Design for RF phasing system of BEPCⅡ injector

RF phasing system of BEPCⅡ Injector is required to reach the precision of ±2° at the frequency of 2.856GHz. Based on the analysis of elements that affect RF phase for accelerating particles, a general design for this system is presented in this paper, which gives the system structures and its control strategy, reduces the system requirement of ±2° into the feasible parameters of key instruments, and explains even its RF phase measurement. Considering the characteristics of electromagnetic environment of BEPCⅡ injector, as many as possible optic devices and digital measurement technique are introduced to improve the EMC performance of the system.