Title screen

[Ref. : p. 274-275 (39 tit.)]

A simple model for calculating the contribution of diffraction of actual photons to the measured spectrum of parametric x radiation (PXR) from relativistic electrons in mosaic crystals is suggested. It is shown that the diffraction of real photons of bremsstrahlung and transition radiation in mosaic crystals whose thickness t is about 0.01 of the radiation length makes a significant contribution to the measurable emission spectrum. The spectra and angular distributions of PXR from electrons with energies 500 and 900 MeV have been measured in mosaic pyrolytic graphite crystals. It is demonstrated that with consideration of diffraction of actual photons in the mosaic crystal, including diffraction of PXR photons, all experimental data presently available agree well with the results of calculations for the suggested model.