Peculiarities of channelling radiation spectra from 100 to 800 MeV electrons and positrons in (1 1 1) Si crystal

By means of numerical calculations, the channelling radiation spectra from relativistic electrons and positrons have been studied in detail for channelling along (1 1 1) double planes in a Si crystal. The evolution of the shape of radiation spectrum is studied under an increase of particles energies from 100 to 800 MeV and a change of the angle of incidence with respect to (1 1 1) double planes. It is shown that the (1 1 1) channelling radiation spectra have much more complicated structure and radiation yield is several times greater compared to the channelling along (1 0 0) or (1 1 0) planes.