X-ray dynamical diffraction wavefront division interferometer (double-slit diffraction) with an asymmetric monochromator. Corrigendum

An error in the article by Mkrtchyan et al. [Acta Cryst. (2025), A81, 438–448] is corrected.

In the paper by Mkrtchyan et al. (2025) after formula (42) of Appendix B the statement is true for all wavelengths only when the reflections in the monochromator and the interferometer crystal are the same. Otherwise is true only for a selected wavelength and will be violated for other wavelengths. Thus, throughout the paper the case of the same reflections in the monochromator and the interferometer crystal must be considered. Accordingly, Figs. 4(a) and 4(b) must be presented for the same Si(440), Mo Kα for both the monochromator and interferometer crystals instead of Si(440), Mo Kα in the monochromator and Si(220), Mo Kα in the interferometer crystal. The parameters are the same as in Section 7.2 of Mkrtchyan et al. (2025), but the source-to-monochromator distance is taken to be L_s = 1 m and the thickness of the interferometer crystal is z = 3 mm, the calculated period of the fringes will be 0.594 mm. Figs. 1(a) and 1(b) in this corrigendum replace Figs. 4(a) and 4(b) of Mkrtchyan et al. (2025).

Figure 1 Intensity distribution in a Si(440) Mo Kα reflection wavefront division interferometer using a Si(440) asymmetrical reflection monochromator, b = 0.026. (a) Interference fringes for the central point source with and . (b) Intensity distribution for an extended incoherent and non-monochromatic source. Interference fringes are observed.