electron microscopy

1. Topic :- Electron microscope
GUIDED BY
• Miss Tuleswari sahu mam
• Ass. Prof. Of zoology
PRESENTED BY
• Name- Priyanka patel
• Class- MSC ZOOLOGY II SEM
• Subject- tools and techniques

2. Synopsis
• INTRODUCTION
• WHAT IS MICROSCOPY
• ELECTRON MICROSCOPE
• PRINCIPLE OF ELECTRON MICROSCOPE
• PARTS OF ELECTRON MICROSCOPE
• TYPE OF ELECTRON MICROSCOPE.
I. SEM
II. TEM
• ADVANTAGES
• DISADVANTAGES
• APPLICATION
• CONCLUSION
• REFRENCE

3. INTRODUCTION
• The microscope magnifies the image of such objects thus making them
visible to the human eye. Microscopes are used to observe the shape of
bacteria, fungi, parasites and host cells in various stained and unstained
preparations. There are many different microscopes available.

4. WHAT IS MICROSCOPY
• The electron microscope uses a beam of electrons and their wave-like
characteristics to magnify an object’s image, unlike the optical microscope
that uses visible light to magnify images.

6. ELECTRON MICROSCOPE
• • An electron microscope is a microscope that uses a beam of accelerated electrons
as a source of illumination.
•
• • The wavelength of an electron can be up to 100,000 times shorter than that of
visible light photons.
•
• • Electron microscopes have a higher resolving power than light microscopes and
can reveal the structure of smaller objects

8. Principle of Electron microscope
• Principle of Electron Microscope The lenses used in the electron
microscope are magnetic coils. These magnetic coils are capable of focusing
the electron beam on the sample such that the sample gets illuminated. As
the flow of current increases, the strength of the magnetic lens increases.

9. Parts of Electron Microscope
Electron Microscope is in the form of a tall vacuum column that is vertically mounted. It has the following components:
1. Electron gun
The electron gun is a heated tungsten filament, which generates electrons.
2. Electromagnetic lenses
The condenser lens focuses the electron beam on the specimen. A second condenser lens forms the electrons into a thin tight
beam.
3. Specimen Holder
The specimen holder is an extremely thin film of carbon or collodion held by a metal grid.
4. Image viewing and Recording System
The final image is projected on a fluorescent screen.Below the fluorescent screen is a camera for recording the image.

10. Types of Electron Microscope:
• There are basic 4 types of Electron Microscope:
1. Analytical Electron Microscopy (AEM)
2. Scanning Transmission Electron Microscope (STEM)
3. Scanning Electron Microscope (SEM)
4. Transmission Electron Microscope (TEM)

11. Transmission Electron Microscope(TEM)
• Is a microscopy technique in which a beam of electrons is transmitted
through an ultra-thin specimen, interacting with the specimen as it passes
through it.
• A transmission electron microscope can achieve better than 50 pm
• resolution and magnifications of up to about 10,000,000x

14. Scanning Electron Microscope (SEM)
A scanning electron
microscope (SEM) is a type of electron microscope that produces images of a
sample by scanning it with a focused beam of electrons.
The electrons interact with atoms in the sample, producing various signals that
contain information about the sample’s
surface topography and composition.

17. Advantages
• The scanning electron microscope has many advantages over traditional
microscopes. The SEM has a large depth of field, which allows more of a
specimen to be in focus at one time. The SEM also has much higher
resolution, so closely spaced specimens can be magnified at much higher
levels.

18. Disadvantages
• Size – Despite the advantages in technology over the years, electron
microscopes are still large,
• bulky pieces of equipment which require plenty of space in a laboratory.
Also,
• as electron microscopes are highly sensitive,
• magnetic fields and vibrations caused by other lab equipment may interfere
with their operation.

19. Application
• Electron microscopy (EM) is a technique for obtaining high resolution
images of biological and non-biological specimens. It is used in biomedical
research to investigate the detailed structure of tissues, cells, organelles and
macromolecular complexes.

20. Conclusion
Scanning electron microscopy is a key tool to study the effect of
physicochemical properties on adhesion phenomena (pH, roughness,
topography, temperature, etc).

21. Reference
• Wikipedia https://en.wikipedia.org/wiki/Electron_microscope
• Microbiology by Lansing M. Prescott.