Techniques for transparent lattice measurement and correction

8th International Particle Accelerator Conference

Cheng, Weixing^1 ; Li, Yongjun^1 ; Ha, Kiman^1

NSLS-II, Brookhaven National Laboratory, Upton

NY

11973, United States^1

关键词: Bunch-by-bunch feedback systems;    Dynamical lattices;    High currents;    Insertion device;    Phase advance;    Position data;    Short periods;    Transparent lattices;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/874/1/012082/pdf
DOI  :  10.1088/1742-6596/874/1/012082

来源: IOP

【 摘 要 】

A novel method has been successfully demonstrated at NSLS-II to characterize the lattice parameters with gated BPM turn-by-turn (TbT) capability. This method can be used at high current operation. Conventional lattice characterization and tuning are carried out at low current in dedicated machine studies which include beam-based measurement/correction of orbit, tune, dispersion, beta-beat, phase advance, coupling etc. At the NSLS-II storage ring, we observed lattice drifting during beam accumulation in user operation. Coupling and lifetime change while insertion device (ID) gaps are moved. With the new method, dynamical lattice correction is possible to achieve reliable and productive operations. A bunch-by-bunch feedback system excites a small fraction (∼1%) of bunches and gated BPMs are aligned to see those bunch motions. The gated TbT position data are used to characterize the lattice hence correction can be applied. As there are ∼1% of total charges disturbed for a short period of time (several ms), this method is transparent to general user operation. We demonstrated the effectiveness of these tools during high current user operation.