Commissioning of Ramp and Squeeze at the LHC

The energy ramp and the betatron squeeze at the CERN Large Hadron Collider (LHC) are particularly critical oper- ational phases that involve the manipulation of beams well above the safe limit for damage of accelerator components. In particular, the squeeze is carried out at top energy with reduced quench limit of superconducting magnets and re- duced aperture in the triplet quadrupoles. In 2010, the commissioning of the ramp from 450 GeV to 3.5 TeV and the squeeze to 2 m in all the LHC experiments have been achieved and smoothly became operational. In this paper, the operational challenges associated to these phases are discussed, the commissioning experience with single- and multi-bunch operation is reviewed and the overall perfor- mance is discussed