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Copyright of System Research & Information Technologies / Sistemnì Doslìdžennâ ta Ìnformacìjnì Tehnologìï is the property of Institute for the Applied System Analysis at the NTUU KPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, examples of all types of signal injection such as different signal , harmonic signal and multiple signal injections in a TWT including hollow electron beam near frequency 1800 MHz and within input powers lower than TWT saturation power has been analyzed using approximate analytical solution of S-MUSE model. Later, the results obtained from approximate analytical solution with large signal code LATTE, that is a Lagrangian model, have been tested and simulated so that the effect of input phase difference between drive and injected wave and the effect of input powers on the amplification value of drive and generated second-order harmonic waves were investigated. The phase difference between drive and harmonic waves is a key parameter in harmonic injection for increasing the output power of drive and second-order harmonic frequencies. [ABSTRACT FROM AUTHOR]

The electron beam additive manufacturing technology named xBeam 3D Metal Printing was presented at EBT-2016 Conference in Varna in summer of 2016. It was announced an expectation that this new technology can solve the most critical problems of numerous existing metal additive manufacturing processes and systems, including conflicts between accuracy and productivity, high quality and production cost, availability and price of raw materials and equipment, numerous after-processing operations as well. Authors will present the technical and technological progress in development of the xBeam 3D Metal Printing achieved on the base of the pilot xBeam 3D Metal Printer in near production environment since that time. Results of numerous experiments with the most important materials for metal additive manufacturing like titanium alloys which have proved possibility to produce defect-free material with good metal structure and high mechanical properties will be demonstrated. Numerous exclusive technological opportunities provided by xBeam 3D Metal Printing will be presented. Economic efficiency of the xBeam 3D Metal Printing will be also analyzed on the base of testing manufacture of real industrial parts from titanium alloys. [ABSTRACT FROM AUTHOR]

A numerical investigation on the spatiotemporal evolution of an electron beam, externally injected in a plasma in the presence of a plasma wake field, is carried out. The latter is driven by an ultra-short relativistic axially-symmetric femtosecond electron bunch. We first derive a novel Poisson-like equation for the wake potential where the driving term is the ultra-short bunch density, taking suitably into account the interplay between the sharpness and high energy of the bunch. Then, we show that a channel is formed longitudinally, through the externally injected beam while experiencing the effects of the bunch-driven plasma wake field, within the context of thermal wave model. The formation of the channel seems to be a final stage of the 3D evolution of the beam. This involves the appearance of small filaments and bubbles around the longitudinal axis. The bubbles coalesce forming a relatively stable axially-symmetric hollow beam structure. [ABSTRACT FROM AUTHOR]

At the heavy ion storage ring HIRFL-CSRe an electron cooler is operated to improve the beam conditions for experiments. The properties of cooled beams have been studied. The longitudinal beam dynamics during the cooling process was measured by a resonant Schottky detector. The dependencies of the parameters electron beam density and profile on cooling times were investigated. The friction force was measured directly with the aid of the high voltage system of the cooler and with the application of the beam bunching system as well. An experiment with bunched cold beam showed a dependence of the bunch length on the beam density. [ABSTRACT FROM AUTHOR]

The use of hollow electron beams permits a significant increase in the diameter of the beam tunnel in comparison with the conventional pencil-beam slow-wave electron devices. As a result, the current density and the heating of the microwave structure are decreased, which allows increasing the average radiation power at high frequencies. To demonstrate this capability, two versions of W-band oscillators, namely, an axisymmetric orotron and a backward-wave oscillator (BWO), have been designed. The electron beam with an outer diameter of 1.6 mm and a 0.1-mm thick wall could be produced in a 30 kV/1 A Pierce-like electron gun with the hundredfold magnetic compression. Oscillators use microwave structures with an azimuthally symmetric corrugation, sinusoidal for the orotron and rectangular for the BWO. Simulations based on the averaged equations and 3-D PIC-code predict an output power up to 1 kW for the orotron and 0.7 kW for the BWO, whereas the thermal regime in the BWO is easier for continuous-wave operation. Wideband frequency tuning of the BWO is simulated. To reduce ohmic losses, a smooth downtaper of the corrugation in the orotron and an abrupt cutoff with a specially optimized last tooth in the BWO were designed. [ABSTRACT FROM AUTHOR]

The dispersion characteristics of electrostatic and electromagnetic modes of an electron tube, with ion channel guiding, in a cylindrical waveguide are presented. The analysis takes into account a relativistic hollow electron beam guided by an ion channel. Dispersion relations are derived and solved numerically to study the waveguide, betatron, and space charge modes. The effect of the annular electron beam thickness on frequencies of the electrostatic and electromagnetic waves is investigated. This paper reveals the strong dependence of the electromagnetic and electrostatic waves' frequencies on the electron beam thickness. The results of this paper are compared with previous works where an electron tube is guided with an axial magnetic field. [ABSTRACT FROM PUBLISHER]

Electron guns installed in electron-cooling devices produce beams whose 2D profiles are variable. The profiles were measured at the test bench by passing a wire across the beam, while the electric current from the wire and the light radiation along the wire were monitored, as well as the position of the wire. [Copyright &y& Elsevier]

A new generation of electron coolers will be used at ion storage rings with high requirements on beam parameters. The electron beam with a variable profile helps to get an ion beam with the emittance and intensity that meet the demands of specific physical experiments. [Copyright &y& Elsevier]

Cooling efficiency in electron cooling systems is closely related to the velocity of electron. The velocity of electron has offset due to the space charge of the intense electron beam in the drift tube of the cooling section and thus increases the temperature of electrons. In order to minimize this effect, a new type of electron gun is adopted to produce a hollow electron beam in HIRFL-CSR e-cooler project. The hot ion beam is cooled by Coulomb interaction with intense and cold hollow electron beams. Using typical parameters of the CSRm e-cooler, theoretical calculations comparing the impact of the space charge field on electron velocity for solid and hollow electron beam are carried out. [Copyright &y& Elsevier]