Xavier MortensonSince 2008, 麻豆传媒 has been involved with the creation of the most powerful accelerator-based neutrino experiment ever built in the United States. It's called NOvA, and after nearly five years of construction, it is enabling scientists to study one of nature's most elusive subatomic particles.
Using the world's most powerful beam of neutrinos, generated at the U.S. Department of Energy's Fermi National Accelerator Laboratory near Chicago, the NOvA experiment can precisely record the telltale traces when one of the ghostly particles interacts with matter.
Construction on NOvA鈥檚 two massive neutrino detectors began in 2009. In September 2014, the Department of Energy officially proclaimed construction of the experiment complete, on schedule and under budget.
鈥淐ongratulations to the NOvA collaboration for successfully completing the construction phase of this important and exciting experiment,鈥� said James Siegrist, DOE associate director of science for high energy physics. 鈥淲ith every neutrino interaction recorded, we learn more about these particles and their role in shaping our universe.鈥�
NOvA鈥檚 particle detectors were both constructed in the path of the neutrino beam sent from Fermilab, in Batavia, Ill., to northern Minnesota. The 300-ton near detector, installed underground at the laboratory, observes neutrinos as they embark on their near-light-speed journey through the earth, with no tunnel needed. The 14,000-ton far detector, constructed in Ash River, Minn., near the Canadian border, spots those neutrinos after their 500-mile trip and allows scientists to analyze how they change over the distance.
For the next six years, Fermilab will send tens-of thousands of billions of neutrinos every second in a beam aimed at both detectors. Neutrinos interact with matter so infrequently that scientists expect to catch only a few each day in the far detector.
From this data, scientists hope to learn more about how and why neutrinos change between one the three types of neutrinos, called flavors: muons, electrons and tau neutrinos. Over longer distances, neutrinos can flip between flavors. NOvA is specifically designed to study muon neutrinos changing into electron neutrinos. Unraveling this mystery may help scientists understand why the universe is composed of matter, and why that matter was not annihilated by antimatter after the Big Bang.
Scientists will also probe the still-unknown masses of the three types of neutrinos in an attempt to determine which is the heaviest.
鈥淣eutrino research is one of the cornerstones of Fermilab鈥檚 future, and an important part of the worldwide particle physics program,鈥� said Fermilab Director Nigel Lockyer. 鈥淲e鈥檙e proud of the NOvA team for completing the construction of this world-class experiment, and we鈥檙e looking forward to seeing the first results in 2015.鈥�
The far detector in Minnesota is believed to be the largest free-standing plastic structure in the world, at 200 feet long, 50 feet high and 50 feet wide. Both detectors are constructed from PVC, and filled with a scintillating liquid that gives off light when a neutrino interacts with it. Fiber optic cables transmit that light to a data acquisition system, which creates 3-D pictures of those interactions for scientists to analyze.
鈥淏uilding the NOvA detectors was a wide-ranging effort that involved hundreds of people in several countries,鈥� said Gary Feldman, co-spokesperson of the NOvA experiment. 鈥淭o see the construction completed and the operations phase beginning is a victory for all of us, and a testament to the hard work of the entire collaboration.鈥�
The NOvA collaboration comprises 208 scientists from 38 institutions in the United States, Brazil, the Czech Republic, Greece, India, Russia and the United Kingdom, including 麻豆传媒 physics professors Nick Solomey, Holger Meyer and Mathew Muether. The experiment receives funding from the U.S. Department of Energy, the National Science Foundation and other funding agencies.
For more information, visit the experiment鈥檚 website, .
For photos, graphics and video of FermiLab鈥檚 NOvA project, visit .