The key elements of the compact accelerator-driving neutron source (CANS) dedicated to academic research and industrial applications (DARIA) have been developed. A pulsed proton linear accelerator with an energy of 13 MeV, a current of 100 mA, a pulse length of 100 μs, and a repetition rate of 100 pulses/s is under development for the DARIA CANS. An improved version of the GISMO ion source has been developed to generate the beam. The parameters of the accelerator line consisting of the RF quadrupole (RFQ) linac and the drift tube linac (DTL) have been determined by numerical simulation. The parameters and model of a hybrid magnetic lens for beam focusing are presented. A Faraday cup for diagnosing a high-intensity beam has been manufactured and tested. The developed prototypes of the target assembly based on beryllium and mesitylene moderator have confirmed the correctness of the selected engineering solutions. The physical parameters of the neutron-guiding systems have been determined in terms of the maximum luminosity of the device at a good instrumental resolution.

Research reactors play a crucial role in advancing scientific understanding, medical diagnostics, and nuclear technology development. This review article provides a comprehensive examination of research reactors, emphasizing classification and highlighting the unique features of periodic pulsed reactors. The classification of research reactors is elucidated, distinguishing between stationary and pulsed reactors. Stationary reactors serve diverse purposes, while pulsed reactors offer distinct advantages in certain applications as time-of-flight research and neutron generation lifetime calculation. Particular attention is given to research fast periodic pulsed reactors in Russia, showcasing their significant contributions to scientific research and technological innovation. Detailed discussions include the IBR-1, IBR-30, IBR-2, and NEPTUNE reactors, elucidating their design, capabilities, and scientific achievements. Furthermore, the article explores the utilization of Neptunium-237 as a promising nuclear fuel for fast pulsed reactors, highlighting advantages such as low neutron generation time, high neutron flux, and the ability to burn up part of dangerous nuclear waste. Overall, this review consolidates essential knowledge on research reactors and underscores the importance of ongoing research and development efforts, particularly in harnessing innovative fuels like Neptunium-237, to meet the evolving demands of science and technology.

The radiotherapeutic Pt-195m is among the most effective Auger electron emitters of the currently studied radionuclides that have a potential theranostic application in nuclear medicine. Production of Pt-195m through double neuron capture of enriched Ir-193 followed by beta(-)-decay to the radioisotope of interest carried out at the research reactor IBR-2 is described. Because of the high radiation background, radiochemical purification procedure of (195)mPt from bulk of iridium was needed to be developed and is detailed here as well. For the first time, cross section and resonance integral for the reaction Ir-194(n,gamma)(195)mIr were determined. Resonance neutrons contribution was established to exceed that of thermal neutrons, and resonance integral for the reaction Ir-194 (n,gamma)(195)mIr is calculated to be 2900 b. Specific activity of (195)mPt was estimated to reach a value of 38.7 GBq/(g Pt) at IBR-2 by the end of bombardment (EOB).

The paper presents the results of neutron-physical calculations for determining the optimum configuration of materials for use as a cryogenic moderator in a DARIA university-grade compact neutron source. It is shown that a cryogenic moderator based on a solid frozen mesitylene of a certain configuration may represent the optimum source of cold neutrons for studying the structure and properties of substances by neutron-physical methods in the DARIA neutron source.

The effect of neutron irradiation on the structural, optical, and electronic properties of doped strained heterostructures with AlGaAs/InGaAs/GaAs and AlGaAs/InGaAs/AlGaAs quantum wells was experimentally studied. Heterostructures with a two-dimensional electron gas of different layer constructions were subjected to neutron irradiation in the reactor channel with the fluence range of 2 × 1014 cm−2 ÷ 1.2 × 1016 cm−2. The low-temperature photoluminescence spectra, electron concentration and mobility, and high-resolution X-ray diffraction curves were measured after the deactivation. The paper discusses the effect of neutron dose on the conductivity and optical spectra of structures based on InGaAs quantum wells depending on the doping level. The limiting dose of neutron irradiation was also estimated for the successful utilization of AlGaAs/InGaAs/GaAs and AlGaAs/InGaAs/AlGaAs heterostructures in electronic applications.

The fast periodic pulsed research reactor IBR-2 started operating in 1982 at the Joint Institute for Nuclear Research in Dubna, Russian Federation. IBR-2M was successfully upgraded and restarted in 2012. The third-generation neutron source reactor IBR-2M has the world's highest neutron flux per pulse. A new neutron source (the NEPTUN reactor) is currently being designed to replace IBR-2M after it is out of service. The NEPTUN reactor is a fourth-generation pulsed neutron source that uses Np-237 as a nuclear fuel for the first time. The optimization of the thermal moderator (water moderator) of the NEPTUN reactor is considered in order to obtain the highest thermal neutron flux on the extracted neutron beam. It is shown that the increase in water thickness leads directly to a shift of faster neutrons towards thermal spectra, but the maximum neutron flux can be obtained only at an optimum thickness.

The present work was carried out to determine the elemental composition of granitoid rock samples from three gold mines (Sukari, Hamash, and Um Hagalig) in the South-eastern part of Egypt and quantification of the extent of the elemental enrichment. A total of 37 samples from the mines were subjected to neutron activation analysis, and the mass fractions of the elements were measured in mg/kg. The results show a dominance of K (76.9%), Fe (11.0%), Ca (8.7%), and Na (3.1%) for Sukari mine; Na (31.2%), Ca (28.5%), K (23.1%), and Fe (9.9%) for the Hamash mine; and for the Um Hagalig mine Na (31.1%), K (22%), Ca (21.7%), and Fe (20.8%). In addition, significant mass fractions of uranium, thorium and rare earth elements were found in Hamash and Um Hagalig. The average mass fractions of U in the investigated areas are measured to be 59.7, 48.2, and 30.8 mg/kg for Hamash, Sukary, and Um Hagalig, respectively. Furthermore, the average mass fractions of Th were significant and measured to be 3905, 1673, and 7 mg/kg for Hamash, Um Hagalig, and Sukary, respectively. Multiple ratio indicators and discrimination diagrams were used to better understand the origin of the elements in the samples studied. The indicators suggest that the provenance of the elements is mainly from metavolcanic and volcanic rocks. The findings should make an important contribution to the study of ores and minerals and thus represent an important area for environmental studies.

We present experimental results on the loading/unloading working fluid of the cryogenic moderator of a DARIA compact neutron source. A technology for loading liquid nonirradiated mesitylene into a specially designed prototype of the cryogenic moderator chamber and a technology for unloading irradiated mesitylene with a different absorbed dose of ionizing radiation are proposed and experimentally validated. During the experiments, the chamber prototype worked flawlessly in conditions as close as possible to real operating conditions of the cryogenic moderator of a compact neutron source.

In this paper, we consider the concept of a test bench for a cryogenic moderator based on solid mesitylene for a compact neutron source. Process diagrams are provided, and the principle of operation, as well as a control and monitoring program for the main systems of the cryogenic-moderator test bench, are described. The main parameters to be determined on the test bench after the experiments upon cooling to 20 K are described in detail.

The current characteristics of the ionizing radiation fields of an irradiation facility intended for studying the radiation resistance of materials on channel no. 3 of the IBR-2 reactor are presented. Flux densities of fast neutrons for the power of 1.55 MW of the IBR-2 reactor are refined. For the first time, the values of absorbed γ-radiation doses have been experimentally obtained. Values exceeding the range of absorbed doses measured by the dosimeters near the IBR-2 water moderator were calculated by the Monte Carlo method. Devices and methods for quantifying characteristics are described. The range of fast neutron densities along the irradiation facility was 3 × 106−8 × 1011 neutrons/(cm2), and the rates of  γ-radiation dose were 3 × 10−4−12 Gy/s.

This work was conducted to focus on pollutant transmission between Poland and Czechia at the most polluted area in the Czech Republic, the Moravian Silesian region. Instrumental neutron activation analysis (INAA) and multivariate statistical analyses were used to determine the mass fractions of inorganic air pollutants accumulated on filters. Particle matters of sizes smaller than 10 µm (PM10) were collected using a high-volume sampler (SAM Hi 30 AUTO WIND). Pollutants PM10 were collected on Whatman QM-A Quartz Microfiber Filters of 150 mm in diameter based on various wind conditions. These filters were irradiated by neutron flux at the experimental reactor IBR-2 at the Joint Institute of Nuclear Research in Dubna, RF. Irradiated samples were measured by gamma spectrometry techniques using HPGe detectors. In total, results are shown for 49 samples (from March to July 2021) and five field blank filters. The mass fractions of 24 elements (Sc, Cr, Fe, Ni, Co, Zn, Se, As, Br, Rb, Mo, Sb, Ba, Cs, La, Ce, Sm, Eu, Tb, Yb, Hf, Au, Th, and U) were determined. The sources of pollution were specified using correlation and exploratory factor analyses and including meteorological conditions. A strong positive correlation was shown between the elements Cr, As, Br, Co, Fe, Sc, Se, Sm, Th, La, and Ce. Elemental exposure to PM10 can be divided based on the factor loadings of common chemical components into three main pollution sources. According to the wind rose, the pollution came from the southeast/west direction; therefore, we can assume that the pollution most likely originated from the metallurgic complex (steel and iron production in the southeast, and a coking plant, metal foundry, and generation plant in the west).

This paper presents the results of an automation of the processes of measuring the dose rate and movement of highly active samples in the controlled zone of the third beam of the IBR-2 reactor. A detailed analysis of the choice of an automated system based on a robotic manipulator with a video-surveillance system and distance measurement, as well as a dosimetric complex for determining the dose rate in the place of its operation, has been carried out. The processes of constructing algorithms and programs to control the robot are described in detail. It has been established that the system operates uninterruptedly and reliably in the fields of high ionizing radiation; is capable of almost completely replacing a person when performing such a work; and, most importantly, significantly—up to 27.4%—reduces the annual dose received by personnel during operation.

In this work cubic phase, silicon carbide nano-powders were irradiated at the high-flux pulsed reactor IBR?2 (Dubna, Russia). The 3C?SiC powder was irradiated with neutron doses up to 1015 n/cm2. The irradiated samples were then analyzed using X-ray diffraction, Raman spectroscopy, Positron annihilation spectroscopy, and Fourier Transform Infrared Spectroscopy. The XRD analysis showed a slight decrease in the lattice parameters with the increase in neutron fluences. The results obtained from positron annihilation measurements were compared to the theoretical calculations, to recognizing the type of structural defect in the samples. A positron lifetime component 355 ps associated with the calculated values for clusters containing of 13?21 vacancies was identified. The concentration of these defects was estimated to be in the region of 5 ppm, and was very similar to the one identified on the unirradiated sample. The results also indicate high irradiation resistivity of the 3C?SiC after irradiation.

The interaction of plasma and its encompassing materials with one another is one of the principle designing issues of fusion reactors. Tungsten is considered one of the primary candidate materials in fusion applications due to its superior properties. In this work, we doped vanadium carbide powders to the tungsten matrix to enhance the properties of tungsten alloys. Tungsten-based composites, which irradiated with 2.5 MeV He-3(+) ions at room temperature, were analyzed by atomic force microscopy (AFM) in order to obtain surface morpohologies after irradiation. Helium ion irradiated tungsten-based composites were studied by using XRD, neutron diffraction technique, raman spectroscopy, and positron annihilation spectroscopy to reveal the microstructural changes. XRD and ND analyses clarified the changes in the crystal structures of the tungsten-based materials after He ion irradiation. The simulation of radiation damage and the calculation of displacements per atom (DPA) was also determined by the SRIM code. SRIM showed that the maximum helium concentration in the specimens takes place in the depth range of 58-65 nm. The crystallite size of tungsten-based composites slightly increased after helium ion irradiation. AFM results revealed that the maximum size of bubbles on the surface of tungsten-based composites shape under 100 nm. Positron annihilation spectroscopy studies of the specimens have been discussed before and after He-3(+) ion irradiation.

The paper presents the results of studying the composition of pottery by neutron activation analysis (involving X-ray fluorescence analysis). The study was based on samples of pottery made from highly ferrous (red-burning) clays originating from archaeological sites investigated in the territory of medieval Rus (Moscow and Ryazan Land) and the Volga River region (the Bolgar and Selitrennoye fortified settlements). They were compared with pottery samples from Byzantium and other regions (the Caucasus, Central Asia). A set of trace elements was identified whose content differs significantly in the pottery of different regions of Eastern Europe and differs also from the pottery of neighbouring countries. Cluster analysis confirmed the presence of noticeable differences in the trace element composition of clay masses from which medieval pottery were made. The results obtained allow the authors to admit the possibility of determining the origin of pottery by its trace element composition, at least at the level of large territories. Within these territories, differences in the composition of pottery have not yet been revealed.

An in-situ study of Hall sensors based on single-layered graphene in neutron fluxes of a nuclear reactor to the fluence of 1.5e20 n/sq,m was conducted. The sensitivity of the sensors to the magnetic field remained stable throughout the experiment, while the resistance changes correlated with the increase in sample temperature due to radiation heating. The experiment confirmed the theoretical expectations regarding the high stability of graphene sensors to neutron irradiation. Necessary further improvement of sensor technology to optimize their characteristics, as well as radiation testing to determine the maximum permissible neutron fluence.

The paper presents the results of measurements of the concentration of gaseous radiolytic hydrogen using gas chromatography, which is produced irradiating the mixture of aromatic hydrocarbons of mesitylene and mxylene in the chamber of the pelletized cold moderator of the IBR-2 reactor during post-irrradiation heating. As it is shown, the hydrogen concentration in the operating mode of the moderator at 22K in the chamber and a reactor power of 1.6 MW does not exceed 0.13%. After post-irradiation heating, with variations of temperature from 20K to 293K, and zero reactor power, the maximum hydrogen concentration is 22.5%. A conclusion is drawn that such concentration of hydrogen in an inert atmosphere of helium cannot lead to the production of an explosive mixture in the moderator chamber in close vicinity to the IBR-2 reactor core.

Investigation of the semiconductor detectors properties under neutron irradiation is very important for their practical application. High-resistivity gallium arsenide detectors (GaAs:Cr) were irradiated with various fast neutron fluences in range from 3.9×10 n cm −2 to 3.7×10 16 cm −2 at the IBR-2 reactor, FLNP, JINR. The neutron fluence was measured by placing silicon planar detectors at the measured points and measuring the 1 MeV (Si) equivalent fast neutron fluence. The charge collection efficiency and the current-voltage characteristics of irradiated detectors were measured, and their degradation after neutron irradiation was compared with the results obtained by irradiation with 21 MeV electrons.