LHC collimation cleaning and operational outlook

Abstract

An overview of the collimation system performance during 2012 is described. The collimator “tight” settings for the 60 cm β⋆ reach are introduced and the evolution of the cleaning inefficiency achieved throughout the year with one single collimator alignment is presented. The performance of the semi-automatic collimator alignment tools is discussed. We investigate the beam losses through the cycle with emphasis on the yearly evolution of the measured instantaneous beam lifetime in critical phases of the operational cycle. The concept of collimators with integrated beam positions monitors (BPM) is presented here and their effect on the β⋆ reach after the long shutdown I is analyzed. The baseline settings strategy for the startup in 2015 is discussed based on the expected performance of the collimators with BPMs. New values of β⋆ reach are discussed.