The Sagnac experiment with X-radiation

The history and physical prerequisites for the realization of the Sagnac experiment, that is of the 'vortex optical effect' in the frame of a rotating interferometer, are considered. General relativity is used to develop the theory of propagation for electromagnetic waves in a noninertially moving material medium. The theoretical analysis of the peculiarities of the X-ray and gamma-radiation diffractions has been performed within the system of the three-mirror monoblock crystalline interferometer and resonator, while taking into account their rotations. Experimental studies of the X-ray 'vortex optical effect' were performed on a specially designed autonomous X-ray apparatus (commonly used for X-ray interference investigations), which was put on the rotating platform. A series of fluctuation effects (the temperature drift, the field of random deformations, etc.), which keep the Sagnac experiment out of reach of the limiting accuracy, have been revealed and investigated. The experimental data, obtained in the investigation of the 'vortex optical effect', are compared with the results of the theoretical analysis.