Observation of coherent X-ray production by 800-MeV electrons in a periodic triple-crystal target

The production of coherent x radiation by 800-MeV electrons in a target consisting of three 16-μm silicon crystals is investigated at the Tomsk synchrotron. The target structure makes it possible to observe from each crystal in turn, as the target is rotated, the radiation due to the summation of parametric x radiation (PXR) and the diffracted resonance transition radiation (DRTR) produced at the surfaces of the preceding crystals. The orientational dependence obtained shows that the contribution of the DRTR increases with the number of the crystal in the series, so that the angular density of the DRTR from the third crystal is approximately 1.7 times higher than the density of the PXR. Pis’ma Zh. éksp. Teor. Fiz. 65, No. 8, 594–599 (25 April 1997)