BG45024

This invention relates to a circuit controlling the electron beams in electron beam evaporators with AC acceleration voltages, finding application in evaporators for welding, fusing and evaporation of metals, materials, lithography, etc. It controls electron beam evaporators, avoiding disadvantages of existing devices which need rectification and qualitative filtering of the acceleration voltage, thus making the invention inexpensive. The circuit includes a reduced number of units and uses AC amplifiers. Focusing adjustable amplifiers and deflection along axes X and Z are respectively connected to focusing and deflection lenses; the output of a square root extraction means is connected to the input of adjustable AC focusing amplifier, the input of which is connected to output of a first phase shift means whose input is connected to the output of a voltage source coinciding in a curve shape, frequency and phase with the acceleration voltage of the respective electron beam. Either electrostatic or electromagnetic focusing lenses can be used. When the focusing lens is electrostatic, the input of the adjustable focusing amplifier is directly coupled to the output of the voltage source. A calculation unit for correcting the focus ratio depending on the electron beam length is connected between the outputs of the deflection amplifiers and the input of the focusing amplifier for the respective electron beam.