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Electron-beam energy recuperation is usually used in electron-cooling systems (ECSs). The operation stability, vacuum conditions, and radiation background (which is especially important in high-voltage coolers) depend on recuperation efficiency. The only way to improve recuperation efficiency in high-voltage coolers is to increase the electron-collector efficiency. This paper describes the variants of electron collectors for high-voltage ECSs.

In order to achieve the design luminosity in the NICA collider, it is planned to equip it with both stochastic and electron cooling. The electron-cooling system (ECS) for 2.5 MeV consists of two coolers which cool both ion beams simultaneously. The Budker Institute of Nuclear Physics (BINP SB RAS) already built and commissioned an electron cooling system for the NICA booster, and now the high-voltage ECS for the collider is being developed. This paper describes the basic elements of the system and the status of the cooler development.

The HV electron cooling system designed at the Budker Institute of Nuclear Physics for the NICA collider is the world’s only setup developed for a collider and makes it possible to simultaneously cool two ion beams with an energy up to 4.5 GeV/u using the magnetized electron flow [1]. Due to the fact that the cooling system should be installed at the NICA collider, the distance between the beam axes of cooling channels corresponds to the distance between collider beams and amounts to 320 mm. This became the first factor affecting the entire structure of the electron-cooling system and limits the maximum possible outer radius of longitudinal field coils. The energy-consumption limitation of 500–700 kW [2] can be considered the other factor, and it directly affects the density of filling the solenoid with the conductor. The design of the central solenoid (cooling solenoid) of the electron-cooling system is described, and it has been developed taking into account the imposed limitations.

The absorption of electromagnetic radiation by a composite based on bimetallic nanoparticles with a “core–shell” type of structure has been analyzed using the Maxwell–Garnett theory. Expressions have been obtained for the real and imaginary parts of the dielectric function of a two-layered particle in the limiting cases of “thick” and “thin” shells. It has been established that the presence of two metals in the composition of the inclusions leads to a splitting of the maxima and minima in the frequency dependences of the dielectric function and of the coefficient of absorption of the nanocomposite. The frequency dependences of the real and imaginary parts of the dielectric function and of the coefficient of absorption of the composite with bimetallic nanoparticles of different metals have been calculated. An essential influence of both the geometric characteristics of the particles-inclusions and of their composition on the optical properties of the composite has been revealed.

The electron cooling system for the NICA booster has been under construction and tested over the last few years at the Institute of Nuclear Physics. The design of this setup and the results of tests are detailed.

Self-consistent computations of the monovacancy formation energy are performed for Na N , Mg N , and Al N (12 < N ≤ 168) spherical clusters in the drop model for stable jelly. Scenarios of the Schottky vacancy formation and “bubble vacancy blowing” are considered. It is shown that the asymptotic behavior of the size dependences of the energy for the vacancy formation by these two mechanisms is different and the difference between the characteristics of a charged and neutral cluster is entirely determined by the difference between the ionization potentials of clusters and the energies of electron attachment to them.

Self-consistent calculations of spatial distributions of electrons, potentials, and energies of dissociation, cohesion, vacancy formation, and electron attachment, as well as the ionization potential of solid Al N , Na N clusters (N ≥ 254), and clusters containing a vacancy (N ≥ 12) have been performed using a model of stable jellium. The contribution of a monovacancy to the energy of the cluster, the size dependences of the characteristics, and their asymptotic forms have been considered. The calculations have been performed on the SKIT-3 cluster at the Glushkov Institute of Cybernetics, National Academy of Sciences of Ukraine (Rpeak = 7.4 Tflops).

In terms of the model of stable jellium, self-consistent calculations of spatial distributions of electrons and potentials, as well as of energies of dissociation, cohesion, vacancy formation, electron attachment, and ionization potentials of solid clusters of Mg N , Li N (with N ≤ 254 ) and of clusters containing a vacancy (N ≥ 12) have been performed. The contribution of a monovacancy to the energy of the cluster and size dependences of its characteristics and of asymptotics have been discussed. Calculations have been performed using a SKIT-3 cluster at Glushkov Institute of Cybernetics, National Academy of Sciences, Ukraine (Rpeak = 7.4 Tflops).

Electron cooling is used for damping both transverse and longitudinal oscillations of heavy particle. The cooling of bunch ion beam (with RF voltage on) is important part of experiments with inner target, ion collision system, stacking and RF manipulation. The short length of an ion bunch increases the peak luminosity, gives a start-time point for using of the time-of-flight methods and obtains a short extraction beam pulse. This article describes the review of last experiments with electron cooling carried out on the CSRm, CSRe (China) and COSY (Germany) storage rings. The accumulated experience may be used for the project of electron cooler on 2.5 MeV (NICA) and 0.5 MeV HIAF for obtaining high luminosity, depressing beam-beam effects and RF manipulation.

A consistent procedure for determining the ionization potential of a large metal cluster of radius R N, v , consisting of N atoms and N v vacancies, is proposed. The perturbation theory in small parameters R v /R N, v and L v /R v (Rv and L v are average distance between vacancies and the length of electron scattering on vacancies, respectively) is constructed in the effective-medium approximation for the electron ground state energy. The effective vacancy potential profile, the electron scattering phase and length are calculated by the Kohn–Sham method for a macroscopic metal in the stable jelly model. The obtained analytical dependences can be useful to analyze the results of photoionization experiments and to determine the size dependence of the vacancy concentration, including that near the melting temperature.

According to the agreement, the electron cooling system for the NICA booster should be commissioned in late 2015. The degree of completion of various units and components of the installation as of September 2015 is characterized in the present report. Part of the report is devoted to discussing the performance parameters of the installation and the engineering solutions that had to be implemented to achieve such parameters.

The vacancy contribution to the work functions of electrons and positrons is demonstrated within our previously proposed models by the example of Al. Physical states of affairs in which the vacancy effect can manifest itself are considered.

The probabilities of the localization of positrons in monovacancies of Al and Cu have been calculated as functions of the energy and temperature. The vacancy was simulated by a void with a radius equal to the radius of the Wigner—Seitz cell in the model of stable jellium. Using the Fermi—Dirac golden rule for transitions, the formula for the rate of positron trapping by a vacancy has been derived as the function of the positron energy. For the thermalized positrons, the rate of localization near the triple point proved to be, on the order of magnitude, close to the rate of annihilation. Within the framework of our previously proposed models, the contribution of vacancies to the work function of electrons and positrons has been demonstrated based on the example of Al. The physical situations where the vacancy effect can manifest have been considered.

The probability of localization of positrons in single vacancies of Al, Cu, and Zn as a function of temperature has been calculated. Vacancy has been simulated by a cavity with a radius of the Wigner–Seitz cell in the stabilized jellium model. A formula for the rate of trapping of a positron by a vacancy as a function of the positron energy has been obtained using the “golden” rule for transitions under the assumption that the positron energy is spent on excitation of electron–hole pairs. The temperature dependence of the localization rate has been calculated for thermalized positrons. It has been found that, in the vicinity of the triple point, the localization rate is close in order of magnitude to the annihilation rate. Based on the results reported in our previous publications devoted to the evaluation of the influence of vacancies on the work function of free positrons, it has been assumed that, near the surface of the metal, there are vacancies charged by positrons. In the approximation of a two-dimensional superlattice, the near-surface vacancy barrier has been estimated. The experimentally revealed shift of the energy distribution of re-emitted positrons has been assumed to be caused by the reflection of low-energy positrons from the vacancy barrier back into the bulk of the metal where they annihilate.

An electron cooler designed at the Budker Institute of Nuclear Physics for the Cooler Synchrotron COSY (Juelich, Germany) has been put into operation. The aim of this cooling device is to prevent the beam scattering on an internal target up to the maximal energy of the transmitted beam. The device provides cooling in a strong longitudinal magnetic field generated in a high-voltage area. The motion of electrons in the magnetic field considerably improves the kinetics of electron—ion collisions, because their transverse velocity component (which is very high as a rule) does not participate in the process. First experiments on electron beam cooling on energy 200 MeV were made in 2013. Early in 2014, sessions on electron beam cooling to 200, 350, 580, and 1660 MeV were carried out. In other experiments, deuterium beams were cooled down. Experimental data for the cooling time are compared with the respective theoretical predictions. These results may be used in cooling projects for the Nuclotron-based Ion Collider fAcility (NICA), Joint Institute for Nuclear Research, Dubna, Russia, and the Facility for Antiproton and Ion Research (FAIR), Darmstadt, Germany.

An electron cooler produced by the Budker Institute of Nuclear Physics was put into operation at the COSY synchrotron (Julich, Germany) in 2013. This electron cooler has been designed for suppressing the effect of beam scattering by an internal target at energies as high as the maximum proton beam energy of 3 GeV. As the electron cooler was developed, many complicated electrotechnical problems were solved. One of these problems was the transfer of the electric power to many electronic consumers kept at a high electric potential. Several practical methods for solving this problem are described. These variants were analyzed and tested while designing the cooler construction. The final decision is based on the principle of operation of the cascade transformer containing 33 sections connected in series. The described design solutions can be used not only for future electron coolers in projects NICA-JINR (Dubna, Russia), FAIR (Germany), and MEIC (United States), but also for other high-voltage facilities requiring power transfer to devices held at a high potential. After decommissioning of the electron cooler at Fermilab (United States), the described facility has become the highest-voltage electron cooler worldwide.

The possibility of neutralization and partial transformation of a widespread and environmentally hazardous electroplating sludge waste into marketable product was demonstrated. The chemical composition of copper electroplating sludge is determined. The process of aluminothermic reduction of copper plating sludge to produce marketable products in the form of a bronze ingot and abrasive was studied.

Carbon nanotubes have been formed as a result of mechanical activation of amorphous carbon obtained after the pyrolytic treatment of brown sphagnum moss. The yield of nanotubes grows from 8 to 75 wt % with increasing the time of mechanical activation from 4 to 27 h. An integrated study of the adsorption properties of carbon materials obtained from sphagnum moss is presented. It is shown that the capability of the oxidative modification of carbon nanotubes depends on the parameters of the formation process, and the efficiency of adsorption capacity is a function of the storage time of the carbon material. The potential of carbon materials obtained from sphagnum moss as enterosorbents is considered.

It is found that the main factors determining the synthesis parameters of tungsten carbide by mechanically stimulated thermal explosion are the structure of carbon modifications and the degree of their aromaticity. The prospects of using carbon modifications obtained from plant raw materials for the synthesis of tungsten carbide with a low content of sulfur are discussed.

The stage of the formation of multiwalled carbon nanotubes with a diameter of 10 to 70 nm as a result of the mechanochemical treatment for 1–27 h of amorphous carbon prepared by pyrolyzing brown peatmoss at 950°C. The formation of carbon nanotubes is demonstrated to take place in an array of activated particles.

Nanometer-sized tungsten monocarbide and titanium carbide are produced by mechanical activation. The formation of the former carbide is shown to be promoted by the introduction of polymethylmethacrylate into the initial charge for synthesizing tungsten carbide. It is found that the main limiting factors of the mechanochemical synthesis in the titanium-carbon system are the structure of carbon modifications and the degree of their aromaticity.

We have studied the sorption properties of nanofibrous carbon (multiwalled nanotubes) produced by milling amorphous carbon prepared through sphagnum moss pyrolysis. The results demonstrate that the sorption capacity of the carbon nanotubes depends on storage time and that their oxidation behavior depends on nanotube preparation conditions.

Two nanocomposite systems—amorphous carbon + nanoparticulate silicon and nanofibrous carbon + nanoparticulate tungsten—have been fabricated from vegetable and mineral raw materials: sphagnum moss, field horsetail, and scheelite. We examine the possibility of using the nanocomposite systems as anode electrodes of lithium-ion polymer batteries.

An efficient collector for high-voltage systems of electron cooling is presented. Its efficiency (ratio of the reflected electron current to the current of the main beam) is greatly improved by suppressing the reflected particle flux in the Wien filter. Secondary electrons deflect in crossed transverse electric and magnetic fields and are absorbed by a special receiver plate (secondary collector). The filter is designed so that the whole backward flow of electrons deflects even if the trajectory and main beam profile are distorted insignificantly. Experiments carried out on a special-purpose test bench show that such a filter raises the efficiency of the collector hundredfold (up to 10−6).

It is established that the main limiting factor in the implementation of mechanochemical synthesis in the Ti + C and WO3 + Mg + C systems is the degree of aromaticity of the carbon ingredient. The possibility of using carbon modifications produced by pyrolysis of plant raw materials for the synthesis of the respective carbides with a minimum sulfur content.

A high-perveance collector with a small secondary emission ratio has been designed for a high-voltage electron cooler. The distinctive feature of this collector is the fact that it consists of the cooled collector itself, which receives the electron flow, and a Wien filter installed ahead of it, which substantially reduces the secondary electron flux emerging from the collector. The main advantage of this design is the combination of the small secondary emission ratio and the high perveance with the small size and ease in manufacturing and adjustment. The results of calculations and experimental investigations of the combined collector are presented, and its different operating modes are investigated. The minimum attained secondary emission ratio is 5 × 10−6. The methods for further reducing this ratio are proposed.

The data presented in this paper show that the limiting factors in the mechanochemical synthesis of titanium carbide from mixtures of titanium and a carbon-containing raw material are the structure of the carbon and the degree of aromaticity of the starting material. Our results demonstrate the possibility of producing mechanochemical titanium carbide using mixtures of carbon black and graphite.

Data from the Hipparcos catalog are used to study the internal kinematics of the Hyades cluster. Cluster members whose proper motions and parallaxes are known with precisions not less than 5 mas/yr and 3 mas were used. The proper motions were reduced to the cluster center. A correlation between a component of the tangential velocity and the parallax provides evidence for possible rotation of the cluster. The total velocity gradient is 0.04±0.03 km s−1 pc−1. The rotation axis is located perpendicular to the direction to the Hyades apex on the celestial sphere.

The dispergation of metal shavings mixed with a destructible high-molecular compound is demonstrated to intensify the grinding process, stimulate metal plasticizing, and protect activated powders against oxidation due to the metal surface plating with organic films.

We demonstrate that grinding of metallic turnings in the presence of a destroyable high-molecular-weight compound intensifies the grinding process and contributes to plasticization of the metal. The grinding of the metal-polymer system is accompanied by reduction reactions and desulfurization of the metal being dispersed.

It was established that the main criteria for achieving mechanochemical synthesis in titanium-carbon system represent the structure of carbon modifications and their degree of aromaticity. The promise of the use of soot + graphite carbon composition for the mechanochemical synthesis of titanium carbide is mentioned. It has been shown that titanium carbide synthesized according to this technology has high sorption activity.

The nonresonance response of silicon metal-oxide-semiconductor field-effect transistors (Si-MOSFETs) with a long channel (1–20 μm) to radiation in the frequency range 43–135 GHz is studied. The transistors are fabricated by the standard CMOS technology with 1-μm design rules. The volt-watt sensitivity and the noise equivalent power (NEP) for such detectors are estimated with the calculated effective area of the detecting element taken into account. It is shown that such transistors can operate at room temperature as broadband direct detectors of sub-THz radiation. In the 4–5 mm range of wavelengths, the volt-watt sensitivity can be as high as tens of kV/W and the NEP can amount to \({{10^{ - 11} - 10^{ - 12} W} \mathord{\left/ {\vphantom {{10^{ - 11} - 10^{ - 12} W} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}\). The parameters of detectors under study can be improved by the optimization of planar antennas.

Interaction of an electron beam with a cooled ion beam makes it possible to reduce its phase volume, perform accumulation of particles, and suppress various “heating” effects. The electron beam can also be used as a target for an electron-ion recombination reaction, which offers a chance to carry out atomic physics experiments and ensure slow uniform extraction of the ion beam from the storage ring. A high-perveance electron beam with a variable profile is required for effective cooling, while a high current density and a low energy of transverse motion of electrons in the beam is needed for extraction by means of recombination. It is shown that a convex cathode placed in a magnetic field can be used to form such a beam. A high current density can be attained with this shape of the cathode, but additional efforts must be focused on optimizing the gun’s optics in order to obtain a low energy of transverse motion of particles. Since ions repeatedly pass through the cooling section during their lifetime at different values of the betatron oscillation phase, the rates of recombination and cooling are dependent on the rms electron velocity averaged over the volume in which the beam interaction occurs. The proposed design of the gun with a convex cathode 10.2 mm in diameter ensures formation of a variable-profile electron beam with a nominal current of 1 A and a current density of 1.2 A/cm2. The rms energy of Larmor gyration of electrons at the exit from the gun, averaged over the beam cross section (the “transverse” temperature) is 1 eV. A focusing electrode that forms the Pierce optics near the edge of the cathode, an electrode controlling the beam profile, and an anode are included in the optics of the electron gun.

A concept of an accelerator mass spectrometer intended for the Siberian Branch of the Russian Academy of Sciences is suggested. Preliminary tests have been conducted, and a carbon isotope having a mass of 14 amu has been detected in a charcoal sample.

We have studied some kinematic features of the coronas of near-solar stellar streams, based on Hipparcos observations. Apex diagrams for kinematic streams, open clusters, and field stars are plotted. In our analysis, we used the apex-diagram (AD) method we developed earlier. We find that the Eggen streams and Arcturus stream have similar properties, providing evidence for kinematic inhomogeneity of their coronas and the existence of stellar groups such as those detected in the corona of the Ursa Major stream.

We consider kinematic inhomogeneities (stellar groups) in the corona of the Ursa Major flow. We show that the orientation of the major axis of the error ellipse for each star is defined by its position relative to its own apex. We apply the AD-diagram method suggested by us earlier; a statistical analysis confirms the existence of stellar groups in the corona of the Ursa Major flow.

The Hyades Cluster is used to analyze details of the AD-diagram method developed in our earlier works and applied to the corona of the Ursa Major stream. Hipparcos data are used to analyze the kinematics of the Hyades Cluster and determine its apex. Evidence for rotation of the cluster is presented.

The structure of the proper-motion diagrams for an ensemble of nearby field stars is analyzed using a simple model. For comparison, the observed proper-motion diagram is constructed using data of the Hipparcos catalog. A complete description is given of the modification of the van Altena method, which allows stars with similar space motions to be identified based on their proper motions. In the original version of this method, the stars had to be located within one-quarter of the celestial sphere, whereas our version is free of this restriction.

Results are presented from experiments on the production and study of a hot dense plasma in the central solenoid of the AMBAL-M fully axisymmetric ambipolar magnetic confinement system. The hot plasma in the solenoid and end cell is produced by filling the system with a thermally insulated current-carrying plasma stream with developed low-frequency turbulence. The plasma stream is generated by a gas-discharge plasma source placed upstream from the magnetic mirror of the solenoid. As a result, an MHD-stabilized plasma with a length of 6 m, a diameter of 40 cm, a density of 2×1013 cm−3, an ion energy of 250 eV, and an electron temperature of 60 eV is produced in the central solenoid. It is found that, in the quiescent decay phase, transverse plasma losses from the solenoid due to low-frequency oscillations and nonambipolar transport are rather small and comparable with the classical diffusion losses.

A hydrodynamic approximation is used to study the behavior of dipole modes of the transverse oscillations of an ion beam in a storage ring with an electron cooling section. It is shown that in addition to the finite interaction time of the beams, instability may be caused by a specific interaction effect between the ion and electron beams in the magnetic field which leads to redistribution of energy between the various modes of the ion beam oscillations. In this case, the condition that the determinant of the transfer matrix for the cooling section does not exceed unity no longer guarantees the stability of the transverse coherent oscillations of the ion beam and all the eigenvalues of the complete matrix of the ion motion including the storage ring must be analyzed. Calculations of the stability of ion beam dipole oscillations are presented for the parameters of CELSIUS.