Lesson: Electron Diffraction and MicroscopyPhysics
In this lesson, we will learn how to describe electron beam diffraction, how it is used in electron microscopy, and how other forms of electron microscopy compare to it.
A rectangular section of an electrostatic lens in an electron microscope is shown in the diagram. The electric potential increases along the length of the lens; the potential is greater than the potential . An electron moves parallel to the axis of the lens. Which of the paths I, II, and III shown does the electron move along?
A beam of electrons passes through a crystal. A diffraction pattern of concentric rings is formed on a screen behind the crystal that records the positions of electrons that arrive at it, as shown in the diagram. The intensity of the rings is plotted against the radial distance from the center of the pattern. The resulting intensity distribution is shown three times, each time compared to another intensity distribution that is shown below it.
Which of the intensity distributions would result from decreasing the velocity of the electrons in the beam?
Which of the intensity distributions would result from decreasing the charge density of the electron beam while not changing the velocity of the electrons in the beam?
Which of the following correctly states the advantage of using electrons to produce images of very small objects compared to using electromagnetic waves?