The World’s Largest Particle Accelerator Is Active Again

After more than three years of upgrades and maintenance work, the world’s largest particle accelerator is active again. CERN’s Large Hadron Collider (LHC) began its third run today at its highest ever energy level after ceasing operations at the end of 2018.

The LHC was built to help scientists to answer key unresolved questions in particle physics. It accelerates protons and ions, which belong to the group of particles called hadrons, from two beams traveling in opposite directions traveling close to the speed of light to collide after traveling through the CERN accelerator complex.

CERN stands for “Conseil Européen pour la Recherche Nucléaire” which translates to the European Council for Nuclear Research. The CERN accelerator complex consists of machines with increasingly higher energy levels. Each machine accelerates a beam of particles to a certain energy level before injecting the beam into the next machine, which brings the beam to a higher energy level. The LHC is the last element of this chain, in which the beams reach their highest energies. It is a 27-kilometer (17-mile) ring of superconducting magnets with several accelerating structures to boost the energy of the particles along the way. The LHC is the most powerful particle accelerator in the world.

To increase the chances of observing rare events, LHC uses the ATLAS detector, which takes 40 million photos per second. The CERN Data Center stores more than 30 petabytes of data per year from the LHC experiments, enough to fill about 1.2 million Blu-ray discs, which is over 250 years of HD video. Over 100 petabytes of data are permanently archived on tape. Researchers at CERN hope that the data collected from the LHC can help them answer some of the sciences’ biggest questions, like what is the origin of mass? Will we discover evidence for supersymmetry? What are dark matter and dark energy? Why is there far more matter than antimatter in the universe? How does the quark-gluon plasma give rise to the particles that constitute the matter of our universe?

Starting its first run on September 10, 2008, the LHC’s first run lasted nearly four and a half years. At the time, the LHC broke records by reaching 8 trillion electronvolts TeV by the end of its run. During the first run, researchers made their most significant discovery to date, the Higgs boson or God particle. The Higgs boson is a subatomic particle that gives other particles like quarks and electrons mass. The first run ended on February 14, 2013. After two years of maintenance, Run 2 began in 2015. Building off of run 1, researchers learned much more about the Higgs boson particle. Thanks to the upgrades, by the end of run 2 in December 2018, the LHC was running comfortably at 13 TeV.

The LHC’s 3rd run set off on July 5, 2022, at 10 AM (EST). Operating at its highest energy level ever, 13.6 TeV, researchers like the Director for Accelerators and Technology, Mike Lamont, are ready for new discoveries. “We will be focusing the proton beams at the interaction points to less than 10-micron beam size to increase the collision rate,” said Lamont. “Compared to Run 1, in which the Higgs was discovered with 12 inverse femtobarns, now in Run 3, we will be delivering 280 inverse femtobarns. This is a significant increase, paving the way for new discoveries.”

Watch the launch live stream here

How LHC works