Particle physics planning process moves into final phase

Editor’s note: This article originally was published by Sanford Underground Research Facility.

Traveling by rail, sea, interstates and shafts, the first components of the international Deep Underground Neutrino Experiment have arrived at the Sanford Underground Research Facility in Lead, South Dakota. The anode plane assemblies, or APAs, will one day capture data left in the wake of neutrino collisions in DUNE’s Far Detector.

“This APA arrival and test lift marks the start of DUNE onsite activities at SURF,” said Mike Headley, executive director of SURF. “I’d like to congratulate the CERN, Fermilab, University of Manchester and SURF joint team for making this first experiment lift a major success.”

DUNE will paint a clearer picture of the origin of matter and how the universe came to be by studying neutrinos, strange subatomic particles that rarely interact with matter. A beam of neutrinos will travel 800 miles through the earth, from the U.S. Department of Energy’s Fermi National Accelerator Laboratory near Chicago to DUNE’s massive underground detectors at SURF.

More than 1,400 scientists and engineers in over 30 countries contribute to the experiment, which is hosted by Fermilab.

“This was a test of the entire logistics chain — from the UK, to Switzerland, to Illinois, and finally to South Dakota,” said Joe Pygott, deputy head of the Fermilab South Dakota Services Division. “After a year of planning, it was satisfying to see the global effort come together.”

Making things awkward

Standing a staggering 19.7 feet tall and 7.5 feet wide (6.0 meters tall; 2.3 meters wide), the APAs are the largest and one of the most fragile components of DUNE. Researchers outfit the APAs’ large steel frames with hundreds of electronic read-out boards. Then, 15-miles of hair-thin copper-beryllium wire is wrapped around the frame, creating a fine, mesh-like appearance.

In total, 150 APAs will be built for DUNE: 136 from the UK and 14 from the US.

“Because of their size, fragility and cost, the APAs are classified as a ‘critical transport,’” said Olga Beltramello, a mechanical engineer at CERN.

To tackle the logistics and transport of unusual components like the APAs, the project formed the appropriately named Awkward Material Transport Team.

Beltramello, a member of the AMTT, led the creation of the frames that would cradle the APAs during transport. Throughout the design phase, she anticipated the dynamics of the journey ahead — the jostle of the rail car, the lurch of ocean waves, the sway of an overhead crane.

“We run analysis to understand how the APA would withstand the dynamics of the transport,” Beltramello said. “The calculations are complex, as vibrations from track transport in Europe are different from the tire transport in the U.S., which are different from sea transport.”

With mass production of APAs underway, the team used the delivery of two prototype APAs to SURF to stress-test their transportation plan. Accelerometers and vibration detectors monitored every wobble along the way, telling researchers just how much stress the components actually experienced during the journey.

By land and sea

The APAs were constructed at the UK’s Science and Technology Facilities Council’s Daresbury Laboratory, then shipped to CERN, the European laboratory for particle physics. There, the APAs were installed and tested in ProtoDUNE. A massive detector in its own right, ProtoDUNE is a prototype of the DUNE detectors to be built at SURF. Researchers wanted to ensure that the APAs could withstand the extreme cold of liquid argon (minus 200 degrees Celsius) and to see if they would yield clear data signals, unobscured by background noise.

“In ProtoDUNE, we saw lovely, clean images,” said Justin Evans, professor of physics at the University of Manchester and academic lead of the UK project for APA production.

The APAs then journeyed by rail to the seaside; by cargo ship across the Atlantic; and 1,600-miles by semitruck across the U.S. The final leg of the journey was down the mile-deep Ross Shaft, to the level where crews are excavating the large caverns that will house the DUNE Far Detector. Due to their size, the APAs will not fit on the elevator-like conveyance used to transport people and materials through the shaft. Instead, the APAs were suspended beneath the cage to lower them underground.

Jeff Barthel, SURF’s rigging supervisor who led the maneuver, said the test lift of the nearly 6,400-pound load “couldn’t have gone smoother.”

Assured by the APA performance in ProtoDUNE and the successful test transport, researchers have started mass producing APAs for DUNE.

“For me, even more important than reaching this technical goal, is the excellent collaboration between groups,” Beltramello said. “This was our first collaboration across these groups, and it was extremely successful. It’s good for the future.”

A neutrino trap

When excavation is complete, the caverns will provide space for detector modules filled with a combined 70,000 tons of liquid argon. The APAs will be submerged side-by-side in the frigid liquid argon, forming a series of net-like walls across the width of the detector.

When neutrinos collide with an argon nucleus, the collisions create a cascade of charged particles. These particles, in turn, knock loose electrons from the shells of argon atoms. An electric field will push the free-floating electrons toward a wall of APAs. Like a spider’s web, the APA wires will ensnare the drifting electrons, sending shivers of data up the wires to the electrical read-out boards. Researchers see this data in the form of particle tracks.

“The electrons are hitting these miles and miles of wires, and we get information from that little pulse of electrical current on the wire,” Evans explained. “The pattern of particles that went through the detector is mirrored in the pattern of electrons colliding with the APAs.”

From these particle tracks, researchers derive information about neutrinos and their antimatter counterparts. The results will shed light on the role neutrinos played in the evolution of the universe.

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.

Dark matter makes up about 27% of the matter and energy budget in the universe, but scientists do not know much about it. They do know that it is cold, meaning that the particles that make up dark matter are slow-moving. It is also difficult to detect dark matter directly because it does not interact with light. However, scientists at the U.S. Department of Energy’s Fermi National Accelerator Laboratory have found a way to look for dark matter using quantum computers.

Aaron Chou, a senior scientist at Fermilab, works on detecting dark matter through quantum science. As part of DOE’s Office of High Energy Physics QuantISED program, he has developed a way to use qubits, the main component of quantum computing systems, to detect single photons produced by dark matter in the presence of a strong magnetic field.

How quantum computers could detect dark matter

A classical computer processes information with binary bits set to either 1 or 0. The specific pattern of ones and zeros makes it possible for the computer to perform certain functions and tasks. In quantum computing, however, qubits exist at both 1 and 0 simultaneously until they are read, due to a quantum mechanical property known as superposition. This property allows quantum computers to efficiently perform complex calculations that a classical computer would take an enormous amount of time to complete.

“Qubits work by manipulating single excitations of information, for example, single photons,” said Chou. “So, if you’re working with such small packets of energy as single excitations, you’re far more susceptible to external disturbances.”

In order for qubits to operate at these quantum levels, they must reside in carefully controlled environments that protect them from outside interference and keep them at consistently cold temperatures. Even the slightest disturbance can throw off a program in a quantum computer. With their extreme sensitivity, Chou realized quantum computers could provide a way to detect dark matter. He recognized that other dark matter detectors need to be shielded in the same way quantum computers are, further solidifying the idea.

“Both quantum computers and dark matter detectors have to be heavily shielded, and the only thing that can jump through is dark matter,” Chou said. “So, if people are building quantum computers with the same requirements, we asked ‘why can’t you just use those as dark matter detectors?’”

Where errors are most welcome

When dark matter particles traverse a strong magnetic field, they may produce photons that Chou and his team can measure with superconducting qubits inside aluminum photon cavities. Because the qubits have been shielded from all other outside disturbances, when scientists detect a disturbance from a photon, they can infer that it was the result of dark matter flying through the protective layers.

“These disturbances manifest as errors where you didn’t load any information into the computer, but somehow information appeared, like zeroes that flip into ones from particles flying through the device,” he said.

So far, Chou and his team have demonstrated how the technique works and that the device is incredibly sensitive to these photons. Their method has advantages over other sensors, such as being able to make multiple measurements of the same photon to ensure a disturbance was not just caused by another fluke. The device also has an ultra-low noise level, which allows for a heightened sensitivity to dark matter signals.

Even the slightest disturbance can throw off a program in a quantum computer. With their extreme sensitivity, Aaron Chou realized quantum computers could provide a way to detect dark matter.

“We know how to make these tunable boxes from the high-energy physics community, and we worked together with the quantum computing people to understand and transfer the technology for these qubits to be used as sensors,” Chou said.

From here, they plan to develop a dark matter detection experiment and continue improving upon the design of the device.

Using sapphire cavities to catch dark matter

“This apparatus tests the sensor in the box, which holds photons with a single frequency,” Chou said. “The next step is to modify this box to turn it into kind of a radio receiver in which we can change the dimensions of the box.”

By altering the dimensions of the photon cavity, it will be able to sense different wavelengths of photons produced by dark matter.

“The waves that can live in the box are determined by the overall size of the box. In order to change what frequencies and which wavelengths of dark matter we want to look for, we actually have to change the size of the box,” said Chou. “That’s the work we’re currently doing; we’ve created boxes in which we can change the lengths of different parts of it in order to be able to tune into dark matter at different frequencies.”

The researchers are also developing cavities made from different materials. The traditional aluminum photon cavities lose their superconductivity in the presence of the magnetic field necessary for producing photons from dark matter particles.

“These cavities cannot live in high magnetic fields,” he said. “High magnetic fields destroy the superconductivity, so we’ve made a new cavity made out of synthetic sapphire.”

Developing these new, tunable sapphire photon cavities will lead the team closer to running dark matter experiments that combine aspects from both physics and quantum science.

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.

Just as charged particles collide into one another in an accelerator, various branches of science ranging from physics and engineering to computer science collide to design, construct and operate particle accelerators. To help develop the next generation of researchers in accelerator science and technology, the U.S. Department of Energy’s Argonne National and Fermi National Accelerator Laboratories jointly run a prestigious summer undergraduate program to achieve this goal.

Established in 2008, the Lee Teng internship gives upper-level university students in the U.S. the opportunity to gain hands-on experience in accelerator science and technology while working with experts in the field. Every summer, 10 students participate in the competitive paid internship. These interns come from a wide range of disciplines, including physics, mathematics, materials science, electrical and mechanical engineering and computer science.

After a two-year pause due to COVID-19, the internship will resume in the summer of 2023. The 10-week program enables new college juniors, seniors and occasionally even talented sophomores to challenge themselves in the exciting world of particle accelerators at either Fermilab or Argonne.

“Accelerator science and technology has enabled countless scientific discoveries with transformative impacts on society and industry,” said Jonathan Jarvis, co-director of the Lee Teng Internship program and head of Fermilab’s Accelerator Research Department. “Programs like LTI are essential for developing the workforce that will produce the next generation of innovations and discoveries.”

“I was very fortunate to have the opportunity to be part of the Lee Teng Internship. The exposure to Fermilab was extremely positive and motivated me to continue working with the different national labs wherever possible.” – Ben Sims, former Fermilab LTI intern

The program fosters the ideas and potential of early-career individuals in this field in honor of theoretical physicist Lee Chang-Li Teng, who led and contributed to numerous global particle accelerator projects while educating those around him. Upon emigrating to the United States, Teng followed his passion for particle physics. He first earned his doctorate at the University of Chicago and then worked at Argonne and Fermilab for decades.

Ideal candidates for LTI show exceptional strength in the classroom but don’t need to have previous accelerator experience. Jarvis said the selection committee of five to six engineers and scientists want to see a promising student who is open and interested in relevant areas like electromagnetism.

The LTI program opens with a two-week trip to the rigorous U.S. Particle Accelerator School, where the interns take the course, “Fundamentals of Accelerator Physics and Technology with Simulations and Measurements Lab,” for academic credit. The interns then return to the labs to work on a collaborative research project alongside a mentor at Argonne or Fermilab.

“Being able to work at Argonne National Lab introduced me to the idea of working at national labs, which is now my goal. Participating in USPAS was also a great experience as it gave me an option for research in graduate school that I pursued,” said Cassandra Phillips, former Argonne LTI intern and Northern Illinois University graduate student. “Now I get to work at the Argonne Wakefield Accelerator facility as a graduate student performing research for structure-based wakefield acceleration.”

In the remaining eight weeks, students are assigned to a mentor and project at either national laboratory that appropriately matches their respective skill sets. For example, a student with interest and experience in machine learning or artificial intelligence might be paired with an accelerator engineer for a project on accelerator control systems. During the internship, interns will tour Fermilab and Argonne and visit the University of Chicago research facilities. They also receive guidance on building graduate school applications. Concluding the program, interns will summarize their summer research and present their projects at a joint research symposium.

“I was very fortunate to have the opportunity to be part of the Lee Teng Internship. The exposure to Fermilab was extremely positive and motivated me to continue working with the different national labs wherever possible. This has led to my current work as a graduate student on beamline simulations of the new low-emittance injector for LCLS-II-HE,” said Ben Sims, a former Fermilab LTI intern and current graduate student at Michigan State University. “I hope to continue my career by working at a national lab in the future.”

Applications for the Lee Teng Internship went live on Fermilab’s website in November 2022.

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

Editor’s note: At 4:40 p.m. today, the neutrino detection system was placed inside the SBND detector hall after a successful move.

After years of construction, testing and planning, an exciting move is currently underway at the U.S. Department of Energy’s Fermi National Accelerator Laboratory.

A neutrino detection system built for the Short-Baseline Near Detector will travel 3 miles today, Dec. 1, from the warehouse-like building in which it was constructed to its final home in the SBND detector hall. There scientists will use a beam of particles called neutrinos to examine the collisions of these particles with atoms. Their goal is to learn more about the mysterious properties of neutrinos.

Moving the system is no easy feat. As a nearly 20-foot cube, it’s the size of a small house. It weighs 20,000 pounds and contains delicate sensors and wiring that, if rattled too much, could compromise the integrity of the system.

Scientists, engineers and Fermilab personnel have anticipated this move for years and spent countless hours preparing for it. Now is the day. The move began at 6 a.m. and is projected to take 8 to 10 hours. Staff began by rolling the detector system through a large roll-up door with just inches of clearance to spare. Next, they will load it onto a flat-bed trailer using a crane. The public can get updates on the move through the lab’s social media platforms.

Once in place on the trailer, the truck will move at a maximum speed of about 2.5 miles per hour on its 3-mile route through the Fermilab campus to the detector hall, where the crane will lift it from the trailer and back onto solid ground. Finally, crews will roll the detection system through a garage door into its new home.

In the coming months, the system will be placed inside a large cryostat, a vessel to cool the system to low temperature that will be filled with liquid argon and complete SBND. In fall 2023, scientists expect to begin receiving data that will shed light on the strange behavior of the ghostly neutrinos.

A large group of people — including scientists, engineers, riggers and safety personnel — have meticulously planned the move for years — even from the very conception of the detector. Now they are excited that the process is finally coming to fruition.

“It’s like taking your baby to the first day of school,” said Fermilab’s Shishir Shetty, a mechanical engineer who helped design the transport system. “So many people have put their time and effort into building the detector and planning for the move, and now we are finally at the point where we get to see the results of those efforts.”

Measurements that have never been done before

SBND will play a key role in understanding neutrinos: subatomic particles that have very little interaction with matter but that could hold the answers to many mysteries surrounding our universe. So far, scientists have discovered three types of neutrinos. SBND, as part of Fermilab’s Short-Baseline Neutrino Program, will help confirm or refute the existence of a potential fourth kind, called a sterile neutrino.

The Short-Baseline Neutrino Program analyzes a neutrino beam with three liquid-argon time projection chamber detectors, including the new SBND. (It is the same technology that scientists will use for the much larger detectors of the Deep Underground Neutrino Experiment.) The three detectors measure the neutrinos as they travel along a straight path, searching for signs of oscillations — the way neutrinos transform into various types as they travel. At 110 meters from the beam source, SBND is the closest detector and will help scientists better understand the original composition of the neutrino beam. (The other detectors are MicroBooNE at 470 meters away and ICARUS at 600 meters away.)

Scientists can predict how many neutrinos and which types of neutrino they should expect to see if they know the original beam composition with high precision. A discrepancy could provide evidence for the existence of sterile neutrinos, or it could lay the groundwork for the discovery of new particles in beyond-the-standard model physics.

“This will give us a dataset that will be 20 to 30 times larger than the current neutrino-argon interaction data set, which will allow us to do measurements that have never been done before,” said Ornella Palamara, a neutrino scientist at Fermilab and co-spokesperson for the international SBND collaboration.

Building the detector within a transport frame

SBND was first proposed in 2014. Construction of the detection system, which involved scientists from around the world, began in the following years. Parts began to arrive at Fermilab in 2018.

From the beginning, scientists and engineers knew the detection system couldn’t be built in the detector hall. They needed a large assembly building to construct the system — which consists of anode and cathode wire planes, as well as light detection systems — before it would be placed in the experiment’s large cryostat, located inside Fermilab’s Booster Neutrino Beam. The cryostat will be filled with liquid argon.

“It’s like taking your baby to the first day of school. So many people have put their time and effort into building the detector and planning for the move, and now we are finally at the point where we get to see the results of those efforts.” – Shishir Shetty, Fermilab mechanical engineer

So the team began to assemble the system in the DZero Assembly Building at Fermilab and designed and built a transport frame that would house the system from the start. To build the steel frame, the engineering team had to ensure it both supported the heavy detector system, which hangs from the top beams of the frame, while also ensuring it could be easily moved when the time came. The frame includes outriggers for support, a towbar for pulling, transport stops to prevent the detector from swinging, and a hinged door to remove the system once it arrives in the detector hall.

To help with transport, the detector system itself sits on moving devices called Hilman rollers. In the days before the move, Fermilab staff laid down steel plate tracks for the rollers to ensure minimal friction. To move it out of the building, the frame was pulled out with a fork truck onto the plates, up a ramp, and out of the building, while another fork truck acted as a brake behind the frame. A specially designed guiding system along the ramp ensured that the rollers didn’t deviate from their tracks.

The frame with the detection system — completely wrapped in black plastic to protect the light-sensitive detector components — moved through the building’s garage door with only inches of clearance. Once outside the building and lifted onto a flatbed trailer, the frame will be driven to its new home.

Finding the right route

This past summer, scientists and engineers conducted three trial runs to find the best transport route. They loaded up the trailer with 66,900 pounds of concrete blocks, corresponding to the weight of the detector and transportation frame. They then used accelerometers and inclinometers, including iPads, to monitor the route’s bumps, as well as the trailer’s roll and pitch around turns.

Because the detector system has a high center of gravity — about 10 feet up — engineers needed to ensure that the route did not include any inclines or turn angles that would change the level of the trailer more than 5 degrees.

“During transportation, we need to keep everything aligned,” said Monica Nunes, a guest scientist who coordinated the SBND assembly. “The detector was built to be transported, but a move like this — with a system that has such a high center of gravity — has never been done at Fermilab before.”

The data showed that the preferred route was along Fermilab’s Ring Road. At a maximum speed of about 2.5 miles per hour, and with an escort from Fermilab security, this part of the transport is expected to take about 90 minutes. Scientists and engineers will be walking alongside the truck as it moves, monitoring the load real-time with accelerators and inclinometers that will transmit data to their cell phones.

The route has been well prepared. In the days before the move, Fermilab’s Infrastructure Services Division inspected the road for potholes, trimmed trees and removed powerlines to ready the route.

“Many people at Fermilab have worked together to make this happen — physicists, students, technical staff, administration, procurement,” said Anne Schukraft, neutrino scientist and SBND technical coordinator. “It has been great to get everyone’s input and to learn from everyone’s expertise. It has been a true team effort.”

After the move

Once the detector system arrives at the detector hall, the crane will unload it from the trailer, placing it on steel tracks for it to be rolled 82 feet into the detector hall. That will complete the move for the day.

“That is when we will be extremely happy,” Shetty said. “You will see a lot of smiles.”

In the coming days and weeks, Fermilab scientists and engineers will unwrap the detector, set up outriggers, and install fall protection to be able to work safely on top of the detector. They will also test each of the subsystems to ensure they were not compromised during the move.

In the coming months, the detector will be fitted with a top cap and placed inside the cryostat. Next summer, the cryostat will be filled with liquid argon. Scientists will test the system to characterize the signals it receives before it begins receiving real data from the neutrino beam in the fall of 2023. Ultimately, SBND will record over a million neutrino interactions per year.

“To finally have data will be really exciting,” Palamara said. “We have been working toward this for eight years.”

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.