Photon intensity and polarization of channeling radiation emitted by 56 MeV positrons in a silicon single crystal

The channeling radiation and its polarization emitted by 56 MeV positrons in a Si crystal have been studied by computer simulation. The photon spectrum of the (111) planar channeling was found to have two peaks which correspond to the wide (111) channel and the narrow (111) channel of an Si crystal with the diamond structure, respectively. The photon spectrum of the [110] axial channeling has three peaks. The first peak is the superposition of the (100), (110), and (111) planar channeling radiations, the second peak corresponds to the narrow (111) planar channeling, and the third peak is due to the radiation from the [110] axial channeling. (orig.)