Live blog (now closed)


Physicists in the ATLAS control room eagerly awaiting collisions in the LHC and the precious data that they will be able to harvest from them (Image: Pierre Descombe/CERN)


Now increasing the beam energy to 6.5 teraelectronvolts (TeV). The black line (beam energy) on the graph on LHC page 1 has started to rise...




The LHC Operations team are ramping the energy of the beams once more to 6.5 teraelectronvolts (TeV) per beam in preparation for collisions. 

Our live webcast will be starting up again shortly. 


Three bunches of 1011 protons are now circulating once more in the LHC at 450 GeV (In the graph below, the red and blue lines show the protons being injected, and the black line is the beam energy.)


Operators in the control room for the LHCb experiment stay in touch by telephone with their colleagues in charge of LHC operations (Image: Laurine Mottet/CERN)


Second probe beam now injected to LHC at 450 GeV.


First probe beam has just been injected to the LHC at 450 GeV.


The accelerator team is still investigating the software issue that stopped the beams earlier. They are injecting probe beams of protons, just as before, followed by three bunches of 1011 protons per beam, to check which subsystems are implicated. This may take half an hour or so, during which we will pause our live webcast, and keep you updated through this live blog. Stay tuned!



The LHC's Conceptual Design Report – a document describing the accelerator's architecture and operation – was published in October 1995. The Report described a collider that could operate with beams at up to 7 teraelectronvolts (TeV) for a collision energy of 14 TeV. So why are we only aiming for 13 TeV today?

Find out here: Restarting the LHC - Why 13 TeV?


Light streams in to the ATLAS experiment control room (Image: Silvia Bondi/CERN)


The Operations team is preparing to refill the LHC once more. Follow along with today's webcast, here, where Tiziano Camporesi of the CMS experiment is describing work on the detector during long shutdown one.


...and the beams have now been sent to the beam dump. 

The team are working through the LHC's subsystems to find the cause of the beam stop. They are investigating a software issue which may have caused a subsystem to trip, and safely send the beams to the beam dump.


The LHC Operations team is increasing the energy of both beams to 6.5 teraelectonvolts (TeV)... 


Follow the path of protons from a bottle of hydrogen gas, through CERN's accelerator chain, all the way to collisions and data-taking in this animation:


The LIVE WEBCAST of today's events has just started. Follow here:


The injection of beams of protons from the Super Proton Synchrotron (SPS) to the Large Hadron Collider (LHC) is now complete. The next step is to "ramp" - increase the energy - of each beam to 6.5 teraelectronvolts (TeV) in preparation for collisions. The Operations team ramps the energy of the beams by increasing the current in the LHC's 1232 superconducting dipole magnets. 



Now injecting a third bunch of 1011 protons, for beam 2 (blue line on the graph below). There are now three bunches in each beam, circulating in separate beam pipes in opposite directions at the energy of 450 GeV (black line on the graph below). 


One of the LHC operators, Laurette Ponce, analyses the many screens of data that physicists use to monitor and operate the machine (Image: M.Brice/CERN)