Radiation of the atomic chains exited by a channeling particle
  Basic properties of radiation of the atomic chains excited by a channeling particle are considered. Using a very simple two-dimensional model of a crystal lattice we have shown that the main part of this radiation is generated on the frequency of oscillations of a channeling particle between the crystal planes, shifted by the Doppler effect. Angular distribution of the radiation of the chain of oscillating atoms is sharply peaked in the direction of the velocity of channeling particle because of coherence of the fields, produced by individual atoms. 
V. Epp and M. A. Sosedova
physics.acc-ph