Electron Microscopy and Matter Waves

KEY CONCEPT: Resolution

Resolution is defined as the act, process, or capability of distinguishing between two separate, but adjacent objects or sources of light, or between two nearly equal wavelengths.

Resolving Power is the ability to make points or lines which are closely adjacent in an object distinguishable in an image.

Resolving Power of the Human Eye

What can we see?

How is Resolution Affected by Wavelength?

CORE TECHNOLOGY: The Electron Gun

• Three main sources of electrons:• Tungsten• LaB6 (lanthanum hexaboride)

• Field Emission Gun (FEG)

• Different costs and benefits of each

• Each selected primarily for their brightness

CORE TECHNOLOGY: Electromagnetic Lenses

electron beam

soft iron pole piece

electrical coil

CORE TECHNOLOGY: The Vacuum

• A vacuum is a region of reduced gas pressure.

• Electron microscopes use a vacuum to make electrons behave like light.

What is a Transmission Electron Microscope?

projector lens

electron source

condenser system

specimen (thin)

objective lens

Matter WavesMatter Waves

•Louis de Broglie•1892-1987