A new method of experimental investigation of high-power electron beam

An equipment for measuring radial current distribution in electron beam pro duced by technology electron optical system with power up to 10 kW is descr ibed. The principle of operation of apparatus and examples of beam characte ristics are presented. Two movable plates: one water-cooled protection plat e and other-analysing plate behind it are used. Every plate is moving in th e direction of one of two perpendicular axis in planes parallel to the foca l beam plane. A slit in every plate, which is perpendicular to the axis of its movement, determines the point of beam current density measurement. The electron beam is analysed in the plane where its cross-section is big enou gh (3-5 mm) relative to a very narrow slit (0.05 mm). The beam changes focu s and deflects regularly to avoid melting or damaging of the protection pla te. During the measurements of the electron beam current density in any poi nt of beam spot, the electron beam is in a static position and the beam pos ition respectively, measuring the current passing through two slits is one and the same. As a result, high resolution and many details of the current distribution in the beam focus spot can be obtained. This gives a possibili ty to adjust the electron gun equally in different runs and to obtain the s ame welding results at other equal technology conditions. A comparison betw een electron beams of the different electron guns is possible. (C) 2000 Els evier Science Ltd. All rights reserved.