Abstract
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.
Highlights
The performance optimisation of the Large Hadron Collider (LHC) relies on a careful tuning of a number of operational parameters, balancing many conflicting constraints
Optics, bunch intensity, crossing angle, emittance, chromaticity and current in the Landau octupoles, they all play a role in the maximisation of the luminosity, the mitigation of non-burnoff losses and the prevention of beam instabilities
The duration of the LHC cycle, which typically extends up to several hours, together with a number of constraints from machine protection, does not allow to probe such a vast parameter space in an experimental manner. It is essential levering on detailed computer simulations aimed at identifying the possible steps for improvements, to be validated in Machine Development sessions or directly applied to the machine
Summary
The performance optimisation of the Large Hadron Collider (LHC) relies on a careful tuning of a number of operational parameters, balancing many conflicting constraints. The duration of the LHC cycle, which typically extends up to several hours, together with a number of constraints from machine protection, does not allow to probe such a vast parameter space in an experimental manner. It is essential levering on detailed computer simulations aimed at identifying the possible steps for improvements, to be validated in Machine Development sessions or directly applied to the machine. The 2016 run of the LHC has been closely followed up by means of dynamic aperture (DA) investigations These studies helped to steer performance of the collider towards the reach of the design luminosity and beyond. The studies focussed on Beam 1, which has shown the weakest lifetime all along the run
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call