Device for and a method of calibrating electron-optical apparatus

Claim 1

A calibrating method for an electron pattern generator, said generator having a sample holder, means for displacing said sample holder in two mutually perpendicular directions, a data processing system for sweeping said sample area by area, and each area line by line, and each line, point by point, said calibrating method comprising the following steps of: manufacturing a marker upon said sample, at a given area bombarded by said beam at its rest position with a material capable of upon the impact of the electron beam, scattering electrons, and generating in response to this impact an electric signal; transducing said signal into an image upon the screen of a cathode ray oscilloscope, by applying said signal upon the control electrode of said tube; applying a programmed pattern simultaneously and synchronously to said oscilloscope and to said generator deflection system for displaying on said screen a predetermined figure centered about the image of said marker; giving a predetermined mechanical displacement to said holder, and applying the voltage corresponding to said displacement to said deflection system of said pattern generator; and centering again said figure about said image of said marker.