Around the labs: A road trip to cryogenic facilities

On April 27 and 28, Fermilab hosted the Neutrino – Latin America Workshop for visiting scientists. The workshop showcased Latin American collaboration with the laboratory throughout the years, and scientists discussed research opportunities both here at Fermilab and at institutions in Central and South America.

“Our intention was to increase the awareness of the DUNE scientific and technical program and to highlight the many areas where Latin American scientists and engineers can make important contributions within DUNE and the broader Fermilab neutrino program, including the short-baseline neutrino experiments,” said Mark Thomson, a co-spokesperson for DUNE and lead organizer of the workshop. Latin America has a rich history in particle physics, and this workshop highlighted the projects that resulted from the longstanding relationship Fermilab has with these nations, he said.

The past

As early as the 1930s, physicists at institutions in Argentina, Brazil and Mexico were studying cosmic rays and theoretical particle physics. Several of these nations expanded their focus in particle physics, but at the time, programs were few, and funding was minimal. In the early 1980s, Leon Lederman, Fermilab’s second director, realized the potential benefits of a relationship between Fermilab and our neighbors to the south after attending several symposia hosted in Latin America. By 1984, Lederman sponsored four Brazilian physicists — the first Latin American scientists to come to Fermilab — to participate on a fixed-target experiment.

“Lederman took a bold step with inviting us to join the experimental high-energy physics program at Fermilab,” said Carlos Escobar, a guest scientist in Fermilab’s Neutrino Division and one of the first four Brazilian physicists to join the lab. “We had physicists working in theory for high-energy physics groups in our home institutions but no experimental groups using accelerators in particle physics. We were the pioneering Latin Americans here at Fermilab.”

Shortly after this group joined the lab, they began to reach out to their students and colleagues at home to train them for future projects. More and more Latin American students and scientists from multiple countries gained opportunities to learn and work at Fermilab, and they eventually became a valuable group to the laboratory’s growing neutrino program.

The present

The first day of the April workshop included presentations and discussions about past neutrino experiments, right up to current projects. Latin America has collaborated with Fermilab on several projects over the years, including MINOS and MINOS+, MiniBooNE, LArIAT and NOvA.

According to Julian Felix, a professor of physics at the University of Guanajuato in Mexico, Latin Americans made up nearly a quarter of the MINERvA collaboration. The proposed CAPTAIN MINERvA experiment, which would be an expansion of its predecessor with a focus in neutrino-argon interaction studies, would continue the tradition of collaboration with Latin American institutions.

“The test beam for the MINERvA experiment was done by several Latin American students, and all of the students made a big difference in this work,” he said in his presentation. “This experiment had the largest contributions from Latin America of any experiment at Fermilab, and my students and I gained a lot of experience from it.”

Today, the in-progress Short-Baseline Neutrino program, with three supporting experiments hunting for a fourth type of neutrino, currently has 55 collaborating institutions from eight countries. Three institutions are from Brazil and one is from Puerto Rico. Workshop participants in the SBN program took the opportunity to invite their Latin American colleagues to join SBN.

“We want to reach out to this specific region of the world because they are valuable and bring a variety of ideas and opinions to our work,” said Regina Rameika, head of Fermilab’s Neutrino Division. “We especially want students to participate so they can gain experience. New programs like SBN are great because students can start at the beginning of the project and see it progress.”

Several workshop participants said that, while experience abroad is valuable, it’s just as important that highly trained professionals who studied at Latin American universities and institutions make their skills and talents available in their home nations.

“Our governments and countries are willing to fund physicists and engineers,” Felix said. “We need skilled professionals in industry in our home countries.”

Rameika said Fermilab is a good training ground for Latin American students, who participate in a particle physics experiment before they head back to their nations to inspire others to become scientists.

“Fermilab could be a part of this loop in which we bring students here, offer them profound experience in their field and then send them back to build stronger programs back home,” she said.

At the workshop, physicists on new projects in Latin America informed and invited Fermilab scientists to participate. ANDES, for example, is an underground laboratory located on the borders between Argentina, Brazil and Chile. It will be one of the first multidisciplinary underground facilities in the Southern Hemisphere. And, CONNIE a neutrino-nucleus interaction experiment led by Fermilab scientist Juan Estrada and located in a nuclear power plant near Rio de Janeiro, Brazil, will produce data to help answer questions about the Standard Model and even test safety applications in nuclear facilities.

The future

On the second day of the workshop, the spotlight was on future opportunities and upcoming experiments.

Fermilab’s future flagship experiment DUNE is among the world’s largest neutrino experiments, currently with 850 collaborators from 149 institutions in 29 countries. Presenters discussed opportunities in software, scientific computing, theory and accelerator engineering for DUNE. The research scope includes supernova neutrinos, neutrino oscillation, proton decay and the universe’s matter-antimatter imbalance.

Several Latin American institutions have developed simulation technologies capable of handling the amount of data DUNE would produce. This is one of the many key areas in which Latin American collaboration is vital to the lab.

“DUNE is an incredibly exciting international partnership and will be the next big thing in particle physics,” Thomson said. “We hope to build on the existing Latin American participation in DUNE and the rest of the Fermilab neutrino program. Latin American scientists bring great expertise, and DUNE is an opportunity to form scientific partnerships in the next major international neutrino experiment. There are many benefits, including providing training for the next generation of Latin American physicists.”

CERN’s ProtoDUNE, the large-scale DUNE prototypes, also has opportunities for Latin American scientists and engineers in Switzerland. CERN enjoys strong Latin American participation, with approximately 300 physicists from 12 nations, according to Gustavo Otero y Garzon, a assistant professor at the University of Buenos Aires in Argentina and a physicist on CERN’s ATLAS experiment.

In 2015, Fermilab had a total of 162 visiting Latin American scientists and students from eight countries contributing to several neutrino experiments.

“Latin America is developing and growing its economy, and this is a perfect opportunity for us to engage their local industry and institutions to develop new technologies and share their expertise,” Escobar said. “These nations share a passion for science with us and will be effective partners for us at the frontier of particle physics.”

On April 27, Fermilab broke ground on the building that will house the future Short-Baseline Near Detector.

The particle detector, SBND, is one of three that, together, scientists will use to search for the sterile neutrino, a hypothesized particle whose existence, if confirmed, could not only help us better understand the types of neutrino we already know about, but also provide clues about how the universe formed.

Members of the Fermilab Neutrino and Particle Physics divisions, working together with international collaborators, are currently refining the design of the detector itself. It will take about eight months to complete the SBND building.

The three detectors make up the laboratory’s Short-Baseline Neutrino Program, which will use a powerful neutrino beam generated by the Fermilab accelerator complex. The beam will pass first through SBND and then through the MicroBooNE detector, which is already installed and taking data, having observed its first neutrino interactions in October. Finally, the beam will travel through ICARUS, the largest of the three detectors. ICARUS, which was used in a previous experiment at the Italian Gran Sasso laboratory, is currently at the CERN laboratory in Switzerland receiving upgrades before its big move to Fermilab in 2017.

“The entire Short-Baseline Neutrino Program is looking for oscillations, or the transformations, of muon neutrinos into electron neutrinos,” said Peter Wilson, SBN program coordinator. “Sterile neutrinos might have a role in this oscillation process.”

The beam coming out of the accelerator comprises primarily muon neutrinos; the detectors will measure their transformation into electron neutrinos.

All three detectors have specific functions in detecting the transformation. As the detector closest to the beam source, SBND will take an initial measurement of the beam’s composition – how much the beam contains each of the different neutrino types.

“The intermediary and far detectors are used to search for sterile neutrinos in two different ways,” said Ornella Palamara, co-spokesperson for the SBND experiment. “Either there’s an appearance of an excess of electron neutrinos or there’s a disappearance of the number of muon neutrinos compared to the number we start with.”

If there are more electron neutrinos than predicted, then muon neutrinos may have oscillated first into sterile neutrinos and then to electron neutrinos. If the data show a smaller number of muon neutrinos than predicted, the muon neutrinos may have transformed only into sterile neutrinos, which cannot be seen in the far detectors.

Scientists first picked up on experimental hints of a sterile neutrino at Los Alamos National Laboratory’s LSND experiment in 1995. When the Fermilab experiment MiniBooNE followed up, scientists could not confirm the sterile neutrino’s existence, but neither could they rule it out.

“That’s the power of this program,” Palamara said. “We’re building off previous measurements, but we have more sensitive tools to measure the neutrinos.”

Part of the sensitivity of SBND lies in its liquid-argon time projection chamber, the active part of the detector, which will contain 112 tons of liquid argon. Neutrinos will interact with the nuclei of the argon atoms, and scientists on SBND will study the resulting particles to better understand the neutrinos that caused the interaction. Their findings will likely have application in future accelerator-based neutrino programs, such as the international Deep Underground Neutrino Experiment hosted by Fermilab.

The Short-Baseline Neutrino Program will begin taking data in 2018.

“The SBND groundbreaking is a noteworthy milestone, but it’s part of a much larger program,” Wilson said. “Many people are working on it, and everyone is excited to get the chance to understand new physics.”

Late April is always a special time of year at Fermilab. Spring is in the air, the leaves are green, the birds are singing, and adorable baby bison are born.

Fermilab welcomed the first baby bison of 2016 on Tuesday, April 26, increasing the herd size to 18. As many as 14 more calves are expected before early June.

All are welcome to visit the laboratory to see and photograph the new baby bison. (They’re always a hit with young children.) The site is open every day from 8 a.m. to 8 p.m., and admission is free. You’ll need a valid photo ID to enter the site.

Fermilab’s first director, Robert Wilson, established the bison herd in 1969 as a symbol of the history of the Midwestern prairie and the laboratory’s pioneering research at the frontiers of particle physics. The herd remains a major attraction for families and wildlife enthusiasts.

And just recently, thanks to the science of genetic testing, Fermilab’s ecologist Ryan Campbell confirmed that the laboratory’s herd is 100 percent bison, with no cattle genes. Farmers during the early settlement era would breed bison with other bovine species to keep them from extinction, but Fermilab’s bison are purebred.

A herd of pure bison is a natural fit for a prairie ecosystem, like the kind that exists on the Fermilab site. Fermilab hosts 1,100 acres of reconstructed tall-grass prairie, and the U.S. Department of Energy designated the 6,800-acre site a National Environmental Research Park in 1989.

While you’re at the Fermilab site visiting the bison, you can learn more about our ecological efforts by hiking the Interpretive Prairie Trail, a half-mile-long trail located near the Pine Street entrance in Batavia. The Lederman Science Center also offers exhibits on the prairie and hands-on physics displays. The Lederman Center hours are Monday-Friday from 8:30 a.m. to 4:30 p.m. and Saturdays from 9 a.m. to 3 p.m.

For up-to-date information for visitors, please visit www.fnal.gov or call 630-840-3351. To learn more about Fermilab’s bison herd, please visit the wildlife area of our website.

Fermilab is America’s premier 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 http://www.fnal.gov and follow us on Twitter @Fermilab. 

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