The Low Energy Ion Ring is a particle accelerator at CERN

CERN

The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...

 used to accelerate lead ions from the LINAC 3 to the Proton Synchrotron

Proton Synchrotron

The Proton Synchrotron is the first major particle accelerator at CERN, built as a 28 GeV proton accelerator in the late 1950s and put into operation in 1959. It takes the protons from the Proton Synchrotron Booster at a kinetic energy of 1.4 GeV and lead ions from the Low Energy Ion Ring at 72...

 (PS) to provide lead

Lead

Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...

 ion

Ion

An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...

s for collisions within the Large Hadron Collider

Large Hadron Collider

The Large Hadron Collider is the world's largest and highest-energy particle accelerator. It is expected to address some of the most fundamental questions of physics, advancing the understanding of the deepest laws of nature....

 (LHC).

History

LEIR was converted from a previous machine the Low Energy Antiproton Ring

Low Energy Antiproton Ring

The Low Energy Anti-Proton Ring was an experiment at CERN designed to decelerate and store antimatter, to study the properties of antimatter and to create atoms of antihydrogen. The experiment was constructed in 1982 and operated until 1996, when it was converted into the Low Energy Ion Ring,...

 (LEAR); an experiment designed to decelerate and store antimatter

Antimatter

In particle physics, antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles...

 which had finished in 1996. LEIR was first proposed in 1993 but it wasn't until 2003 that work to transform the old experiment in to the new accelerator was started. The upgrade took just over over two years being commissioned in October 2005 and tested for 4 months. In Autumn 2006 it was used to re-commission the PS to handle ions and then again a year later it was used to re-commission the SPS

Super Proton Synchrotron

The Super Proton Synchrotron is a particle accelerator of the synchrotron type at CERN. It is housed in a circular tunnel, in circumference, straddling the border of France and Switzerland near Geneva, Switzerland. The SPS was designed by a team led by John Adams, director-general of what was...

. However it wasn't until November 2010, five years later, that it successfully carried out it's primary role to provide the lead ions to the LHC for it's first ion collisions.

Operation

LEIR takes long bunches of lead ions from the LINAC 3, and splits them into 4 bunches. Each bunch contains 2.2x10⁸ lead ions which is accelerated from 4.2 MeV

Electronvolt

In physics, the electron volt is a unit of energy equal to approximately joule . By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an electric potential difference of one volt...

to 72 MeV before passing them through to the PS for storage. Each group of two bunches takes about 2.5 seconds to accelerate, with the LHC using 592 bunches of ions, it takes around 10 minutes for a complete fill of the LHC for operations.