A new resonator design for Smith-Purcell free electron lasers

Summary form only given. A Smith-Purcell free electron laser test-facility has been developed. The structure is used to conduct detailed explorations of effects of resonator design on tunability, start current and other performance criteria. Initial emphasis is on sources which operate at millimeter wavelengths and utilize moderate energy electron beams. The Smith-Purcell radiation is produced by passing a 3-15 kV, submillimeter diameter electron beam over a metal grating with a rectangular profile. Radiation is produced at 35-40 GHz, 75 GHz and 95-100 GHz using different gratings.