Electron microscopy

Electrons in a 300kV microscope have a wavelength close to…

• 5 nm

• 5 Å

• 50 pm

• 5 pm

Which of these is NOT an electron source

• Tungsten filament

• LaB6 crystal

• Tungsten needle

• Piezoelectric crystal

Electromagnetic lenses focus electrons due to the Lorentz force, which is given by

• F = q(E + vxB)

• F = v(qExB)

• F = qV + ExB

• F = vxE + qB

The maximum resolution in electron microscopes is limited by

• Aberrations

• Diffraction

• Tip radius

• Electron size

Which SEM image comes from SE/BSE electron detectors?

• Left: SE

  Right: BSE

• Left: BSE

  Right: SE

Which is SEM and which is TEM?

• Top: TEM

  Bottom: SEM

• Top: SEM

  Bottom: TEM

Which of these is NOT a source of contrast in the TEM?

• Bragg scattering

• Back scattered electrons

• Rutherford scattering

• Phase contrast