Abstract
The LHC is currently operating with a proton energy of 4 TeV and ${\ensuremath{\beta}}^{*}$ functions at the ATLAS and CMS interaction points of 0.6 m. This is close to the design value at 7 TeV (${\ensuremath{\beta}}^{*}=0.55\text{ }\text{ }\mathrm{m}$) and represented a challenge for various aspects of the machine operation. In particular, a huge effort was put into the optics commissioning and an unprecedented peak $\ensuremath{\beta}$ beating of around 7% was achieved in a high energy hadron collider.
Highlights
High energy colliders have not traditionally required high precision control of their optics
An illustration of the achieved peak beating in various high energy colliders is shown in Table I as collected during the ‘‘Optics Measurements, Corrections and Modeling for High-Performance Storage Rings’’ workshop [1]
The record low beta beating is held by CESR, the smallest of these colliders with a 768 m circumference
Summary
High energy colliders have not traditionally required high precision control of their optics. The CERN LHC is the first high energy collider with tight design tolerances on optics errors to guarantee the machine protection during operation with beam. In August a beta squeeze down to à 1⁄4 1 m was successfully commissioned [18], apparently without requiring further optics corrections, precise à measurements were not performed. Between these two periods of different Ã, the luminosity imbalance between the ATLAS and CMS experiments increased from roughly 5% to 10% [19] (providing more luminosity for CMS).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callMore From: Physical Review Special Topics - Accelerators and Beams
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
