Microwave production by a free-electron laser bunched beam driving a resonant cavity at 35 GHz

In the two-beam accelerator scheme, a high-current electron beam, bunched a t the resonant frequency, traverses extraction cavities, where it generates power intended to drive accelerating cavities on the main beam, Here, we r eport on work performed to test some aspects of this scheme. We used a free -electron-laser (FEL) amplifier at 35 GHz to bunch a beam of electrons, whi ch is then transported and focused into a resonant cavity. The results of e arlier bunching experiments had demonstrated the capacity of the FEL suppli ed by an induction linac to generate an appropriate drive beam, A summary o f this earlier work is presented along with measurements of power from the cavity. This constitutes the first observation of high-frequency power extr action using a FEL in this scheme.