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Posts Tagged ‘Fermilab’

A version of this article appeared in symmetry on April 8, 2014.

Physicist Aaron Chou keeps the Holometer experiment—which looks for a phenomenon whose implications border on the unreal—grounded in the realities of day-to-day operations. Photo: Reidar Hahn

Physicist Aaron Chou keeps the Holometer experiment—which looks for a phenomenon whose implications border on the unreal—grounded in the realities of day-to-day operations. Photo: Reidar Hahn

The beauty of the small operation—the mom-and-pop restaurant or the do-it-yourself home repair—is that pragmatism begets creativity. The industrious individual who makes do with limited resources is compelled onto paths of ingenuity, inventing rather than following rules to address the project’s peculiarities.

As project manager for the Holometer experiment at Fermilab, physicist Aaron Chou runs a show that, though grandiose in goal, is remarkably humble in setup. Operated out of a trailer by a small team with a small budget, it has the feel more of a scrappy startup than of an undertaking that could make humanity completely rethink our universe.

The experiment is based on the proposition that our familiar, three-dimensional universe is a manifestation of a two-dimensional, digitized space-time. In other words, all that we see around us is no more than a hologram of a more fundamental, lower-dimensional reality.

If this were the case, then space-time would not be smooth; instead, if you zoomed in on it far enough, you would begin to see the smallest quantum bits—much as a digital photo eventually reveals its fundamental pixels.

In 2009, the GEO600 experiment, which searches for gravitational waves emanating from black holes, was plagued by unaccountable noise. This noise could, in theory, be a telltale sign of the universe’s smallest quantum bits. The Holometer experiment seeks to measure space-time with far more precision than any experiment before—and potentially observe effects from those fundamental bits.

Such an endeavor is thrilling—but also risky. Discovery would change the most basic assumptions we make about the universe. But there also might not be any holographic noise to find. So for Chou, managing the Holometer means building and operating the apparatus on the cheap—not shoddily, but with utmost economy.

Thus Chou and his team take every opportunity to make rather than purchase, to pick up rather than wait for delivery, to seize the opportunity and take that measurement when all the right people are available.

“It’s kind of like solving a Rubik’s cube,” Chou says. “You have an overview of every aspect of the measurement that you’re trying to make. You have to be able to tell the instant something doesn’t look right, and tell that it conflicts with some other assumption you had. And the instant you have a conflict, you have to figure out a way to resolve it. It’s a lot of fun.”

Chou is one of the experiment’s 1.5 full-time staff members; a complement of students rounds out a team of 10. Although Chou is essentially the overseer, he runs the experiment from down in the trenches.

Aaron Chou, project manager 
for Fermilab’s Holometer, tests the experiment’s instrumentation. Photo: Reidar Hahn

Aaron Chou, project manager 
for Fermilab’s Holometer, tests the experiment’s instrumentation. Photo: Reidar Hahn

The Holometer experimental area, for example, is a couple of aboveground, dirt-covered tunnels whose walls don’t altogether keep out the water after a heavy rain. So any time the area needs the attention of a wet-dry vacuum, he and his team are down on the ground, cheerfully squeegeeing, mopping and vacuuming away.

“That’s why I wear such shabby clothes,” he says. “This is not the type of experiment where you sit behind the computer and analyze data or control things remotely all day long. It’s really crawling-around-on-the-floor kind of work, which I actually find to be kind of a relief, because I spent more than a decade sitting in front of a computer for more well-established experiments where the installation took 10 years and most of the resulting experiment is done from behind a keyboard.”

As a graduate student at Stanford University, Chou worked on the SLD experiment at SLAC National Accelerator Laboratory, writing software to help look for parity violation in Z bosons. As a Fermilab postdoc on the Pierre Auger experiment, he analyzed data on ultra-high-energy cosmic rays.

Now Chou and his team are down in the dirt, hunting for the universe’s quantum bits. In length terms, these bits are expected to be on the smallest scale of the universe, the Planck scale: 1.6 x 10-35 meters. That’s roughly 10 trillion trillion times smaller than an atom; no existing instrument can directly probe objects that small. If humanity could build a particle collider the size of the Milky Way, we might be able to investigate Planck-scale bits directly.

The Holometer instead will look for a jitter arising from the cosmos’ minuscule quanta. In the experiment’s dimly lit tunnels, the team built two interferometers, L-shaped configurations of tubes. Beginning at the L’s vertex, a laser beam travels down each of the L’s 40-meter arms simultaneously, bounces off the mirrors at the ends and recombines at the starting point. Since the laser beam’s paths down each arm of the L are the same length, absent a holographic jitter, the beam should cancel itself out as it recombines. If it doesn’t, it could be evidence of the jitter, a disruption in the laser beam’s flight.

And why are there two interferometers? The two beam spots’ particular brightening and dimming will match if it’s the looked-for signal.

“Real signals have to be in sync,” Chou says. “Random fluctuations won’t be heard by both instruments.”

Should the humble Holometer find a jitter when it looks for the signal—researchers will soon begin the initial search and expect results by 2015—the reward to physics would be extraordinarily high, especially given the scrimping behind the experiment and the fact that no one had to build an impossibly high-energy, Milky Way-sized collider. The data would support the idea that the universe we see around us is only a hologram. It would also help bring together the two thus-far-irreconcilable principles of quantum mechanics and relativity.

“Right now, so little experimental data exists about this high-energy scale that theorists are unable to construct any meaningful models other than those based on speculation,” Chou says. “Our experiment is really a mission of exploration—to obtain data about an extremely high-energy scale that is otherwise inaccessible.”

What’s more, when the Holometer is up and running, it will be able to look for other phenomena that manifest themselves in the form of high-frequency gravitational waves, including topological defects in our cosmos—areas of tension between large regions in space-time that were formed by the big bang.

“Whenever you design a new apparatus, what you’re doing is building something that’s more sensitive to some aspect of nature than anything that has ever been built before,” Chou says. “We may discover evidence of holographic jitter. But even if we don’t, if we’re smart about how we use our newly built apparatus, we may still be able to discover new aspects of our universe.”

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This article originally appeared in symmetry on March 31, 2014.

Three decades ago in March, scientists from Latin America came to do research at Fermilab, forming the ties of a lasting collaboration.

Three decades ago in March, scientists from Latin America came to do research at Fermilab, forming the ties of a lasting collaboration.

In 1983, Fermilab Director Leon Lederman put his money on the table at the second Pan American Symposium on Elementary Particles and Technology in Rio de Janeiro. His daring proposition: If the Brazilian Research Council would not at the time fund that nation’s physicists to do research at Fermilab, he would pay the salaries himself.

His parlay worked. A year later, 30 years ago this month, four physicists from Brazil took paid leave to work on the E691 fixed-target experiment at Fermilab. They were Fermilab’s first Latin American scientists and the beginning of its relationship with the region.

“Lederman made the bold offer in that meeting,” says Carlos Escobar, one of the four trailblazing Brazilians who crossed over the Equator to Fermilab. “That was the deciding factor.”

Mexico soon followed, spearheaded by then Universidad Nacional Autónoma de México professor Clicerio Avilez. The university sent two scientists and a graduate student, the first Latin American student to get his PhD for work done at Fermilab.

Since then, the collaboration between Fermilab and Latin American institutions has grown to also include Argentina, Chile, Colombia, Ecuador and Peru. Twenty-one Latin American institutions participate in the collaboration, which consists of theorists and members of eight experiments: CMS, DAMIC, DZero, LBNE, MINERvA and MINOS, as well as on the Dark Energy Survey and the Pierre Auger Observatory—both of which reside in South America. That’s in addition to the nine fixed-target experiments that completed their runs in the 1990s.

Lederman began planting the seeds of collaboration in 1979, noting that Latin American nations boasted strong scientific groups and an impressive history of innovation.

“Latin America represented a huge potential treasure of human resources which would, I was sure, eventually be devoted to scientific research to the benefit of the nations of South and Central America and, indeed, the world,” he wrote in a 2006 paper.

Since those days, the collaboration with Fermilab, as well as steadily gaining economic strength and higher publicity for science, have placed particle physics research south of the Rio Grande on firmer ground. Fermilab not only provided scientists with particle physics experiments to work on, it also hosted workshops that were attended by Latin American engineers, physicists, technicians and students.

“When I first started, there were only two groups in Mexico cultivating theoretical high-energy physics, and none tilling the field of experimental high-energy physics,” says Julian Felix Valdez, a University of Guanajuato professor whose connection with Fermilab began in 1990, when he was a graduate student. Then, he says, things changed as Universidad Nacional Autónoma de México and Instituto Politécnico Nacional began sending students to Fermilab.

“Thirty years later, there are groups in experimental high-energy physics at eight Mexican universities, as well as other groups emerging at other Mexican universities,” Felix Valdez says. He estimates about 100 Mexican scientists work on particle physics at home and an additional 30 abroad.

The flow of students hasn’t abated, and most now come to Fermilab to work on neutrino research. For future generations, it could mean working on Fermilab’s Long-Baseline Neutrino Experiment.

“There’s a good stream of people. Once the connection’s established, it doesn’t sever. It keeps flowing,” says Pontificia Universidad Católica del Perú master’s student Maria Jose Bustamante, who is on the MINERvA neutrino experiment. “Of course you need an institution to do that.”

Enlisting more institutions to invigorate the flow is perhaps still the biggest challenge facing the collaboration today. To that end, Fermilab’s fifth director, Pier Oddone, and his deputy, Young-Kee Kim, picked up where Lederman left off, says MINERvA scientist Jorge Morfin, one of the founding members of the Latin American collaboration. Oddone and Kim helped formalize the Latin American Initiative in 2010, suggesting more written agreements between Fermilab and Latin American institutions and funding agencies.

“No one on MINERvA would doubt that the contribution of these Latin American students has been significant. This has been a real working benefit for the experiment here at Fermilab,” Morfin says. The number of students that work or have worked on MINERvA totals 24 master’s students, nine doctoral students and two postdocs. “Now they can work on experiments throughout the world. It’s been a nice return, a give and take,” he says.

Collaboration also provides opportunities for visiting scientists to bring technologies from their home countries to Fermilab. Escobar notes that Brazilian companies provided several pieces of instrumentation for Fermilab experiments, including drift chambers and detectors for DZero. It goes the other way, too: Scientists take new technologies developed at Fermilab back to industries at home.

“People see the local industries benefit from this kind of collaboration with a place that does fundamental research,” Morfin says. “It translates into actual progress for local industries and local technology.”

To see another 30 years of flourishing high-energy physics in the western hemisphere requires an investment in physics from both sides of the Equator, Felix Valdez says.

“Physics—especially high-energy physics—is an international task,” he says.

Leah Hesla

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This article appeared in Fermilab Today on March 26, 2014.

Tom Wicks, rigging superintendent at Joliet Steel & Construction, stands next to the stripped-down CDF detector at Fermilab. His mother, Lois Anderson, helped build the detector as an ironworker nearly 30 years ago. Photo: Amanda Solliday

Tom Wicks, rigging superintendent at Joliet Steel & Construction, stands next to the stripped-down CDF detector at Fermilab. His mother, Lois Anderson, helped build the detector as an ironworker nearly 30 years ago. Photo: Amanda Solliday

One day when Tom Wicks was a child, he biked over to see his mom, Lois Anderson, working at an office in Aurora, Ill. She was at the top of the building, welding and torching as ironworkers do.

“That’s when my son told me, ‘I want to do that,’” Anderson said.

Both mother and son have worked as ironworkers on Fermilab experiments throughout their careers. Anderson, known as “Sarge” during business hours and the only female on her crew for decades, began ironworking at CDF — one of two detectors located on the Tevatron ring — when it was “a hole in the ground” in the early 1980s. Anderson and Wicks, rigging superintendent at Joliet Steel & Construction, worked together on the last upgrade of the detector in 2001.

Now Wicks is dismantling much of the roughly 4,000-ton particle detector that he, his mother and his stepfather helped build.

“She likes to tease me about it. ‘All that work we’ve put into it, and now you’re tearing it apart?’” Wicks said.

CDF ran for more than two decades, collecting data from proton-antiproton collisions from 1985 until the Tevatron shut down in 2011. Scientists at CDF and its sister detector DZero discovered the last quark predicted by the Standard Model, the top quark. Both collaborations still analyze valuable data collected from the detectors.

In its heyday, the large orange and blue CDF detector drew crowds when upgrades required rolling the machine from the collision tunnel to an open assembly hall.

“During the last upgrade, it was like a football game,” Wicks said. “There were so many people watching, you couldn’t get a space along the rail to watch us do it.”

Wicks and his crew began working with Fermilab staff to remove equipment from the CDF detector in March 2013. They will likely finish next month, leaving intact the multmillion-dollar solenoid magnet at the core of the detector.

John Wackerlin, a fellow ironworker and foreman at Walbridge, led one of the teams tasked with decommissioning the experiment. Like Wicks, he’s laying to rest something his family helped build. His father, Bob Wackerlin, welded together the structure that houses the 30-foot-tall detector.

The elder Wackerlin’s work at Fermilab started even before CDF. When his wife was pregnant with John, Bob Wackerlin worked underground in the 4-mile Tevatron tunnel while it was still being dug. He retired after 42 years as an ironworker and said he’s proud of his family’s connection to the laboratory.

“I’ve worked in just about every building on this site,” Bob Wackerlin said. “Fermilab projects are some of the best jobs that come across our ironworkers union. It’s employed a lot of people over the years.”

His son added, “Working with physicists and the talent and brainpower here — it’s unreal.”

Although CDF is turned off and its many wires and cables scrapped, much of the detector will find a home in future experiments. The solenoid magnet, for example, could be reused in another particle experiment, said Fermilab scientist Jonathan Lewis. Scientists are recycling parts of the detector for other high-energy physics projects at Fermilab, and electronics, phototubes and assorted pieces of CDF have also been shipped to other labs and universities in the United States, Europe and Japan.

Both families see this as progress.

“Once you’ve learned something from one experiment, it makes way for new experiments,” John Wackerlin said. “So now we can go on to even bigger and better things. I’m excited about it.”

Amanda Solliday

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This article appeared in symmetry on March 19, 2014.

An international team of scientists from Fermilab’s Tevatron and CERN’s Large Hadron Collider has produced the world’s best value for the mass of the top quark.

An international team of scientists from Fermilab’s Tevatron and CERN’s Large Hadron Collider has produced the world’s best value for the mass of the top quark.

Scientists working on the world’s leading particle collider experiments have joined forces, combined their data and produced the first joint result from Fermilab’s Tevatron and CERN’s Large Hadron Collider. These machines are the past and current holders of the record for most powerful particle collider on Earth.

Scientists from the four experiments involved—ATLAS, CDF, CMS and DZero—announced their joint findings on the mass of the top quark today at the Rencontres de Moriond international physics conference in Italy.

Together the four experiments pooled their data analysis power to arrive at a new world’s best value for the mass of the top quark of 173.34 ± 0.76 GeV/c2.

Experiments at the LHC at the CERN laboratory in Geneva, Switzerland and the Tevatron collider at Fermilab in Illinois, USA are the only ones that have ever seen top quarks—the heaviest elementary particles ever observed. The top quark’s huge mass (more than 100 times that of the proton) makes it one of the most important tools in the physicists’ quest to understand the nature of the universe.

The new precise value of the top-quark mass will allow scientists to test further the mathematical framework that describes the quantum connections between the top quark, the Higgs particle and the carrier of the electroweak force, the W boson. Theorists will explore how the new, more precise value will change predictions regarding the stability of the Higgs field and its effects on the evolution of the universe. It will also allow scientists to look for inconsistencies in the Standard Model of particle physics—searching for hints of new physics that will lead to a better understanding of the nature of the universe.

“The combining together of data from CERN and Fermilab to make a precision top quark mass result is a strong indication of its importance to understanding nature,” says Fermilab director Nigel Lockyer. “It’s a great example of the international collaboration in our field.”

Courtesy of: Fermilab and CERN

Courtesy of: Fermilab and CERN

A total of more than six thousand scientists from more than 50 countries participate in the four experimental collaborations. The CDF and DZero experiments discovered the top quark in 1995, and the Tevatron produced about 300,000 top quark events during its 25-year lifetime, completed in 2011. Since it started collider physics operations in 2009, the LHC has produced close to 18 million events with top quarks, making it the world’s leading top quark factory.

“Collaborative competition is the name of the game,” says CERN’s Director General Rolf Heuer. “Competition between experimental collaborations and labs spurs us on, but collaboration such as this underpins the global particle physics endeavor and is essential in advancing our knowledge of the universe we live in.”

Each of the four collaborations previously released their individual top-quark mass measurements. Combining them together required close collaboration between the four experiments, understanding in detail each other’s techniques and uncertainties. Each experiment measured the top-quark mass using several different methods by analyzing different top quark decay channels, using sophisticated analysis techniques developed and improved over more than 20 years of top quark research beginning at the Tevatron and continuing at the LHC. The joint measurement has been submitted to the arXiv.

A version of this article was originally issued by Fermilab and CERN as a press release.

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This article appeared in symmetry on February 28, 2014.

The Cryogenic Dark Matter Search has set more stringent limits on light dark matter.

The Cryogenic Dark Matter Search has set more stringent limits on light dark matter.

Scientists looking for dark matter face a serious challenge: No one knows what dark matter particles look like. So their search covers a wide range of possible traits—different masses, different probabilities of interacting with regular matter.

Today, scientists on the Cryogenic Dark Matter Search experiment, or CDMS, announced they have shifted the border of this search down to a dark-matter particle mass and rate of interaction that has never been probed.

“We’re pushing CDMS to as low mass as we can,” says Fermilab physicist Dan Bauer, the project manager for CDMS. “We’re proving the particle detector technology here.”

Their result, which does not claim any hints of dark matter particles, contradicts a result announced in January by another dark matter experiment, CoGeNT, which uses particle detectors made of germanium, the same material as used by CDMS.

To search for dark matter, CDMS scientists cool their detectors to very low temperatures in order to detect the very small energies deposited by the collisions of dark matter particles with the germanium. They operate their detectors half of a mile underground in a former iron ore mine in northern Minnesota. The mine provides shielding from cosmic rays that could clutter the detector as it waits for passing dark matter particles.

Today’s result carves out interesting new dark matter territory for masses below 6 billion electronvolts. The dark matter experiment Large Underground Xenon, or LUX, recently ruled out a wide range of masses and interaction rates above that with the announcement of its first result in October 2013.

Scientists have expressed an increasing amount of interest of late in the search for low-mass dark matter particles, with CDMS and three other experiments—DAMA, CoGeNT and CRESST—all finding their data compatible with the existence of dark matter particles between 5 billion and 20 billion electronvolts. But such light dark-matter particles are hard to pin down. The lower the mass of the dark-matter particles, the less energy they leave in detectors, and the more likely it is that background noise will drown out any signals.

Even more confounding is the fact that scientists don’t know whether dark matter particles interact in the same way in detectors built with different materials. In addition to germanium, scientists use argon, xenon, silicon and other materials to search for dark matter in more than a dozen experiments around the world.

“It’s important to look in as many materials as possible to try to understand whether dark matter interacts in this more complicated way,” says Adam Anderson, a graduate student at MIT who worked on the latest CDMS analysis as part of his thesis. “Some materials might have very weak interactions. If you only picked one, you might miss it.”

Scientists around the world seem to be taking that advice, building different types of detectors and constantly improving their methods.

“Progress is extremely fast,” Anderson says. “The sensitivity of these experiments is increasing by an order of magnitude every few years.”

Kathryn Jepsen

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This Fermilab press release was published on February 24.

Matteo Cremonesi, left, of the University of Oxford and the CDF collaboration and Reinhard Schwienhorst of Michigan State University and the DZero collaboration present their joint discovery at a forum at Fermilab on Friday, Feb. 21. The two collaborations have observed the production of single top quarks in the s-channel, as seen in data collected from the Tevatron. Photo: Cindy Arnold

Matteo Cremonesi, left, of the University of Oxford and the CDF collaboration and Reinhard Schweinhorst of Michigan State University and the DZero collaboration present their joint discovery at a forum at Fermilab on Friday, Feb. 21. The two collaborations have observed the production of single top quarks in the s-channel, as seen in data collected from the Tevatron. Photo: Cindy Arnold

Scientists on the CDF and DZero experiments at the U.S. Department of Energy’s Fermi National Accelerator Laboratory have announced that they have found the final predicted way of creating a top quark, completing a picture of this particle nearly 20 years in the making.

The two collaborations jointly announced on Friday, Feb. 21, that they had observed one of the rarest methods of producing the elementary particle – creating a single top quark through the weak nuclear force, in what is called the s-channel. For this analysis, scientists from the CDF and DZero collaborations sifted through data from more than 500 trillion proton-antiproton collisions produced by the Tevatron from 2001 to 2011. They identified about 40 particle collisions in which the weak nuclear force produced single top quarks in conjunction with single bottom quarks.

Top quarks are the heaviest and among the most puzzling elementary particles. They weigh even more than the Higgs boson – as much as an atom of gold – and only two machines have ever produced them: Fermilab’s Tevatron and the Large Hadron Collider at CERN. There are several ways to produce them, as predicted by the theoretical framework known as the Standard Model, and the most common one was the first one discovered: a collision in which the strong nuclear force creates a pair consisting of a top quark and its antimatter cousin, the anti-top quark.

Collisions that produce a single top quark through the weak nuclear force are rarer, and the process scientists on the Tevatron experiments have just announced is the most challenging of these to detect. This method of producing single top quarks is among the rarest interactions allowed by the laws of physics. The detection of this process was one of the ultimate goals of the Tevatron, which for 25 years was the most powerful particle collider in the world.

“This is an important discovery that provides a valuable addition to the picture of the Standard Model universe,” said James Siegrist, DOE associate director of science for high energy physics. “It completes a portrait of one of the fundamental particles of our universe by showing us one of the rarest ways to create them.”

Searching for single top quarks is like looking for a needle in billions of haystacks. Only one in every 50 billion Tevatron collisions produced a single s-channel top quark, and the CDF and DZero collaborations only selected a small fraction of those to separate them from background, which is why the number of observed occurrences of this particular channel is so small. However, the statistical significance of the CDF and DZero data exceeds that required to claim a discovery.

“Kudos to the CDF and DZero collaborations for their work in discovering this process,” said Saul Gonzalez, program director for the National Science Foundation. “Researchers from around the world, including dozens of universities in the United States, contributed to this important find.”

The CDF and DZero experiments first observed particle collisions that created single top quarks through a different process of the weak nuclear force in 2009. This observation was later confirmed by scientists using the Large Hadron Collider.

Scientists from 27 countries collaborated on the Tevatron CDF and DZero experiments and continue to study the reams of data produced during the collider’s run, using ever more sophisticated techniques and computing methods.

“I’m pleased that the CDF and DZero collaborations have brought their study of the top quark full circle,” said Fermilab Director Nigel Lockyer. “The legacy of the Tevatron is indelible, and this discovery makes the breadth of that research even more remarkable.”

Fermilab is America’s national laboratory for particle physics 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 @FermilabToday.

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.

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Fermilab released this press release on Feb. 11, 2014.

Workers at the NOvA hall in northern Minnesota assemble the final block of the far detector in early February 2014, with the nearly completed detector in the background. Each block of the detector measures about 50 feet by 50 feet by 6 feet and is made up of 384 plastic PVC modules, assembled flat on a massive pivoting machine. Photo courtesy of NOvA collaboration

Workers at the NOvA hall in northern Minnesota assemble the final block of the far detector in early February 2014, with the nearly completed detector in the background. Each block of the detector measures about 50 feet by 50 feet by 6 feet and is made up of 384 plastic PVC modules, assembled flat on a massive pivoting machine. Photo courtesy of NOvA collaboration

Scientists on the world’s longest-distance neutrino experiment announced today that they have seen their first neutrinos.

The NOvA experiment consists of two huge particle detectors placed 500 miles apart, and its job is to explore the properties of an intense beam of ghostly particles called neutrinos. Neutrinos are abundant in nature, but they very rarely interact with other matter. Studying them could yield crucial information about the early moments of the universe.

“NOvA represents a new generation of neutrino experiments,” said Fermilab Director Nigel Lockyer. “We are proud to reach this important milestone on our way to learning more about these fundamental particles.”

Scientists generate a beam of the particles for the NOvA experiment using one of the world’s largest accelerators, located at the Department of Energy’s Fermi National Accelerator Laboratory near Chicago. They aim this beam in the direction of the two particle detectors, one near the source at Fermilab and the other in Ash River, Minn., near the Canadian border. The detector in Ash River is operated by the University of Minnesota under a cooperative agreement with the Department of Energy’s Office of Science.

Billions of those particles are sent through the earth every two seconds, aimed at the massive detectors. Once the experiment is fully operational, scientists will catch a precious few each day.

Neutrinos are curious particles. They come in three types, called flavors, and change between them as they travel. The two detectors of the NOvA experiment are placed so far apart to give the neutrinos the time to oscillate from one flavor to another while traveling at nearly the speed of light. Even though only a fraction of the experiment’s larger detector, called the far detector, is fully built, filled with scintillator and wired with electronics at this point, the experiment has already used it to record signals from its first neutrinos.

“That the first neutrinos have been detected even before the NOvA far detector installation is complete is a real tribute to everyone involved. That includes the staff at Fermilab, Ash River Lab and the University of Minnesota module facility, the NOvA scientists, and all of the professionals and students building this detector,” said University of Minnesota physicist Marvin Marshak, Ash River Laboratory director. “This early result suggests that the NOvA collaboration will make important contributions to our knowledge of these particles in the not so distant future.”

Once completed, NOvA’s near and far detectors will weigh 300 and 14,000 tons, respectively. Crews will put into place the last module of the far detector early this spring and will finish outfitting both detectors with electronics in the summer.

“The first neutrinos mean we’re on our way,” said Harvard physicist Gary Feldman, who has been a co-leader of the experiment from the beginning. “We started meeting more than 10 years ago to discuss how to design this experiment, so we are eager to get under way.”

The NOvA collaboration is made up of 208 scientists from 38 institutions in the United States, Brazil, the Czech Republic, Greece, India, Russia and the United Kingdom. The experiment receives funding from the U.S. Department of Energy, the National Science Foundation and other funding agencies.

The NOvA experiment is scheduled to run for six years. Because neutrinos interact with matter so rarely, scientists expect to catch just about 5,000 neutrinos or antineutrinos during that time. Scientists can study the timing, direction and energy of the particles that interact in their detectors to determine whether they came from Fermilab or elsewhere.

Fermilab creates a beam of neutrinos by smashing protons into a graphite target, which releases a variety of particles. Scientists use magnets to steer the charged particles that emerge from the energy of the collision into a beam. Some of those particles decay into neutrinos, and the scientists filter the non-neutrinos from the beam.

Fermilab started sending a beam of neutrinos through the detectors in September, after 16 months of work by about 300 people to upgrade the lab’s accelerator complex.

“It is great to see the first neutrinos from the upgraded complex,” said Fermilab physicist Paul Derwent, who led the accelerator upgrade project. “It is the culmination of a lot of hard work to get the program up and running again.”

Different types of neutrinos have different masses, but scientists do not know how these masses compare to one another. A goal of the NOvA experiment is to determine the order of the neutrino masses, known as the mass hierarchy, which will help scientists narrow their list of possible theories about how neutrinos work.

“Seeing neutrinos in the first modules of the detector in Minnesota is a major milestone,” said Fermilab physicist Rick Tesarek, deputy project leader for NOvA. “Now we can start doing physics.”

Note: NOvA stands for NuMI Off-Axis Electron Neutrino Appearance. NuMI is itself an acronym, standing for Neutrinos from the Main Injector, Fermilab’s flagship accelerator.

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This article appeared in symmetry on January 30, 2014.

A video from Fermilab highlights some of the many steps needed to build the largest neutrino experiment in the United States.

A video from Fermilab highlights some of the many steps needed to build the largest neutrino experiment in the United States.

Coordinating the construction of an international particle physics experiment is never an easy task.

This is indeed the case for NOvA, a US-based physics experiment that studies a beam of hard-to-catch particles sent an unprecedented 500 miles through the Earth toward a 14,000-ton particle detector. Building the experiment has required harmonizing the efforts of several dozen laboratories, universities and companies from the United States, Brazil, the Czech Republic, Greece, India, Japan, Russia and the United Kingdom.

“It sinks in,” says John Perko, a construction technician at the NOvA facility in Ash River, Minnesota, in a new video about the process of building the NOvA detector. “It makes you feel that the whole world’s watching.”

The scientists on the NOvA collaboration have come together to study neutrinos, particles that are abundant in nature but that physicists still don’t quite understand. They are mysteriously lightweight, leading physicists to wonder if something other than the Higgs boson gives them their masses. Neutrinos come in three types, and they morph from one to another. Scientists think they might hold clues to what caused the imbalance between matter and antimatter in our universe.

To study these elusive particles, scientists on the NOvA collaboration designed a set of two detectors—a 300-ton one located near the source of the neutrino beam and a 14,000-ton one located in Ash River, Minnesota.

Fermilab recently posted a video highlighting some of the many steps required to build these detectors, from extruding 50-foot-long plastic tubes at a company in Manitowoc, Wisconsin, to assembling them into modules at a facility staffed by students at the University of Minnesota, to putting together the world’s largest free-standing plastic structure.

“I’m familiar with all the neutrino projects that are going on, and getting to actually be a part of one of those projects is pretty exciting,” University of Minnesota physics student Nicole Olsen says in the video.

Workers are scheduled to finish building the detectors this spring, and they plan to finish outfitting them with electronics in the summer. They have already begun to take data with portions of the experiment, and their capabilities will only improve as they get closer to completing construction.

Kathryn Jepsen



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This article appeared in Fermilab Today on Jan. 29, 2014.

The Department of Energy recently gave the Muon g-2 experiment approval to proceed to the next phase of design. Photo: Cindy Arnold

The Department of Energy recently gave the Muon g-2 experiment approval to proceed to the next phase of design. Photo: Cindy Arnold

2013 was a big year for the Muon g-2 experiment.

Over the summer, the 52-foot-wide electromagnet that forms the core of the experiment was transported from New York to Illinois in a flurry of publicity. Construction began on the building that will house that device and should be completed in the next couple of months.

And in December, the Department of Energy granted Critical Decision 1 approval to the experiment, marking a major milestone and charting the path forward.

Chris Polly, project manager for Muon g-2, said this approval process was the first time that DOE officials have reviewed the entire scope of the experiment, from the design to the cost to the timeline. In order to get to this stage, the collaboration developed a 500-page report, designing and costing every element of the project and then laying those elements out in a schedule consisting of 1,500 activities spanning four years.

“It was an incredible amount of work that required everyone on the collaboration to really focus, thoroughly think through the whole experiment and document it all for the reviewers,” Polly said.

The reviewers were pleased with the work and only had a few recommendations. Most notably, the committee suggested that the experiment team work with the DOE to develop an accelerated schedule.

The review took place in September, and the intervening months were spent working out the timeline and funding profile. The work that had already been done to transport the electromagnet and begin construction of the MC-1 Building helped convince the reviewers that the team could keep to such a schedule.

“CD-1 approval is a very important milestone for the experiment, and we appreciate all the strong support that we received from DOE and the laboratory management in getting us to this point,” said Lee Roberts, co-spokesperson for the experiment.

The Muon g-2 collaboration received more good news this month as well: The omnibus budget bill signed into law on Jan. 17 includes funding to continue the design and begin construction of the experiment. (That funding is not explicitly spelled out in the bill but is covered.)

2014 will be another big year with the reassembly of the storage ring in its new home, the development of detectors for the experiment and the start of construction for the muon source. And this summer the Muon g-2 team will undergo the next step in the approval process, an extensive CD-2 review.

Andre Salles

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This originally appeared in Fermilab Today on Jan. 23, 2014.

Fermilab docent Toni Mueller shows students a model of a beamline. The Midwest Conference for Undergraduate Women in Physics coordinators offered participants a tour of Fermilab or Argonne. Photo: Amanda Solliday

Fermilab docent Toni Mueller shows students a model of a beamline. The Midwest Conference for Undergraduate Women in Physics coordinators offered participants a tour of Fermilab or Argonne. Photo: Amanda Solliday

Seventy female college students in hard hats descended into the MINOS cavern, walked through the Tevatron tunnel and explored the Linac beamline as part of the Midwest Conference for Undergraduate Women in Physics Friday, Jan. 17.

“The first time I toured Fermilab, it wasn’t what I was expecting at all, even after two years of college-level physics,” said Savannah Thais, a senior physics major at The University of Chicago. “I had no idea what it was like to do science all day, every day.”

Thais attended the 2013 conference and this year volunteered for the local organizing committee. She hopes participants will see the scientists and engineers at national laboratories as potential role models. The conference organizers also aim to provide female physics students a chance to connect with each other.

“Many times, especially at smaller colleges and universities, there are not many women in physics departments. You might be the only girl in your classes,” Thais said. “So we hope the participants can meet other female undergrads who share some of the same goals as they do.”

Sahar Jalal, a senior math and physics double major at Grinnell College, says she enjoys learning about the large-scale research projects.

“I didn’t know there were so many international collaborations at Fermilab,” Jalal said during lunch at Wilson Hall.

In between tour stops, 28 Fermilab scientists, engineers, science writers and docents met with students over the noon meal.

The Conferences for Undergraduate Women in Physics rotate each year to different sites nationwide. The University of Chicago hosted this year’s Midwest conference, partnering with other area universities and institutions.

The location allowed organizers to offer a Fermilab tour for the first time. The 250 Midwest participants could also choose to visit Argonne, while students at the other regional conferences visited Berkeley, Brookhaven and Livermore national laboratories.

Particle physicists play a particularly active role in the conferences, said Kevin Pitts, a physics professor at the University of Illinois. He notes the two national co-chairs and three Midwest organizing committee members work in particle physics.

Sam Zeller, a Fermilab staff scientist on the local committee, welcomed the chance to offer young scientists a glimpse into the life of a researcher.

“Seeing a national laboratory was a big thing for me as an undergraduate,” Zeller said. “It made me think about physics as a career, so it’s nice to give that opportunity back to the next generation of students.”

Amanda Solliday

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