用于PKU-FEL注入器的腔式BPM的设计

摘要

A cavity beam position monitor (BPM) is designed for the injector of PKU-FEL Facility. The designed frequency of the dipole mode TM110 is 1.3 GHz, which is equal to the frequency of the main accelerator in PKU-FEL Facility. The cross-talk problem is solved by introducing two rectangular recesses into the cavity. The position resolution of the cavity BPM is about 10 μm, the dynamic range is more than 30 mm and the time response is bunch to bunch, which are sufficient for the PKU-FEL injector. Compared with the bunch power, the power dissipation of the main resonant modes excited by e-bunches can be neglected.%设计了用于PKU-FEL注入器的腔式位置诊断装置.该BPM腔采用的偶极模TM110模的频率与PKU-FEL主加速器的基模频率一致,都是1.3 GHz；通过在圆形腔上镶入两个完全一致的矩形腔解决了腔式BPM的Cross-Talk问题. 根据PKU-FEL的设计要求,所设计的BPM腔的最小位置响应约10 μm,动态范围大于30 mm,时间响应小于束团间距.还估算了该BPM腔引起的束团功率损耗.结果表明,BPM腔引起的束团功率损耗是可以忽略的.