Tevatron - Wikipedia 01/01/2025, 00:41

Tevatron
The Tevatron was a circular particle accelerator
Tevatron
(active until 2011) in the United States, at the
Fermi National Accelerator Laboratory (called
Fermilab), 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 The Tevatron (background) and Main Injector
ring to energies of up to 1 TeV, hence its rings
name.[1][2] The Tevatron was completed in 1983 General properties
at a cost of $120 million and significant upgrade Accelerator type synchrotron
investments were made during its active years of
Beam type proton, antiproton
1983–2011.
Target type collider
The main achievement of the Tevatron was the Beam properties
discovery in 1995 of the top quark—the last
Maximum energy 1 TeV
fundamental fermion predicted by the Standard
Maximum 4 × 1032/(cm2⋅s)
Model of particle physics. On July 2, 2012,
luminosity
scientists of the CDF and DØ collider experiment
teams at Fermilab announced the findings from Physical properties
the analysis of around 500 trillion collisions Circumference 6.28 kilometres
produced from the Tevatron collider since 2001, (6,280 m)
and found that the existence of the suspected Location Batavia, Illinois
Higgs boson was highly likely with a confidence of
Institution Fermilab
99.8%,[3] later improved to over 99.9%.[4]
Dates of operation 1983–2011
The Tevatron ceased operations on 30 September
2011, due to budget cuts[5] and because of the completion of the LHC, which began operations
in early 2010 and is far more powerful (planned energies were two 7 TeV beams at the LHC
compared to 1 TeV at the Tevatron). The main ring of the Tevatron will probably be reused in
future experiments, and its components may be transferred to other particle accelerators.[6]

History
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December 1, 1968, saw the breaking of ground for the linear accelerator (linac). The
construction of the Main Accelerator Enclosure began on October 3, 1969, when the first shovel
of earth was turned by Robert R. Wilson, NAL's director. This would become the 6.3 km
circumference Fermilab's Main Ring.[1]

The linac first 200 MeV beam started on December 1, 1970. The booster first 8 GeV beam was
produced on May 20, 1971. On June 30, 1971, a proton beam was guided for the first time
through the entire National Accelerator Laboratory accelerator system including the Main Ring.
The beam was accelerated to only 7 GeV. Back then, the Booster Accelerator took 200 MeV
protons from the Linac and "boosted" their energy to 8 billion electron volts. They were then
injected into the Main Accelerator.[1]

On the same year before the completion of the Main Ring, Wilson testified to the Joint
Committee on Atomic Energy on March 9, 1971, that it was feasible to achieve a higher energy
by using superconducting magnets. He also suggested that it could be done by using the same
tunnel as the main ring and the new magnets would be installed in the same locations to be
operated in parallel to the existing magnets of the Main Ring. That was the starting point of the
Tevatron project.[7] The Tevatron was in research and development phase between 1973 and
1979 while the acceleration at the Main Ring continued to be enhanced.[8]

A series of milestones saw acceleration rise to 20 GeV on January 22, 1972, to 53 GeV on
February 4 and to 100 GeV on February 11. On March 1, 1972, the then NAL accelerator system
accelerated for the first time a beam of protons to its design energy of 200 GeV. By the end of
1973, NAL's accelerator system operated routinely at 300 GeV.[1]

On 14 May 1976 Fermilab took its protons all the way to 500 GeV. This achievement provided
the opportunity to introduce a new energy scale, the teraelectronvolt (TeV), equal to 1000 GeV.
On 17 June of that year, the European Super Proton Synchrotron accelerator (SPS) had
achieved an initial circulating proton beam (with no accelerating radio-frequency power) of only
400 GeV.[9]

The conventional magnet Main Ring was shut down in 1981 for installation of superconducting
magnets underneath it. The Main Ring continued to serve as an injector for the Tevatron until
the Main Injector was completed west of the Main Ring in 2000.[7] The 'Energy Doubler', as it
was known then, produced its first accelerated beam—512 GeV—on July 3, 1983.[10]

Its initial energy of 800 GeV was achieved on February 16, 1984. On October 21, 1986,
acceleration at the Tevatron was pushed to 900 GeV, providing a first proton–antiproton
collision at 1.8 TeV on November 30, 1986.[11]

The Main Injector, which replaced the Main Ring,[12] was the most substantial addition, built
over six years from 1993 at a cost of $290 million.[13] Tevatron collider Run II begun on March
1, 2001, after successful completion of that facility upgrade. From then, the beam had been
capable of delivering an energy of 980 GeV.[12]

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On July 16, 2004, the Tevatron achieved a new peak luminosity, breaking the record previously
held by the old European Intersecting Storage Rings (ISR) at CERN. That very Fermilab record
was doubled on September 9, 2006, then a bit more than tripled on March 17, 2008, and
ultimately multiplied by a factor of 4 over the previous 2004 record on April 16, 2010 (up to
4 × 1032 cm−2 s−1).[11]

The Tevatron ceased operations on 30 September 2011. By the end of 2011, the Large Hadron
Collider (LHC) at CERN had achieved a luminosity almost ten times higher than Tevatron's (at
3.65 × 1033 cm−2 s−1) and a beam energy of 3.5 TeV each (doing so since March 18, 2010),
already ~3.6 times the capabilities of the Tevatron (at 0.98 TeV).

Mechanics
The acceleration occurred in a number of stages. The first stage was the 750 keV Cockcroft–
Walton pre-accelerator, which ionized hydrogen gas and accelerated the negative ions created
using a positive voltage. The ions then passed into the 150 meter long linear accelerator (linac)
which used oscillating electrical fields to accelerate the ions to 400 MeV. The ions then passed
through a carbon foil, to remove the electrons, and the charged protons then moved into the
Booster.[14]

The Booster was a small circular synchrotron, around which the protons passed up to 20,000
times to attain an energy of around 8 GeV. From the Booster the particles were fed into the
Main Injector, which had been completed in 1999 to perform a number of tasks. It could
accelerate protons up to 150 GeV; produce 120 GeV protons for antiproton creation; increase
antiproton energy to 150 GeV; and inject protons or antiprotons into the Tevatron. The
antiprotons were created by the Antiproton Source. 120 GeV protons were collided with a nickel
target producing a range of particles including antiprotons which could be collected and stored
in the accumulator ring. The ring could then pass the antiprotons to the Main Injector.

The Tevatron could accelerate the particles from the Main Injector up to 980 GeV. The protons
and antiprotons were accelerated in opposite directions, crossing paths in the CDF and DØ
detectors to collide at 1.96 TeV. To hold the particles on track the Tevatron used 774 niobium–
titanium superconducting dipole magnets cooled in liquid helium producing the field strength
of 4.2 tesla. The field ramped over about 20 seconds as the particles accelerated. Another 240
NbTi quadrupole magnets were used to focus the beam.[2]

The initial design luminosity of the Tevatron was 1030 cm−2 s−1, however, following upgrades,
the accelerator had been able to deliver luminosities up to 4 × 1032 cm−2 s−1.[15]

On September 27, 1993, the cryogenic cooling system of the Tevatron Accelerator was named an
International Historic Landmark by the American Society of Mechanical Engineers. The system,
which provided cryogenic liquid helium to the Tevatron's superconducting magnets, was the

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largest low-temperature system in existence upon its completion in 1978. It kept the coils of the
magnets, which bent and focused the particle beam, in a superconducting state, so that they
consumed only ⅓ of the power they would have required at normal temperatures.[8]

Discoveries
The Tevatron confirmed the existence of several subatomic particles that were predicted by
theoretical particle physics, or gave suggestions to their existence. In 1995, the CDF experiment
and DØ experiment collaborations announced the discovery of the top quark, and by 2007 they
measured its mass (172 GeV) to a precision of nearly 1%. In 2006, the CDF collaboration
reported the first measurement of Bs oscillations, and observation of two types of sigma
baryons.[16] In 2007, the DØ and CDF collaborations reported direct observation of the
"Cascade B" (Ξ−
b ) Xi baryon.
[17]

In September 2008, the DØ collaboration reported detection of the Ω− b , a "double strange"

Omega baryon with the measured mass significantly higher than the quark model
prediction.[18][19] In May 2009 the CDF collaboration made public their results on search for
Ω−b based on analysis of data sample roughly four times larger than the one used by DØ
experiment.[20] The mass measurements from the CDF experiment were 6 054.4 ± 6.8 MeV/c2
and in excellent agreement with Standard Model predictions, and no signal has been observed
at the previously reported value from the DØ experiment. The two inconsistent results from DØ
and CDF differ by 111 ± 18 MeV/c2 or by 6.2 standard deviations. Due to excellent agreement
between the mass measured by CDF and the theoretical expectation, it is a strong indication
that the particle discovered by CDF is indeed the Ω− b . It is anticipated that new data from LHC
experiments will clarify the situation in the near future.

On July 2, 2012, two days before a scheduled announcement at the Large Hadron Collider
(LHC), scientists at the Tevatron collider from the CDF and DØ collaborations announced their
findings from the analysis of around 500 trillion collisions produced since 2001: They found
that the existence of the Higgs boson was likely with a mass in the region of 115 to 135
GeV.[21][22] The statistical significance of the observed signs was 2.9 sigma, which meant that
there is only a 1-in-550 chance that a signal of that magnitude would have occurred if no
particle in fact existed with those properties. The final analysis of data from the Tevatron did
however not settle the question of whether the Higgs particle exists.[3][23] Only when the
scientists from the Large Hadron Collider announced the more precise LHC results on July 4,
2012, with a mass of 125.3 ± 0.4 GeV (CMS)[24] or 126 ± 0.4 GeV (ATLAS)[25] respectively, was
there strong evidence through consistent measurements by the LHC and the Tevatron for the
existence of a Higgs particle at that mass range.

Disruptions due to earthquakes

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Even from thousands of miles away, earthquakes caused strong enough movements in the
magnets to negatively affect the quality of particle beams and even disrupt them. Therefore,
tiltmeters were installed on Tevatron's magnets to monitor minute movements and to help
identify the cause of problems quickly. The first known earthquake to disrupt the beam was the
2002 Denali earthquake, with another collider shutdown caused by a moderate local quake on
June 28, 2004.[26] Since then, the minute seismic vibrations emanating from over 20
earthquakes were detected at the Tevatron without a shutdown including the 2004 Indian
Ocean earthquake, the 2005 Nias–Simeulue earthquake, New Zealand's 2007 Gisborne
earthquake, the 2010 Haiti earthquake and the 2010 Chile earthquake.[27]

See also
Bevatron
Large Hadron Collider
Superconducting Super Collider
Ultra-high-energy cosmic ray
Relativistic Heavy Ion Collider

References
1. "Accelerator History—Main Ring" (https://web.archive.org/web/20120509085138/http://histor
y.fnal.gov/main_ring.html#start). Fermilab History and Archives Project. Archived from the
original (http://history.fnal.gov/main_ring.html#start) on 9 May 2012. Retrieved 7 October
2012.
2. R. R. Wilson (1978). "The Tevatron" (http://lss.fnal.gov/archive/test-tm/0000/fermilab-tm-076
3.shtml). Fermilab. FERMILAB-TM-0763. {{cite journal}}: Cite journal requires
|journal= (help)
3. "Tevatron scientists announce their final results on the Higgs particle" (http://www.fnal.gov/p
ub/presspass/press_releases/2012/Higgs-Tevatron-20120702.html). Fermi National
Accelerator Laboratory. July 2, 2012. Retrieved July 7, 2012.
4. "Tevatron experiments observe evidence for Higgs-like particle" (https://cerncourier.com/a/te
vatron-experiments-observe-evidence-for-higgs-like-particle/). CERN. 23 August 2012.
Retrieved 21 April 2021.
5. Mark Alpert (29 September 2011). "Future of Top U.S. Particle Physics Lab in Jeopardy" (htt
p://www.sciam.com/article.cfm?id=future-of-top-us-particle). Scientific American. Retrieved
7 October 2012.
6. Wisniewski, Rhianna (2012-02-01). "The Tevatron's proud legacy" (https://www.symmetrym
agazine.org/article/february-2012/the-tevatrons-proud-legacy). Symmetry Magazine.
Fermilab/SLAC.
7. "Accelerator History—Main Ring transition to Energy Doubler/Saver" (https://web.archive.or
g/web/20121218092249/http://history.fnal.gov/transition.html). Fermilab History and
Archives Project. Archived from the original (http://history.fnal.gov/transition.html) on 18
December 2012. Retrieved 7 October 2012.

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8. "The Fermilab Tevatron Cryogenic Cooling System" (http://www.asme.org/getmedia/54536a

ae-9831-4a29-aabc-55b93beba1a4/169-Cryogenic-Cooling-System-Fermilab-Tevatron.aspx
). ASME. 1993. Retrieved 2015-08-12. {{cite journal}}: Cite journal requires
|journal= (help)
9. "Super Proton Synchrotron marks its 25th birthday" (http://cerncourier.com/cws/article/cern/
28470). CERN courier. 2 July 2011. Retrieved 7 October 2012.
10. "1983—The Year the Tevatron Came to Life" (http://www.fnal.gov/pub/ferminews/ferminews
03-11-01/p4.html). Fermi News. 26 (15). 2003.
11. "Interactive timeline" (http://www.fnal.gov/pub/tevatron/milestones/interactive-timeline.html).
Fermilab. Retrieved 7 October 2012.
12. "Run II begins at the Tevatron" (http://cerncourier.com/cws/article/cern/28420). CERN
courier. 30 April 2001. Retrieved 7 October 2012.
13. "Main Injector and Recycler Ring History and Public Information" (https://web.archive.org/we
b/20111015015038/http://www-fmi.fnal.gov/History/history.html). Fermilab Main Injector
department. Archived from the original (http://www-fmi.fnal.gov/History/history.html) on 15
October 2011. Retrieved 7 October 2012.
14. "Accelerators—Fermilab's Chain of Accelerators" (http://www.fnal.gov/pub/inquiring/physics/
accelerators/chainaccel.html). Fermilab. 15 January 2002. Retrieved 2 December 2009.
15. The TeVatron Collider: A Thirty-Year Campaign (http://www-ppd.fnal.gov/EPPOffice-W/collo
q/Abstracts/Peoples_3_10_10.htm) Archived (https://web.archive.org/web/20100527092615
/http://www-ppd.fnal.gov/EPPOffice-W/colloq/Abstracts/Peoples_3_10_10.htm) 2010-05-27
at the Wayback Machine
16. "Experimenters at Fermilab discover exotic relatives of protons and neutrons" (http://www.fn
al.gov/pub/presspass/press_releases/sigma-b-baryon.html). Fermilab. 2006-10-23.
Retrieved 2006-10-23.
17. "Back-to-Back b Baryons in Batavia" (http://www.fnal.gov/pub/presspass/press_releases/ba
cktobackBaryons.html). Fermilab. 2007-07-25. Retrieved 2007-07-25.
18. "Fermilab physicists discover "doubly strange" particle" (http://www.fnal.gov/pub/presspass/
press_releases/Dzero_Omega-sub-b.html). Fermilab. September 3, 2008. Retrieved
2008-09-04.
19. V. M. Abazov et al. (DØ collaboration) (2008). "Observation of the doubly strange b baryon
Ω−b". Physical Review Letters. 101 (23): 231002. arXiv:0808.4142 (https://arxiv.org/abs/0808
.4142). Bibcode:2008PhRvL.101w2002A (https://ui.adsabs.harvard.edu/abs/2008PhRvL.10
1w2002A). doi:10.1103/PhysRevLett.101.232002 (https://doi.org/10.1103%2FPhysRevLett.1
01.232002). PMID 19113541 (https://pubmed.ncbi.nlm.nih.gov/19113541). S2CID 30481085
(https://api.semanticscholar.org/CorpusID:30481085).
20. T. Aaltonen et al. (CDF Collaboration) (2009). "Observation of the Ω−b and Measurement of
the Properties of the Ξ−b and Ω−b". Physical Review D. 80 (7): 072003. arXiv:0905.3123 (https
://arxiv.org/abs/0905.3123). Bibcode:2009PhRvD..80g2003A (https://ui.adsabs.harvard.edu/
abs/2009PhRvD..80g2003A). doi:10.1103/PhysRevD.80.072003 (https://doi.org/10.1103%2
FPhysRevD.80.072003). S2CID 54189461 (https://api.semanticscholar.org/CorpusID:54189
461).
21. "Updated Combination of CDF and DØ's Searches for Standard Model Higgs Boson
Production with up to 10.0 fb-1 of Data" (http://tevnphwg.fnal.gov/results/SM_Higgs_Summe
r_12/index.html). Tevatron New Phenomena & Higgs Working Group. June 2012. Retrieved
August 2, 2012.
22. Aaltonen, T.; et al. (CDF, D0) (July 2012). "Evidence for a particle produced in association
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22. Aaltonen, T.; et al. (CDF, D0) (July 2012). "Evidence for a particle produced in association
with weak bosons and decaying to a bottom-antibottom quark pair in Higgs boson searches
at the Tevatron" (http://tevnphwg.fnal.gov/results/Higgs_bb_Summer_12/index.html).
Physical Review Letters. 109 (7): 071804. arXiv:1207.6436
(https://arxiv.org/abs/1207.6436). Bibcode:2012PhRvL.109g1804A (https://ui.adsabs.harvar
d.edu/abs/2012PhRvL.109g1804A). doi:10.1103/PhysRevLett.109.071804 (https://doi.org/1
0.1103%2FPhysRevLett.109.071804). PMID 23006359 (https://pubmed.ncbi.nlm.nih.gov/23
006359). S2CID 20050195 (https://api.semanticscholar.org/CorpusID:20050195). Retrieved
August 2, 2012.
23. Rebecca Boyle (July 2, 2012). "Tantalizing Signs of Higgs Boson Found By U.S. Tevatron
Collider" (http://www.popsci.com/technology/article/2012-07/us-scientists-almost-found-higg
s-boson-time-ran-out). Popular Science. Retrieved July 7, 2012.
24. CMS collaboration (31 July 2012). "Observation of a new boson at a mass of 125 GeV with
the CMS experiment at the LHC". Physics Letters B. 716 (2012): 30–61. arXiv:1207.7235 (h
ttps://arxiv.org/abs/1207.7235). Bibcode:2012PhLB..716...30C (https://ui.adsabs.harvard.ed
u/abs/2012PhLB..716...30C). doi:10.1016/j.physletb.2012.08.021 (https://doi.org/10.1016%2
Fj.physletb.2012.08.021).
25. ATLAS collaboration (31 July 2012). "Observation of a New Particle in the Search for the
Standard Model Higgs Boson with the ATLAS Detector at the LHC". Physics Letters B. 716
(2012): 1–29. arXiv:1207.7214 (https://arxiv.org/abs/1207.7214).
Bibcode:2012PhLB..716....1A (https://ui.adsabs.harvard.edu/abs/2012PhLB..716....1A).
doi:10.1016/j.physletb.2012.08.020 (https://doi.org/10.1016%2Fj.physletb.2012.08.020).
S2CID 119169617 (https://api.semanticscholar.org/CorpusID:119169617).
26. Was that a quake? Ask the Tevatron (http://www.symmetrymagazine.org/cms/?pid=1000767
#5)
27. Tevatron Sees Haiti Earthquake (http://news.discovery.com/space/tevatron-sees-haiti-earthq
uake.html)

Further reading
Valery Lebedev, Vladimir Shiltsev, ed. (2014). Accelerator Physics at the Tevatron Collider (
https://cds.cern.ch/record/1707550). Particle Acceleration and Detection. Springer.
Bibcode:2014aptc.book.....L (https://ui.adsabs.harvard.edu/abs/2014aptc.book.....L).
doi:10.1007/978-1-4939-0885-1 (https://doi.org/10.1007%2F978-1-4939-0885-1). ISBN 978-
1-4939-0884-4.

External links
Media related to Tevatron at Wikimedia Commons
Live Tevatron status (http://www-bd.fnal.gov/notifyservlet/www?project=outside)
FermiLab page for Tevatron (http://www.fnal.gov/pub/tevatron/tevatron-accelerator.html) –
with labelled components
The Hunt for the Higgs at Tevatron (http://apps3.aps.org/aps/meetings/april10/roser.pdf)
Technical details of the accelerators (https://web.archive.org/web/20100528045751/http://w
ww-bdnew.fnal.gov/operations/rookie_books/Concepts_v3.6.pdf)

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