CERN Accelerating science

Internal Note
Report number	CERN-ACC-NOTE-2022-0078
Title	Amplitude Detuning from Nonlinear-Corrector- and Triplet-Misalignments at flat-orbit in the LHC and HL-LHC
Author(s)	Dilly, Joschua Werner (CERN) ; Maclean, Ewen Hamish (CERN) ; Tomas Garcia, Rogelio (CERN)
Corporate author(s)	CERN. Geneva. ATS Department
Publication	2022
Imprint	04 Nov 2022
Subject category	Accelerators and Storage Rings
Accelerator/Facility, Experiment	CERN LHC
Keywords	amplitude detuning ; LHC ; HL-LHC ; misalignment ; nonlinear ; correctors ; triplets ; feed-down
Abstract	Feed-down effects from high-order magnetic fields can have a detrimental impact on beam stability and lifetime in the LHC. Due to the strong magnetic fields and the very large β-functions in the insertion regions close to the interaction points, feed-down effects are enhanced in these areas of the LHC collider and the upcoming HL-LHC upgrade. It was thus of interest, to investigate the feed- down to amplitude detuning upon misalignment of the nonlinear-correctors and triplets, located in the aforementioned regions. These studies were conducted via simulations for top-energy optics for the current LHC and future HL-LHC machine configurations and the results are presented within this report. It was found that while an increase in detuning could indeed be found, the observed magnitude is within the range of tolerability for machine operation and well below the contributions to feed-down from other sources present.
Submitted by	[email protected]