Dr. S. H. Burungale's document discusses scanning electron microscopy. It notes that Ernst Ruska won the Nobel Prize in Physics in 1986 for his work developing the first electron microscope. The document compares light microscopes and electron microscopes, noting that electron microscopes have much higher magnifications and resolving power but are more expensive. It explains that electron microscopes work by generating a beam of electrons that is accelerated, focused by electromagnetic lenses, and scanned across a specimen, with secondary electrons from the specimen detected to form an image.

1. Scanning Electron microscopy
Dr. S. H. Burungale
Department of chemistry
Yashwantrao Chavan College of Science, Karad

2. Ernst August Friedrich Ruska (25
December 1906 – 27 May 1988) was
a German physicist who won Nobel
prize in Physics in 1986 for his work
in electron optics, including the design
of the first electron microscope

3. Difference Between Light Microscope and electron Microscope
Light Microscope Electron Microscope
Source Light electron
Magnificati
on
magnification of
around 1000X with
resolving power of 0.2um
magnification of 10,00,000X and
resolving power up to 0.5nm.
Lenses In Light Microscope
projection screen and glass
lenses are used
fluorescent screen and an
Electromagnetic screen is used.
Samples Living and natural color of
the specimen is obtained
dead(fixed), black and white
but 3D images are obtained.
Cost less expensive and easily
available
expensive and not easy to
handle.
Voltage there is no such
requirement.
high voltage which is around
50,000

5. Principle:
A Beam of electrons is generated by suitable
source like Tungsten filament gun and field
emission gun .
 The electron beam is accelerated through a high
voltage 20kv and pass through a system of
objective aperture, electromagnetic lenses to
produce a thin beam of electrons.
The thin beam of electrons scan the surface of
the specimen , the emitted electrons is detected by
suitable detector.

8. Electron
Source
Anode
Magnetic Lens
Scan Coils
Objective Lens
specimen
Secondary
electron

23. Thank you