ALS Booster Ring RF System Upgrade for Top-Off Mode of Operation

Advanced Light Source (ALS) is one of the first 3^rd-generation synchrotron light sources and it has been in operation at the Berkeley Lab since 1993. In the present ALS operation scenario, 1.5GeV electron beam is injected from the booster into the storage ring every 8 hours where it is accelerated to the final energy of 1.9GeV. The beam decays between fills from 400mA to 200mA with the time average current of 250mA. In order to increase beam brightness the ALS team plans to increase the beam current to 500mA and maintain it constant during machine operation (“Top-Off” mode of operation). This operation scenario will require full energy injection from the booster ring into the storage ring and constant operation of the injector (10 bunches with the total charge of 1nC every 30-35 second). In this paper we will present the results of the ALS injector RF system analysis for Top-Off mode of operation and describe the way we intend to implement the necessary modifications to the booster RF system.