One embodiment disclosed relates to a scanning electron beam apparatus including an objective lens, scan deflectors, de-scan deflectors, an energy-filter drift tube, and a segmented detector. The objective lens may be an immersion lens configured with a high extraction field so as to preserve azimuthal angle discrimination of the electrons scattered from the specimen surface. The de-scan deflectors may be used to compensate for the scanning of the incident electron beam. The energy-filter drift tube is configured to align the scattered electrons according to polar angles of trajectory from the specimen surface.