A proof-of-principle experiment has been designed to examine harmonic operation of the ubitron/free electron laser (FEL) interaction
mechanism in an amplifier configuration at low voltages. Harmonics are a key in reducing the high voltage requirements of ubitrons.
The configuration of the experiment consists of a 250kV/100A electron gun, an input transition from single mode to overmoded
waveguide, a linear wiggler, mode selective output couplers, and a calorimeter/water load.The experiment has been assembled and
initial operation is underway. Details of the final experimental design are presented along with results to date on propagation of the
electron beam through the meter long linear wiggler.
R. H. Jackson, R. H. Jackson,
"Harmonic ubitron amplifier experiment", Proc. SPIE 1514, 15th International Conference on Infrared and Millimeter Waves, 15140M (1 December 1990); doi: 10.1117/12.2301432; https://doi.org/10.1117/12.2301432