1. IFFAT FATIMA UOG

2. ELECTRON MICROSCOPE

3. Contents History LM Vs EM Electron microscope Principle Types of EM Application & importance

4. History of Microscope 1590-tube microscope by dutch glass maker 1665-Robert hooke’s microscope

5. Continued…………………………… 1674-Antonee van leeuwenhooke TEM co-invented by Ernst Ruska (1931)

6. Main characteristics of microscope Resolution

7. Magnification

8. Light Microscope Vs Electron microscope

9. Comparison Light microscope Resolution: 0.2μm to 200nm Magnification: 2000x Illumination: Light Glass lenses Objects seen: frog's egg cells‚ cell wall‚ cilia‚ flagella‚ nucleus & other organelles etc. Living specimen Lower resolving power Focus: condenser lense Electron microscope Resolution: 0.2nm Magnification: 2‚000‚000x Illumination: Electron Electromagnetic lenses Objects seen: orgenelles‚ proteins‚ viruses‚ small molecules etc. Dead specimen Higher resolving power Focus: vaccum & magnetic lense

11. Electron microscope Electron microscope is a scientific instrument that uses a beam of energetic electrons to examine objects on a very fine scale. Why electron beam? Wave nature of particles

12. Types of Electron microscope

13. Transmission electron microscope Instrumentation Electron Source Electromagnetic lense system Sample holder Imaging system

14. Working Emission of a high voltage beam of electrons. Focusing of beam on specimen. Transmission through the specimen. Magnification of the image. Recording of the image by fluorescent screen, light sensitive sensor (camera).

15. TEM

16. Sample preparation Fixation Rinsing Post fixation Dehydration Infiltration Polymerization Sectioning

17. Applications Ultra-structure analysis Crystal structure

18. Scanning Electron microscope Emission of a beam of by an electron gun. Passage of electron beam through the vacuum. Focusing of beam down toward the sample. Ejection of X-rays & es. From sample after hitting. Collection of by detectors & conversion to a signal. Transmission of signal to a screen/ final image

19. Scanning EM

20. Sample preparation Metals require no preparation Non metals require coating of a thin layer of conductive material.

21. Applications Medical & physical science Semiconductor industry Examination of a large specimen range.

22. Any Q?