Guide to the Large Hadron Collider



Flash plug-in required

To view the advanced features of this page you need to have the Adobe Flash 7 or higher plugin installed on your system.

Click here to download the Flash plugin from the Adobe website

Tunnel

David Shukman gets on his bike in the LHC's tunnel

Flash plug-in required

To view the advanced features of this page you need to have the Adobe Flash 7 or higher plugin installed on your system.

Click here to download the Flash plugin from the Adobe website

IN PICTURES: TUNNEL

info-graphic
info-graphic
info-graphic
info-graphic
1 of 4

The main structure of the LHC is a 27 km (17 mile) circumference accelerator ring of superconducting magnets.

Its primary job is to boost the energy of particles which will be smashed at the various detectors located around the ring.

Inside the tunnel are two separate vacuum tubes which channel particles at close to the speed of light. These "beam lines" travel in opposite directions.

The particles are guided around ring by a strong magnetic field. Thousands of magnets of different size and type are used to direct the beams around the accelerator.

These include more than 1200 "dipole" magnets, each of which is 15m (49ft) in length and are used to bend the beams around the loop.

Nearly 400 "quadrupole" magnets, each 5 to 7m (16-23ft) long are used to focus the beams.

A third type of magnet is used to squeeze the beams closer together to increase the chances of a collision.

Many of these magnets are built from coils of superconducting electric cable which conducts electricity with little resistance, and therefore little loss of energy.

To achieve this effect the cables are cooled close to absolute zero (-273C/ -459F) using liquid helium. This is fed into a sealed network in the accelerator at eight "cryoplants" located around the ring.

All of this is monitored and managed from the control centre. Here, scientists will steer the particle beams to ensure that collisions occur at the detectors located around the circuit.

TUNNEL FACTS
1 pixel filler
The LHC is not a perfect circle but a series of arcs
Magnet coils in the machine are wound from cable of up to 36 twisted 15mm (0.6 inch) strands
Each strand is made up of 6,400 filaments, each filament seven micrometres in diameter (human hair is 50 micrometres thick)
There are 7,600km (4,723 miles) of cable, corresponding to 270,000km (167,778 miles) of strand - enough to circle the Earth six times
If the component filaments were unravelled, they would stretch to the Sun and back more than five times

Source: Cern




FEATURES, VIEWS, ANALYSIS
Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit

BBC iD

Sign in

BBC navigation

Copyright © 2019 BBC. The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.

Americas Africa Europe Middle East South Asia Asia Pacific