Spectral and angular characteristics of parametric X-rays (PX) from diamond and silicon crystals with different thicknesses have been experimentally studied for 300–900 MeV electrons. Measurements were carried out for PX generation with Bragg, Laue and extremely asymmetric diffraction geometries. The influence of multiple scattering on the PX characteristics was investigated. Conditions of quantitative and qualitative agreement between experiment and theory were determined.

The development of new large accelerators arises a problem of the measurements of super-high energy beam parameters. One of the comparatively new physical effects, which can be used for solution of this problem is parametric X-rays (PX) generated by an ultra-relativistic particle passing in a single crystal with uniform velocity. Dependence of the PX intensity and angular distribution on the charged particle Lorenz factor is shown. The possibilities of the PX application for energy determination and identrfcation of the high energy particles and ions have been discussed.

Parametric X-ray radiation (PXR), caused by protons with an energy of 70 GeV in a silicon crystal, has been detected. Experimental values of the PXR quantum yield for two Bragg angles and its angular distribution have been determined and a comparison with the corresponding theoretically calculated values has been made.

A parametric x-ray emission caused by 70-GeV protons in a silicon crystal has been observed. Values of the quantum yield of this emission were found experimentally for two observation angles. The angular distribution of the emission was found. The results are compared with corresponding theoretical predictions.

The results of the first experiment on detection and investigation of parametric X-ray radiation of a GaAs monocrystal are given.