Interactive · Large Hadron Collider

Build your own collision

Inject proton bunches, accelerate them to almost the speed of light and cross the beams in the heart of a detector, all live, driven by sliders.

The simulation is illustrative: it captures how the LHC ring works (injection from the SPS, acceleration in RF cavities, bending by 1232 dipole magnets and collisions at ATLAS, CMS, ALICE, LHCb), and the numbers are approximate.

Ring empty
Hover to pan the view. Values are approximate.
Energy √s...
Speed...
Magnet field...
Magnet temp.1.9 K
Luminosity...
Collisions0 M/s
Beam 1 (protons)Beam 2 (counter-rotating)1232 dipole magnets4 detectors
The proton's path

Six steps from hydrogen to a collision

Before the protons meet in a detector, they pass through the whole chain of CERN accelerators.

1

Source

An electric field strips electrons from hydrogen, leaving bare protons.

2

Chain

Linac → Booster → PS → SPS gradually speed the beam up before the LHC.

3

Injection

Bunches enter the two counter-rotating pipes of the ring.

4

Ramp-up

RF cavities add energy on every lap, up to 6.8 TeV per beam.

5

Collision

At 4 points the beams cross 40 million times a second.

6

Detection

Detector layers reconstruct the tracks of decay products.

The four eyes of the LHC

Detectors at the collision points

Each of the four main experiments looks at collisions differently, switch to Detector mode to see the decay tracks.

ATLAS

46 m long, 25 m across, the largest LHC detector. Co-discoverer of the Higgs boson.

CMS

Compact, but heavier than the Eiffel Tower. The second team that confirmed the Higgs.

ALICE

Studies the quark-gluon plasma in heavy lead-ion collisions.

LHCb

Tracks subtle differences between matter and antimatter in b-quark decays.

Questions

Frequently asked questions

The energy of a single collision is huge on a particle scale, but the total beam energy is roughly that of a speeding train. Cosmic rays constantly hit Earth with particles of higher energy.

From the CRT to the accelerator

The same idea, an accelerated beam of particles, at the scale of your living room and at the scale of 27 kilometres.