BEPCⅡ直线加速器束流能量反馈系统设计

Design of the Beam Energy Feedback System in BEPCⅡ Linac

为满足BEPCⅡ储存环对注入束流的要求,BEPCⅡ直线加速器末增设了束流能量反馈系统。该系统由束流能量在线测量单元,图形界面应用软件和相控执行单元构成。束流能量测量单元使用3个BPM对束流能量进行在线非阻拦式测量,测量结果实行人机交互与控制逻辑输出,相控执行单元使用消除回程差的控制方法。该系统束流中心能量调节频率为2 Hz,注入速率波动小于10m A/min,束流中心能量稳定度不大于±0.1%。

In order to meet the higher demands made by the BEPCII storage ring on the injection beam, the beam energy feedback system was added at the exit of the linac. The system consists of a beam energy measurement unit, a graphical interface application and an execution unit. The measurement unit makes the non- interceptive online beam energy measurement by using three BPMs; the measuring results are used for user interaction and the control algorithms ; the execution unit uses a control method eliminating the return difference of the phase shifter. This system can adjust the beam center energy with a rate of 2 Hz, make the peak to peak value of the injection rate fluctuation less than 10 mA/min and maintain the stability of the beam center energy within 0. 1%.