[en] Material processing with electron beams has become an inevitable technique in this rapidly expanding technological world. Almost all the developed and developing nations have indigenized this technology to cater the requirement of their nuclear, defense and aeronautical industries. In India, BARC has been the hub of indigenous EB machines over the past four decades. The EB welding and melting machines developed at BARC have been successfully deployed in various DAE as well as other units. The indigenous EB machine development programme at BARC has now attained technological competence, squarely resting on knowledge base, user base and vendor base. This talk mainly highlights on the different facets of indigenous electron beam machines, especially the technological challenges during the course of development

[en] It is shown that nonrelativistic electron beams (EB) provide a convenient means for simulating the process of ion acceleration occurring during the injection of relativistic EB into a neutral gas. It is also found that the ion acceleration time is much smaller than the time over which the number of ions in the system decreases appreciably

[en] The welding effects (weld deep and quality) obtained by means of classic and double refracted, rotating electron beams have been compared. The better weld parameters have been obtained in the case of the second beam use. 8 refs, 5 figs

[en] In this colloquium, the following topics were discussed: beam-metal interaction, physical study of welded areas, weldability and metallurgy of joints, welding machine technology, melting and use of specific high power beams

[en] The uses of electron beam machines for welding, perforating and surface treatment is described and problems of vacuum chambers are discussed. Examples of manufactured items illustrated include motor vehicle front axle supports and motor commutators as well as perforated jet engine combustion chambers. The use of computer-controlled electron beams for welding is referred to. (G.M.E.)

[en] The invention relates to devices used in electrothermal and electrophysical process engineering and refers particularly to electron beam devices for the thermal treatment of objects by electron bombardment. It can be used to weld metals, to evaporate different substances, to process casting models by melting, for treatment true to dimensions etc. in aircraft industry, in steel and iron industry, in ship-building industry and other branches. (orig./RW)

[en] It is shown that the Electron-Cyclotron Maser interaction can be made compatible with exclusively axial injection of the electron beam, by introducing an appropriate slow-wave structure. With an appropriate choice for the relevant parameters, the resulting interaction is found to be extremely efficient, with efficiencies approaching 100 percent, and to possess a moderate frequency upshift from the nonrelativistic gyrofrequency. The nonlinear theory of the interaction is outlined and preliminary designs are presented

[en] Short communication. 8 refs, 7 figs

[en] Power loss in electron beam processes, due to the thermal convection in the molten pool created in evaporation, melting and welding processes, is experimentally and analytically studied; laminar calculations are carried out with Boussinesq equations for incompressible liquid. For turbulent regime, an empirical law is derived from experiments (Cerium evaporation) for the Nusselt number, leading to a scaling law covering a wide range of metals. The energy balance shows the paramount importance of heat convection phenomena and especially turbulent thermal convection, in the melt pool power loss. 1 fig., 11 refs

[en] The invention concerns a device for electron beam machining, in particular welding. It is aimed at continuous operation of the electron irradiation device. This is achieved by combining the electron gun with a beam guiding chamber, to which vacuum chambers are connected. The working parts to be welded can be arranged in the latter