The Resnatron as a 200-MC Power Amplifier

Tetrode amplifiers (resnatrons) used to power the Minnesota Linear Proton Accelerator are described. These demountable tubes are continuously pumped, grid pulsed 202-mc amplifiers capable of a peak power output of 3.5 megw during 300-μsec pulses with two per cent duty cycle. A transconductance of 0.12 mho and power gains of 10 have been observed. Reliability has been surprisingly good. Life limitation is due to crystallization of the pure tungsten filaments. The average time between pull-downs because of filament trouble varies from 700 to 1140 hours of operation. The lower life corresponds to higher power service conditions.