Measurements of electron-RF interactions and noise in a low frequency crossed-field amplifier

A low-frequency (100 to 200 MHz), low-power crossed-field amplifier has been constructed for studying nonlinear RF-wave-electron interactions, for investigating noise mechanisms, and for verifying numerical simulations by using in situ diagnostics during amplification. Operating in the injected-beam mode, the device has achieved gain as high as 7 dB at 150 MHz with a 10 W drive. Measurements of the local RF field in two dimensions show gain in the local field at the output end of the circuit. Measurements of the electron density profile verify the predicted cycloidal beam pattern, and measurements during amplification show local electron density increases near the anode. Measurements of the noise using an RF probe indicate noise generation during secondary electron emission from the sole.<>