The AGS Conversion Radio Frequency Power Amplifier

Abstract

To double the rate of particle energy gain per unit time, to offset heavier beam loading and to remove the electronic components to a radiation-free area, the AGS radio frequency acceleration system must be redesigned and rebuilt. The new system will be capable of delivering a total of 1440 kW RF power into 12 pairs of 50-ohm coaxial transmission lines 1100 feet long, terminating at 12 accelerating stations. Voltage amplitude and phase responses are closely controlled over a working frequency range of 1.4 - 4.5 MHz. The AGS conversion radio frequency power amplifier is composed of twelve final power amplifier stages, driven in groups of six by two paralleled drivers. These latter units are in turn driven by a cascade of lower level predriver stages. The final and driver stages are identical push-pull wideband ferrite transformer coupled grounded grid triode circuits housed in separate enclosures, each with its necessary control and safety system. The predriver is a four stage push-pull amplifier cascade with grounded grid triodes and grounded cathode tetrodes and pentodes, initially excited by a fractional voltage input signal of the proper frequency and phase. The anticipated successful performance of the system is attributable to the stable push-pull grounded grid amplifier configuration, to the carefully selected power tube complement and to the specially designed ferrite core interstage and output transformers and their associated networks.