Electron Microscopy Flashcards
Compare light and electron microscopes
What is the Rayleigh criteria
What is the relationship between the resolution limit and wavelength
What is meant by resolution
What are the properties of electrons
What could happen when an electron encounters an atom
What different sources can be used in an electron microscope
Thermionic emission source
Field emission gun
Electrons emitted by source
What is a thermionic source
What is a field emission gun
What does the electromagnetic lens do in an electron microscope
What three types of lenses are there in an electron microscope
What are apertures
How were images recorded in the past
What is a charged coupled device
What is a direct electron detector
Label the different parts of an electron microscope
How is an image generated in electron microscopy (EM)
What are the 2 types of contrast
Amplitude contrast
Phase contrast
Due to electron wave-particle duality
What is amplitude contrast
What are the 3 factors that contribute to amplitude contrast
What is phase contrast
How does a complex wave propagate
Why is the amplitude of the scattered complex waves small
What happens when the scattered and in scattered waves encounter the objective lens of an EM
What are the threes ways in which the small amplitude of the scattered wave can contribute to the unscattered wave
Maximally in the opposite direction of the unscattered wave
Minimally to the unscattered wave
Maximally in the same direction of the scattered wave
How can the small amplitude of the scattered wave can contribute to the unscattered wave maximally in the opposite direction
(Detector sees sum of scattered and unscattered wave)
How can the small amplitude of the scattered wave can contribute to the unscattered wave minimally to the scattered wave (edit)
How can the small amplitude of the scattered wave can contribute to the unscattered wave maximally in the same direction