RF system for high beam intensity acceleration in the CERN PS

Heavy beam loading is encountered in the main RF system of the CERN Proton Synchrotron (PS). This consists of 11 ferrite loaded cavities, each one capable of developing 20 kVp between 2.6 and 10 MHz. Harmonic 20 is normally used for acceleration, and feedforward compensation has been used in the past to suppress beam loading instabilities. This technique could not satisfy the stringent requirements of the antiproton production beam for the Antiproton Collector. RF feedback around the final amplifier and the cavity has been implemented. All power amplifiers have been rebuilt, adding amplification stages and auxiliary equipment, but keeping the same high-power tetrode to drive the cavity (RS 1084 with 80-kW plate dissipation). The installation was completed in February 1988, and many different types of beams have been successfully handled since, including a record intensity of 2.34 e13 protons per pulse