Secondary particle detection system of scanning electron microscope

A scanning electron microscope includes: a retarding power source configured to apply a retarding voltage to a specimen; a combined objective lens configured to focus the primary beam on a surface of the specimen; an electrostatic deflection system configured to deflect the primary beam to direct the primary beam to each point in a field of view on the surface of the specimen; a first scintillation detector having a first scintillator configured to emit light upon incidence of secondary electrons which have been emitted from the specimen; a Wien filter configured to deflect the secondary electrons in one direction without deflecting the primary beam; and a second scintillation detector having a second scintillator configured to detect the secondary electrons deflected by the Wien filter. The second scintillator has a distal end located away from the axis of the primary beam.