Experimental investigation of a Cerenkov grating amplifier for implementation with a sheet electron beam

Summary form only given. A new facility to investigate the feasibility and physics of low-voltage sheet-beam Cerenkov amplifiers is described. While work progresses on the design of a suitable sheet beam source and periodic magnetic focusing system, initial experiments near 14 GHz will be conducted using a pencil beam from a 10-kV, 0.25 A Piece electron source matched into a 1-kG solenoid guide field. The interaction region consists of a uniform grating with adiabatic tapers at both ends for a good match between the TE/sub x10/ hybrid slow-wave mode and the TE/sub 10/ waveguide mode. Two prototype gratings, with periods of 0.035" and 0.070", have bee fabricated and tested. The magnet system has been constructed and tested at high current; a soft-iron magnetic shield and cathode trim coil have been designed for a smooth transition of the beam into the guide field; and EGUN simulations indicate that a thin (< 2mm dia.) high-quality electron beam will be available at the interaction region.