| Preprint | |
| 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)) |
| 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 | [email protected] |
Element opprettet 2019-02-04, sist endret 2019-02-06
