Magnetic deflection system for high-power electron beam - incorporates rotationally symmetric diverging yoke

摘要

The magnetic deflection system for a high-powder electron beam - which is used for melting or vapourizing preferably metal materials - with a large cross-sectional area is new. The system has a) a rotationally symmetric yoke (10) with an inner surface (40) and an outer surface (41), with the distance of the inner surface (40) from the axis of rotation increasing from top to bottom; (b) a saddle coil (13 to 18) which is compatible with the shape of the rotationally symmetric yoke (10). The distance of the inner surface (40) from the axis of rotation is given by a mathematical formula involving four variable parameters. The yoke with saddle coil is positioned over a material subjected to an electron-beam process. Two magnetic lenses are located between the yoke and a gun producing the electron beam. The saddle coil is connected to a current supply (24) controlled by a system (26) receiving a signal from a magnetic field sensor (25) of the soft-iron yoke (10). The current frequency lies between 100 Hz and 10 kH. USE/ADVANTAGE - For vapourisation of metal materials in surface coating processes, for example. It enables high-power electron beams with large cross-sectional areas to be deflected at high rates.