OPERATING EXPERI ENCE WITH THE RF SYSTEM

At RIKEN RIB-factory (RIBF) an accelerator complex as an energy booster which consists of superconducting ring cyclotron (SRC), intermediate-stage ring cyclotron (IRC) and fixed-frequency ring cyclotron (FRC) provides very heavy ion beams like uranium with an energy of 345 MeV/u [1]. In December 2006, the SRC has become operational and it was succeeded to extract the first beam from SRC[2]. Since then, we have experienced various problems with the rf system for SRC and improvements have been made to achieve designed performance solving the problems one by one. This paper will discuss on our efforts to understand the source of troubles and improvements and modifications of the rf system.