Multiparametric response of the LHC Dynamic Aperture in presence of beam-beam effects

8th International Particle Accelerator Conference

Pellegrini, D.^1 ; Antoniou, F.^1 ; Fartoukh, S.^1 ; Iadarola, G.^1 ; Papaphilippou, Y.^1

CERN, Geneva, Switzerland^1

关键词: Crossing angles;    Dynamic aperture;    Emittances;    Octupoles;    Operational scenario;    Operational space;    Strong approximation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/874/1/012006/pdf
DOI  :  10.1088/1742-6596/874/1/012006

来源: IOP

【 摘 要 】

We performed extended simulations of LHC dynamic aperture (DA) in the presence of beam-beam effects in the weak-strong approximation, evaluating the contributions of parameters such as: tunes, optics, bunch intensity, crossing angle, emittance, chromaticity and current in the Landau octupoles. Here we present a summary of these studies, giving an overview of the amplitude of the LHC operational space and pointing out the remaining margins for mitigation of instabilities. These studies supported the actions deployed during the 2016 run of the LHC, which aimed at maximising its performances. Examples of such actions are the switch to lower emittance beams, the reduction of crossing angle and tune trims. More recently, DA scans have been used to help the definition of the operational scenarios for the 2017 run. Additional room for improvements, for instance by deploying crossing angle levelling, will be explained.