View source for Fermilab

{{short description|High-energy particle physics laboratory in Illinois, US}}
{{Use mdy dates|date=August 2024}}
{{Infobox laboratory
| name            = Fermi National Accelerator Laboratory
| logo            = Fermilab logo.svg
| logo_size       =
| image           = Fermilab satellite.gif
| image_size      = 246
| caption         = A satellite view of Fermilab. The two circular structures are the Main Injector Ring (smaller) and [[Tevatron]] (larger).
| established     = {{start date and age|November 21, 1967}} (as National Accelerator Laboratory)
| budget = $739 million (2024)<ref>{{cite web | title=DOE FY 2025 Congressional Justification | access-date=September 7, 2024 | url=https://www.energy.gov/sites/default/files/2024-03/doe-fy-2025-budget-lab-table.pdf | page = 26 }}</ref>
| type            = [[Accelerator physics]]
| research_field  = Accelerator physics
| director        = [[Lia Merminga]]
| city            = [[Winfield Township, DuPage County, Illinois|Winfield Township, DuPage County]], [[Illinois]], United States
| address         = P.O. Box 500
| coordinates     = {{Coord|41|49|55|N|88|15|26|W|region:US-IL_type:landmark|display=inline,title}}
| location_map    = USA Illinois
| nickname        = Fermilab
| affiliations    = [[United States Department of Energy|U.S. Department of Energy]]<br />[[University of Chicago]]<br />[[Universities Research Association]]
| nobel_laureates = [[Leon Lederman|Leon Max Lederman]]
| website         = {{URL|fnal.gov}}
}}

'''Fermi National Accelerator Laboratory''' ('''Fermilab'''), located in [[Batavia, Illinois]], near [[Chicago]], is a [[United States Department of Energy]] [[United States Department of Energy National Labs|national laboratory]] specializing in high-energy [[particle physics]].

Fermilab's Main Injector, two miles (3.3 km) in circumference, is the laboratory's most powerful [[particle accelerator]].<ref>{{cite web |last1=Brown |first1=Bruce |title=Current and Future High Power Operation of Fermilab Main Injector |url=https://www.researchgate.net/publication/239886364 |website=Researchgate |access-date=February 25, 2021}}</ref> The accelerator complex that feeds the Main Injector is under upgrade, and construction of the first building for the new PIP-II linear accelerator began in 2020.<ref name="auto">{{cite web |last1=Biron |first1=Lauren |title=Two construction projects reach major milestones at Fermilab |url=https://news.fnal.gov/2020/07/two-construction-projects-reach-major-milestones-at-fermilab/ |website=Fermilab |date=July 22, 2020 |publisher=United States Government |access-date=February 25, 2021}}</ref> Until 2011, Fermilab was the home of the 6.28&nbsp;km (3.90&nbsp;mi) circumference [[Tevatron]] accelerator. The ring-shaped tunnels of the Tevatron and the Main Injector are visible from the air and by satellite.

Fermilab aims to become a world center in [[neutrino]] physics. It is the host of the multi-billion dollar [[Deep Underground Neutrino Experiment]] (DUNE) now under construction.<ref name=procarionov21>{{cite web |url=https://science.osti.gov/-/media/hep/hepap/pdf/202111/HEPAP_PROCARIO_202111.pdf |title=HEP Project Status, Mike Procario|website=High Energy Physics Advisory Panel November 1–2, 2021 Agenda}}</ref>  The project has suffered delays and, in 2022, the journals ''Science'' and ''Scientific American'' each published articles describing the project as "troubled".<ref name=aaasmar22>{{Cite news |author=Adrian Cho |date=March 29, 2022|publisher=Science, American Association for the Advancement of Science |url=https://www.science.org/content/article/trying-stay-ahead-competition-u-s-pares-down-troubled-3-billion-neutrino-experiment/|title=Trying to stay ahead of competition, U.S. pares down troubled $3 billion neutrino experiment}}</ref><ref name=SciAmApr22>{{cite news |last1=Lewton |first1=Thomas |title=Troubled U.S. Neutrino Project Faces Uncertain Future–and Fresh Opportunities |url=https://www.scientificamerican.com/article/troubled-u-s-neutrino-project-faces-uncertain-future-and-fresh-opportunities/ |access-date=April 13, 2022 |publisher=Scientific American |date=April 13, 2022}}</ref>
Ongoing neutrino experiments are [[ICARUS experiment|ICARUS]] (Imaging Cosmic and Rare Underground Signals) and [[NOνA]] ([[NuMI]] Off-Axis ν<sub>e</sub> Appearance). Completed neutrino experiments include [[MINOS]] (Main Injector Neutrino Oscillation Search), [[MINOS+]], [[MiniBooNE]] and [[SciBooNE]] (SciBar Booster Neutrino Experiment) and [[MicroBooNE]] (Micro Booster Neutrino Experiment).

On-site experiments outside of the neutrino program include the [[Fermilab E-906/SeaQuest|SeaQuest]] fixed-target experiment and [[Muon g-2]]. Fermilab continues to participate in the work at the [[Large Hadron Collider]] (LHC); it serves as a Tier 1 site in the Worldwide LHC Computing Grid.<ref>{{cite web|author      = National Science Foundation|url         = http://www.uslhc.us/The_US_and_the_LHC/Computing|title       = The US and LHC Computing|access-date  = January 11, 2011|url-status  = dead|archive-url  = https://web.archive.org/web/20110110155355/http://uslhc.us/The_US_and_the_LHC/Computing|archive-date = January 10, 2011}}</ref> Fermilab also pursues research in quantum information science.<ref>{{cite news |last1=Caine |first1=Paul |title=Argonne, Fermilab at Forefront of 'Transformational' Quantum Research |url=https://news.wttw.com/2020/09/01/argonne-fermilab-forefront-transformational-quantum-research |access-date=March 9, 2021 |publisher=WTTW |date=September 1, 2020}}</ref> It founded the Fermilab Quantum Institute in 2019.<ref>{{cite web |last1=Salles |first1=Andre |title=Fermilab launches new institute for quantum science |url=https://news.fnal.gov/2019/11/fermilab-launches-new-institute-for-quantum-science/ |website=Fermilab |date=November 18, 2019 |publisher=United States Government |access-date=March 9, 2021}}</ref> Since 2020, it also is home to the SQMS (Superconducting Quantum Materials and Systems) Center.<ref>{{cite web |last1=Biron |first1=Lauren |title=White House Office of Technology Policy, National Science Foundation and Department of Energy announce over $1 billion in awards for artificial intelligence and quantum information science research institutes |url=https://news.fnal.gov/2020/08/white-house-office-of-technology-policy-national-science-foundation-and-department-of-energy-announce-over-1-billion-in-awards-for-artificial-intelligence-and-quantum-information-science-research-in/ |website=Fermilab |date=August 26, 2020 |publisher=United States Government |access-date=March 9, 2021}}</ref>

From 2007 through 2024, Fermilab was operated by the Fermi Research Alliance (FRA), a joint venture of the [[University of Chicago]], and the [[Universities Research Association]] (URA).   Starting January 1, 2025, the management will be taken over by the Fermi Forward Discovery Group, LLC (FFDG), which is a consortium of FRA, Amentum Environment & Energy, Inc., and Longenecker & Associates. The management shake-up resulted from serious performance issues,<ref name="chomarch23">{{cite news |last1=Cho |first1=Adrian |date=March 22, 2023 |title=Major shake-up coming for Fermilab, the troubled U.S. particle physics center |url=https://www.science.org/content/article/major-shake-coming-fermilab-troubled-u-s-particle-physics-center |access-date=March 23, 2023 |publisher=Science}}</ref><ref name="wttwOct2024">{{cite news |last1=Rutecki |first1=Jared |title=US Department of Energy Awards New Fermilab Management Contract Amid Turbulent Period for the Research Facility |url=https://news.wttw.com/2024/10/01/us-department-energy-awards-new-fermilab-management-contract-amid-turbulent-period |access-date=1 October 2024 |publisher=WTTW Investigations |date=1 October 2024}}</ref> including those reflected in the July 15, 2024 "whistleblowers" report.<ref name="whistleblow">{{cite arXiv |last1=A Group of Whistleblowers from Fermilab |title=Preparing Fermilab to Carry Out the P5 Plan |date=2024 |class=physics.acc-ph |eprint=2407.13924 }}</ref> 

Fermilab is a part of the [[Illinois Technology and Research Corridor]]. [[Argonne National Laboratory]], which is another USDoE national laboratory, is located approximately 20 miles away.

Asteroid [[11998 Fermilab]] is named in honor of the laboratory.

==History==<!-- This section is linked from [[Michael Witherell]] -->
[[File:Fermilab Robert Rathbun Wilson Hall 2011.jpg|thumb|Robert Rathbun Wilson Hall]]

[[Weston, DuPage County, Illinois|Weston, Illinois]], was a community next to [[Batavia, Illinois|Batavia]] voted out of existence by its village board in 1966 to provide a site for Fermilab.<ref>
{{cite web|author      = Fermilab|url         = http://history.fnal.gov/exhibit/weston.html|title       = Before Weston|access-date  = November 25, 2009|url-status     = live|archive-url  = https://web.archive.org/web/20100305000103/http://history.fnal.gov/exhibit/weston.html|archive-date = March 5, 2010}}</ref>

The laboratory was founded in 1969 as the '''National Accelerator Laboratory''';<ref>{{cite news |last1=Kolb |first1=Adrienne |title=The founding of Fermilab |url=https://cerncourier.com/a/the-founding-of-fermilab/ |access-date=February 25, 2021 |publisher=Cern Courier |date=May 19, 2017}}</ref> it was renamed in honor of [[Enrico Fermi]] in 1974. The laboratory's first director was [[Robert Rathbun Wilson]], under whom the laboratory opened ahead of time and under budget. Many of the sculptures on the site are of his creation. He is the namesake of the site's high-rise laboratory building, whose unique shape has become the symbol for Fermilab and which is the center of activity on the campus.

After Wilson stepped down in 1978 to protest the lack of funding for the lab, [[Leon M. Lederman]] took on the job. It was under his guidance that the original accelerator was replaced with the Tevatron, an accelerator capable of colliding [[proton]]s and [[antiproton]]s at a combined energy of 1.96 TeV. Lederman stepped down in 1989 and remained director emeritus until his death. The science education center at the site was named in his honor.

The later directors are:
* [[John Peoples, Jr.|John Peoples]], 1989 to 1996
* [[Michael S. Witherell]], July 1999 to June 2005
* [[Piermaria Oddone]], July 2005 to July 2013<ref>{{cite news|title=Fermilab director Oddone announces plan to retire next year|url=http://beaconnews.suntimes.com/news/14177501-418/fermilab-director-oddone-announces-plan-to-retire-next-year.html|access-date=July 10, 2013|newspaper=The Beacon-News|date=August 2, 2012|url-status=dead|archive-url=https://web.archive.org/web/20131004213627/http://beaconnews.suntimes.com/news/14177501-418/fermilab-director-oddone-announces-plan-to-retire-next-year.html|archive-date=October 4, 2013}}</ref>
* [[Nigel Lockyer]], September 2013 to April 2022<ref>
{{cite news|title=New Fermilab director named|url=http://www.chicagobusiness.com/article/20130621/NEWS07/130629955/new-fermilab-director-named|access-date=July 10, 2013|newspaper=Crain's Chicago Business|date=June 21, 2013|url-status=live|archive-url=https://web.archive.org/web/20171114203543/http://www.chicagobusiness.com/article/20130621/NEWS07/130629955/new-fermilab-director-named|archive-date=November 14, 2017}}</ref>
* [[Lia Merminga]], April 2022 to present<ref>{{cite news |title=Lia Merminga appointed director of Fermi National Accelerator Laboratory |url=https://news.fnal.gov/2022/04/lia-merminga-appointed-director-of-fermilab/ |access-date=April 16, 2022 |publisher=Fermilab News |date=April 5, 2022}}</ref>

==Accelerators==
===Tevatron===
Prior to the startup in 2008 of the [[Large Hadron Collider]] (LHC) near Geneva, Switzerland, the [[Tevatron]] was the most powerful particle accelerator in the world, accelerating protons and antiprotons to energies of 980&nbsp;[[GeV]], and producing proton-antiproton collisions with energies of up to 1.96&nbsp;[[TeV]], the first accelerator to reach one "tera-electron-volt" energy.<ref>{{cite arXiv |last1=Shiltsev |first1=Vladimir |title=Achievements and Lessons from Tevatron |year=2012 |class=physics.acc-ph |eprint=1205.0536}}</ref>  At {{convert|3.9|mi|km}}, it was the world's fourth-largest particle accelerator in circumference.  One of its most important achievements was the 1995 discovery of the [[top quark]], announced by research teams using the Tevatron's [[Collider Detector at Fermilab|CDF]] and [[DØ experiment|DØ]] detectors.<ref>{{cite journal |last1=Bandurin, Dmitry |display-authors=etal |title=Review of physics results from the Tevatron |journal=International Journal of Modern Physics A |year=2015 |volume=30 |issue=6 |doi=10.1142/S0217751X15410018 |arxiv=1409.4861|bibcode=2015IJMPA..3041001B |s2cid=118699490 }}</ref> It was shut down in 2011.

===Fermilab Accelerator Complex===
Since 2013, the first stage in the acceleration process (pre-accelerator injector) in the Fermilab chain of accelerators<ref>{{cite web |title=Animation of Fermilab's Accelerator Complex |url=https://www.youtube.com/watch?v=vElqxVUoKSE&feature=youtu.be | archive-url=https://ghostarchive.org/varchive/youtube/20211211/vElqxVUoKSE| archive-date=December 11, 2021 | url-status=live|website=YouTube | date=March 21, 2018 |publisher=Fermilab |access-date=February 25, 2021}}{{cbignore}}</ref> takes place in two [[ion source]]s which ionize [[hydrogen]] gas. The gas is introduced into a container lined with molybdenum electrodes, each a matchbox-sized, oval-shaped cathode and a surrounding anode, separated by 1&nbsp;mm and held in place by glass ceramic insulators. A [[magnetron|Cavity_magnetron]] generates a plasma to form the ions near the metal surface. The ions are accelerated by the source to 35&nbsp;[[keV]] and matched by low energy beam transport (LEBT) into the [[radio-frequency quadrupole]] (RFQ) which applies a 750&nbsp;[[keV]] electrostatic field giving the ions their second acceleration. At the exit of RFQ, the beam is matched by medium energy beam transport (MEBT) into the entrance of the [[linear accelerator]] (linac).<ref>{{cite conference |first1=J.P. |last1=Carneiro |first2=F.G. |last2=Garcia |first3=J.-F. |last3=Ostiguy |first4=A. |last4=Saini |first5=R. |last5=Zwaska |title=Transmission efficiency measurement at the FNAL 4-rod RFQ (FERMILAB-CONF-14-452-APC) |journal=27th International Linear Accelerator Conference (LINAC14) |date=November 13, 2014 |url=https://www-ad.fnal.gov/proton/PIP/Communicate/Calendar/Repository/2014/MOPP050_Linac2014_Carneiro.pdf |access-date=August 12, 2015 |arxiv=1411.3614 |isbn=978-3-95450-142-7 |pages=168–170 |bibcode=2014arXiv1411.3614C |url-status=live |archive-url=https://web.archive.org/web/20160423174912/https://www-ad.fnal.gov/proton/PIP/Communicate/Calendar/Repository/2014/MOPP050_Linac2014_Carneiro.pdf |archive-date=April 23, 2016 }}</ref>

The next stage of acceleration is a linear particle accelerator (linac). This stage consists of two segments. The first segment has five drift tube cavities, operating at 201&nbsp;MHz. The second stage has seven&nbsp;side-coupled cavities, operating at 805&nbsp;MHz. At the end of linac, the particles are accelerated to 400&nbsp;[[MeV]], or about 70% of the [[speed of light]].<ref name=slideshow>{{cite web |title=Fermilab Linac Slide Show Description |url=http://www-ad.fnal.gov/proton/NewProtonWWW/NewLinacWWW/images/stamps/slideShow.html |website=Fermilab |access-date=August 12, 2015 |url-status=live |archive-url=https://web.archive.org/web/20160418203333/http://www-ad.fnal.gov/proton/NewProtonWWW/NewLinacWWW/images/stamps/slideShow.html |archive-date=April 18, 2016}}</ref><ref>{{cite book |last1=Kubik |first1=Donna |title=Fermilab |date=2005 |url=http://home.fnal.gov/~kubik/Accelerators/Fermilab.pdf |access-date=August 12, 2015 |url-status=live |archive-url=https://web.archive.org/web/20160422151506/http://home.fnal.gov/~kubik/Accelerators/Fermilab.pdf |archive-date=April 22, 2016}}</ref> Immediately before entering the next accelerator, the H<sup>−</sup> ions pass through a carbon foil, becoming H<sup>+</sup> ions ([[proton]]s).<ref name=accelerator>{{cite web |title=Accelerator |url=http://www.fnal.gov/pub/tevatron/tevatron-accelerator.html |website=Fermilab |access-date=August 12, 2015 |url-status=live |archive-url=https://web.archive.org/web/20150804144005/http://www.fnal.gov/pub/tevatron/tevatron-accelerator.html |archive-date=August 4, 2015}}</ref>

The resulting protons then enter the booster ring, a {{cvt|468|m|ft}} circumference circular accelerator whose magnets bend beams of protons around a circular path. The protons travel around the Booster about 20,000&nbsp;times in 33&nbsp;milliseconds, adding energy with each revolution until they leave the Booster accelerated to 8&nbsp;[[GeV]].<ref name=accelerator/> In 2021, the lab announced that its latest superconducting [[Yttrium barium copper oxide|YBCO]] magnet could increase field strength at a rate of 290 [[Tesla (unit)|tesla]] per second, reaching a peak magnetic field strength of around 0.5 tesla.<ref>{{Cite web|last=Lavars|first=Nick|date=December 2, 2021|title=Next-gen particle accelerator magnet ramps up at record speed|url=https://newatlas.com/technology/next-generation-particle-accelerator-magnet-record-speed/|access-date=December 2, 2021|website=New Atlas|language=en-US}}</ref>

The final acceleration is applied by the Main Injector [circumference {{cvt|3319.4|m|ft}}], which is the smaller of the two rings in the last picture below (foreground). Completed in 1999, it has become Fermilab's "particle switchyard"<ref>{{cite web |title=Switchyard |url=https://www.fnal.gov/pub/news03/definitions/switchyard.html |website=Operation Terminology |publisher=Fermilab |access-date=1 October 2024}}</ref> in that it can route protons to any of the experiments installed along the beam lines after accelerating them to 120&nbsp;GeV. Until 2011, the Main Injector provided protons to the [[antiproton]] ring [circumference {{cvt|6283.2|m|ft}}] and the [[Tevatron]] for further acceleration but now provides the last push before the particles reach the beam line experiments.

<gallery mode="packed" class="center">
Two ion sources at Fermilab.jpg|Two ion sources at the center with two high-voltage electronics cabinets next to them<ref name=35years>{{cite web |title=35&nbsp;years of H<sup>−</sup> ions at Fermilab |url=http://www-ad.fnal.gov/proton/PIP/Communicate/Calendar/Repository/2014/35%20years%20of%20H-%20ions%20at%20Fermilab.pdf |website=Fermilab |access-date=12 August 2015 |url-status=live |archive-url=https://web.archive.org/web/20151018080322/http://www-ad.fnal.gov/proton/PIP/Communicate/Calendar/Repository/2014/35%20years%20of%20H-%20ions%20at%20Fermilab.pdf |archive-date=18 October 2015}}</ref>
RFQ MEBT and linac at Fermilab.jpg|Beam direction right to left: RFQ (silver), MEBT (green), first drift tube linac (blue)<ref name=35years/>
The 7835 power amplifiers at Fermilab.JPG|A 7835 power amplifier that is used at the first stage of linac<ref name=slideshow/>
A 12 MW klystron at Fermilab.jpg|A 12&nbsp;MW [[klystron]] used at the second stage of linac<ref name=slideshow/>
The 805 MHz side-couple cavities.jpg|A cutaway view of the 805&nbsp;MHz side-couple cavities<ref>{{cite conference |last1=May |first1=Michael P. |last2=Fritz |first2=James R. |last3=Jurgens |first3=Thomas G. |last4=Miller |first4=Harold W. |last5=Olson |first5=James |last6=Snee |first6=Daniel |title=Mechanical construction of the 805&nbsp;MHz side couple cavities for the Fermilab Linac upgrade |conference=Linear Accelerator Conference |date=1990 |journal=Proceedings of the 1990 Linear Accelerator Conference |url=https://accelconf.web.cern.ch/accelconf/l90/papers/mo423.pdf |access-date=13 August 2015 |location=Albuquerque, New Mexico, USA |url-status=live |archive-url=https://web.archive.org/web/20150707145718/http://accelconf.web.cern.ch/AccelConf/l90/papers/mo423.pdf |archive-date=7 July 2015}}</ref>
Booster ring at Fermilab.jpg|Booster ring<ref>{{cite web |title=Wilson Hall & vicinity |url=https://www.fnal.gov/pub/visiting/map/wilson.html |website=Fermilab |access-date=12 August 2015 |url-status=live |archive-url=https://web.archive.org/web/20150917055551/http://www.fnal.gov/pub/visiting/map/wilson.html |archive-date=17 September 2015}}</ref>
Fermilab.jpg|Fermilab's accelerator rings. The main injector is in the foreground, and the [[antiproton]] ring and [[Tevatron]] (inactive since 2011) are in the background.
Fermilab g-2 (E989) ring.jpg| The E989 storage-ring magnet at Fermilab
</gallery>

===Proton improvement plan===
Recognizing higher demands of proton beams to support new experiments, Fermilab began to improve their accelerators in 2011. Expected to continue for many years,<ref name=pip/> the project has two phases: Proton Improvement Plan (PIP) and Proton Improvement Plan-II (PIP-II).<ref name=mwproton>{{cite report |last1=Holmes |first1=Steve |title=MegaWatt Proton Beams for Particle Physics at Fermilab |date=December 16, 2013 |publisher=Fermilab |url=https://pip2.fnal.gov/files/P5_SDH_v5.pdf |access-date=August 15, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150905210745/http://pip2.fnal.gov/files/P5_SDH_v5.pdf |archive-date=September 5, 2015 }}</ref>

;PIP (2011–2018)
The overall goals of PIP are to increase the repetition rate of the Booster beam from 7&nbsp;Hz to 15&nbsp;Hz and replace old hardware to increase reliability of the operation.<ref name=mwproton/> Before the start of the PIP project, a replacement of the pre-accelerator injector was underway. The replacement of almost 40&nbsp;year-old [[Cockcroft–Walton generator]]s to RFQ started in 2009 and completed in 2012. At the Linac stage, the analog beam position monitor (BPM) modules were replaced with digital boards in 2013. A replacement of Linac vacuum pumps and related hardware is expected to be completed in 2015. A study on the replacement of 201&nbsp;MHz drift tubes is still ongoing. At the boosting stage, a major component of the PIP is to upgrade the Booster ring to 15&nbsp;Hz operation. The Booster has 19&nbsp;radio frequency stations. Originally, the Booster stations were operating without [[Solid-state electronics|solid-state]] drive system which was acceptable for 7&nbsp;Hz but not 15&nbsp;Hz operation. A demonstration project in 2004 converted one of the stations to solid state drive before the PIP project. As part of the project, the remaining stations were converted to solid state in 2013. Another major part of the PIP project is to refurbish and replace 40&nbsp;year-old Booster cavities. Many cavities have been refurbished and tested to operate at 15&nbsp;Hz. The completion of cavity refurbishment is expected in 2015, after which the repetition rate can be gradually increased to 15&nbsp;Hz operation. A longer term upgrade is to replace the Booster cavities with a new design. The research and development of the new cavities is underway, with replacement expected in 2018.<ref name=pip>{{cite conference |title=Proceedings of IPAC2014 |year=2014 |place=Dresden, Germany |isbn=978-3-95450-132-8 |pages=3409–3411 |conference=5th International Particle Accelerator Conference |conference-url=http://accelconf.web.cern.ch/AccelConf/IPAC2014 |chapter-url=http://accelconf.web.cern.ch/AccelConf/IPAC2014/papers/thpme075.pdf |access-date=August 15, 2015 |chapter=FNAL – The Proton Improvement Plan (PIP) |url-status=live |archive-url=https://web.archive.org/web/20150626175507/http://accelconf.web.cern.ch/AccelConf/IPAC2014/papers/thpme075.pdf |archive-date=June 26, 2015 }}</ref>

;PIP-II
[[File:Two AES 5-cells cavities.jpg|thumb|Prototypes of [[superconducting radio frequency|SRF]] cavities to be used in the last segment of PIP-II Linac<ref>{{cite conference |conference=27th Linear Accelerator Conference (LINAC2014) |conference-url=http://linac14.org/ |location=Geneva, Switzerland |date=September 2014 |isbn=978-3-95450-142-7 |pages=171–173 |title=Development of 5&nbsp;Cell Beta=0.9&thinsp;650&nbsp;MHz Cavities for Project&nbsp;X |url=http://accelconf.web.cern.ch/AccelConf/LINAC2014/papers/mopp052.pdf |access-date=August 16, 2015 |first1=M.H. |last1=Awida |first2=M. |last2=Foley |first3=I. |last3=Gonin |first4=A. |last4=Grassellino |first5=C. |last5=Grimm |first6=T. |last6=Khabiboulline |first7=A. |last7=Lunin |first8=A. |last8=Rowe |first9=V. |last9=Yakovlev |url-status=live |archive-url=https://web.archive.org/web/20150702020105/http://accelconf.web.cern.ch/AccelConf/LINAC2014/papers/mopp052.pdf |archive-date=July 2, 2015}}</ref>]]

The goals of PIP-II include a plan to delivery 1.2&nbsp;MW of proton beam power from the Main Injector to the [[Deep Underground Neutrino Experiment]] target at 120&nbsp;GeV and the power near 1&nbsp;MW at 60&nbsp;GeV with a possibility to extend the power to 2&nbsp;MW in the future. The plan should also support the current 8&nbsp;GeV experiments including Mu2e, Muon g−2, and other short-baseline neutrino experiments. These require an upgrade to the Linac to inject to the Booster with 800&nbsp;MeV. The first option considered was to add 400&nbsp;MeV "afterburner" superconducting Linac at the tail end of the existing 400&nbsp;MeV. This would have required moving the existing Linac up {{Convert|50|m}}. However, there were many technical issues with this approach. Instead, Fermilab is building a new 800&nbsp;MeV superconducting Linac to inject to the Booster ring.

Construction of the first building for the PIP-II accelerator began in 2020.<ref name="auto"/> The new Linac site will be located on top of a small portion of [[Tevatron]] near the Booster ring in order to take advantage of existing electrical and water, and cryogenic infrastructure. The PIP-II Linac will have low energy beam transport line (LEBT), radio frequency quadrupole (RFQ), and medium energy beam transport line (MEBT) operated at the room temperature at with a 162.5&nbsp;MHz and energy increasing from 0.03&nbsp;MeV. The first segment of Linac will be operated at 162.5&nbsp;MHz and energy increased up to 11&nbsp;MeV. The second segment of Linac will be operated at 325&nbsp;MHz and energy increased up to 177&nbsp;MeV. The last segment of linac will be operated at 650&nbsp;MHz and will have the final energy level of 800&nbsp;MeV.<ref>{{cite report |title=Proton Improvement Plan&nbsp;II |date=December 12, 2013 |publisher=Fermilab |url=http://projectx-docdb.fnal.gov/cgi-bin/RetrieveFile?docid=1232&filename=1.2%20MW%20Report_Rev5.pdf&version=3 |access-date=August 15, 2015 |url-status=live |archive-url=https://web.archive.org/web/20160422155048/http://projectx-docdb.fnal.gov/cgi-bin/RetrieveFile?docid=1232&filename=1.2%20MW%20Report_Rev5.pdf&version=3 |archive-date=April 22, 2016}}</ref>

As of 2022, the estimated PIP-II accelerator start date for the accelerator is 2028.<ref name=enddate>{{cite news| title=PIP-II: An international effort breaking new ground in particle physics| url=https://www.innovationnewsnetwork.com/pip-ii-enhancements-fermilab-accelerator-complex/18907/|date=March 4, 2022|work=Innovation News Network}}</ref> The project was approved for construction in April 2022 with an expected cost to the Department of Energy of $978M and with an additional $330M in contributions from international partners.<ref>{{cite news |last1=Thomas |first1=Will |title=Fermilab Accelerator Upgrade Moves Into Construction Phase |url=https://www.aip.org/fyi/fyi-this-week/week-april-25-2022 |publisher=FYI: American Institute of Physics |date=April 25, 2022}}</ref>

==Experiments==
===Discoveries by Fermilab experiments===
The following particles were first directly observed at Fermilab:
[[File:Fermilab - CDF detector rolling in for run 2.jpg|thumb|Fermilab's CDF detector]]
* The [[top quark]]<ref>{{cite news |last1=Johnson |first1=George |title=Physicists Weigh In: The Quark Is a Porker |url=https://www.nytimes.com/1995/03/05/weekinreview/feb.26-march-4-physicists-weigh-in-the-quark-is-a-porker.html |access-date=April 30, 2022 |work=New York Times |date=March 5, 1995}}</ref> announced in 1995 by the [[DØ experiment]] and [[CDF experiment]].
* The [[bottom quark]], which was observed as a quark-antiquark pair called the [[Upsilon meson]]<ref>{{Cite web |url=https://history.fnal.gov/historical/experiments/botqrk.html |series=Fermilab History and Archives Project |title=Discovery of the bottom quark, Upsilon |website=history.fnal.gov |access-date=July 10, 2021 }}</ref> announced in 1977 by Experiment 228.
* The [[tau neutrino]], announced in July 2000 by the [[DONUT]] collaboration.<ref>{{cite news |last1=Jackson |first1=Judy |title=Physicists Find First Direct Evidence for Tau Neutrino at Fermilab |url=https://news.fnal.gov/2000/07/physicists-find-first-direct-evidence-tau-neutrino-fermilab/ |access-date=April 30, 2022 |publisher=Fermilab News |date=July 20, 2000}}</ref>
* The [[omega baryon|bottom Omega baryon]] ({{SubatomicParticle|Bottom Omega-}}), announced by the [[DØ experiment]] of Fermilab in 2008.<ref>{{cite news |publisher=Fermilab |date=September 9, 2008 |title=Fermilab physicists discover "doubly strange" particle |url=http://www.fnal.gov/pub/presspass/press_releases/Dzero_Omega-sub-b.html |url-status=live |archive-url=https://web.archive.org/web/20080905221150/http://www.fnal.gov/pub/presspass/press_releases/Dzero_Omega-sub-b.html |archive-date=September 5, 2008}}</ref>

In 1999, physicists at on the KTeV experiment were also the first to observe [[CP violation#CP violation in the Standard Model|direct CP violation]] in [[kaon]] decays.<ref>{{cite news |last1=O'Boyle |first1=LuAnne |title=Fermilab Physicists Find New Matter-Antimatter Asymmetry |url=https://news.fnal.gov/1999/03/fermilab-physicists-find-new-matter-antimatter-asymmetry/ |access-date=April 30, 2022 |publisher=Fermilab News |date=March 1, 1999}}</ref>

The [[DØ experiment]] and [[CDF experiment]] each made important contributions to the observation of the [[Higgs Boson]], announced in 2012.<ref>{{cite news |last1=Kurt |first1=Reisselmann |title=Tevatron scientists announce their final results on the Higgs particle |url=https://news.fnal.gov/2012/07/tevatron-scientists-announce-final-results-higgs-particle/ |access-date=April 30, 2022 |publisher=Fermilab News |date=July 2, 2012}}</ref>

===Evolution of the post-Tevatron experimental program===
Fermilab dismantled the CDF ([[Collider Detector at Fermilab]])<ref>{{cite news |last1=Ayshford |first1=Emily |title=Retired equipment lives on in new physics experiments |url=https://www.symmetrymagazine.org/article/retired-equipment-lives-on-in-new-physics-experiments |access-date=February 25, 2021 |publisher=Symmetry |date=January 30, 2019}}</ref> experiment to make the space available for IARC (Illinois Accelerator Research Center).<ref>{{cite journal |last1=Kroc |first1=Thomas |title=Illinois Accelerator Research Center |journal=Physics Procedia |year=2017 |volume=90 |page=92 |doi=10.1016/j.phpro.2017.09.030 |arxiv=1705.00073|bibcode=2017PhPro..90...92K |s2cid=113419509 }}</ref>

Fermilab physicists continue to play a key role in the world-wide collider program.
The LHC Physics Center (LPC) at Fermilab is a regional center of the [[Compact Muon Solenoid]] Collaboration (the experiment is housed at [[CERN]]). The LPC offers a vibrant community of CMS scientists from the US and plays a major role in the CMS detector commissioning, and in the design and development of the detector upgrade.<ref>{{Cite web |url=https://lpc.fnal.gov/|title=LHC Physics Center |website=lpc.fnal.gov |access-date=November 12, 2019 }}</ref> Fermilab is the host laboratory for USCMS,<ref>{{cite web | title=USCMS web page |url=https://uscms.org}}</ref> which includes researchers from 50 U.S. universities including 715 students. Fermilab hosts the largest CMS Tier 1 computing center, handling approximately 40% of global CMS Tier 1 computing requests. On February 9, 2022, Fermilab's [[Patricia McBride (physicist)]] was elected spokesperson of the CMS collaboration.<ref>{{cite web | title=Fermilab's Patty McBride elected next CMS spokesperson | date=March 3, 2022| url=https://news.fnal.gov/2022/03/fermilabs-patty-mcbride-elected-next-cms-spokesperson/}}</ref>

During this time-frame, the laboratory also established a new program in research in cutting-edge information science, including the development of quantum teleportation technology<ref>{{cite journal |last1=Valivarthi, Raju |display-authors=etal |title=Teleportation Systems Toward a Quantum Internet |journal=PRX Quantum |year=2020 |volume=1 |issue=2 |page=020317 |doi=10.1103/PRXQuantum.1.020317 |arxiv=2007.11157|bibcode=2020PRXQ....1b0317V |s2cid=220686903 }}</ref> for the quantum internet and increasing the lifetime of superconducting resonators<ref>{{cite journal |last1=Romanenko, A |display-authors=etal |title=Three-Dimensional Superconducting Resonators at T < 20 mK with Photon Lifetimes up to τ = 2 s |journal=Physical Review Applied |date=March 2020 |volume=13 |issue=3 |page=034032 |doi=10.1103/PhysRevApplied.13.034032 |arxiv=1810.03703 |bibcode=2020PhRvP..13c4032R |doi-access=free}}</ref> for use in quantum computers.

===On-site program in the 2020s===
The on-site program in the 2020s is largely focused on the ''Intensity Frontier'' of particle physics, especially neutrino physics and rare physics searches using muons.   A program exploring nucleon structure is also continuing.

====List of recent past, ongoing, and planned experiments running on-site====
* [[ANNIE]]: The Accelerator Neutrino Neutron Interaction Experiment <ref>{{cite web |title=ANNIE |url=https://annie.fnal.gov/ |website=Fermilab |publisher=Fermi National Accelerator Laboratory |access-date=July 2, 2023}}</ref> (Status, June 2023:  completed run, planned future run)
* [[Deep Underground Neutrino Experiment]] (DUNE), formerly known as Long Baseline Neutrino Experiment (LBNE)<ref>{{cite web |title=LBNF/DUNE: An international flagship neutrino experiment |url=https://www.fnal.gov/pub/science/lbnf-dune/index.html |website=Fermilab |access-date=June 7, 2019}}</ref>  (Status, June 2023:  planned future run)
* [[ICARUS experiment]]: Originally located at the [[Laboratori Nazionali del Gran Sasso]] (LNGS) and moved to Fermilab. <ref>{{cite web |title=ICARUS |url=https://icarus.fnal.gov/ |website=Fermilab |publisher=Fermi National Accelerator Laboratory |access-date=July 2, 2023}}</ref>  (Status, June 2023: running)
* [[MiniBooNE]]: Mini Booster Neutrino Experiment<ref>{{cite web |title=Intensity Frontier {{!}} MiniBooNE |url=https://www.fnal.gov/pub/science/experiments/intensity/miniboone.html |website=Fermilab |access-date=June 7, 2019}}</ref> (Status, June 2023:  completed run)
* [[MicroBooNE]]: Micro Booster Neutrino Experiment<ref>{{cite web |title=MicroBooNE Collaboration |url=https://microboone.fnal.gov/collaboration/ |website=Fermilab |access-date=June 7, 2019}}</ref> (Status, June 2023:  completed run)
* [[MINERνA]]: Main INjector ExpeRiment with νs on As<ref>{{cite web |title=MINERvA: Bringing neutrinos into sharp focus |url=https://minerva.fnal.gov/ |website=Fermilab |access-date=June 7, 2019}}</ref>  (Status, June 2023:  completed run)
* [[Mu2e]]: Muon-to-Electron Conversion Experiment<ref>{{cite web |title=Mu2e: muon-to-electron-conversion experiment |url=https://mu2e.fnal.gov/ |website=Mu2e Fermilab |access-date=June 7, 2019}}</ref> (Status, June 2023:  planned future run)
* [[Muon g−2]]: Measurement of the [[anomalous magnetic dipole moment]] of the [[muon]]<ref>{{cite web |title=Muon g-2 Experiment |url=http://muon-g-2.fnal.gov/ |website=Muon-g-2 Fermilab |access-date=June 7, 2019}}</ref> (Status, June 2023:  completed run)
* [[NOνA]]: NuMI Off-axis ν<sub>e</sub> Appearance<ref>{{cite web |title=NOvA Experiment |url=https://novaexperiment.fnal.gov/ |website=NOvA Experiment Fermilab |access-date=June 7, 2019}}</ref> (Status, June 2023:  running)
* [[Fermilab E-906/SeaQuest|SeaQuest]]<ref>{{cite web |title=Argonne Physics Division - E-906/SeaQuest |url=https://www.phy.anl.gov/mep/drell-yan/index.html |website=www.phy.anl.gov |access-date=June 7, 2019}}</ref> (Status, June 2023:  completed run)
* SBND: Short-Baseline Neutrino Detector<ref>{{cite journal |last1=Machado |first1=Pedro |title=The Short-Baseline Neutrino Program at Fermilab |journal=Annual Review of Nuclear and Particle Science |year=2019 |volume=69 |pages=363–387 |doi=10.1146/annurev-nucl-101917-020949 |arxiv=1903.04608|bibcode=2019ARNPS..69..363M |s2cid=119088967 }}</ref> (Status, June 2023: planned future run)
* SpinQuest <ref>{{cite web |title=SpinQuest |url=https://spinquest.fnal.gov/ |website=Fermilab |publisher=Fermi National Accelerator Laboratory |access-date=July 2, 2023}}</ref> (Status, June 2023:  planned future run)

====LBNF/DUNE====
Fermilab strives to become the world leader in [[neutrino]] physics through the [[Deep Underground Neutrino Experiment]] at the [[Long Baseline Neutrino Facility]]. Other leaders are [[CERN]], which leads in [[Accelerator physics]] with the [[Large Hadron Collider]] (LHC), and Japan, which has been approved to build and lead the [[International Linear Collider]] (ILC). Fermilab will be the site of LBNF's future beamline, and the [[Sanford Underground Research Facility]] (SURF), in Lead, SD, is the site selected to house the massive far detector. The term "baseline" refers to the distance between the neutrino source and the detector. The far detector current design is for four modules of instrumented liquid argon with a fiducial volume of 10 kilotons each.

According to the 2016 Conceptual Design Report, the first two modules were expected to be complete in 2024, with the beam operational in 2026. The final modules were planned to be operational in 2027.<ref>{{cite arXiv |eprint=1601.05471 |display-authors=etal |last1=Acciarri |first1=R. |title=Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 1: The LBNF and DUNE Projects |class=physics.ins-det |year=2016}}</ref> In 2022, the cost for two far detector modules and the beam, alone, had risen to $3B. This led to a decision by the Department of Energy Office of Science to phase the experiment.<ref name=aaasmar22/> Phase I would consist of two modules, to be completed in 2028–29, and the beamline, to be completed in 2032. The installation of phase II, the remaining two far detector modules, is not yet planned and will be at a cost above the $3B estimate for phase I.<ref name=aaasmar22/>

A large prototype detector constructed at CERN took data with a test beam from 2018 to 2020. The results show that ProtoDUNE performed with greater than 99% efficiency.<ref>{{cite journal |last1=Abi, B |display-authors=etal |title=First results on ProtoDUNE-SP liquid argon time projection chamber performance from a beam test at the CERN Neutrino Platform |journal=Journal of Instrumentation |date=December 3, 2020 |volume=15 |issue=12 |pages=12004 |doi=10.1088/1748-0221/15/12/P12004 |arxiv=2007.06722 |bibcode=2020JInst..15P2004A |doi-access=free}}</ref>

LBNF/DUNE program in neutrino physics plans to measure fundamental physical parameters with high precision and to explore physics beyond the [[Standard Model]]. The measurements DUNE will make are expected to greatly increase the physics community's understanding of neutrinos and their role in the universe, thereby better elucidating the nature of matter and anti-matter. It will send the world's highest-intensity neutrino beam to a near detector on the Fermilab site and the far detector 800 miles (1300&nbsp;km) away at SURF.

====About other neutrino experiments====
The MiniBooNE detector was a {{convert|40|ft|m|adj=on}} diameter sphere containing 800 tons of mineral oil lined with 1,520 [[photomultiplier|phototube detectors]]. An estimated 1 million neutrino events were recorded each year.  SciBooNE sat in the same [[Accelerator neutrino|neutrino beam]] as MiniBooNE but had fine-grained tracking capabilities. The NOνA experiment uses, and the MINOS experiment used, Fermilab's [[NuMI]] (Neutrinos at the Main Injector) beam, which is an intense beam of neutrinos that travels {{convert|455|mi|km}} through the Earth to the [[Soudan Mine]] in [[Minnesota]] and the Ash River, Minnesota, site of the NOνA far detector. In 2017, the [[ICARUS experiment|ICARUS neutrino experiment]] was moved from [[CERN]] to Fermilab.<ref>{{Cite web|url=https://news.fnal.gov/2015/04/icarus-neutrino-experiment-to-move-to-fermilab/|title=ICARUS neutrino experiment to move to Fermilab|date=April 22, 2015}}</ref><ref name="symmertry">{{cite web|url=https://www.symmetrymagazine.org/article/icarus-prepares-to-chase-a-fourth-neutrino|title=ICARUS prepares to chase a fourth neutrino|first=Catherine N.|last=Steffel|date=March 2, 2020|access-date=March 3, 2020|publisher=symmetrymagazine.org}}</ref>

====Muon g−2====
{{main|Muon g−2}}

[[Muon g−2]]: (pronounced "gee minus two") is a [[particle physics]] experiment to measure the anomaly of the magnetic moment of a muon to a precision of 0.14&nbsp;[[Parts per million|ppm]], which will be a sensitive test of the [[Standard Model]].

[[File:Muon g-2 building at Fermilab.jpg|thumb|[[Muon g-2|Muon g−2]] building (white and orange) which hosts the magnet]]
Fermilab is continuing an experiment conducted at [[Brookhaven National Laboratory]] to measure the [[anomalous magnetic dipole moment]] of the [[muon]].

The magnetic dipole moment (''g'') of a charged lepton ([[electron]], muon, or [[tau (particle)|tau]]) is very nearly 2. The difference from 2 (the "anomalous" part) depends on the lepton, and can be computed quite exactly based on the current [[Standard Model of particle physics]]. Measurements of the electron are in excellent agreement with this computation. The Brookhaven experiment did this measurement for muons, a much more technically difficult measurement due to their short lifetime, and detected a tantalizing, but not definitive, [[statistical significance|3&nbsp;''σ'' discrepancy]] between the measured value and the computed one.

The Brookhaven experiment ended in 2001, but 10&nbsp;years later Fermilab acquired the equipment,<ref>{{Cite web |title=Physics Phoenix: Plotting the Journey of Muon&nbsp;g–2 |url=https://www.bnl.gov/newsroom/news.php?a=22567 |first=Emily |last=Ruppel |date=September 30, 2011 |publisher=Brookhaven National Laboratory |url-status=live |archive-url=https://web.archive.org/web/20151208044744/https://www.bnl.gov/newsroom/news.php?a=22567 |archive-date=December 8, 2015 }}</ref> and is working to make a more accurate measurement (smaller&nbsp;''σ'') which will either eliminate the discrepancy or, hopefully, confirm it as an experimentally observable example of [[physics beyond the Standard Model]].

[[File:Photo of the Week- An Incredible Journey -- Transporting a 600-ton Magnet (9324124048).jpg|thumb|Transportation of the 600&nbsp;ton magnet to Fermilab]]

Central to the experiment is a 50&nbsp;foot-diameter [[superconducting magnet]] with an exceptionally uniform magnetic field. This was transported, in one piece, from Brookhaven in [[Long Island]], New York, to Fermilab in the summer of 2013.  The move traversed 3,200&nbsp;miles over 35&nbsp;days, mostly on a barge down the [[East Coast of the United States|East Coast]] and up the [[Mississippi River|Mississippi]].

The magnet was refurbished and powered on in September&nbsp;2015,<ref>{{Cite news |journal=Aurora Beacon-News |via=Chicago Tribune |title=Fermilab brings super magnet to life after 10&nbsp;years |url=http://www.chicagotribune.com/suburbs/aurora-beacon-news/news/ct-abn-fermilab-st-0928-20150925-story.html |first=Steve |last=Lord |date=September 26, 2015 |url-status=live |archive-url=https://web.archive.org/web/20151208095422/http://www.chicagotribune.com/suburbs/aurora-beacon-news/news/ct-abn-fermilab-st-0928-20150925-story.html |archive-date=December 8, 2015 }}</ref> and has been confirmed to have the same {{val|1300|ul=ppm}} (0.13%) [[peak-to-peak|p-p]] basic magnetic field uniformity that it had before the move.<ref name=2015-10-26>{{Cite report |url=https://www.fnal.gov/directorate/program_planning/all_experimenters_meetings/special_reports/Kiburg-g-2-AEM-10-26-15.pdf |title=G-2 Report |date=October 26, 2015 |first=Brendan |last=Kiburg |access-date=December 5, 2015 |url-status=live |archive-url=https://web.archive.org/web/20151208080946/https://www.fnal.gov/directorate/program_planning/all_experimenters_meetings/special_reports/Kiburg-g-2-AEM-10-26-15.pdf |archive-date=December 8, 2015}}</ref>{{Rp|4}}

The project worked on [[shim (magnetism)|shim]]ming the magnet to improve its magnetic field uniformity.<ref name=2015-10-26/> This had been done at Brookhaven,<ref>{{Cite conference |chapter-url=http://accelconf.web.cern.ch/accelconf/p99/PAPERS/THP91.PDF |chapter=Magnetic Field shimming, Measurement and Control for the BNL Muon (g-2) Experiment |first=S.I. |last=Redin |title=Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366) |conference=1999 Particle Accelerator Conference |location=New York |year=1999 |volume=5 |pages=3167–3169 |doi=10.1109/PAC.1999.792238 |isbn=0-7803-5573-3 |url-status=live |archive-url=http://archive.wikiwix.com/cache/20151207084923/http://accelconf.web.cern.ch/accelconf/p99/PAPERS/THP91.PDF |archive-date=December 7, 2015 }}</ref> but was disturbed by the move and had to be re-done at Fermilab.

In 2018, the experiment started taking data at Fermilab.<ref>{{cite web |last1=Martin |first1=Bruno |title=Fermilab's Muon g-2 experiment officially starts up |url=https://news.fnal.gov/2018/02/fermilabs-muon-g-2-experiment-officially-starts-up/ |website=Fermilab |date=February 6, 2018 |publisher=United States Government |access-date=February 25, 2021}}</ref> In 2021, the laboratory reported that results from initial study involving the particle challenged the [[Standard Model]], with the potential for discovery of new forces and particles.<ref name="NYT-20210407">{{cite news |last=Overbye |first=Dennis |authorlink=Dennis Overbye |title=Finding From Particle Research Could Break Known Laws of Physics - It's not the next Higgs boson — yet. But the best explanation, physicists say, involves forms of matter and energy not currently known to science. |url=https://www.nytimes.com/2021/04/07/science/particle-physics-muon-fermilab-brookhaven.html |date=April 7, 2021 |work=The New York Times |accessdate=April 7, 2021 }}</ref><ref name="FL-20210407">{{cite news |last=Marc |first=Tracy |title=First results from Fermilab's Muon g-2 experiment strengthen evidence of new physics |url=https://news.fnal.gov/2021/04/first-results-from-fermilabs-muon-g-2-experiment-strengthen-evidence-of-new-physics/ |date=April 7, 2021 |work=Fermilab |accessdate=April 7, 2021 }}</ref>

In August 2023, the Fermilab group said they may be getting closer to proving the existence of a new force of nature. They have found more evidence that sub-atomic particles, called muons, are not behaving in the way predicted by the current theory of sub-atomic physics.<ref>{{Cite news |date=August 10, 2023 |title=Scientists at Fermilab close in on fifth force of nature |language=en-GB |work=BBC News |url=https://www.bbc.com/news/science-environment-66407099 |access-date=August 11, 2023}}</ref>

==Delays, cost overruns, safety failures, and management turmoil in the 2010s and 2020s==
Starting in the 2010s, delays and cost over-runs led to substantial concerns about mismanagement of the laboratory.

===Oversight issues that developed between 2014 and 2024===
In 2014, the [[Particle Physics Project Prioritization Panel]] ("P5") recommended<ref name="report">{{Citation | title = Report of the Particle Physics Project Prioritization Panel | date = May 2014 | url = https://science.energy.gov/~/media/hep/hepap/pdf/May-2014/FINAL_P5_Report_053014.pdf }}</ref> three major initiatives for construction on the Fermilab site.  Two were particle physics experiments: the [[Deep Underground Neutrino Experiment]] and [[Mu2e]]. The third was the PIPII accelerator upgrade described above.    Also, P5 recommended Fermilab participation in LHC at [[CERN]].

As of 2022, two P5-recommended Fermilab projects had suffered substantial delays:
* The [[Deep Underground Neutrino Experiment]] with the enabling Long Baseline Neutrino Facility was proposed to P5 as a $1B project; the cost estimate in 2021 dollars was more than $3B, with far detector operations beginning 2029 and full operation by 2032.<ref>{{cite web |title=LBNF/DUNE Status | url=https://science.osti.gov/-/media/hep/hepap/pdf/202111/LBNF-DUNE_Status_HEPAP_202111.pdf}}</ref>
* The [[Mu2e]] experiment was to produce preliminary results in 2020,<ref name=fermilab-mu2e>{{cite web|title=Mu2e: muon-to-electron-conversion experiment|url=http://mu2e.fnal.gov/|publisher=Fermilab|accessdate=April 30, 2015|date=April 21, 2015}}</ref> but this is now delayed until 2026.<ref name=ferminews-mu2e-2022>{{cite news|last1=Bernstein|first1=Maxwell|title=Straws, crystals and the quest for new subatomic physics|url=https://news.fnal.gov/2022/03/straws-crystals-and-the-quest-for-new-subatomic-physics/ |work=Fermilab News|date=March 24, 2022}}</ref>

Even smaller experiments, below the cost-level of individual P5 approval, that were proposed at the time of the 2014 P5 suffered considerable delay.  The Short-Baseline Near Detector (SBND) that was proposed in 2014 <ref name=sbndarticle>{{cite web |title=Neutrino Detector On the Move|last1=Ayshford |first1=Emily |url=https://news.fnal.gov/2022/12/neutrino-detector-on-the-move/ |website=Fermilab News |date=December 2022 |publisher=Fermi National Accelerator Laboratory |access-date=December 26, 2022}}</ref> with a $10M cost scale was originally scheduled for data taking in spring 2018,<ref>{{cite web |last1=Wilson |first1=Peter |title=SBN Program Coordinator |url=https://indico.fnal.gov/event/11088/ |website=Director's Progress Review of the SBN Program, December 15, 2015 |date=December 15, 2015 |publisher=Fermilab |access-date=December 26, 2022}}</ref> but is now scheduled to begin in autumn 2023.<ref name=sbndarticle />

The Department of Energy raised flags as early as Fiscal Year (FY) 2019. Each year, the US Department of Energy Office of Science reviews and grades the national laboratories in its portfolio on eight performance metrics.<ref>{{cite web |title=Laboratory Appraisal Process |url=https://science.osti.gov/lp/Laboratory-Appraisal-Process |website=U.S. Department of Energy Office of Science |date=December 13, 2022 |access-date=December 22, 2022}}</ref>  Fermilab has received the lowest grades among the national laboratories in FY2019, 2020, 2021 and 2022.  A rare C grade was assigned for project management in 2021, reflective of the delays and cost overruns.<ref>{{cite web |title=Fermi National Accelerator Laboratory FY 2021 Report Card |url=https://science.osti.gov/lp/Laboratory-Appraisal-Process/FY-2021/FermiLab |website=Laboratory Appraisal Process |date=December 20, 2021 |publisher=Office of Science, Department of Energy |access-date=December 26, 2022}}</ref>   In an article in the journal ''Science'', James Decker, who was principal deputy director of DOE's Office of Science from 1973 to 2007, stated that the performance evaluation for 2021 was "one of the most scathing I have seen".<ref name=chomarch23 />

Also, in 2020, the high-energy physics community expressed concern that the cost of major projects at Fermilab have led to diversion of funds from the high-energy physics core research program, harming the health of the field.<ref name=COV2020>{{cite web |title=2020 HEPAP COV Report on HEP Program|url=https://science.osti.gov/-/media/sc-2/pdf/cov-hep/2021/HEP_COV_2020_Report.pdf|publisher=Department of Energy Office of Science}}</ref><ref name=aipdec20>{{cite news |author=Will Thomas  |title=Particle Physicists Feel Squeeze From Major Projects |url=https://www.aip.org/fyi/2020/particle-physicists-feel-squeeze-major-projects?_ga=2.191517418.1751103614.1649778405-12991540.1646562579|publisher=FYI, American Institute of Physics |date=December 16, 2020 }}</ref> Congress increased the annual HEP budget from less than $800 million by about $250M to more than $1 billion—a 30% increase that went mainly to support large projects at Fermilab.<ref name=phystoday21>{{cite journal |author=William Thomas  |title=US high-energy physics faces compounding budget tensions |url=https://physicstoday.scitation.org/do/10.1063/PT.6.2.20211119a/full |journal=Physics Today |date=November 21, 2021 |volume=2021 |issue=2 |pages=1119a |doi=10.1063/PT.6.2.20211119a |bibcode=2021PhT..2021b1119. |s2cid=244441879 }}</ref>

The Fermilab project delays led to substantial change in leadership in 2022.<ref name=aaasmar22 /> In September 2021, [[Nigel Lockyer]], Director of Fermilab, resigned.<ref name=ferminewsSept21>{{cite news  |title=Nigel Lockyer to step down as Fermilab director|url=https://news.fnal.gov/2021/09/nigel-lockyer-to-step-down-as-fermilab-director|publisher=Fermilab News |date=September 10, 2021}}</ref> Lockyer was replaced by [[Lia Merminga]], head of the PIP II project.<ref name=ferminewsApr5-22>{{cite news  |title=Lia Merminga appointed director of Fermi National Accelerator Laboratory|url=https://news.fnal.gov/2022/04/lia-merminga-appointed-director-of-fermilab/|publisher=Fermilab News |date=April 5, 2022}}</ref>  On March 31, 2022, James Siegrist, associate director for High Energy Physics in the Department of Energy Office of Science, who had overseen the response to the P5 report, stepped down.<ref name=aipfeb7>{{cite news |author=Will Thomas  |title=DOE High Energy Physics Program Head to Retire |url=https://www.aip.org/fyi/fyi-this-week/week-february-7-2022|publisher=FYI, American Institute of Physics |date=February 7, 2022}}</ref> 
In September 2022, it was announced that deputy director for Research Joseph Lykken would step down, to be replaced by Yale Professor Bonnie Fleming, who previously served as Deputy Chief Research Officer for the neutrino program at Fermilab.<ref>{{cite news |title=Groundbreaking particle physicist named Fermilab chief research officer and deputy director, UChicago professor |url=https://physicalsciences.uchicago.edu/news/article/groundbreaking-particle-physicist-named-uchicago-professor/ |access-date=September 19, 2023 |agency=Physical Sciences |publisher=University of Chicago |date=September 7, 2022}}</ref>
Regina (Gina) Rameika joined the DOE's Office of Science as the associate director for the Office of High Energy Physics in his place on November 7, 2022, moving from her role as spokesperson of the DUNE Experiment.<ref>{{cite web |last1=Berhe |first1=Asmeret Asefaw |title=SC's New Associate Director for High Energy Physics |url=https://www.energy.gov/science/articles/scs-new-associate-director-high-energy-physics |website=Office of Science |publisher=Department of Energy |access-date=December 26, 2022}}</ref> 

Although these replacements represent a substantial turn-over of the top ranks, the new management was drawn from the 2014-2022 management team and Fermilab has continued to suffer turmoil since this change-over. In particular,
new issues arose with regard to safety and access of employees, visitors and contractors.

On May 25, 2023, a contractor fell 23 ft while attempting to secure reinforcing bars on a wall for the new PIP II project site.<ref name=trib23>{{cite news |last1=Channick |first1=Robert |title=Fermilab's $1 billion accelerator project remains on hold during investigation into May accident that injured a construction worker |url=https://www.chicagotribune.com/business/ct-biz-fermilab-proton-construction-accident-investigation-20230914-yj5c6gnhfnejtaixtm4qsktla4-story.html |access-date=September 19, 2023 |agency=Chicago Tribune |publisher=Tribune Publishing |date=September 14, 2023}}</ref>  The contractor was air-lifted to hospital in an accident considered the worst on site in decades.<ref>{{cite news |last1=Jones |first1=Megan |title=Injured worker flown to trauma center after fall at Fermilab construction site |url=https://www.chicagotribune.com/suburbs/aurora-beacon-news/ct-abn-fermilab-injury-st-0526-20230525-fhcqfqi4b5arzcknvy57y4iu2u-story.html |access-date=May 28, 2023 |agency=Aurora Beacon News |publisher=Chicago Tribune |date=May 25, 2023}}</ref> A DOE-appointed Accident Investigation Board concluded that the incident was preventable and "recommended a long list of managerial and safety controls needed to prevent a recurrence of such an accident."<ref name=trib23 />   As a result of the accident, the $1B PIP II project that is crucial for the success of the DUNE Experiment has been delayed.<ref name=trib23 /> 

On September 1, 2023, Chief Research Officer Bonnie Fleming announced that the Fermilab accelerator system was temporarily shut down for safety reasons.<ref>{{Citation |title=DOE O 420.2D Implementation Assist Visit |date=September 26, 2023 |url=https://indico.fnal.gov/event/61410/ |access-date=October 22, 2023 |contribution=9:30 Current Program Overview|publisher=Environment, Safety and Health Dept., Fermilab}}</ref> On September 9, 2022, DOE issued order DOE O 420.2D entitled "Safety of Accelerators".  This document establishes the accelerator-specific safety requirements for DOE-funded accelerators and their operations. Fermilab management had one year to comply with the order, but did not meet the requirements in that timeframe. The Fermilab Main Accelerator resumed running after the DOE O 420.2D implementation was complete, in late spring, 2024.

In mid-2024, Fermilab faced a budget shortfall.  This resulted in an initial furlough of employees and closure of its operations and public access for one week in August---an action that added to the considerable strife at the laboratory.<ref name="strife24">{{cite news |last1=Cho |first1=Adrian |title=Trouble and strife deepen at famed U.S. particle physics lab |url=https://www.science.org/content/article/trouble-and-strife-deepen-famed-u-s-particle-physics-lab |access-date=29 August 2024 |agency=American Association for the Advancement of Science |volume=385 |issue=6710 |publisher=Science |date=14 August 2024}}</ref>  The need for a furlough was surprising since the budget grew "a hefty 7.6% to $739 million" <ref name="strife24" /> in fiscal year (FY) 2024. Beyond this, the six month accelerator shut down for DOE O 420.2D noncompliance should have represented substantial savings in the operations budget. According to the journal ''Science'', the crisis stemmed from poorly managed growth: "from 2022 to 2023 alone, [laboratory staff] grew by 176 members, or 9%, to 2160."<ref name=strife24 />  The steps taken did not fully address the issue, and in November, 2.5% of the workforce was laid off.<ref>{{cite news |last1=Rutecki |first1=Jared |title=Fermilab Announces Layoffs of 53 Employees Amid Budgetary Pressure |url=https://news.wttw.com/2024/11/14/fermilab-announces-layoffs-53-employees-amid-budgetary-pressure |access-date=19 November 2024 |publisher=WTTW News |date=14 November 2024}}</ref>  Despite this, Tracy Marc, head of Fermilab's media services, told WTTW News that "the overall financial health of the laboratory remains intact and is being managed".<ref>{{cite news |last1=Rutecki |first1=Jared |title=Fermilab to Close Temporarily in August Due to Budget Issues |url=https://news.wttw.com/2024/07/19/fermilab-close-temporarily-august-due-budget-issues |access-date=July 28, 2024 |publisher=WTTW News |date=July 19, 2024}}</ref>

===2024 Whistleblower Report===
On July 15, 2024, a report containing very serious allegations of cover-ups at the laboratory was uploaded to the [[arXiv]] physics preprint server. <ref name=whistleblow />  The allegations, which were also reported in the press,<ref name=strife24 /><ref>{{cite news |last1=Rutecki |first1=Jared |title=Fermilab Whistleblower Report Alleges Sexual Harassment, Loaded Gun and 'Chaotic' Finances |url=https://news.wttw.com/2024/08/16/fermilab-whistleblower-report-alleges-sexual-harassment-loaded-gun-and-chaotic-finances |access-date=August 20, 2024 |publisher=WTTW News |date=August 16, 2024}}</ref><ref name=PWwhistle>{{cite news |last1=Gwynne |first1=Peter |title=Fermilab is 'doomed' without management overhaul claims whistleblower report |url=https://physicsworld.com/a/fermilab-is-doomed-without-management-overhaul-claims-whistleblower-report/ |access-date=August 20, 2024 |agency=IOP Publishing |publisher=Physics World |date=August 15, 2024}}</ref> included:
* "The alleged sexual assault of the NOvA and DUNE collaborator who filed and won her 2022 lawsuit in the UK [after it] was dismissed by FNAL staff."
* "A cover-up of a case of guns on site in 2023, with promotion of the perpetrator and pretextuous firing of the witness."
* "A cover-up of an attempt at badly hurting with an industrial vehicle a female electrician by a ... male employee."
* "A cover-up of Beryllium windows blasting, with subsequent promotion of the person in charge."
* "A hostile work environment, where constructive criticism is most often ignored and retaliated against."
The report also recounted a litany of complaints concerning day-to-day running of the laboratory that have been reported in this article, above, as well as a new claim of "PIP-II contingency overruns within one year from CD3 approval" that could potentially impact the LBNF/DUNE program.

For credibility, the report provided detailed eye-witness accounts to support the allegations. <ref name=whistleblow />  Beyond that, some information was previously publicly reported.  For example, the first allegation concerning an egregious case of sexual harassment was reported in ''The Guardian''<ref>{{cite news |last1=Abdul |first1=Geneva |title=Former UCL academic to pay damages after harassing colleague for months |url=https://www.theguardian.com/education/2022/oct/12/former-ucl-academic-to-pay-damages-after-harassing-colleague-for-months |access-date=July 28, 2024 |work=The Guardian |date=October 12, 2022}}</ref> and the fact that the claimant had submitted a complaint to Fermilab which took no action appeared in court documents.<ref>{{cite web |title=Smith v Backhouse |url=http://www.5rb.com/wp-content/uploads/2022/10/Erica-Smith-v-Christopher-Backhouse-SIOC.pdf |website=www.5rb.com |publisher=5RB Media and Communications Law |access-date=July 28, 2024}}</ref>
Scientists expressed fear of retribution by Fermilab leadership.<ref name=strife24 />    In order for the whistleblowers to remain anonymous, the report was uploaded to the arXiv preprint server by Giorgio Bellettini, a respected leader in the field of particle physics who served as spokesman of the collaboration for the [[Collider Detector at Fermilab]] twice.<ref name=bellettini>{{cite web |last1=Bellettini |first1=Giorgio |title=Giorgio Bellettini |url=https://history.fnal.gov/historical/people/bellettini_landing.html |website=Fermilab Historical Information |publisher=Fermi National Accelerator Laboratory |access-date=July 28, 2024}}</ref>  A second signed letter of support from William Barletta of the Massachusetts Institute of Technology was also included.

The report was delivered to the deputy director for Operations of the DOE Office of Science Dr. Juston Fontaine and the DOE Under Secretary for Science and Innovation Geraldine Richmond in June 2024. <ref name=whistleblow />  It was released to the public one month later, after DOE officials did not respond. <ref name=whistleblow /> On July 29, 2024, Fermilab Director Lia Merminga issued a terse response to concerned scientists, saying:  "The [whistleblower] document asserts various challenges at Fermilab, some of which are inaccurate, and others of which [the Fermi Research Alliance] has been working hard to address for some time."<ref name=PWwhistle /> At an All Hands Meeting, Merminga also told scientific staff to "stop whining.”<ref name="strife24" />

===New Management in 2025 by the Fermi Forward Discovery Group, LLC===
In view of the many issues facing the laboratory, in January 2023, the DOE announced a two-year process to rebid the contract for the management of the laboratory<ref>{{cite web |title=Department of Energy Issues Request for Information and Launches New Website for the Fermi National Accelerator Laboratory Management and Operating Contract Competition |url=https://www.energy.gov/science/articles/department-energy-issues-request-information-and-launches-new-website-fermi |website=Department of Energy Office of Science |access-date=March 23, 2023}}</ref>  due to the performance issues.<ref name=chomarch23 />   The DOE announcement of the competition explained:  "the purpose of this contract competition is to solicit and award a new M&O contract that will result in improved contractor performance and efficiencies at FNAL. DOE expects that this competition will elicit new and innovative approaches for planning the Laboratory's future."<ref>{{cite web |title=M&O Contract Competitions |url=https://science.osti.gov/Acquisition-Management/M-and-O-Competitions |website=Office of Acquisition Management |date=December 6, 2022 |publisher=Department of Energy Office of Science |access-date=March 25, 2023}}</ref>  At an informational meeting for potential bidders on March 1, 2023, the presentation slides expanded upon issues under "Major Challenges/Risks" including highlighting the concern:  "The Laboratory continues to have challenges in Financial Management and Acquisition Management. Audits repeatedly highlight the same deficiencies and control failures year after year. Any corrective actions implemented have resulted in little to no progress. Significant procurement issues have hindered the laboratory's ability to successfully deliver efficient and effective business systems/resources to enable the Science Mission. Substantial concerns remain regarding the ability to expend Government funds in an effective, efficient, and compliant manner."<ref name=rebid>{{cite web |title=Informational Meeting |url=https://science.osti.gov/Acquisition-Management/M-and-O-Competitions/Procurement-Information/Informational-Meeting |website=Office of Acquisitions Management |date=March 7, 2023 |publisher=Department of Energy Office of Science |access-date=March 25, 2023 |ref=Presentation Slides, p.53}}</ref>
The myriad issues facing a new contractor were listed in January 2024 in the news section of the journal ''Nature''.<ref>{{cite news |last1=Garisto |first1=Daniel |title=Leading US particle-physics lab faces uncertain future |url=https://www.nature.com/articles/d41586-024-00150-4 |access-date=July 28, 2024 |publisher=Nature |date=January 24, 2024}}</ref>

On October 1, 2024, the Department of Energy announced that the $5B awarded the contract to operate Fermi National Accelerator to the newly-formed Fermi Forward Discovery Group, LLC (FFDG).<ref>{{cite web |title=Energy Department Awards New Contract to Manage and Operate Fermi National Accelerator Laboratory |url=https://www.energy.gov/science/articles/energy-department-awards-new-contract-manage-and-operate-fermi-national |website=Office of Science |publisher=Department of Energy |access-date=1 October 2024}}</ref>   FFDG will assume management of Fermilab operations on January 1,  2025, with a five-year contract.

The FFDG represents an incremental change in management from the previous decade because the group includes the past management team for the laboratory, the FRA,<ref>{{cite web |title=Fermilab Research Alliance, LLC |url=https://fra-hq.org/ |website=Fermilab Research Alliance, LLC}}</ref> that consisted of the University of Chicago and the Universities Research Association (URA).  There are  two additions:  Amentum Environment & Energy, Inc., which specializes in advanced engineering, and Longenecker & Associates, which specializes in project management. <ref>{{cite news |last1=Cho |first1=Adrian |title=Fermilab’s not-quite-new boss aims to end turmoil, boost performance |url=https://www.science.org/content/article/fermilab-s-not-quite-new-boss-aims-end-turmoil-boost-performance |access-date=19 November 2024 |agency=AAAS |issue=6718 |publisher=Science |date=4 October 2024}}</ref>   Thus, the selection leaves the scientific and human resources management unchanged, but does  strengthen expertise to deliver large projects. 

==Site==
===Access===
Fermi National Accelerator Laboratory (aka Fermilab) was founded in 1967 as an open science research laboratory, and, to this day, does not conduct classified research. The initial plans called for Fermilab to employ a guard force "...to control movement of personnel onto the site when tests are being conducted" as noted in the December 1971 Environmental Statement and "..to enforce the site boundary".  Early leadership moved toward greater public openness  allowing for ease of scientific collaboration and public enjoyment to include the relocated bison heard.

In the late 2010s and early 2020s, the management of Fermilab began to introduce severe restrictions on access to the Fermilab site by the public and by scientists.  By spring 2023, the restrictions had become so onerous that more than 2500 physicists and visitors to the laboratory signed an "open petition to elected representatives to reopen Fermilab."<ref>{{cite web |title=Petition to Reopen Fermilab |url=https://www.reopenfermilab.com/ |website=Reopen Fermilab |publisher=Physicists and visitors to Fermilab |archive-url=https://web.archive.org/web/20230705155017/https://www.reopenfermilab.com/ |access-date=April 28, 2023|archive-date=July 5, 2023 }}</ref>    The petition stated that:   "The access policy changes undermine critical aspects of the scientific process as well as the basic functioning of Fermilab. Hosting research meetings, interviewing prospective employees, collaborating with scientists outside the lab, and enacting our famously impactful education programs have all been hindered."    With respect to the general public, the petition stated:  "Today, the general public is only permitted to access the main road, and with ID requirements that are becoming increasingly stringent, soon its doors will be closed to tourists and even to some immigrants. We can no longer drive or bike around the premises freely. The dog park, Wilson Hall with its exhibits on the top floor, and other areas are no longer generally accessible. Fishing and other activities open to the public have been canceled."   The petition emphatically requested that access policies be reverted to the open laboratory model that governed the laboratory prior to 2020.

In May 2023, Director Lia Merminga posted a response to the petition on the Fermilab website,<ref>{{cite web |last1=Merminga |first1=Lia |title=From Director Lia Merminga: Accessing Fermilab's Batavia site |url=https://news.fnal.gov/2023/05/from-lia-merminga-accessing-fermilabs-batavia-site/ |website=Fermilab News |date=May 16, 2023 |publisher=Fermi National Accelerator Laboratory |access-date=May 16, 2023}}</ref> noting that
some areas on site remain open to the public during specific hours with ID access requirements.  Merminga's response justifies the new restrictions because the lab "manage[s] a large amount of non-public information"---reasoning that conflicts with the petition that points out that the lab is fully tax-payer funded, does no classified research, and has a government mandate to publish all of its scientific results.   Further coverage of the petition and the management response appeared in the magazines ''Physics Today''<ref>{{cite journal |last1=Feder |first1=Toni |title=Scientists and the public petition to roll back Fermilab access restrictions |journal=Physics Today |url=https://doi.org/10.1063/PT.6.2.20230525a |access-date=May 28, 2023 |publisher=American Institute of Physics |date=May 25, 2023|volume=2023 |issue=5 |pages=0525a |doi=10.1063/PT.6.2.20230525a |bibcode=2023PhT..2023e2386F }}</ref> and ''Physics World''.<ref>{{cite news |last1=Gwynne |first1=Peter |title=Fermilab faces protest over visitor restrictions |url=https://physicsworld.com/a/fermilab-faces-protest-over-visitor-restrictions/ |access-date=June 22, 2023 |agency=Physics World |publisher=IOP Publishing |date=June 19, 2023}}</ref>

In keeping with Real ID requirements for DOE facilities, all unescorted adult visitors entering the site must present a government-issued photo ID compliant with the [[Real ID Act]].<ref>{{cite news |last1=Marc |first1=Tracy |title=Fermilab site reopens to the public, welcomes visitors |url=https://news.fnal.gov/2022/03/fermilab-site-reopens-to-the-public-welcomes-visitors/ |publisher=Fermilab News |date=March 28, 2022}}</ref>  Up-to-date specifics about access can be found on the Fermilab website.<ref name=tritfaq>{{cite web |title=Visit Fermilab |url=https://www.fnal.gov/pub/visiting/index.html |publisher=Fermilab |access-date=April 13, 2022}}</ref>

===Architecture===
[[File:Interior of Fermi Lab Wilson Hall.JPG|thumb|Interior of Wilson Hall]]

Fermilab's first director, Robert Wilson, insisted that the site's aesthetic complexion not be marred by a collection of concrete block buildings. The design of the administrative building (Wilson Hall) was inspired by [[Beauvais Cathedral|St.&nbsp;Pierre's Cathedral]] in [[Beauvais]], [[France]],<ref>{{Cite web |url=https://history.fnal.gov/GoldenBooks/gb_wilson2.html |title=Fermilab History and Archives Project |url-status=live |archive-url=https://web.archive.org/web/20170118014849/http://history.fnal.gov/GoldenBooks/gb_wilson2.html |archive-date=January 18, 2017 }}</ref> though it was realized in a [[Brutalism|Brutalist]] style. Several of the buildings and sculptures within the Fermilab reservation represent various mathematical constructs as part of their structure.

The [[Archimedean Spiral]] is the defining shape of several [[pumping station]]s as well as the building housing the MINOS experiment. The reflecting pond at Wilson Hall also showcases a {{convert|32|ft|m|adj=mid|-tall}} [[hyperbola|hyperbolic]] obelisk, designed by Wilson. Some of the high-voltage [[transmission line]]s carrying power through the laboratory's land are built to echo the Greek letter [[pi|π]]. One can also find structural examples of the [[DNA]] double-helix spiral and a nod to the [[geodesic sphere]].

Wilson's sculptures on the site include ''Tractricious'', a free-standing arrangement of steel tubes near the Industrial Complex constructed from parts and materials recycled from the Tevatron collider, and the soaring ''[[Broken Symmetry (sculpture)|Broken Symmetry]]'', which greets those entering the campus via the Pine Street entrance.<ref>{{Cite web |url=http://fnal.gov/pub/about/campus/sculptures.html |series=About Fermilab |title=The Fermilab Campus |date=December 1, 2005 |access-date=February 27, 2007 |url-status=live |archive-url=https://web.archive.org/web/20070403134748/http://www.fnal.gov/pub/about/campus/sculptures.html |archive-date=April 3, 2007 }}</ref> Crowning the [[Robert F. Ramsey|Ramsey Auditorium]] is a representation of the [[Möbius strip]] with a diameter of more than {{convert|8|ft}}. Also scattered about the access roads and village are a massive hydraulic press and old magnetic containment channels, all painted blue.

===Wildlife===
In 1967, Wilson brought five [[American bison]] to the site, a bull and four cows, and an additional 21 were provided by the Illinois Department of Conservation.<ref>{{Cite news|last=Shivni|first=Rashmi|date=January 27, 2016|title=The genetic purity and diversity of the Fermilab bison herd|url=https://news.fnal.gov/2016/01/the-genetic-purity-and-diversity-of-the-fermilab-bison-herd/|access-date=November 22, 2020|work=Fermilab News|language=en-US}}</ref><ref>{{Cite news|last=Sharos|first=David|date=April 22, 2019|title=Baby bison born at Fermilab|url=https://www.chicagotribune.com/suburbs/aurora-beacon-news/ct-abn-fermilab-baby-bison-st-0423-story.html|access-date=November 22, 2020|work=The Beacon-News |via=Chicago Tribune}}</ref> Some fearful locals believed at first that the bison were introduced in order to serve as an alarm if and when radiation at the laboratory reached dangerous levels, but they were assured by Fermilab that this claim had no merit. Today, the [[Fermilab bison herd]] is a popular attraction that draws many visitors<ref>
{{cite web|website = Fermilab|date = December 30, 2005|title = Safety and the Environment at Fermilab|url = http://www.fnal.gov/pub/about/safety/questions.html|access-date = January 6, 2006|url-status = dead|archive-url = https://web.archive.org/web/20060926124711/http://www.fnal.gov/pub/about/safety/questions.html|archive-date = September 26, 2006}}</ref> and the grounds are also a sanctuary for other local wildlife populations.<ref>{{cite web |website=Fermi National Accelerator Laboratory |url=http://www.fnal.gov/pub/about/campus/ecology/wildlife/ |title=Ecology/Nature - Wildlife |access-date=October 26, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20030301181223/http://www.fnal.gov/pub/about/campus/ecology/wildlife/ |archive-date=March 1, 2003 |date=August 24, 2001}}</ref><ref>{{cite web |url=http://ecology.fnal.gov/ |title=Nature and Ecology |website=Fermilab |access-date=September 9, 2018 |url-status=live |archive-url=https://web.archive.org/web/20180701083401/http://ecology.fnal.gov/ |archive-date=July 1, 2018 }}</ref> A [[Christmas Bird Count]] has occurred at the lab every year since 1976.<ref>{{Cite web|url=http://www.fnal.gov/ecology/wildlife/cbc/|title=Fermilab Christmas Bird Count|website=Fermilab|access-date=February 22, 2019}}</ref>

Working with the [[Forest Preserve District of DuPage County]], Fermilab has introduced [[Western barn owl|barn owl]]s to selected structures around the grounds.<ref>{{Cite web|date=July 6, 1978|title=Birds Find Haven at Fermilab|url=https://history.fnal.gov/historical/site/birds_find_haven.html|access-date=April 27, 2021|website=Fermilab {{!}} History and Archives {{!}} Site and Natural History}}</ref>

===Tritium on site===
During running, particle beams produce [[tritium]], an isotope of hydrogen consisting of a proton and two neutrons that is weakly radioactive with a half-life of 12.3 years. This can bind with oxygen to form [[tritiated water]]. Tritium levels measured on site are low compared to federal health and environmental standards. Fermilab monitors tritium leaving the site in surface and sewer water, and provides an FAQ sheet for those who want to learn more.<ref>{{cite web |title=Tritium at Fermilab |url=https://www.fnal.gov/pub/tritium/index.html |publisher=Fermilab |access-date=April 13, 2022}}</ref>

At an informational meeting for potential bidders for the management contract, held on March 1, 2023, the presentation slides indicated that although the rate of tritium leaving site is below the required standards, there is sufficient tritium contamination on site to represent a "challenge".<ref name=rebid />  In particular, tritium produced in the NuMI beamline that sends neutrinos to experiments in Minnesota has been pumped into the industrial water cooling system that is used for equipment across the Fermilab campus.  As a result, it is concluded that now "tritium contamination is largely throughout the research complex."<ref name=rebid />

==See also==
* [[Big Science]]
* [[Center for the Advancement of Science in Space]] — operates the US National Laboratory on the ISS
* [[CERN]]
* [[Fermi Linux LTS]]
* [[Scientific Linux]]
* [[Stanford Linear Accelerator Center]]

==References==
{{Reflist|25em}}

==External links==
{{Commons|Fermilab}}
* [http://www.fnal.gov/ Fermi National Accelerator Laboratory]
 [http://www.fnal.gov/pub/today/ ''Fermilab Today'' Daily newsletter]
 [http://www.fnal.gov/pub/publications/index.html Other Fermilab online publications]
 [https://web.archive.org/web/20060316074800/http://www.fnal.gov/pub/about/tour/index.html Fermilab Virtual Tour]
 [http://www.fnal.gov/pub/about/campus/architecture.html Architecture at the Fermilab campus]

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