Experimental investigation of beam instabilities in BEPCII

With the high current physical operations of the upgraded Beijing Electron–Positron Collider (BEPCII), thresholds on collision luminosity and beam current have been presented due to various factors such as collision background, noise, equipment stability under high power operation, and so on. One of the most serious influences on beam dynamics was beam instability which has been clearly exhibited. The comprehensive experimental investigation of beam instabilities in BEPCII is an indispensable part of beam physics research and can provide references for the upgrade project of BEPCII. Over the past two years, the experimental investigation of beam instabilities in BEPCII has been carried on with the single and multiple bunch filling in the storage ring. With the optimization of the bunch-bunch feedback system, the designed collision luminosity , 1.0x10^33cm^-2s^-1 was achieved during the physical operation and the primary process on configuration of Feedback system will be introduced. For comprehensive understanding the feedback system, a physical model is developed and analysis is conducted to demonstrate the relationship between feedback capability and various parameters. This comprehensive physical model and analysis of the practical feedback system may provide valuable insights into the optimization of the feedback system.