The KEKB injector linac

The KEKB injector linac has been continuously improved to enhance the stability of many devices and the efficiency of beam operation. These improvements include the development of the new C-band accelerating structure, pulse compressor, klystron, rf window, compact modulator, and the new positron production target using crystalline tungsten. We have also achieved two-bunch beam acceleration, the development of an energy spread monitor, a safety system upgrade, and an event-based timing and control system. These developments and practical applications for advanced linac beam handling result in the success of the simultaneous top-up injection among the three independent storage rings. This result greatly improves the integrated luminosity and the operation stability of the KEKB rings. In this paper, we present the progress of the KEKB injector linac in this decade. (author)