Research in coherent, free electron, millimeter-wave sources at the University of Wisconsin

Summary form only given. An experimental/theoretical research program is being established at the University of Wisconsin (UW) to study millimeter-wave, free-electron masers (FEMs). The program will concentrate on the investigation of devices using low-voltage (<100-kV), axially streaming, periodically focused electron beams and slow-wave structures. Topics of particular attention include efficiency optimization and average power handling enhancement in the above-mentioned devices. The use of sheet electron beams for increasing the power-handling capabilities of low-voltage FEMs is investigated. Dispersion relations and growth rates for dielectric liner and periodic gratings are evaluated. Nonlinear effects such as tapering, mode-competition, and beam space-charge-as well as beam quality-are quantitatively studied for their impact on efficiency optimization. Experimental research is conducted on a streaming beam experimental (SBX) facility, which is capable of operating in single-pulse (0.1-100-μs) burst, or CW mode and delivers beams of up to 50 kV and 2 A (with later upgrade to 75 kV)