Evolution of the RF Systfem of the CPS Booster Since the Beginning of Its Operation

Since the first beams were accelerated in 1972, the RF system has performed very satisfactorily. In particular, the simple air-cooled design of the cavity and final amplifier has proved to be very trouble free in operation. As the bean intensities gradually reached and then exceeded the design value of 2.5 × 1012 protons per ring, a number of improvements were introduced to cope with the increased beam loading and to permit the special beam gymnastics that have been found useful at the highest intensities. Modifications include: i) provision for reducing the Q of the cavity during trapping; ii) an improved system for synchronizing the four rings prior to ejection; iii) measures taken to control longitudinal instabilities; iv) safety precautions to protect the cavity and amplifier against transients.