RF drivers for the Bevalac injector final stage RF amplifiers

A 200-MHz intermediate power amplifier system, comprising of four separate chassis or cavity amplifiers is being developed as a driver stage for the Bevalac injector final RF amplifiers. The initial stage is a 200-W, solid-state, RF amplifier with 44 dB of gain. The two succeeding stages are cavity amplifiers that incorporate vacuum tubes. The first of the tube-type amplifiers is driven by the 200-W amplifier and contains a 3CPX800A7 triode calculated to output a maximum of 5 kW. The next stage, driven by the 5-kW amplifier, contains a 4CW25000B tetrode and is designed to drive the final amplifier. The 4CW25K stage is calculated to provide a maximum output power of 50 kW. The final stage is designed to operate with either a Varian 4CW100000e or a TH535 manufactured by Thomson-CSF. The final stage gain, using the 4CW100Ke, is calculated to be 13 dB at approximately 300-kW output. Using the Thomson tube, the stage gain is calculated to be slightly greater; however, the maximum achievable RF output power is approximately 300 kW. The system construction, design, and initial high power test results are presented.<>