Abstract: A new optical system has been developed which employs a snorkel type conical objective lens that allows high resolution imaging at high tilt angles, up to 45 degrees. An E cross B field for detecting secondary electrons is utilized in this optical system in order to avoid influence upon the primary beam from the extraction field generated by the usual scintillator secondary electron detector. Spatial resolution of better than 4 nm at an accelerating voltage of 1 kV has been obtained from a secondary electron image, with a working distance of 3 mm.!7
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