LEP (Large Electron-Position)
Particle accelerators, some of the largest scientific instruments built, are used to
probe the smallest pieces of matter that exist. By speeding up sub-atomic particles
and then colliding them together, physicists are able to explore what matter is made
of and the forces that hold it together, and to produce unstable , exotic varieties of
matter that have not existed since the beginning of the Universe.
Particle Accelerators
=======================
Particle accelerators speed up charged particles, such as electrons, positrons,
and protons along straight or circular vacuum tubes and make them collide with
each other or with stationary targets. The energy released by the collisions is
turned into different forms of matter, some previously unseen but predicted by
theory, revealing information about the fundamental forces of nature and the
history of the Universe. Particle accelerators are not just tools for research;
hospitals use small accelerators to create radioisotopes for imaging , and
nearly every house has a simple accelerator, the cathode-ray tube inside a TV,
which accelerates electrons and collides them with a phospor screen.
LEP at CERN
================
The Large Electron-Position (LEP) collider at CERN, near Geneva , Switzerland,
is the largest existing accelerator. It is being modified to make a new machine,
the Large Hadron Collider (LHL), which will accelerate and collide protons and ions.
Accelerator
==============
Pulses of radio waves emitted in cavities in the accelerator transfer a burst of energy
to bunches of particles each time they pass. This gradually increases the speed of the
bunches until they are traveling at close to the speed of light. The accelerator uses
super-conducting materials, which must be kept extremely cold.
