Operation and Configuration of the LHC in Run 1

Between 2010 and 2013 the LHC was operated with protons at beam energies of 3.5 and 4 TeV. The proton beams consisted of single bunches and trains of 150 ns (2010), 75 ns (2011) and 50 ns (2011 and 2012). Performances well beyond what had been expected initially have been achieved with 50 ns beams, culminating in the discovery of a 125 GeV/c2 Higgs boson by the ATLAS and CMS experiments. The nominal bunch spacing of 25 ns was only used for electron-cloud scrubbing runs at injection and for collision tests in view of future operation. The cycle structure evolved over the years, and the operational * for ATLAS and CMS was lowered in steps from 3.5 m (2010) to 0.6 m (2012). Lead ion, mixed proton-lead, intermediate proton energy (1.38 TeV) and high-beta runs were also performed. This note provides an overview of LHC operation between 2010 and 2013. The aim is to document the various operational configurations and highlights of Run 1.