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Theory: Max von Laue; experiment: Walther Friedrich and Paul Knipping. Academy proceedings, pp. 303–322; presented 8 June 1912.

Max von Laue proposed crystal X-ray diffraction and wrote the theoretical section; Walther Friedrich and Paul Knipping performed the experiments.^[ref]

An X-ray tube, lead apertures and shielding supplied a narrow beam through a crystal on a goniometer. Photographic plates recorded the direct beam and separate spots. Copper(II) sulfate trials preceded oriented zinc blende. Optical alignment was checked with X-rays. Removing the crystal removed the extra spots; grinding destroyed their ordered arrangement; translation preserved it, while tilt changed it. Rotation about the beam rotated the pattern.^[ref]

Spots and orientation dependence supported wave interference and three-dimensional crystal periodicity. They determined neither all atomic positions nor an absolute wavelength scale. The authors left open whether the selected radiation originated as crystal fluorescence or was already in the incident beam. This differs from the modern Laue method.^[ref]

The 1914 Nobel Prize in Physics went to Max von Laue; the discovery's experimental account remains jointly credited to Walther Friedrich and Paul Knipping.^[ref] The subsequent inference of particular crystal structures is developed under X-ray crystallography.

Max von Laue proposed using a crystal's periodic atomic arrangement to test the wave character of X-rays. Scattering from regularly spaced atoms can interfere constructively only in selected directions, producing a pattern tied to the lattice. The measurements by Walther Friedrich and Paul Knipping connected that idea with photographic evidence. The result simultaneously linked short-wavelength radiation with a wave description and made atomic crystal order accessible to diffraction measurements.^[ref]

A physicist.^[ref]

The Laue X-ray diffraction experiment of 1912 connects a periodic crystal structure to a pattern of diffracted X-rays. Its history links a proposed wave test to the measurements made by Walther Friedrich and Paul Knipping.

Walther Friedrich coauthored the experimental observation of X-ray diffraction by a crystal with Paul Knipping and Max von Laue. A beam transmitted through the sample produced separated spots on a photographic plate. Their geometry connected the periodic structure of the crystal with constructive interference of the scattered radiation. The apparatus turned a proposed wave test into an observable pattern, providing a method for investigating matter on atomic length scales.^[ref]

A physicist.^[ref]