Investigation of the Effect of Defocusing on the Interference Patterns Obtained Using Three-Block X-ray Interferometers

We present the results on the impact of defocusing on the interference patterns obtained using three-block X-ray interferometers. Three types of defocused interferometers are constructed, manufactured, and tested: without a thick analyzer block, with a thick analyzer block, and with a separate thick block (magnifier). Fine structures in the interference patterns obtained from the three-block defocused interferometers are observed in cases where the interferometer analyzer block is thick or a magnifier (fourth thick block) is applied. Theoretical calculations show that the presence of defocusing, resulting from the overlap of beams on the input surface of the interferometer analyzer, forms an interference pattern in the form of parallel stripes (lines) lying in the scattering plane. The coordinates of the maxima of the interference fringes (lines) and the period of the fringes are calculated in cases with and without a thick crystal and the magnification factor. Experimental evidence shows that a thick crystal (magnifying crystal) does not introduce new information into the interference pattern but only increases its dimensions in the scattering plane.