Generation of hard quanta in the cross-grooved resonator of a free electron laser

A new approach to the generation of powerful tunable hard radiation in the cross-grooved resonator (CGR) of a free electron laser is proposed and discussed. Gamma quanta are generated upon backward Compton scattering of intracavity radiation by the electron beam of a free electron laser with a CGR. The use of a CGR considerably increases the power of intracavity radiation, and hence the power of gamma radiation, and also solves the problem of extraction of hard radiation by eliminating the losses in the depth of the cavity mirror, which were inevitable earlier.