Intensive coherent X-rays from multilayer mirrors

The results of experiment on further investigations of coherent X-ray emission produced by relativistic electrons passing through the periodic multilayer nanostructures well-known in X-ray optic as X-ray mirrors. Recently, we observed this new effect in the experiment carried out at the Tomsk "Sirius" synchrotron and found that a X-ray mirror might be used as a novel radiator for generation of monochromatic and narrow directed X-rays emitting at the large (Bragg) angle θ₀=1.9° with respect to the mirror surface and at the angle θ_D=3.8° with respect to the electron beam direction. In this work we present the vertical spatial distributions and orientational dependencies of the spectra of this type of radiation. The results were also obtained at the Tomsk synchrotron with 500 MeV electrons and with two mirrors having the uniform and cluster graded periods. Both the spatial distributions and rocking-curves of radiation yield show the peaks having the narrow minima in the centre of the dependencies. The form and parameters of the dependencies allow to discus the mechanism of the novel effect