Abstract: In a scanning electron microscope device having the plastic scintillator type reflected electron detector 17 that is installed below the front end surface 14a of the object lens 14 to detect reflected electrons from the specimen, the reflected electron detector 17 has the front end portion 38 of its scintillator 17a formed into the semicircular portion 44 having a radius almost equal to the radius of the front end surface 14a of the object lens 14. At least a part of the edge of the semicircular portion 44 is formed with the notched surface 39 that extends along the extension of the inclined surface 14b of the object lens 14. This increases the viewing angle of the optical microscope, which is used to locate the position of the specimen being observed, and also increases the solid angle of the detection plane of the detector with respect to the specimen. The reflected electron detector thus can arrest reflected electrons from the specimen efficiently.

Abstract: In a backscattered electron detector for an electron beam apparatus which consists of scintillators, a photo-multiplier and an amplifier, a plurality of scintillators are disposed in a specimen chamber between an objective lens and a specimen and are arranged close together with their ends facing each other. The scintillators are formed with a notch at the facing ends so that a gap or opening is formed by the opposing notches to allow an electron beam to pass through the scintillators. Since each scintillator has no end portion beyond a hole, which is found in the conventional backscattered electron detector and whose electron sensing portion has low detection efficiency, backscattered electrons released from the specimen are collected by an electron sensing portion on the scintillator that is not interrupted by the hole and which thus has a high detection efficiency. This enhances the detection efficiency of the back-scattered electron detector.