Principles and design of Laue-case X-Ray interferometers
A theory of the interference mechanism in the Laue case interferometer is presented. Owing to the strong Borrmann effect a straightforward plane wave approach yields complete agreement with observed fringe patterns. The problem of coherence is discussed in some detail. It is shown that the geometrical precision of actual interferometers does not have to be better than 1 to 10 micron. The theory demonstrates that the “ideal” geometry can also be obtained with the transmission mirrors in different planes, allowing the construction of a modified interferometer with especially long and separated beam paths. This type is particularly suitable for practical interferometry.