Brief history of the powder diffraction method

The x-ray powder diffraction method dates back to Debye and Scherrer who were the first to observe diffraction from LiF powder and succeeded in solving its crystal structure. Later, HulF suggested and Hanawalt, Rinn and FreveP formalized the approach enabling one to identify crystalline substances based on their powder diffraction patterns. Since that time the powder diffraction method has enjoyed enormous respect in both academia and industry as a technique that allows one to readily identify the substance both in a pure form and in a mixture in addition to its ability to provide information about the crystal structure (or the absence of crystallinity) of an unknown powder. 

From the locations of Debye rings on the film plus their varying intensity (degree of darkening), it is possible to identify the material and to establish its crystal structure. Given the analogue nature of the film, it is nearly as easy to grasp the overall structure of the diffraction pattern, as it is 

Scherrer, Interferenzen an regellos orientierten Teilchen in Rontgenlight, Phys. Z. 17, 277(1916). 

Despite the undeniable historical significance, x-ray film data are seldom employed today in a practical powder diffraction analysis, and in this book we will only be concerned with electronic powder diffi actometry. An interested reader is referred to several excellent texts which are dedicated to the analysis of film data, for example those written by Azaroff and Buerger, Lipson and Steeple, Klug and Alexander, and Cullity.  

The last few decades of the 20 century transformed the powder diffraction experiment from a technique familiar to a few into one of the most broadly practicable analytical diffraction experiments, particularly because of the availability of a much greater variety of sources of radiation -sealed and rotating anode x-ray tubes were supplemented by intense neutron and brilliant synchrotron radiation sources. Without a doubt, the accessibility of both neutron and synchrotron radiation sources started a revolution in powder diffraction, especially with respect to previously unimaginable kinds of information that can be extracted from a one-dimensional projection of the three-dimensional reciprocal lattice of a crystal. Yet powder diffraction fundamentals remain the same, no matter what is the brilliancy of the source of particles or x-ray photons employed to produce diffraction peaks, and how basic or how advanced is the method used to record the powder diffraction data. 

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