Measurement of the coherence length of highly collimated X-rays from the visibility of equal-thickness fringes

The coherence length of highly collimated X-rays produced by a collimator system, using successive asymmetric reflections, has been determined for the first time from the visibility of equal-thickness fringes in the Laue geometry. Observed transverse and longitudinal components of the coherent length were more than 220 and 40 μm, respectively, at a wavelength of 0.70 Å.