Report number
| CERN-ACC-2019-0029 |
Title
| Detailed review of the LHC optics commissioning for the nonlinear era |
Author(s)
|
Maclean, Ewen Hamish (University of Malta (MT)) ; Tomas Garcia, Rogelio (CERN) ; Carlier, Felix Simon (Technische Universiteit Delft (NL)) ; Coello De Portugal - Martinez Vazquez, Jaime Maria (Universitat Politecnica Catalunya (ES)) ; Fol, Elena (Johann-Wolfgang-Goethe Univ. (DE)) ; Fuchsberger, Kajetan (CERN) ; Garcia-Tabares Valdivieso, Ana (Universidad Complutense (ES)) ; Giovannozzi, Massimo (CERN) ; Hofer, Michael (Vienna University of Technology (AT)) ; Malina, Lukas (CERN) ; Persson, Tobias Hakan Bjorn (CERN) ; Skowronski, Piotr Krzysztof (CERN) ; Solfaroli Camillocci, Matteo (CERN) ; Wegscheider, Andreas (Hamburg University (DE)) Show all 14 authors |
Publication
| 2019 |
Imprint
| 04 Feb 2019 |
Number of pages
| mult. |
Subject category
| Accelerators and Storage Rings |
Accelerator/Facility, Experiment
| CERN LHC |
Abstract
| In 2017, optics commissioning strategy for low-β∗ operation of the CERN Large Hadron Collider (LHC) underwent a major revision. This was prompted by a need to extend the scope of beam-based commissioning at high-energy, beyond the exclusively linear realm considered previously, and into the nonlinear regime. It also stemmed from a recognition that, due to operation with crossing angles in the experimental insertions, the linear and nonlinear optics quality were intrinsically linked through potentially significant feed-down at these locations. Following the usual linear optics commissioning therefore, corrections for (normal and skew) sextupole and (normal and skew) octupole errors in the high-luminosity insertions were implemented. For the first time, the LHC now operates at top-energy with beam-based corrections for nonlinear dynamics, and for the effect of the crossing-scheme on beta-beating and dispersion. The new commissioning procedure has improved the control of various linear and nonlinear characteristics of the LHC, yielding clear operational benefits. This report gives a detailed account of the beam-based measurements carried out during the experimental campaigns. |
Submitted by
| alessia.valenza@cern.ch |