Transmission electron microscopy uses electrons instead of light to image samples. Ernst Ruska developed the first electron microscope in 1931. A TEM uses an electron gun to produce an electron beam that passes through a thin sample. Electron lenses magnify the beam up to 250,000x to form an image on a screen. Key components include the electron gun, lens system, vacuum pumps, specimen stage and aperture. TEMs are expensive but can provide very high resolution imaging down to the atomic scale, finding wide application in fields like materials science and biology.

1. TRANSMISSION ELECTRON
MICROSCOPY
NADLENE PAMELA
DAIYANITHA

2. HISTORY
• Ernst Ruska developed the first
electron microscope,with the help of
his assistance of Max Knolls in 1931.
• After significant improvements to the
quality of magnification
• Ruska joined the Sieman’s Company in
the late 1930s as an electrical engineer,
where he assisted in the manufacturing
of his TEM.

3. What is transmission
electron microscopy?
•Electrons pass through a (very thin)
sample to form an image.
•Can magnify up to 250,000x
•UPM,USM , and IMR.

4. Principle
• TEM images are formed using
transmitted electrons (instead of the
visible light) which can produce
magnification details.
• The images can be resolved over a
fluorescent screen or a photographic
film.

5. APPLICATION.
• Metallugy -studies the physical and
chemical behavior of metallic elements
• Pharmaceuticals - to produce drug
substance
• Semiconductors - production and the
manufacturing of computer and silicon
chips.
• Research and studies in college &
universities

6. Transmission Electron
Microscopic (TEM)

7. Components of
TEM
•The Electron Gun
•The Lens System
•Vacuum Pumps
•Specimen stage
•Aperture

8. Electron gun
• An electron gun (also called electron
emitter) is an electrical component that
produces an electron beam that has a
precise kinetic energy.
• Most often used in television
sets and computer displays and in other
instruments, such as electron
microscopes.

9. Lenses
• Electron lenses are designed to
act in a manner emulating that of
an optical lens, by focusing parallel
rays at some constant focal length.
• Lenses may operate
electrostatically or magnetically.
• Electron lenses are made up of
from iron, iron-cobalt or nickel
cobalt alloys.

10. Vacuum pumps
•To increase the average
distance travelled by a
moving particle.
•Equiped with multiple
pumping system

11. Specimen stage
• TEM specimen stage designs
to allow for insertion of the specimen holder
into the vacuum with minimal increase in
pressure
• Standard TEM grid sizes are a 3.05 mm
diameter ring, with a thickness and size
ranging from a few to 100 μm.
• A wide variety of designs of stages and
holders exist.

12. APERTURE
•Apertures are metallic
plates
•consist of a small metallic
disc it is to prevent
electrons from passing
through the disc

13. SAMPLE
PREPARATION
• Fixation– uranyl acetate, to preserve
the tissue during dehydration
• Dehydration – removal of water using
alcohol or ethanol
• Embedding- using plastic that can
polymerize into solid hard block
• Sectioning –using diamond knife in an
ultramicrotome

14. • Staining - section placed on a copper grid
coated with plastic. Stained with heavy
metal salt to form “shadow” around the
grid.
• Freeze etch - sample frozen and then
fractured to reveal its internal structure.
• Ion beam milling - gallium ion are used to
thin samples until they are transparent
• Conductive coating - to coat on sample to
give negative like appearance using
platinum.

15. IRON BEAM MILLING
FREEZE ETCHING

16. IMAGING
• high-resolution, black and white image
• Sample need to be thin enough to allow
electron to pass through.
• When electron can pass through
greatly, the image apprears lighter.
• Image appear darker when sample are
dense or not thin enough.

17. IMAGES

18. ADVANTAGE’S
•Offer the most powerful magnification
•Wide-range of applications (medical,
educational and industrial fields)
•Images are high-quality and detailed
•Able to yield information of the features,
shape, size and structure

19. DISADVANTAGE’S
•large and very expensive
•require special housing and maintenance
•Images are black and white
•Complicated sample preparation
•Operation and analysis requires special
training

20. CONCLUSION
• TEM are invented when scientist
realized electron can be used to study
specimens under microscope.
• The sample preparation takes very long
thus it is not suitable for daily
laboratory practices.
• Helpful in research based studies.

21. REFERENCE
• http://www.tech-faq.com/transmission-electron-
microscope.html
• http://www.emez.ethz.ch/equipment/pips.pdf
• http://www.rsic.iitb.ac.in/Tem.html
• http://www.microscopemaster.com/transmission-
electron-microscope.html
• http://www.authorstream.com/Presentation/kaushalbhatt
-1369384-tem/