Present state and prospects of using monocrystals at relativistic particle accelerators

The present state and prospects of producing quasimonochromatic linearly-polarized high-energy photon beams in electron-positron interactions with monocrystals are described. Experiments performed on the Kharkov linear accelerator showed a sharp decrease in the positron radiation intensity as compared with electron intensity depending on the silicon crystal orientation. Data about the effect of the positrons and electrons moving parallel to the silicon monocrystal axis proved that an increase in thermal variations of lattice atoms results in a still greater suppression of positron radiation and in a rise in radiation of electrons. The intensity of channeling positron radiation in the range of photon energies from 0.3 to 0.8 MeV exceeds the radiation intensity in a disoriented crystal. Experiments on 1 GeV positrons showed a decrease in multiple scattering. It is shown that in devising accelerating structures the monocrystals can be used to produce beams with a limiting current density and to form high-energy beams