Detailed studies of the effect of electron beam optics on the gain characteristics of a rectangular grating backwards wave amplifier

Summary form only given. We are examining a low-voltage(<=10 kV), sheet-beam-compatible, grating backward wave amplifier for the Ku-band of frequencies. The linear gain vs, beam energy and the corresponding current density variation is studied, The GRAting AMPlifier(GRAMP) code is used to obtain the theoretical gain. We explain certain experimental gain observations which differ from the conventional theoretical model, These effects include the asymmetry of the absorption and gain portions of the beam energy scan as well as the narrowing of the gain tuning curve. The experimental configuration and results are analyzed and extensions are made to the theoretical model. The special features can be explained in terms of beam optics effects which include beam energy spread, alignment with waveguide axis and waveguide entrance conditions. The results of these detailed analyses will be presented and discussed.