On May 20, protons collided in the Large Hadron Collider (LHC) at a record-breaking energy of 13 TeV for the first time.

These test collisions were to set up the systems that protect the machine and detectors from particles that stray from the edges of the beam. A key part of the process was setting up the collimators, devices that absorb stray particles, in colliding-beam conditions. This setup will give the accelerator team the data they need to ensure that the LHC magnets and detectors are fully protected.

The tests continued on May 21, with colliding beams staying in the LHC for several hours. The LHC Operations team will continue to monitor beam quality and optimization of the set-up. This is an important part of the process that will allow the experimental teams running the detectors ALICE, ATLAS, CMS and LHCb to switch on their experiments fully. Data taking and the start the LHC’s second run is planned for early June.

The three images below and the one above all show protons colliding at 13 TeV, sending showers of particles through the four detectors.