The wavelength of X-rays is similar to the distance between the atomic planes inside the crystal, and the crystal can serve as a spatial diffraction grating for X-rays. When a beam of X-rays is irradiated on an object, it is scattered by the atoms in the object, and each atom produces scattered waves that interfere with each other, resulting in diffraction. The superposition of diffraction waves results in an increase in the intensity of the rays in certain directions and a decrease in other directions. By analyzing the diffraction results, the crystal structure can be obtained. The above is an important scientific foresight proposed by German physicist M. von Laue in 1912