The amplitude and phase control of the ALS storage ring RF system

A 500 MHz, 300 kW klystron power amplifier provides RF power to the ALS storage ring. In order to accommodate the amplitude and phase changes during beam stacking and decay, which demand continuously varying power levels from the klystron, four loops are used to keep the system operating properly, with two of those loops dedicated to keeping the two cavity tuners on tune. Description of the control loops and their performance data will be given. Using the modulation anode of the klystron in the amplitude loop will be discussed.