Measurement of the temporal and spatial phase variations of a pulsed free electron laser amplifier

We report temporal and spatial phase measurements of a pulsed free electron laser amplifier (FEL) operating in combined wiggler and axial guide magnetic fields. The system uses a mildly relativistic electron beam (750 kV, 90-300 A, 30 ns), and is excited by a high power 33.39 GHz magnetron source. The phase during the voltage pulse is measured by an interferometric technique from which frequency chirping is determined.<
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