The Everhart-Thornley detector, a secondary electron detector, is an essential component in scanning electron microscopy (SEM). SEM is a powerful imaging technique that uses a focused beam of electrons to generate high-resolution images of a sample's surface. The Everhart-Thornley detector is specifically designed to detect secondary electrons produced during this process.

1. KONGU
ENGINEERING
COLLEGE
Presented by:
SHRISH C (23MER044)
DEEPAK KUMAR R (23MER005)
DATE: 05/01/2024

2. Everhart Thornley
Detector(SED)
Presented by
23MER044

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 Objective Lens
 Sample Cell
 Secondary Electron Detector

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6. • The detector is above and close to the sample.
• A collector electrode is placed in front of the aluminium-coated scintillator.
• A voltage is applied to the collector to create an electric field that collects
secondary electrons.
• The guided secondary electrons hit the scintillator, causing light emission.
• The light guide tube directs the emitted light to a PMT.
• In the PMT, the light is converted into electrons again, then multiplied.
• The multiplied electrons reach the PMT anode, generating a voltage signal
amplified by an electric circuit connected to the PMT.
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8. Use in High-Resolution SEM:
• In high-resolution SEM, where the specimen is placed inside or close to the
objective lens, the ET detector is positioned inside the microscope column.
• This positioning allows for collecting secondary electrons generated in or entering
the objective lens.
• The ET detector is known for its high response speed, allowing for fast scanning
or movement of the specimen stage without blurring or time lag.
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9. HIGH-Resolution
Images Of SEMs
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10. Common industrial dust 10

11. Complex chrysalis of monarch butterfly 11

12. The surface of overload fracture 12

13. Micrograph of a butterfly scales 13

14. Cancer malignant cells 14

15. 1/14/2024 Red blood cells 15

16. 1/14/2024 Human hair (diameter 0.0060 mm) 16

17. 1/14/2024 Yeast cells 17

18. THANK YOU
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