Super Proton Synchrotron

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Super Proton Synchrotron
Beamfeedingams.JPG
Test beamline delivered from the SPS. In photo 20 GeV positrons are used to calibrate the Alpha Magnetic Spectrometer.
General properties
Accelerator type Synchrotron
Beam type protons, heavy ions
Target typeInjector for LHC, fixed target
Beam properties
Maximum energy450 GeV
Physical properties
Circumference6.9 kilometres (4.3 mi)
Coordinates 46°14′06″N6°02′33″E / 46.23500°N 6.04250°E / 46.23500; 6.04250
Institution CERN
Dates of operation1976–present
Preceded by SppS
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 Super Proton Synchrotron (SPS) is a particle accelerator of the synchrotron type at CERN. It is housed in a circular tunnel, 6.9 km (4+1⁄3 miles) in circumference, [1] straddling the border of France and Switzerland near Geneva, Switzerland. [2]

Contents

History

A proton-antiproton collision from the UA5 experiment at the SPS in 1982 CERN UA5 - ppbar interaction at 540GeV.jpg
A proton – antiproton 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]

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 1991, 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.

From 2006 to 2012, the SPS was used by the CNGS experiment to produce a neutrino beam to be detected at the Gran Sasso laboratory in Italy, 730 km (450 miles) from CERN.

Later operations

The SPS is 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 to 450 GeV. The LHC itself then accelerates them to several teraelectronvolts (TeV).

Operation as an injector allows continuation of the ongoing fixed-target research program, where the SPS provides 400 GeV proton beams for a number of active fixed-target experiments, including COMPASS, NA61/SHINE and NA62.

The SPS has served, and continues to be used as a test bench for new concepts in accelerator physics. In 1999 it served as an observatory for the electron cloud phenomenon. [5] In 2002 and 2004, SPS produced gold nuclei from lead targets. [6] [7] [8] In 2003, SPS was the first machine where the Hamiltonian resonance driving terms were directly measured. [9] And in 2004, experiments to cancel the detrimental effects of beam encounters (like those in the LHC) were carried out. [10]

The SPS RF cavities operate at a center frequency of 200.2  MHz .

Major discoveries

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

Upgrade for high luminosity LHC

The Large Hadron Collider will require an upgrade to considerably increase its luminosity during the 2020s. This would require upgrades to the entire linac/pre-injector/injector chain, including the SPS.

As part of this, the SPS will need to be able to handle a much higher intensity beam. One improvement considered in the past was increasing the extraction energy to 1 TeV. [13] However, the extraction energy will be kept at 450 GeV while other systems are upgraded. The acceleration system will be modified to handle the higher voltages needed to accelerate a higher intensity beam. The beam dumping system will also be upgraded so it can accept a higher intensity beam without sustaining significant damage. [14]

Notes and references

  1. ↑ "SPS Presentation at AB-OP-SPS Home Page". Archived from the original on 5 October 2011. Retrieved 15 September 2008.
  2. ↑ Information on CERN Sites Archived 8 July 2012 at archive.today . CERN. Updated 26 January 2010.
  3. ↑ CERN courier
  4. ↑ The LEP Collider – from Design to Approval and Commissioning Archived 18 June 2014 at the Wayback Machine , by S. Myers, section 3.8. Last accessed 28 February 2010.
  5. ↑ "observation of e-cloud" (PDF). Archived from the original (PDF) on 29 September 2011. Retrieved 20 July 2006.
  6. ↑ Cecchini, S.; Giacomelli, G.; Giorgini, M.; Mandrioli, G.; Patrizii, L.; Popa, V.; Serra, P.; Sirri, G.; Spurio, M. (2002). "Fragmentation cross sections of 158AGeV Pb ions in various targets measured with CR39 nuclear track detectors". Nuclear Physics A. 707 (3–4): 513–524. arXiv: hep-ex/0201039 . doi: 10.1016/S0375-9474(02)00962-4 . Retrieved 13 May 2025.
  7. ↑ Scheidenberger, C.; Pshenichnov, I. A.; Sümmerer, K.; Ventura, A.; Bondorf, J. P.; Botvina, A. S.; Mishustin, I. N.; Boutin, D.; Datz, S.; Geissel, H.; Grafström, P.; Knudsen, H.; Krause, H. F.; Lommel, B.; Møller, S. P.; Münzenberg, G.; Schuch, R. H.; Uggerhøj, E.; Uggerhøj, U.; Vane, C. R.; Vilakazi, Z. Z.; Weick, H. (29 July 2004). "Charge-changing interactions of ultrarelativistic Pb nuclei" (PDF). Physical Review C. 70 (1). doi: 10.1103/PhysRevC.70.014902 . ISSN   0556-2813 . Retrieved 13 May 2025.
  8. ↑ "ALICE detects the conversion of lead into gold at the LHC". CERN. 8 May 2025. Retrieved 13 May 2025.
  9. ↑ Measurement of resonance driving terms Archived 16 July 2011 at the Wayback Machine
  10. ↑ "wire compensation" (PDF). Archived from the original (PDF) on 29 September 2011. Retrieved 24 July 2006.
  11. ↑ "CERN.ch La". Public.web.cern.ch. Retrieved 20 November 2010.
  12. ↑ Fanti, V.; et al. (1999). "A new measurement of direct CP violation in two pion decays of the neutral kaon". Physics Letters B . 465 (1–4): 335–348. arXiv: hep-ex/9909022 . Bibcode:1999PhLB..465..335F. doi:10.1016/S0370-2693(99)01030-8. S2CID   15277360.
  13. ↑ Super-SPS
  14. ↑ Hanke, Klaus; Damerau, Heiko; Deleu, Axelle; Funken, Anne; Garoby, Roland; Gilardoni, Simone; Gilbert, Nicolas; Goddard, Brennan; Holzer, Eva Barbara; Lombardi, Alessandra; Manglunki, Django; Meddahi, Malika; Mikulec, Bettina; Shaposhnikova, Elena; Vretenar, Maurizio (2014). "Status of the LIU Project at CERN". Proceedings of the 5th Int. Particle Accelerator Conf. IPAC2014. Petit-Jean-Genaz Christine (Ed.), Arduini Gianluigi (Ed.), Michel Peter (Ed.), Schaa, Volker RW (Ed.): 3 pages, 0.320 MB. doi:10.18429/JACOW-IPAC2014-THPME070.
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