Optics Correction in the LHC

Optics correction in the LHC is challenged by the tight aperture constrains and the demand of a highly performing BPM system. To guarantee that the LHC optics remains within a maximum allowable beta-beating of 20% several methods are being investigated through computer simulations and experiments at existing hadron machines. A software package to consolidate the implementation of the various techniques during LHC operation is underway (or nearing completion)

Beta-Beating Corrections in the SPS as a Testbed for the LHC

For several years optics measurement and correction algorithms have been developed for the LHC. During 2008 these algorithms have been tested in the SPS and RHIC. The experimental results proving the readiness of the applications are presented

90 m optics commissioning

http://accelconf.web.cern.ch/AccelConf/IPAC2011/papers/tupz001.pdfInternational audienceSpecial β∗ = 90 m optics have been developed for the two very high luminosity insertions of the LHC [1] [2], as a rst step to allow for very low angle precision measure- ments of the proton-proton collisions in the LHC. These optics were developed to be compatible with the stan- dard LHC injection and ramp optics. The target value of β∗ = 90 m is reached by an un-squeeze from the injection β∗ = 11 m. We report about the implementation of this op- tics and the rst experience gained in commissioning with beam during two machine studies

90m Optics Studies and Operation in the LHC

ISBN 978-3-95450-115-1 - http://accelconf.web.cern.ch/AccelConf/IPAC2012/papers/moppc006.pdfInternational audienceA high β* = 90 m optics was commissioned and used for first very forward physics operation in the LHC in 2011. The experience gained from working with this optics in 5 studies and operation periods in 2011 was very positive. The target β* = 90 m was reached by a de-squeeze from the standard 11 m injection and ramp optics on the first attempt and collisions and first physics results obtained in the second study. The optics was measured and corrected with good precision. The running conditions were very clean and allowed for measurements with roman pots very close to the beam

First beta-beating measurement in the LHC

In 2008 beam successfully circulated in the LHC. Thanks to an excellent functioning of the beam position monitor (BPM) system and the related software, injection oscillations were recorded for the first 90 turns at all BPMs. The analysis of these data gives the unique opportunity of evaluating the periodic optics and inferring possible error sources

First β-beating measurement and optics analysis for the CERN Large Hadron Collider

Proton beams were successfully steered through the entire ring of the CERN Large Hadron Collider (LHC) on September the 10th of 2008. A reasonable lifetime was achieved for the counterclockwise beam, namely beam 2, after the radiofrequency capture of the particle bunch was established. This provided the unique opportunity of acquiring turn-by-turn betatron oscillations for a maximum of 90 turns right at injection. Transverse coupling was not corrected and chromaticity was estimated to be large. Despite this largely constrained scenario, reliable optics measurements have been accomplished. These measurements together with the application of new algorithms for the reconstruction of optics errors have led to the identification of a dominant error source

OPERATIONAL PERFORMANCE OF THE LHC PROTON BEAMS WITH THE SPS LOW TRANSITION ENERGY OPTICS

Abstract An optics in the SPS with lower integer tunes (20 versus 26) was proposed and introduced in machine studies since 2010, as a measure for increasing transverse and longitudinal instability thresholds, especially at low energy, for the LHC proton beams. After two years of machine studies and careful optimisation, the new Q20 optics became operational in September 2012 and steadily delivered beam to the LHC until the end of the run. This paper reviews the operational performance of the Q20 optics with respect to transverse and longitudinal beam characteristics in the SPS, enabling high brightness beams injected into the LHC. Aspects of longitudinal beam stability, transmission, high-energy orbit control and beam transfer are discussed

OPERATIONAL PERFORMANCE OF THE LHC PROTON BEAMS WITH THE SPS LOW TRANSITION ENERGY OPTICS

Abstract An optics in the SPS with lower integer tunes (20 versus 26) was proposed and introduced in machine studies since 2010, as a measure for increasing transverse and longitudinal instability thresholds, especially at low energy, for the LHC proton beams. After two years of machine studies and careful optimisation, the new Q20 optics became operational in September 2012 and steadily delivered beam to the LHC until the end of the run. This paper reviews the operational performance of the Q20 optics with respect to transverse and longitudinal beam characteristics in the SPS, enabling high brightness beams injected into the LHC. Aspects of longitudinal beam stability, transmission, high-energy orbit control and beam transfer are discussed