Method to eliminate the impact of magnetic fields on the position of the electron beam during EBW

Abstract

The paper presents the approximate formulas for calculating the deflection angle and the misalignment of the electron beam from the optical axis of the electron gun caused by the action of magnetic fields during the electron beam welding. Mathematical model of the effect of magnetic field induced by thermoelectric currents on the electron beam position in the process of electron beam welding of dissimilar materials is presented. The method of monitoring of the misalignment of the scanning electron beam and its mathematical model are proposed. Monitoring of the misalignment of the scanning electron beam is based on the processing of the signal of the collimated X-ray sensor directed to the optical axis of the electron gun by synchronous detection method. The method of compensation of the effect of magnetic fields by passing through the welded seam the currents which compensate thermoelectric currents is considered.