Методика автоматизированного измерения пространственных распределений плотности тока технологических электронных пучков

Abstract

The importance of developing an automated technique for measuring spatial current density distributions of process electron beams is shown. It has been proven that immediate methods based on directly measuring the electron beam current components are of the main interest for constructing monitoring and control systems in electron beam-based process installations, because it is only these methods that can provide reliable information about the spatial distribution of current density. Experimental investigations of spatial current density distributions for electron beams with power capacities up to 6 kW have been carried out. The distributions obtained by the probe method are analyzed, and their deviations from the normal distribution function and axial symmetry are revealed. The limitations of the probe method based on the heat flux density and beam power are determined, and an express method for measuring the current density radial distribution over the electron beam cross section is proposed, which is based on using the direct edge method and on numerically processing the time dependences of the current. A scheme for quantifying the radial distribution of the electron beam current density is given. The possibility of applying the proposed technique for measuring the characteristics of beams with a power density up to 1.8∙104 W/cm2 using a copper collector has been experimentally confirmed. It is shown that the developed technique is necessary for mathematically reconstructing the current density volume distribution using the basic principles of electronic optics.