MEASUREMENTS OF MICROWAVE-POWER AND FREQUENCY IN A PULSED FREE-ELECTRON LASER-AMPLIFIER

We report output power and frequency measurements of a pulsed free ele ctron laser (FEL) operating as an amplifier at 35 GHz, without guiding field. The experiment used an induction linac, which delivers an 800- A relativistic electron beam (2.2 MeV) with a flat-top of 40 ns into t he helical wiggler, The input signal furnished by a 35-GHz magnetron s ource is amplified to power levels of the order of 80 MW, The experime ntal results are in good agreement with our simulations, Frequency chi rping is observed, and its behavior as a function of the basic FEL par ameters is discussed.