50 years of discoveries and innovations: world’s first permanent-magnet accelerator

This year Fermilab celebrates a half-century of groundbreaking accomplishments. In recognition of the lab’s 50th birthday, we will post (in no particular order) a different innovation or discovery from Fermilab’s history every day between April 27 and June 15, the date in 1967 that the lab’s employees first came to work.

The list covers important particle physics measurements, advances in accelerator science, astrophysics discoveries, theoretical physics papers, game-changing computing developments and more. While the list of 50 showcases only a small fraction of the lab’s impressive resume, it nevertheless captures the breadth of the lab’s work over the decades, and it reminds us of the remarkable feats of ingenuity, engineering and technology we are capable of when we work together to do great science.

27. Fermilab constructs the world’s first permanent-magnet accelerator

The antiproton Recycler was the world’s first permanent-magnet accelerator. Fermilab’s 8-GeV ring greatly improved the efficiency of antiproton accumulation and cooling, using some 400 permanent magnets. Other accelerators had traditionally used electromagnets, but designers found that using naturally magnetic materials reduced cost and improved stability. This feat was also the result of many technical innovations developed along the way. Bill Foster and Gerry Jackson won an IEEE Particle Accelerator Science and Technology award for the innovation.


26. Fermilab scientists set upper limit for Higgs boson mass

In 1977, theoretical physicists at Fermilab — Ben Lee and Chris Quigg, along with Hank Thacker — published a paper setting an upper limit for the mass of the Higgs boson. This calculation helped guide the design of the Large Hadron Collider by setting the energy scale necessary for it to discover the particle. The Large Hadron Collider turned on in 2008, and in 2012, the LHC’s ATLAS and CMS discovered the long-sought Higgs boson — 35 years after the seminal paper.


25. Fermilab discovers bottom quark

In 1977, an experiment led by physicist and Nobel laureate Leon Lederman at Fermilab provided the first evidence for the existence of the bottom quark. It was observed as part of a quark-antiquark pair known as the Upsilon meson, which is 10 times more massive than a proton. The bottom quark is one of six that make up the quark family of particles.


24. Tevatron’s cryogenic system sets benchmark

Upon its commissioning in 1983, the Tevatron’s liquid-helium cooling system was the largest cryogenic system ever built. The system set a benchmark in large-scale superconducting magnet design and has been a model for similar systems worldwide. Its many innovations included advances in gas compression, gas filtering and large-scale system integrity. In 1993, the system was named an International Historic Landmark by the American Society of Mechanical Engineers.


23. Sloan Digital Sky Survey confirms evidence of dark energy

When the universe’s expansion was found to be accelerating in 1998, it seemed to be defying gravity with some unknown force. That force, dark energy, is now thought to make up two thirds of the universe. The Sloan Digital Sky Survey, a collaboration that includes Fermilab, confirmed its existence. Their analysis of large clusters of galaxies also confirmed the universe’s accelerating expansion.


22. Fermilab hosts the first USSR group in a U.S. high-energy physics experiment

When Fermilab began its experimental program in 1972, Cold War tensions were high. Nevertheless, Fermilab extended an olive branch for science. Its first experiment, E-36, was also the first U.S. high-energy physics collaboration with the Soviet Union. It marked the beginning of a long tradition of east-west collaboration at the lab and served as a model of international partnership for the decades to come.


21. Fermilab establishes world-record efficiency for an accelerating cavity

Sometimes it pays to dust off old papers. In 2012, scientist Anna Grassellino began researching superconducting accelerator cavities made of a niobium-nitride alloy, an idea mostly abandoned since the 1990s. Within the year, she had developed the world’s most energy-efficient cavity. The milestone completely changed what people thought about the limits of SRF technology.


20. Fermilab theorists spearhead lattice QCD method for predicting quark properties

Fermilab theorists spearheaded the use of a method that predicted with uncanny accuracy the properties of quarks and the composite objects they form. Fermilab scientists were among the collaborators who, in 2003, demonstrated that the method, called lattice QCD (for lattice quantum chromodynamics), could be carried out with unprecedented precision. What followed was a world-leading program for lattice QCD thanks to advances by Fermilab’s Andreas Kronfeld, Paul Mackenzie, Jim Simone and Ruth van de Water. These calculations, which require high-performance computing facilities, have been indispensable for researchers in all areas.


19. Fermilab discovers exotic building blocks of matter

From 1998 to 2011, Fermilab experiments discovered five baryons, particle cousins of the proton, and one more distantly related meson: Ξb0, Σb and Σb*, Ξb, Ωb and Bs. These particles were important in our understanding of how matter forms and holds together at the most fundamental level.


18. Fermilab scientists propose dark matter may be made of sterile neutrinos

No one knows what dark matter is, but we’re pretty sure it’s out there: Given their observable mass, the spin rate of galaxies is far too fast. Some other matter — matter we can’t see — must also play a role to cause them to spin with such velocity. Physicists have proposed a number of possibilities for what dark matter is, and Fermilab scientist Scott Dodelson and his colleague Lawrence Widrow were the first to propose that dark matter might be made of sterile neutrinos — hypothetical particles even more weakly interacting than neutrinos. The standard theory of the electroweak force with the addition of sterile neutrinos is one of the simplest ways to accommodate dark matter.


17. That’s quite an antimatter collection you’ve got there

At some 300 billion antiprotons per hour, the Tevatron’s antiproton source was the most intense, consistent source of antiprotons in the world. At this impressive rate, about 17 nanograms of antiprotons were generated at Fermilab over the years, accounting for more than 90 percent of the world’s manmade production of nuclear antimatter. Along with protons, the rare antiparticles were the second half of the Tevatron’s collision equation. The world record for antiproton production made the collider a success.


16. In physics theory, brevity is sometimes the soul of particle physics, too

A (very short!) 1986 paper by Fermilab theorists Stephen Parke and Tomasz Taylor presented an astonishing result: that the result of a very complex Feynman diagram calculation could be summarized in a single line. The full implications of this new mathematical structure are still being explored today in an active area called “amplitudes” research. This leads to both new ways of learning about quantum field theory and practical applications to LHC calculations.


15. Fermilab contributes to Higgs boson discovery

Without the Higgs boson, atoms would not form, and there would be no chemistry, no biology and no life. Its discovery at CERN laboratory was the culmination of nearly five decades of work and included research at Fermilab’s Tevatron accelerator, in particular on the CDF and DZero experiments, and on the CMS experiment at CERN’s Large Hadron Collider. Fermilab is the host laboratory for U.S. CMS collaborators. It contributed new ideas and physics models, CMS experiment construction and operation, and computing power and intellectual leadership in data analysis at CMS.


14. Fermilab unveils first proton accelerator for cancer treatment

On Jan. 4, 1989, Fermilab unveiled the first-ever small proton accelerator designed and built expressly for cancer treatment, developed for Loma Linda University Medical Center in California. The room-sized accelerator provided an advanced form of radiation therapy with a beam that could target diseased cells more precisely than traditional x-rays, protecting nearby healthy cells.

13. Holometer is the first detector for Planck-scale physics

In 2014, Fermilab scientist Craig Hogan’s team began taking measurements with a 40-meter-long instrument they called the Holometer, designed to test a mind-boggling proposition: that the 3-D universe in which we appear to live is no more than a hologram. They built the Holometer to test ideas for ways that space could really be made up of discrete, 2-D pieces that carry information we perceive in three dimensions. This experiment measures reality on the smallest scale we can conceive, where atoms are gigantic compared to the tiny grains of space and time Fermilab researchers are searching for.


12. Observation of direct CP violation in kaon decays

On Feb. 24, 1999, physicists from Fermilab’s KTeV collaboration established the existence of direct CP violation in the decay of kaon particles. The observation was a significant step in understanding why the universe displays an abundance of matter, while antimatter disappeared at an early stage in its evolution.


11. Fermilab scientists are first to invent and apply hollow electron beams in proton colliders

The more tightly the particles are packed into a particle beam, the better chances that the particles will collide in an accelerator. The dynamics of dealing with dense, high-power beams are an enormous challenge. Fermilab scientists were the first to invent, develop and apply what are called “hollow” electron beams to proton colliders. The hollow electron beams enclose a circulating proton beam, cutting down on beam losses that could potentially damage the accelerators and detectors. This halo collimation technique, successfully demonstrated at the Tevatron, is now the technology of choice for current and future particle colliders, including the Large Hadron Collider and the Future Circular Collider.


10. COUPP uses bubble chamber technology for dark matter detection

The proud, magnificent, 15-foot bubble chamber that detected particle collisions at Fermilab may have been decommissioned in 1988, but its legacy was rekindled 20 years later when the fundamental concept returned in the search for dark matter. In 2008, Fermilab physicists completed the first run of the COUPP experiment that filled a 1-liter bell jar of superheated liquid, in hopes that dark matter particles would collide with it, theoretically disturbing the liquid and causing it to boil.


9. Fermilab discovers polarization in hyperon production

The 1994 Panofsky Prize, a prestigious award in physics, went to Thomas Devlin and Lee Pondrom, who discovered at Fermilab that, contrary to expectations, certain particle relatives of the proton were polarized when they are produced in collision experiments. This gave the particles properties physicists could measure to better understand the strong force, which glues the particles together and is one of four fundamental forces.


8. Fermilab develops Scientific Linux

Worldwide, both scientists and nonscientists use Scientific Linux, an operating system originally developed for particle physics at Fermilab. The operating system runs on computers at top universities, national laboratories and even in industry.


7. Fermilab is first to scale up electron cooling for antiproton beams

In 2005, Fermilab was the first to scale up a technology known as electron cooling to adapt it for relativistic high-energy antiproton beams. The implementation of the cooling in Fermilab’s Recycler ring by a team led by Sergei Nagaitsev helped increase the rate of particle interactions in the Tevatron collider by a factor of three. Nagaitsev earned a U.S. Particle Accelerator School Prize for Achievement in Accelerator Physics and Technology for the innovation.


6. Fermilab physicist proposes looking for gravitational waves by detecting B-mode polarization

In 1996 Fermilab astrophysicist Albert Stebbins, along with scientists Marc Kamionkowski and Arthur Kosowsky, proposed a way to look for signals of gravitational waves in the cosmic microwave background: by detecting something called B-mode polarization. It would present itself as a distinct pattern in the sky. These very faint signals, “curls” of light from the early universe, could provide evidence of the theory of inflation, which says that the universe underwent a rapid expansion soon after the Big Bang. The BICEP2 experiment later detected B-mode polarization, in 2014, but their signal was likely sourced by astrophysical foregrounds. Upcoming experiments are aiming to detect the primordial signal.


5. Fermilab produces a single top quark

Only one in 20 billion proton-antiproton collisions produces a single top quark instead of much more common pairs. The extremely rare process was discovered at Fermilab in 2009 — 14 years nearly to the day after Fermilab discovered the top quark — and produced some of the world’s most sophisticated data analysis methods in the process.


4. Fermilab develops QIE microelectronics for improved data analysis

Transforming the complex signals that detectors produce from particle collisions into digital data requires sophisticated electronics. Performing this task at the heart of many physics labs worldwide, including the CMS detector at the Large Hadron Collider, are devices called QIEs. Smaller than a penny, these integrated circuits, designed and improved upon at Fermilab, combine data from analog signals into a form researchers can analyze with excellent resolution.


3. Tevatron sets world energy record (again, and again)

At 3:37 p.m. on July 3, 1983, the Tevatron claimed the world energy record by operating its particle beam at 512 GeV. Fermilab held the honor until 2009, beating its own record time and again eventually achieving its namesake energy level, 1 TeV. Scientist Helen Edwards, one of the Tevatron’s architects, was awarded the National Medal of Technology and the APS Robert R. Wilson Prize for her work on the collider.


2. Dark Energy Camera opens its modern eye to ancient light

Eight billion years ago, rays of light from distant galaxies began their long journey to Earth. That ancient starlight now finds its way to a mountaintop in Chile, where the Dark Energy Camera, the world’s most powerful camera and mirror system, captured it for the first time on September 12, 2012. That light may hold within it the answer to one of the biggest mysteries in physics – why the expansion of the universe is speeding up. The 570-megapixel Dark Energy Camera was constructed at Fermilab with the partnership of 26 research institutions and more than one hundred companies.


1. Fermilab DONUT experiment discovers tau neutrino

On July 21, 2000, Fermilab announced the first direct evidence for a particle called the tau neutrino, the third kind of neutrino known to particle physicists. It had been hypothesized but never directly observed until the 2000 discovery, which was made by the DONUT (Direct Observation of the Nu Tau) experiment at Fermilab. The other two types, the electron neutrino and the muon neutrino, had been discovered in 1956 and 1962, respectively.