Super Proton Synchrotron

Super Proton Synchrotron

Hadron colliders
Intersecting Storage Rings CERN, 1971–1984
Super Proton Synchrotron CERN, 1981–1984
ISABELLE BNL, cancelled in 1983
Tevatron Fermilab, 1987–2011
Relativistic Heavy Ion Collider BNL, 2000–present
Superconducting Super Collider Cancelled in 1993
Large Hadron Collider CERN, 2009–present
Very Large Hadron Collider Theoretical

The Super Proton Synchrotron (SPS) is a particle accelerator of the synchrotron type at CERN. It is housed in a circular tunnel, 6.9 kilometres (4.3 mi) in circumference,[1] straddling the border of France and Switzerland near Geneva, Switzerland.[2]


  • History 1
  • Current operations 2
  • Major discoveries 3
  • SPS upgrade: the Super-SPS 4
  • Notes and references 5


A protonantiproton collision from the UA5 experiment at the SPS in 1982

The SPS was designed by a team led by John Adams, director-general of what was then known as Laboratory II. Originally specified as a 300 GeV accelerator, the SPS was actually built to be capable of 400 GeV, an operating energy it achieved on the official commissioning date of 17 June 1976. However, by that time, this energy had been exceeded by Fermilab, which reached an energy of 500 GeV on 14 May of that year.[3]

Test beamline delivered from the SPS. In photo 20 GeV positrons are used to calibrate the Alpha Magnetic Spectrometer.

The SPS has been used to accelerate protons and antiprotons, electrons and positrons (for use as the injector for the Large Electron–Positron Collider (LEP)[4]), and heavy ions.

From 1981 to 1984, the SPS operated as a hadron (more precisely, proton–antiproton) collider (as such it was called SppS), when its beams provided the data for the UA1 and UA2 experiments, which resulted in the discovery of the W and Z bosons. These discoveries and a new technique for cooling particles led to a Nobel Prize for Carlo Rubbia and Simon van der Meer in 1984.

Current operations

The SPS is now used as the final injector for high-intensity proton beams for the Large Hadron Collider (LHC), which began preliminary operation on 10 September 2008, for which it accelerates protons from 26 GeV to 450 GeV. The LHC itself then accelerates them to several teraelectronvolts (TeV).

Operation as injector still allows continuation of the ongoing fixed-target research program, where the SPS is used to provide 400 GeV proton beams for a number of active fixed-target experiments, notably COMPASS, NA61/SHINE and NA62. The SPS is also being used by the CNGS experiment to produce a neutrino stream to be detected at the Gran Sasso laboratory in Italy, 730 km from CERN.

The SPS has served as a test bench for new concepts in accelerator physics. In 1999 it served as an observatory for the electron cloud phenomenon.[5] In 2003, SPS was the first machine where the Hamiltonian resonance driving terms were directly measured.[6] And in 2004, experiments to cancel the detrimental effects of beam encounters (like those in the LHC) were carried out.[7]

Major discoveries

Major scientific discoveries made by experiments that operated at the SPS include the following.

SPS upgrade: the Super-SPS

It has been proposed that the Large Hadron Collider will require an upgrade to considerably increase its luminosity by 2015. This would require upgrades to the entire linac/pre-injector/injector chain, including the SPS. The improvements to the SPS would most likely focus on increasing the extraction energy of the Super-SPS up to 1 TeV.[10]

Notes and references

  1. ^ SPS Presentation at AB-OP-SPS Home Page
  2. ^ Information on CERN Sites. CERN. Updated 2010-01-26.
  3. ^ CERN courier
  4. ^ The LEP Collider - from Design to Approval and Commissioning, by S. Myers, section 3.8. Last accessed 2010-02-28.
  5. ^ observation of e-cloud
  6. ^ Measurement of resonance driving terms
  7. ^ wire compensation
  8. ^ " La". Retrieved 20 November 2010. 
  9. ^ Fanti, V.; et al. (1998). "A new measurement of direct CP violation in two pion decays of the neutral kaon".  
  10. ^ Super-SPS