In a scanning electron microscope, an emitted primary electron beam is
diverted by an angle of at least about 45 degrees prior to incidence with
a specimen. The beam may be bent by a magnetic separator. The separator
may also serve to deflect secondary electron and back scattered
electrons. As the angle of emissions and reflections from the specimen is
close to the angle of incidence, bending the primary electron beam prior
to incidence, allows the electron source to be located so as not to
obstruct the travel of emissions and reflections to suitable detectors.