Automation of cathode positioning in multiple beam electron gun

To assure even cut-off voltages of the multiple beam electron gun, it is necessary to position the cathodes within the deviations not worse than plusmn1 mum from the positions, which are individually defined, taking in to account the displacements of another electrodes of the gun. The electron gun cathode position tracking system measures and calculates the desired distance between the surface of the cathode and the modulator by the means of mechanically contacting probe. During the measurement process the unfastening force, produced by the compressed air, is being applied to the probe in order to avoid the damage of the surface of the cathode. An additional source of mechanical vibrations is used to reduce the still friction force