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Scanning Electron Microscope (1948 (Improving micrograph using signal…
Scanning Electron Microscope
1926
Hans Busch studies the trajectories of charged particles in axially symmetric electric and magnetic field and claimed that field could act as particle lenses.
He invented the first electromagnetic lens
A French physicist de Broglie introduced the concept of corpuscule waves.
1963
SEM V
Three magnetic lenses
An Everhart-Thornley detector
1948
Improving micrograph using signal processing
Introduced nonlinear signal amplication and improved the scanning system
Charles Oatley begin SEM development based on Zworykin’s microscope
Insert a stigmator in the SEM to correct lens cylindrical imperfections
1960
Everhart and Thornley improved the secondary electron detector
1965
Cambridge Scientific Instruments released the first commercial SEM
Named as the Stereoscan Mark I
1938
Manfred von Ardenne built the first scanning electron microscope
Resolution limit was around 100 micrometer
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1931
Ernst Ruska and Max Knoll created the first transmission electron microscope with resolution higher than a light microscope (-12 000x)
Found using de Broglie equation that electron wavelength < light wavelength
Ruska and Knoll tried to implement Busch’s lens formula
Reinhold Rudenberg acquired the electron microscope patent
1933
Ernst Ruska develop an electron microscope with higher resolution than optical microscopy
1942
Vladimir Zworykin described and developed the first true SEM
Showed the secondary electron provided topographic contrast
Reached a resolution of 50nm
Used electon multiplier tube as preamplifier of the secondary electron emission current