Study of deformation fields as a function of the temperature gradient in the mirror block of an interferometer

The formation of moiré fringes in an X-ray interferometer is studied. It is shown experimentally that the well-known expression for calculating the period of moiré pattern cannot be always used to calculate the period of moire patterns obtained in an X-ray interferometer. The change in the moiré period caused by the temperature gradient in the crystal block of an interferometer is calculated.