. Results of the simulation of experimental conditions and experimental data are jointly analyzed. Estimation of the bunch length based on experimental data and obtained theoretical model deviates from the expected value.

The yields of photonuclear reactions in the Ag-107, In-113, and In-115 nuclei were measured. Monte Carlo simulations were performed using the Geant4 code, and the results were compared with the experimental values. The isomeric ratios of the yields in the reactions Ag-107(gamma, n)(106)m,g Ag and In-113(gamma, n)(112)m,g In were determined, and the cross sections for the reactions Ag-107(gamma, n)(106)g Ag and Ag-107(gamma, 2n)Ag-105 at an energy of 20 MeV were calculated based on the experimental data.

The flux weighted average cross sections 〈σ〉 and cross sections per equivalent photon σq were first measured for the photonuclear multiparticle reactions natSe(γ, xnyp) at end-point bremsstrahlung gamma energies ranging from 20 to 80 MeV. The experiments were performed with the beam from the electron linear accelerator LINAC-200 with the use of the γ-activation technique. The bremsstrahlung photon flux was calculated with the program Geant4. The theoretical values of the flux weighted average cross sections 〈σ〉 and the cross sections per equivalent photon σq were calculated using the partial cross section σ(E) computed with the TALYS package code and the combined model of photonuclear reactions.

The cross sections for the reactions 165 Ho(γ, n) 164 Ho, 165 Ho(γ, 3n) 162m Ho, 165 Ho(γ, 4n) 161 Ho, 165 Ho(γ, 5n) 160m1 Ho, 165 Ho(γ, 5n) 160 Ho, and 165 Ho(γ, 6n) 159 Ho were experimentally determined in the energy range from 50 to 110 MeV. Also, calculations were performed using the Geant4 code and the Talys program to determine the cross section of reactions in holmium samples. Calculation results are compared with the obtained experimental results. The dependence of the isomeric ratio 160m1 Ho/ 160 Ho on the electron energy has been measured.

The weighted average yields for 177,178mTa in (γ, xn) reactions have been measured for the first time at the 20, 40, and 55 MeV boundary energies of bremsstrahlung γ-quanta. Simulation results using the TALYS-1.9 program code demonstrate the dominance of statistical processes.

In the framework of the NICA project for the development of an accelerator collider facility at the LHEP JINR, Dubna, the design and commissioning of two injectors are under way. The Heavy Ion Linear accelerator (HILAC) is intended to inject the gold ions into the superconducting synchrotron Booster and designed to accelerate particles with a charge-mass ratio Z/A >= 0.16 up to an energy of 3.2 MeV u(-1). HILAC in 2015 installed in the workplace in the hall of the injection facility. In 2018, a series of tests on HILAC commissioning had been done to measure the energy and estimate transmission of accelerated beams of the carbon ions from the laser ion source. The Light Ion Linear accelerator (LILAC) is intended for injection into the superconducting synchrotron Nuclotron the polarized deuterons and protons, as well as the light ions from LIS and is in the design stage for accelerating particles with a charge-mass ratio of Z/A >= 0.33 to 7 MeV/u. The stable beam intensity from LIS is strongly desirable for the tasks listed above. The article describes the use of the beams from a laser ion source based on an Nd:YAG laser in the injection facility and presents a method for solving the problem of beam instability due to uncontrolled emission caused by reflected radiation.

The construction of an experimental facility with test electron beams is under way at the Dzhelepov Laboratory of Nuclear Problems at the Joint Institute for Nuclear Research (Dubna, Russia). The facility is based on the MEA accelerator that was transferred from NIKHEF to JINR at the beginning of the 2000s. Despite the long service life of the accelerator, it is in good condition and still has a significant operation potential. The linac is being commissioned and the first 200-MeV beam has been generated. For now, the machine is controlled by a set of standalone subsystems that were created as required. Certain systems (e.g., vacuum) are controlled and monitored locally. However, a global control system is required to operate the accelerator as a user facility. The system requirements are formulated in this paper. The key issues of controlling the accelerator and its auxiliary (evacuation, cooling, etc.) systems are considered. The design of a new Tango-based control system of the Linac-200 is presented.

The authors of the report simulated the existing modulator circuit, identified shortcomings, and developed a klystron modulator based on IJBT transistors in order to increase the power and improve the characteristics of the accelerated electron beam of the LINAC-200 accelerator. The calculation model with a detailed description of the individual elements of the modulator is presented in this research.

A joint team from the Joint Institute for Nuclear Research (JINR) (Dubna, Russia) and Bevatech GmbH (Frankfurt-am-Main, Germany) has been developing a new light-ion linac LILac as part of the NICA project. The resonator design and the beam dynamics calculations are presented.

Lead converter was irradiated with electron beams with energies of 60, 80 and 100 MeV. And holmium samples were irradiated with a flux of bremsstrahlung, which was formed in a lead converter. The rates of about 20 photonuclear reactions in 165Ho, which are induced by bremsstrahlung, were measured. Simulations to determine the fluence of electrons, photons, neutrons for holmium samples and the reaction rates for the obtained isotopes in the samples were performed using the Geant4 code. For those radionuclides that are determined in experimental measurements, the results were compared.