Free-electron maser based on a cavity with two- and one-dimensional distributed feedback

Abstract

The study of a coaxial free-electron maser (FEM) based on two-dimensional (2D) and one-dimensional (1D) distributed feedback, driven by a 70mm diameter, annular electron beam is presented. A new cavity formed with 2D and 1D periodic lattices, positioned at the input and output of the interaction region, respectively, was used. It has been demonstrated that 2D distributed feedback in the input mirror allowed 8mm radiation emitted from different parts of the electron beam to be synchronized. The FEM operating in the 35.9–38.9GHz frequency region generated 65MW, 150ns duration millimeter wave pulses which contained ∼10J of energy in the pulse.