Figure 1. Simplified setup. (a) An electron beam passes through a wall with two
slits in it. A movable mask is positioned to block the electrons, only allowing
the ones traversing through slit 1 (P1), slit 2 (P2), or both (P12) to reach the
backstop and detector. (b), (c) Probability distributions are shown (experimental
in false-color intensity) for electrons that pass through a single slit (b), or the
double-slit (c). Inset 1, 2: electron micrographs of the double-slit and mask are
shown. The individual slits are 62 nm wide ×4μm tall with a 150 nm support
structure midway along its height, and separated by 272 nm. The mask is 4.5μm
wide ×20μm tall. Reprinted from The Feynman Lectures on Physics, vol III,
by Richard P Feyman, Robert B Leighton and Matthew Sands. Available from
Basic Books, an imprint of The Perseus Books Group. Copyright © 2011.