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

<span class="mw-page-title-main">CERN</span> European research centre in Switzerland

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 Meyrin, western suburb of Geneva, on the France–Switzerland border. It comprises 24 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 American particle accelerator at Fermilab in Illinois (1983–2011)

The Tevatron was a circular particle accelerator in the United States, at the Fermi National Accelerator Laboratory, east of Batavia, Illinois, and was the highest energy particle collider until the Large Hadron Collider (LHC) of the European Organization for Nuclear Research (CERN) was built near Geneva, Switzerland. The Tevatron was a synchrotron that accelerated protons and antiprotons in a 6.28 km (3.90 mi) circumference 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">Linear particle accelerator</span> Type of particle accelerator

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<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.

<span class="mw-page-title-main">CERN Hadron Linacs</span> Group of particle accelerators

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

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

The Large Hadron Electron Collider (LHeC) is an accelerator study for a possible upgrade of the existing LHC storage ring – the currently highest energy proton accelerator operating at CERN in Geneva. By adding to the proton accelerator ring a new electron accelerator, the LHeC would enable the investigation of electron-proton and electron-ion collisions at unprecedented high energies and rate, much higher than had been possible at the electron-proton collider HERA at DESY at Hamburg, which terminated its operation in 2007. The LHeC has therefore a unique program of research, as on the substructure of the proton and nuclei or the physics of the newly discovered Higgs boson. It is an electron–ion collider, similar to the plans in the US and elsewhere, although the present design would not include polarized protons.

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

The Super Proton–Antiproton Synchrotron was a particle accelerator that operated at CERN from 1981 to 1991. To operate as a proton-antiproton collider the Super Proton Synchrotron (SPS) underwent substantial modifications, altering it from a one beam synchrotron to a two-beam collider. The main experiments at the accelerator were UA1 and UA2, where the W and Z bosons were discovered in 1983. Carlo Rubbia and Simon van der Meer received the 1984 Nobel Prize in Physics for their contributions to the SppS-project, which led to the discovery of the W and Z bosons. Other experiments conducted at the SppS were UA4, UA5 and UA8.

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

The LEP Pre-Injector (LPI) was the initial source that provided electrons and positrons to CERN's accelerator complex for the Large Electron–Positron Collider (LEP) from 1989 until 2000.

Extra Low ENergy Antiproton ring (ELENA) is a 30 m hexagonal storage ring that decelerates antiproton beams and delivers it to different AD experiments. It is situated inside the Antiproton Decelerator (AD) complex at CERN, Geneva. It is designed to further decelerate the antiproton beam coming from the Antiproton decelerator to an energy of 0.1 MeV for more precise measurements. The first beam circulated ELENA on 18 November 2016. The ring is expected to be fully operational by the end of the Long Shutdown 2 (LS2) in 2021.

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. Archived from the original (PDF) on 8 November 2011. Retrieved 14 October 2011.
  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.