In the presented paper problems of particles dynamics in linear electron accelerators with standing wave are discussed. The focus of the study is a possibility of use of focusing properties of electromagnetic accelerating field for passing an electronic beam through aperture of biperiodic slow-wave structure (BSS), which will lead to a significant reduction of an accelerator's sizes. The calculation methodology is proposed and results of the study of particle dynamics in accelerators with standing wave based on BSS are presented, which prove a possibility of beam passing without using external focusing elements. The proposed methodology can be used for a calculation and design of linear electron accelerator (LEA).Keywords: linear electron accelerator, biperiodic slow-wave structure, standing wave, particle dynamics, aperture of passing channel, power lines of electric field, electromagnetic field of cell, passing bushing, range of sustainable radial motion, acceleration range, field of passing channel

This article discusses the properties of modified biperiodic structures with standing wave and improved focusing properties for effective electron acceleration in linear accelerators. Main attention is paid to possible application of the focusing properties of electromagnetic accelerating field for transmission of electron beam through aperture of biperiodic decelerating system, which would reduce significantly accelerator dimensions. Predictions of particle dynamics in standing wave accelerators based on biperiodic decelerating structures are presented, which confirms possibility of the beam transmission without application of external focusing elements. The discussed procedure can be applied for designing and development of standing wave linear particle accelerators.

This article discusses possibility of harness wiring with the use of focusing system of high frequency eigenfields of accelerating resonators in standing wave linear accelerators on the basis of biperiodic slowing systems. The scopes of business activities and specificity of existing engineering processes applied in industry, especially in chemistry and metallurgy, require for special measures on environmental protection. At present electron linear accelerators operating in pulse mode are used for application purposes. Such accelerators can be characterized by sufficient beam power for efficient industrial use and for environmental protection. The results of numerical analysis of electron dynamics in two-section accelerator upon various initial conditions are presented. The obtained results are applied for development of actual accelerator, calculated and experimental data are given. The performed experimental study confirmed possibility of development of standing wave linear accelerator without external magnetic focusing system with output beam diameter of not higher than . The results of calculations of beam dynamics are experimentally verified.

This article discusses the issue of increase in intensity of electron flow in small-size accelerator for efficient application in industry, medicine, and other fields of science and engineering, where the sizes of unit are important. A possible approach to solve this problem is to combine acceleration and focusing of flow of charged particles in a single structure. Comparison of various types of accelerating structures demonstrates that at injection voltages not higher than 100 kV, the most preferred are biperiodic decelerating structures. Since the increase in intensity of beams of accelerated particles only by improvement of acceleration and focusing has certain limits, then it is proposed to improve technical and economic specifications of accelerator by conversion from regular accelerating system to multichannel design. Transportation and focusing of beams in multibeam structures, which significantly improve acceleration efficiency without noticeable increase in transversal sizes of radiating unit, seems to be possible only by means of high frequency focusing.

When using accelerators in industry and medicine, important are the dimensions of the device used, especially the radial ones. In the linear electron accelerators based on a biperiodic retarding structure, which operates in the standing wave mode, there is a possibility to provide focusing of the accelerated particles with the help of high-frequency fields without the use of external focusing elements. In the accelerating cell, due to the presence of the far protruding drift sleeves, the electric field lines become strongly curved, which leads to the appearance in the regions adjacent to these sleeves of a substantial in magnitude radial component of the electric field. The particles entering the accelerating gap experience the action of a force directed toward the axis of the system, and at the exit, of a force directed away from the axis. Under certain conditions, alternation of the focusing and defocusing fields can lead to a general focusing effect. In the paper we study the focusing properties of a modified biperiodic structure with standing wave. The main attention is paid to the possibility of using the focusing properties of the electromagnetic accelerating field for guiding the electron beam through the aperture of the accelerating system, which will lead to a significant reduction in the accelerator sizes. The proposed method can be applied in the calculation and design of linear electron accelerators.