FESEM
Ernst Ruska (1906-1987)
Awarded the Nobel prize in 1986
Ruska (1986)
History
FESEM
is the acronym for Field Emission Scanning Electron Microscope. It was Ernest
Ruska (1906 – 1987) whom in his PhD. thesis mentioned the
potential for electrons to be used in a microscope. In 1933 Ruska and
Knoll constructed the first electron microscope and in 1935 Knoll wrote
the first work describing the concept of a SEM. In 1938 Von Ardenne built
a scanning transmission microscope (STEM) adding coils to a transmission
electron microscope.
The first SEM used
to study a solid surface was described by Zworykin et al (1942) working
for the RCA laboratories in the United States. As a practice in the early
days the gun was located in the bottom so the specimen chamber and was
high enough for the operator but the specimen might fall down the column.
The first
micrographs showing the striking three-dimensional imaging capability were obtained in Cambridge at the Engineering Department in 1952 by Dennis
McMullan who was continuing the work by Ken Sander (both under C. W.
Oatley supervision). The next important step was also in Cambridge when
Oatley improved the secondary electron detector by adding a scintillator to
convert electrons to photons, and let the way for improvement in
signal to noise ratio.