This wavelength can be measured in terms of inter-atomic spacing using a crystal diffraction pattern, and related to the metre through an optical measurement of the lattice spacing on the same crystal.
12.
When the scattered radiation is collected on a flat plate detector, the rotational averaging leads to smooth diffraction rings around the beam axis, rather than the discrete Laue spots observed in single crystal diffraction.
13.
At a conference in celebration of von Laue s 80th birthday in 1959, Wagenfeld met a great pioneer in the field of crystal diffraction, Prof . Paul Peter Ewald, Head of the Physics Department at Brooklyn Polytechnic in New York City.
