Home Out & About Excursions Visiting the Large Hadron Collider: A factfile
Last update on November 05, 2019
Written by European Organisation for Nuclear Research (CERN)

Find out why Europe’s Large Hadron Collider (LHC), located in Switzerland, is the most powerful particle smasher in the world.

The world’s most powerful particle smasher, Europe’s Large Hadron Collider (LHC), started a new run in 2015 with almost doubled energy levels. The LHC is where physicists conduct experiments at the very frontiers of mankind’s scientific knowledge, with the aim of recreating the beginnings of the universe.

Visit the Large Hadron Collider (LHC)

Visitors in groups can take a tour of the LHC, located near Geneva, which are free. Due to high demand, bookings should be made several weeks or a couple of months in advance.

The LHC in numbers

  • Hydrogen protons (a type of hadron) are accelerated to 99.9 percent the speed of light and rammed into one another in an attempt to create conditions similar to those that existed just after the ‘Big Bang’ that formed the universe 13.7 billion years ago.
  • More than 1,200 superconducting dipole magnets guide two particle beams in parallel but opposite directions in an ultra-high vacuum, about 20 centimetres (eight inches) apart.
  • The beams run into each other at four points along a 27-kilometre (17-mile) ring-shaped tunnel that runs about 100 metres (328 feet) underground. Some of the protons collide but the others survive and continue around the racetrack.
  • The collision points represent the LHC’s four experiments – called ATLAS, CMS, LHCb and ALICE, where physicists look for new particles.
  • The beams will each have a maximum potential energy of 7 teraelectronvolts (TeV), thus a collision energy of 14 TeV, though the experiments will start at 13 TeV – the highest ever achieved in a lab.
  • One TeV is about the energy of a flying mosquito, but at the LHC it is squeezed into a space about a million million times smaller than a mosquito.
  • At full energy, each beam will have energy equivalent to a 400-tonne train travelling at 150km (93 miles) per hour.
  • Every beam contains about 2,800 ‘bunches’ or ‘packets’ travelling with about seven metres (23 feet) between them. Each bunch contains about 100-150 billion protons.
  • Each proton will go around the ring more than 11,000 times a second.
  • A beam may circulate for 10 hours, travelling more than 10 billion kilometres, which is enough to get to Neptune and back.
  • The LHC magnets produce a magnetic field of about 8 tesla, about 150,000 times bigger than Earth’s magnetic field.
  • To create resistance-free conditions inside the tunnel, the magnets must be chilled with liquid helium to 1.9 Kelvin (–271.3 degrees Celsius), which is colder than outer space.
  • There will be a collision every 25 nanoseconds (one nanosecond is a billionth of a second), yielding about 15 million gigabytes of data per year – representing a stack of CDs about 20km high.
  • The LHC cost about CHF 6.5 billion (Swiss francs) (USD 7 billion, EUR 6.2 billion) to build, with an annual budget of a billion francs a year.
  • More than 10,000 scientists work directly or indirectly on the LHC’s four experiments.