Abstract: An inspection system employing high collection efficiency energy filtered backscatter electrons. At least two detectors are positioned relative to the sample at spaced locations. Each detector has a canister with a fiberoptic bundle mounted therein. A scintillator detector is mounted at the end of the fiberoptic bundle. A ground grid is mounted at an opening of the canister in axial alignment with the scintillator detector. An energy filter is interposed between the scintillator detector and the ground grid. The energy filter is an electrostatic retarding potential grid to permit detection of only high energy backscatter electrons. The geometry of the detectors relative to the specimen together with the conical shape of the detector housing achieves maximum collection efficiency of the targeted electrons.