The idea of using a crystal lattice or a superlattice as an undulator for a free electron laser is explored. A purely classical treatment of relativistic positrons channeling through the proposed structure is performed in a self-consistent fashion involving the wave equation for the radiating electromagnetic field and the kinetic equation for the positron distribution function. The gain coefficient for a forward radiating field is obtained in closed analytical form and is studied numerically for a (110) planar channeling in Si. This result, combined with a feedback mechanism arising from Bragg diffraction within the basic crystal lattice, may lead to an instability of the radiation inside the crystal.
ASJC Scopus subject areas
- Nuclear and High Energy Physics