Energy-Spread Feedback System for the KEKB Injector Linac

Some feedback loops are needed to perform the stable beam operation in the long term. The beam orbit and energy feedback loops are widely used for the linac beam operations of many facilities. In addition, the beam energy spread control is also effective for the stable beam operation. In order to realize the energy-spread feedback, the non-destructive beam-energy-spread monitor (ESM) has been developed for the KEKB injector linac. This monitor is an ordinary strip-line type beam monitor with eight electrodes instead of four electrodes. Three EMSs have been installed in the KEKB injector linac for a regular energy-spread measurement. One of them is used for the energy-spread feedback operation. This system works well. In this paper, we will present the energy-spread feedback system for the KEKB injector linac in detail.