Abstract: An electron beam image of a microcircuit pattern is projected from an irradiated photocathode window to a resist-coated silicon wafer through two successive lens systems having field-containing regions which communicate through a small aperture in a common pole structure that otherwise shields these regions from each other. The lens region in which the photocathode is located contains electrostatic and magnetic fields for accelerating the electrons and focusing the beam toward a crossover point in the aperture. The region in which the wafer is positioned contains only a magnetic field to correct aberrations of the beam image. The arrangement permits reduction of the image size. Beam registration detectors and deflecting devices are located near the aperture in the common pole structure. Because it is isolated from objects located outside of its own lens region, the electrostatic field is not perturbed by these detecting and deflecting devices or by variations in flatness of the wafer surface.