Fermilab
Fermi National Accelerator Laboratory (Fermilab), located in Batavia, Illinois, near Chicago, is a United States Department of Energy national laboratory specializing in high-energy particle physics.
Established
Fermilab's Main Injector, two miles (3.3 km) in circumference, is the laboratory's most powerful particle accelerator.[2] 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.[3] Until 2011, Fermilab was the home of the 6.28 km (3.90 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.[4] The project has suffered delays and, in 2022, the journals Science and Scientific American each published articles describing the project as "troubled".[5][6]
Ongoing neutrino experiments are ICARUS (Imaging Cosmic and Rare Underground Signals) and NOνA (NuMI Off-Axis νe 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).
Since 2007, Fermilab has been operated by the Fermi Research Alliance (FRA), a joint venture of the University of Chicago, and the Universities Research Association (URA); although in 2023, the Department of Energy (DOE) opened bidding for a new contractor due to concerns about the FRA performance.[7] Fermilab is a part of the Illinois Technology and Research Corridor.
On-site experiments outside of the neutrino program include the 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.[8] Fermilab also pursues research in quantum information science.[9] It founded the Fermilab Quantum Institute in 2019.[10] Since 2020, it also is home to the SQMS (Superconducting Quantum Materials and Systems) Center.[11]
Asteroid 11998 Fermilab is named in honor of the laboratory.
Weston, Illinois, was a community next to Batavia voted out of existence by its village board in 1966 to provide a site for Fermilab.[12]
The laboratory was founded in 1969 as the National Accelerator Laboratory;[13] 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 protons and antiprotons 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:
Accelerators[edit]
The Tevatron[edit]
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 GeV, and producing proton-antiproton collisions with energies of up to 1.96 TeV, the first accelerator to reach one "tera-electron-volt" energy.[17] At 3.9 miles (6.3 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 CDF and DØ detectors.[18] It was shut down in 2011.
Fermilab Accelerator Complex[edit]
Since 2013, the first stage in the acceleration process (pre-accelerator injector) in the Fermilab chain of accelerators[19] takes place in two ion sources 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 mm and held in place by glass ceramic insulators. A magnetron generates a plasma to form the ions near the metal surface. The ions are accelerated by the source to 35 keV and matched by low energy beam transport (LEBT) into the radio-frequency quadrupole (RFQ) which applies a 750 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).[20]
The next stage of acceleration is linear particle accelerator (linac). This stage consists of two segments. The first segment has five drift tube cavities, operating at 201 MHz. The second stage has seven side-coupled cavities, operating at 805 MHz. At the end of linac, the particles are accelerated to 400 MeV, or about 70% of the speed of light.[21][22] Immediately before entering the next accelerator, the H− ions pass through a carbon foil, becoming H+ ions (protons).[23]
The resulting protons then enter the booster ring, a 468 m (1,535 ft) circumference circular accelerator whose magnets bend beams of protons around a circular path. The protons travel around the Booster about 20,000 times in 33 milliseconds, adding energy with each revolution until they leave the Booster accelerated to 8 GeV.[23] In 2021, the lab announced that its latest superconducting YBCO magnet could increase field strength at a rate of 290 tesla per second, reaching a peak magnetic field strength of around 0.5 tesla.[24]
The final acceleration is applied by the Main Injector [circumference 3,319.4 m (10,890 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" in that it can route protons to any of the experiments installed along the beam lines after accelerating them to 120 GeV. Until 2011, the Main Injector provided protons to the antiproton ring [circumference 6,283.2 m (20,614 ft)] and the Tevatron for further acceleration but now provides the last push before the particles reach the beam line experiments.
Site[edit]
Access[edit]
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.”[93] 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,[94] 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[95] and Physics World.[96]
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.[97] Up-to-date specifics about access can be found on the Fermilab website.[98]