The proton journey
From a hydrogen bottle to a collision
Every proton in the LHC starts as ordinary bottled hydrogen. Before it collides at 13.6 TeV it passes through a relay of ever larger accelerators. Follow the whole road.
A beam flows along the line: each stage hands the particles to the next, ever faster.
A bottle of hydrogenstart
the start of the road
The source of protons is ordinary hydrogen. The atoms become hydrogen ions and set off into the complex. One bottle could feed the LHC for years.
LINAC4160 MeV
linear accelerator · 86 m
The first push: the ions fly through a row of radio-frequency cavities arranged in a line. At the entrance to the next machine only bare protons remain.
PS Booster2 GeV
4 stacked rings · 157 m
Four small rings working one above another squeeze and speed up the proton bunches, preparing them for the older brother.
Proton Synchrotron26 GeV
ring · 628 m · since 1959
The veteran of the complex, running since 1959. This is where bunches get the timing structure they will keep until the collision.
Super Proton Synchrotron450 GeV
ring · 7 km
CERN's second largest machine. The W and Z bosons were discovered with it in the 1980s; today it feeds the beam straight into the LHC.
LHC6.8 TeV
ring · 26.7 km · 1.9 K
Two counter-rotating beams circulate in side-by-side pipes while 1232 superconducting dipoles hold them on track. Ramping to full energy takes about 20 minutes.
Collision13.6 TeV
ATLAS · CMS · ALICE · LHCb
At four points of the ring the beams cross and protons collide head-on. New particles are born from the collision energy, and the detectors take their pictures.
Mini game: keep the beam
The beam drifts and you are the correction system. Keep it inside the pipe with the arrow keys (or the buttons) and count the laps.
Controls: up and down arrows, W and S keys, or the buttons.