Reaching record-lowβ*at the CERN Large Hadron Collider using a novel scheme of collimator settings and optics

• DOI: 10.1016/j.nima.2016.12.039
• Publication Date: 2016-12-23T11:02:43Z
• Authors: R. Bruce; C. Bracco; R. De Maria; M. Giovannozzi; A. Mereghetti; D. Mirarchi; S. Redaelli; E. Quaranta; B. Salvachua
• Keywords: Collimator; Aperture (computer memory); Collimated light

The Large Hadron Collider (LHC) at CERN is built to collide intense proton beams with an unprecedented energy of 7 TeV. design stored per beam 362 MJ makes the LHC highly destructive, so that any losses risk cause quenches superconducting magnets or damage accelerator components. Collimators are installed protect machine and they define a minimum normalized aperture, below which no other element allowed. This imposes limit on achievable luminosity, since when squeezing β* (the β-function collision point) smaller values for increased in final focusing system increases. leads aperture risks go allowed collimation aperture. In first run LHC, this was main limitation β*, constrained above specification. article, we show through theoretical experimental studies how tighter collimator openings new optics specific phase-advance constraints allows as small 40 cm, factor 2 than β*=80 cm used 2015 significantly value β*=55 spite lower energy. proposed configuration β*=40 has been successfully put into operation throughout 2016 baseline. decrease compared essential contribution reaching surpassing, 2016, luminosity time, accumulating record-high integrated around fb−1 one year, using less bunches design.