<P> CERN originally planned that the LHC would run through to the end of 2012, with a short break at the end of 2011 to allow for an increase in beam energy from 3.5 to 4 TeV per beam . At the end of 2012 the LHC was planned to get shut down until around 2015 to allow upgrade to a planned beam energy of 7 TeV per beam . In late 2012, in light of the July 2012 discovery of the Higgs boson, the shutdown was postponed for some weeks into early 2013, to allow additional data to be obtained prior to shutdown . </P> <P> The LHC was shut down on 13 February 2013 for its 2 - year upgrade, which would touch on many aspects of the LHC: enabling collisions at 14 TeV, enhancing its detectors and pre-accelerators (the Proton Synchrotron and Super Proton Synchrotron), as well as replacing its ventilation system and 100 km of cabling impaired by high - energy collisions from its first run . The upgraded collider began its long start - up and testing process in June 2014, with the Proton Synchrotron Booster starting on 2 June 2014, the final interconnection between magnets completing and the Proton Synchrotron circulating particles on 18 June 2014, and the first section of the main LHC supermagnet system reaching operating temperature of 1.9 K (− 271.25 ° C), a few days later . Due to the slow progress with "training" the superconducting magnets, it was decided to start the second run with a lower energy of 6.5 TeV per beam, corresponding to a current of 11,000 amperes . The first of the main LHC magnets were reported to have been successfully trained by 9 December 2014, while training the other magnet sectors was finished in March 2015 . </P> <P> On 5 April 2015, the LHC restarted after a two - year break, during which the electrical connectors between the bending magnets were upgraded to safely handle the current required for 7 TeV per beam (14 TeV). However, the bending magnets were only trained to handle up to 6.5 TeV per beam (13 TeV total), which became the operating energy for 2015 to 2017 . The energy was first reached on 10 April 2015 . The upgrades culminated in colliding protons together with a combined energy of 13 TeV . On 3 June 2015 the LHC started delivering physics data after almost two years offline . In the following months it was used for proton - proton collisions, while in November the machine switched to collisions of lead ions and in December the usual winter shutdown started . </P> <P> In 2016, the machine operators focused on increasing the luminosity for proton - proton collisions . The design value was first reached 29 June, and further improvements increased the collision rate to 40% above the design value . The total number of collisions in 2016 exceeded the number from Run 1 - at a higher energy per collision . The proton - proton run was followed by four weeks of proton - lead collisions . </P>

When is the large hadron collider being turned on