Massive caverns excavated for new particle accelerator in South Dakota

The U.S. Department of Energy has formally approved the start of full production for the $200 million DOE-funded contributions to the upgrade of the CMS experiment at CERN. Together with contributions from other international partners, the upgrade will significantly improve the capabilities of the CMS detector and enable scientists to explore uncharted territory on the particle physics landscape.

“We want to understand what nature is telling us,” said Patty McBride, the CMS spokesperson and a distinguished scientist at DOE’s Fermi National Accelerator Laboratory. “These upgrades will allow us to extract more information from our detector and unlock more about the world and universe.”

CMS is an international collaboration of scientists who study the fundamental properties of matter using the CMS detector at CERN, an international physics laboratory on the Franco-Swiss border. More than 1,800 researchers from U.S. institutions work on the experiment.

Physicists use the CMS detector to collect data from high-energy particle collisions produced by the Large Hadron Collider, the world’s biggest particle accelerator. At the end of the decade, the scientific reach of the LHC will become even more impressive thanks to the high-luminosity upgrade to the machine, which will begin in 2026. The recently released recommendations by the U.S. Particle Physics Project Prioritization Panel, known as the 2023 P5 report, lists the completion of the HL-LHC as a top priority for the U.S. particle physics community.

The upgrade will increase the collision rate by a factor of five, giving scientists a massive dataset to look for new particles and study rare subatomic processes. To keep up with the more intense particle beams, the CMS experiment needs a massive overhaul.

“We need new functionalities to cope with the harsh HL-LHC environment,” said Fermilab scientist Steve Nahn, the project manager for the U.S.-funded CMS upgrade. The project also receives funding from the U.S. National Science Foundation and is part of the international CMS upgrade plan.

Between 2029 and 2042, CMS scientists plan to collect 10 times more data than recorded since the startup of the LHC in 2010. Among many scientific goals, the additional data will enable scientists to develop a deeper understanding of the Higgs boson and how the Higgs field influenced the development and acted as dispersant of matter in the early universe.

“It’s not just looking at what’s unexpected; it’s also about having a deeper understanding of the particles we already know about, especially the Higgs,” McBride said.

The rapid increase in data poses many challenges. The experiment will go from seeing about 60 proton-proton collisions every time the LHC beams cross to around 200. This jump in collision rate means that scientists not only need more bandwidth on their electronics, but new components that will help them get the most out of this surge in data. For example, a new timing detector will tag particles emerging from the collisions with an accuracy of around 30 picoseconds, giving scientists the ability to better determine the trajectory of the particles and gain a better understanding of how the particles interacted with each other.

“We’re not just replacing old pieces; we are pushing the envelope,” Nahn said. “The HL-LHC is going to be a proving ground for new detector technology.”

The U.S.-funded work will be carried out by scientists, engineers and technicians from Fermilab and 45 universities located in 23 states. Much of the work will be done by students, who make up a sizable fraction of the experiment.

“This is a huge opportunity for students,” said Robin Erbacher, a professor at the University of California, Davis, and the chair of the U.S. CMS collaboration board. “We don’t build detectors every day.”

 

The worldwide CMS collaboration—which comprises 6,000 scientists from 57 countries—has been planning detector upgrades since the early 2000s. In 2016, the U.S.-funded CMS institutions, which make up about one-third of the collaboration, started the approval process with the US funding agencies for their planned contributions.

“This has been in the works for a long time,” Erbacher said.

During the approval process for the upgrade project, experts reviewed the physics goals, technical design reports, construction schedules and cost for the proposed detector components. The DOE approval, known as Critical Decision 3 and announced on January 11, allows the U.S.-funded CMS collaborators to move into full production on the proposed upgrades.

U.S. CMS collaborators will complete and ship their contributions to CERN between 2026 and 2027. The start-up of the high-luminosity LHC is foreseen for 2029.

Fermi National Accelerator Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

Excavation workers have finished carving out the future home of the gigantic particle detectors for the international Deep Underground Neutrino Experiment. Located a mile below the surface, the three colossal caverns are at the core of a new research facility that spans an underground area about the size of eight soccer fields.

Hosted by the U.S. Department of Energy’s Fermi National Accelerator Laboratory, DUNE scientists will study the behavior of mysterious particles known as neutrinos to solve some of the biggest questions about our universe. Why is our universe composed of matter? How does an exploding star create a black hole? Are neutrinos connected to dark matter or other undiscovered particles?

The caverns provide space for four large neutrino detectors—each one about the size of a seven-story building (see 2-minute animation). The detectors will be filled with liquid argon and record the rare interaction of neutrinos with the transparent liquid.

Trillions of neutrinos travel through our bodies each second without us even knowing it. With DUNE, scientists will look for neutrinos from exploding stars and examine the behavior of a beam of neutrinos produced at Fermilab, located near Chicago, about 800 miles east of the underground caverns. The beam, produced by the world’s most intense neutrino source, will travel straight through earth and rock from Fermilab to the DUNE detectors in South Dakota. No tunnel is necessary for the neutrinos’ path.

“The completion of the excavation of these enormous caverns is a significant achievement for this project,” said U.S. Project Director Chris Mossey. “Completing this step prepares the project for installation of the detectors starting later this year and brings us a step closer towards fulfilling the vision of making this world-class underground facility a reality.”

Engineering, construction and excavation teams have been working 4,850 feet below the surface since 2021 at the Sanford Underground Research Facility, home of the South Dakota portion of DUNE.  Construction crews dismantled heavy mining equipment and, piece by piece, transported it underground using an existing shaft. Underground, workers reassembled the equipment, and workers spent almost two years blasting and removing rock. Close to 800,000 tons of rock were excavated and transported from underground into an expansive former mining area above ground known as the Open Cut.

Workers will soon begin to outfit the caverns with the systems needed for the installation of the DUNE detectors and the daily operations of the research facility. Later this year, the project team plans to begin the installation of the insulated steel structure that will hold the first neutrino detector. The goal is to have the first detector operational before the end of 2028.

“The completion of the three large caverns and all of the interconnecting drifts marks the end of a really big dig. The excavation contractor maintained an exemplary safety record working over a million hours without a lost-time accident. That’s a major achievement in this heavy construction industry,” said Fermilab’s Michael Gemelli, who managed the excavation of the caverns by Thyssen Mining. “The success of this phase of the project can be attributed to the safe, dedicated work of the excavation workers, the multi-disciplined backgrounds of the project engineers and support personnel. What a remarkable achievement and milestone for this international project.”

DUNE scientists are eager to start the installation of the particle detectors. The DUNE collaboration, which includes more than 1,400 scientists and engineers from over 200 institutions in 36 countries, has successfully tested the technology and assembly process for the first detector. Mass production of its components has begun. Testing of the technologies underlying both detectors is underway using particle beams at the European laboratory CERN.

Fermilab is America’s premier national laboratory for particle physics and accelerator research. A U.S. Department of Energy Office of Science laboratory, Fermilab is located near Chicago, Illinois, and operated under contract by the Fermi Research Alliance LLC. Visit Fermilab’s website at www.fnal.gov and follow us on Twitter at @Fermilab.

The DOE Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

Using nonstick cookware to fry your bacon and eggs can make your life easier at that moment, but scientists believe there may be long-term consequences because the chemicals used to make it nonstick are so difficult to destroy. Perfluoroalkyl and polyfluoroalkyl substances — commonly known as PFAS and often called forever chemicals — are everywhere. PFAS, a suite of thousands of chemicals that have been around at least since the 1950s, are used for a wide variety of things, from the stain protectant on some of your clothing and linens to the food wrappers on your burgers.

The problem is that natural processes are ineffective at breaking PFAS down, so they accumulate in the environment and body, much like Styrofoam does in a landfill. Experts in science and industry are seeking ways to prevent PFAS contamination from occurring in the future, but they also aim to reduce what already exists in the world today.

It turns out that high-energy electron beams are excellent candidates for destroying PFAS in the environment. Researchers at the U.S. Department of Energy’s Fermi National Accelerator Laboratory, in collaboration with 3M, have successfully demonstrated that an electron beam can destroy the two most common types of PFAS in water — PFOA and PFOS.

“The electron beam is a promising technology to break down PFAS in large volumes of water that contain high concentrations of PFAS,” said Fermilab principal investigator Charlie Cooper.

The Fermilab team, which includes scientist Slavica Grdanovska, engineering physicist Yichen Ji and Cooper, used an electron beam accelerator at the laboratory for their testing. Used for proof-of-concept testing, the Accelerator Application Development and Demonstration accelerator, or A2D2, at the Illinois Accelerator Research Center on Fermilab’s campus is also available to industry, universities and other federal laboratories as a research tool.

“The fact that we were working with 3M, a world expert in PFAS, was really the first time that you had the experts on ionizing radiation, electron beam accelerators and PFAS working on the same project,” said Cooper.

Electron beams to the rescue

Conventional water treatment methods, such as reverse osmosis, granular activated carbon or ion exchange resin, do not destroy PFAS; they simply concentrate PFAS in a form which subsequently requires treatment or disposal. In some cases, conventional water treatment techniques can even make the environmental contamination worse.

In contrast, the electron beam actively destroys the forever chemicals and does so quickly, enabling a larger volume of water to be treated in the same amount of time as some other methods. PFAS molecules are difficult to break down because they contain a carbon-fluorine bond, which is very strong and the reason PFAS are commonly used in the chemical manufacturing industry. But the strength of that C-F bond is also the reason they don’t break down in nature. The electron beam, however, is very effective at breaking that C-F bond.

Electron beams could be used in pump-and-treat methods, a common groundwater treatment approach, or in a manufacturing facility, directly treating waste streams before they leave the facility.

Demonstrating its effectiveness

The Fermilab team used PFAS-contaminated water samples provided by 3M that were sealed in gastight containers the size of a whiteboard marker. Each of the containers was made of borosilicate glass, which wouldn’t be significantly affected by exposure to electron beams, and an aluminum seal was crimped onto the glass with a piece of PFAS-free rubber between the aluminum and the glass. Great care was taken to ensure there were no PFAS in any of the materials used to house the samples. Fermilab irradiated these samples with the electron beam and shipped them back to 3M.

3M sampled both the headspace — the air at the top of the container — and the liquid to verify that the PFAS of concern had been destroyed without releasing hazardous products to the air.

PFAS are prevalent in many industries, and so is the human reliance on essential products that contain PFAS, such as computers and lithium-ion batteries. One of the most problematic PFAS-containing products in terms of environmental contamination has historically been aqueous film forming foam, or AFFF, which was used for firefighting at airports and in the military; it’s made of PFOA and PFOS. When you spray AFFF onto a liquid, it moves to the surface and extinguishes the fire by preventing oxygen from getting to it. But, when used it can seep into soil and groundwater. AFFF has been used in the United States and worldwide for decades, largely by the military and aviation industry.  Recently, both government and industry started examining PFAS-free substitutes. Alternatives, however, do not exist in many applications and are hard to find or perform less effectively.

Although electron beams are very effective at breaking down entire suites of PFAS compounds, not every compound has been tested so far. The researchers found that all of the PFAS compounds the U.S. Environmental Protection Agency is currently considering regulating in drinking water were effectively destroyed by electron beam technology. But there may be types of PFAS an electron beam cannot destroy.

Research continues on several fronts to find alternatives to PFAS. At the same time, leaders in science and industry will continue to search for and enhance methods to eradicate these forever chemicals in the environment. Fermilab and its electron-beam technology stand at the forefront of this research.

This work is supported by the Office of Energy Efficiency and Renewable Energy of the U.S. Department of Energy Office of Science and 3M.

Fermi National Accelerator Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.