Low Energy Ion Ring

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CERN Complex
CERN accelerator complex 2022.png
Current particle and nuclear facilities
LHC Accelerates protons and heavy ions
LEIR Accelerates ions
SPS Accelerates protons and ions
PSB Accelerates protons
PS Accelerates protons or ions
Linac 3 Injects heavy ions into LEIR
Linac4 Accelerates ions
AD Decelerates antiprotons
ELENA Decelerates antiprotons
ISOLDE Produces radioactive ion beams
MEDICIS Produces isotopes for medical purposes

The Low Energy Ion Ring particle accelerator at CERN Low Energy Ion Ring.jpg
The Low Energy Ion Ring particle accelerator at CERN

The Low Energy Ion Ring (LEIR) is a particle accelerator at CERN used to accelerate ions from the LINAC 3 to the Proton Synchrotron (PS) to provide ions for collisions within the Large Hadron Collider (LHC).

Contents

History

LEIR was converted from a previous machine, the Low Energy Antiproton Ring (LEAR), a facility to decelerate and store antiprotons [1] and to deliver them to experiments; the last LEAR antiproton run took place in 1996. LEIR was first proposed in 1993 [2] but it wasn't until 2003 that work to transform the old experiment into the new accelerator was started. The upgrade took just over two years, being commissioned in October 2005 [3] [4] 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. However, it wasn't until November 2010, five years later, that it successfully carried out its primary role to provide the lead ions to the LHC for its first ion collisions. [5]

During 2017, LEIR was running with xenon ions, sending them normally to SPS and, exceptionally to the LHC [6] for one day of physics. In 2018, the machine was running again with lead ions and had the objective to reach an LIU performance of more than 9×1010 charges extracted. On 6 June 2018 that performance was achieved and also a new extraction record of 10.35×1010 charges was accomplished.

Operation

Electron cooler (left) at LEIR. The electron source and dump are installed in the upper metallic cylinders. LEIR img 1001.jpg
Electron cooler (left) at LEIR. The electron source and dump are installed in the upper metallic cylinders.

LEIR takes long bunches of lead-208 ions from the LINAC 3, and splits them into 4 bunches. Each bunch contains 2.2×108 lead ions, which are accelerated from 4.2  MeV per nucleon to 72 MeV per nucleon [7] before passing them through to the PS for storage.

The most important function of LEIR is not acceleration, but electron cooling to reduce the emittance of the ion beam in order to maintain high luminosity of the final LHC beam. Each group of two bunches takes about 2.5 seconds to accelerate and cool, so with the LHC using 592 bunches of ions, it takes around 10 minutes for a complete fill of the LHC for operations. [8]

Related Research Articles

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The European Organization for Nuclear Research, known as CERN, is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in a northwestern suburb of Geneva, on the France–Switzerland border. It comprises 23 member states. Israel, admitted in 2013, is the only non-European full member. CERN is an official United Nations General Assembly observer.

<span class="mw-page-title-main">Tevatron</span> Defunct particle accelerator at Fermilab in Illinois, USA (1983–2011)

The Tevatron was a circular particle accelerator in the United States, at the Fermi National Accelerator Laboratory, east of Batavia, Illinois, and is the second highest energy particle collider ever built, after the Large Hadron Collider (LHC) of the European Organization for Nuclear Research (CERN) near Geneva, Switzerland. The Tevatron was a synchrotron that accelerated protons and antiprotons in a 6.28 km (3.90 mi) ring to energies of up to 1 TeV, hence its name. The Tevatron was completed in 1983 at a cost of $120 million and significant upgrade investments were made during its active years of 1983–2011.

<span class="mw-page-title-main">Large Hadron Collider</span> Particle accelerator at CERN, Switzerland

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<span class="mw-page-title-main">Proton Synchrotron</span> CERNs first synchrotron accelerator

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<span class="mw-page-title-main">Proton Synchrotron Booster</span> CERN particle accelerator

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<span class="mw-page-title-main">Particle accelerator</span> Research apparatus for particle physics

A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams.

<span class="mw-page-title-main">Low Energy Antiproton Ring</span> Former CERN infrastructure

The Low Energy Anti-Proton Ring (LEAR) was a particle accelerator at CERN which operated from 1982 until 1996. The ring was designed to decelerate and store antiprotons, to study the properties of antimatter and to create atoms of antihydrogen. Antiprotons for the ring were created by the CERN Proton Synchrotron via the Antiproton Collector and the Antiproton Accumulator (AA). The creation of at least nine atoms of antihydrogen were confirmed by the PS210 experiment in 1995.

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<span class="mw-page-title-main">Antiproton Accumulator</span> Part of the CERN proton-antiproton collider

The Antiproton Accumulator (AA) was an infrastructure connected to the Proton–Antiproton Collider – a modification of the Super Proton Synchrotron (SPS) – at CERN. The AA was built in 1979 and 1980, for the production and accumulation of antiprotons. In the SppS the antiprotons were made to collide with protons, achieving collisions at a center of mass energy of app. 540 GeV. Several experiments recorded data from the collisions, most notably the UA1 and UA2 experiment, where the W and Z bosons were discovered in 1983.

<span class="mw-page-title-main">LHeC</span> Accelerator study for a possible upgrade of the existing LHC storage ring

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<span class="mw-page-title-main">Super Proton–Antiproton Synchrotron</span> Particle accelerator at CERN

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<span class="mw-page-title-main">LEP Pre-Injector</span>

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References

  1. "The matter-antimatter asymmetry problem".
  2. "A low energy accumulation ring of ions for LHC (a feasibility study) - CERN Document Server".
  3. "LEIR gets ions on course for the LHC – CERN Courier". 25 November 2005.
  4. Belochitskii, P.; et al. (2006). LEIR commissioning in Proceedings of EPAC 2006, Edinburgh, Scotland (PDF). JACoW. pp. 1876–1878.
  5. The Daily Telegraph
  6. "For one day only LHC collides xenon beams".
  7. A. Beuret; et al. (July 2004). The LHC Lead Injector Chain (PDF). Ninth European Particle Accelerator Conference (EPAC'04). Lucerne, Switzerland.
  8. Chanel, Michel (September 2003). "LEIR: The Low Energy Ion Ring at CERN" (PDF). Nuclear Instruments and Methods in Physics Research A. 532 (1–2): 137–143. Bibcode:2004NIMPA.532..137C. doi:10.1016/j.nima.2004.06.040. CERN-AB-2003-086. Archived from the original (PDF) on 29 March 2012.