Experimental 8-MM Klystron Power Amplifiers

Experimental klystron amplifiers, which were used to investigate the cw power obtainable at a wavelength of 8 mm, are described. Working at 5000 volts with a beam current of 0.2 a, these tubes produced an output power of 75 watts cw. Operation was limited by the maximum current density of 1.5 a/cm2 which could be drawn from sprayed-oxide cathodes.