Planar channeling radiation by relativistic electrons in different structures of silicon carbide

Spectral distributions of channeling radiation by relativistic electrons channeled in different crystallographic planes of different types of polytype silicon carbide crystals such as hexagonal, zincblende and rhombohedral are presented. For every structure we have found the planes where the emission of channeling radiation is possible. Using the Doyle-Turner approximation to the atomic scattering factor and taking in to account thermal vibrations of crystal atoms, the continuum potentials for different planes in different structures of a SiC single crystal have been calculated. In the framework of quantum mechanics, the theory of channeling radiation was applied to calculate transverse electron states, transition energies, radiation linewidths, the depth dependence of the occupation of quantum states and spectral-angular distributions of channeling radiation. At electron energies larger than 100 MeV, the trajectories, velocities and accelerations of channeled electrons have been obtained by means of classical mechanics, and the spectral-angular distributions were calculated by means of classical electrodynamics using realistic trajectories, velocities and accelerations of channeled electrons. Specific properties of planar channeling radiation generated in different structures of SiC are discussed.