SEM- Schematic Overview. Electron Detection Tungsten Filament Electron Source.

SEM- Schematic Overview

Electron Detection

Tungsten Filament Electron Source

Filament Emission

Field Emission Gun

Magnetic Lenses

Focusing Optics

Effect of Working distance

Effect of Condenser Lense

Aberations to Minimum Spot Size

Voltage and Atomic Number Effect on Backscatter Electrons

Monte Carlo Simulation and Secondary Electron Generation

Electron- Atom Interaction

X-ray Emission

X-ray Generation

Characteristic X-rays

• Characteristic radiation intensity is proportional to the tube current and the difference between the accelerating voltage and the excitation voltage. n ~ 1.5

X-ray Transitions

Energy Spectrum for Pure Ni

Auger Electron Spectroscopy

Energy Versus Penetration

SEM Operational Components

Line Scan Process

Pixel Element and Sample area Scanned

Effect of Working Distance and Aperture on Depth of Focus ( in m)

Electron Detector and Electron Sources

Non Dispersive X-ray Detection

Non Dispersive Detector

Multichannel Analyzer

Super Alloy X-ray Spectrum

Peak Broadening Due to Resolution of Si Detector

X-ray Energies 1-10 KeV

Mid Energy K and L Spectra

Bi M and Cu Spectra

Common Interfering X-ray Lines

EDS Spectra of Glass

Wavelength Dispersive X-ray Detector

X-ray Detection

Gas Proportional Counter Single Channel Pulse HeightDetector

Detector Output

Wavelength Dispersive Spectra

Comparison of EDS and WDS

EDS Spectra of Glass

WDS Spectra of High Z Glass

Corrections to Measured X-ray Spectra

X-ray Generation with Depth (z)

Absorption of X-rays Through Specimen

Effect of Absorption on (z)