Microwave transport system for the MTX

The design and construction, as well as the initial operation, of the Microwave Transmission System is presented. The system consists of containment vessels, mirror boxes, mirrors, an alignment system, two turbomolecular pump vacuum stations, and a microwave source. Pulses of 50-ns-length and of 6-MeV electrons pass through a free electron laser (FEL) wiggler. A 300-W, 140-GHz extended interaction oscillator (EIO) supplies the seed signal for amplification in the wiggler. The electron beam is dumped and the microwave beam is quasi-optically transmitted 90 ft by six aluminum mirrors through an evacuated tube. Three of the mirrors are elliptical paraboloids and the others are flat. A seventh mirror is rotated into the microwave beam to divert it into a load tank. The transport vacuum vessel is a 20-in-diameter stainless steel tube with bellows and mirror boxes at each mirror. Two vacuums systems at each end of the transport tube allow a base pressure of 10^-7 torr to be attained by 7000 L/s of turbomolecular pumping. At each mirror, at the MTX vessel, and at the two ends of the wiggler waveguide are He-Ne laser detectors used for vacuum alignment. The major components, their requirements, system requirements, and the initial operation of the system and its performance are described