cross section of an electron microscope

Electron microscope: it uses an electron beam (as opposed to light) to provide magnification that is markedly superior to that of an optical microscope.

stage

Adjustable metal plate (stage) on which the specimen is mounted in order to study it.

aperture diaphragm

Device with an opening whose diameter can be changed to narrow or widen the diameter of the electron beam.

aperture changer

Device that adjusts the diaphragm opening in order to change the diameter of the beam.

condenser

System of magnetic lenses (electromagnets producing a magnetic field when excited by an electric current) that concentrates the beam onto the specimen under study.

vacuum manifold

Conduit connected to a pump that creates enough of a vacuum in the microscope that it can function.

electron gun

Device that usually consists of a tungsten filament that is heated to produce an intense electron beam, which illuminates the specimen.

vacuum chamber

Part of the microscope in which pressure can be reduced so that the electrons can move.

visual transmission

The electron beam explores the surface of the specimen, which in turn emits electrons to form a point-by-point image on the screen.

focusing lenses

System of magnetic lenses (electromagnets) that concentrate the electron beam on one spot on the specimen.

beam diameter reduction

The two lenses of the condenser cause the divergent electron beam emitted by the gun to converge.

electron beam positioning

Control that positions the electron beam along the optical axis so that it reaches the specimen.

electron beam

Set of negatively charged particles that propagate toward the specimen.