Status of the SPring-8 linac

In FY2008, the total operation time of SPring-8 injector linac was 5150 hours. The total downtime was 0.21% (The frequency of fault was 0.33 times per day) and as the stable as the last few years. In the first cycle, the electron gun modulator broke down due to an electric discharge in the PFN condenser. And the gun cathode heater power supply and grid bias power supply broke down in the 1st and 2nd cycle. A twin electron gun system was constructed to eliminate long-time interruption of the beam injections caused by electron gun's accidents. The thyratron stands were replaced with new ones which were designed to enhance their maintainability and reliability. These improvements have finally reduced the total fault rate of the modulators to 0.06 events per day. (author)