NOvA Neutrino Particle Detector in Minnesota Records First 3D Tracks of Ghost Particles

The first completed section of the NOvA neutrino detector in Minnesota has recorded its initial three-dimensional images of particles. Compiled from data from cosmic rays, these landmark recordings mark a significant milestone in the NOvA neutrino experiment.

U of M students and faculty at the university’s Minneapolis-based NOvA (NuMI Off-Axis Electron Neutrino Appearance) Module Laboratory are currently constructing the detector’s more than 10,000 modules.

"These initial images are a testament to the innovation and ingenuity of University of Minnesota faculty and collaborating researchers around the globe," said Marvin Marshak, laboratory director and professor in the university’s School of Physics and Astronomy. "We are thrilled to receive these first tangible results and are excited for the remarkable research the NOvA detector will allow in the near future."

The NOvA far detector is housed near Ash River, Minn., in a first-of-its-kind laboratory of the School of Physics and Astronomy in the University of Minnesota’s College of Science and Engineering. The completed section of the detector is about 12 feet long, 15 feet wide and 20 feet tall. It catches cosmic rays – particles produced by a constant rain of atomic nuclei falling on the Earth’s atmosphere from space – at a rate of 3,000 rays per second. When cosmic rays pass through the NOvA detector, they leave straight tracks and deposit well-known amounts of energy – a perfect tool for calibrating a new detector.

"It’s taken years of hard work and close collaboration among universities, national laboratories and private companies to get to this point," said Pier Oddone, director of the Department of Energy’s Fermi National Accelerator Laboratory. Fermilab manages the project to construct the detector.

An international collaboration, the $283 million NOvA experiment involves 169 scientists and engineers from 34 global universities and laboratories. When the detector in Minnesota is completed, physicists will use it to explore the mysterious behavior of neutrinos, fundamental building blocks of matter that are thought to have originated in the Big Bang.

"Neutrino research is a journey to discover how our universe began," said Marshak. "To actually construct the device that will enable this discovery is a special opportunity for our students."

Later this year, Fermilab, outside Chicago, will start sending a beam of neutrinos 500 miles through the earth to the NOvA detector in northern Minnesota. When a neutrino interacts in the NOvA detector, the particles it produces leave trails of light in their wake. The detector records these streams of light, enabling physicists to identify the original neutrino and measure the amount of energy it had.

More than 250 U of M undergraduates and six full-time staff are currently employed at the module factory. The finished NOvA far detector will be constructed from individual modules weighing 1,100 pounds each. All told, the detector will comprise more than 11 million pounds of PVC and rank as the world’s largest PVC structure. The full detector will measure more than 200 feet long, 50 feet wide and 50 feet tall.

The NOvA laboratory in Ash River is no ordinary building. It contains a shielded detector hall that is 280 feet long and 67 feet wide with a 70-foot ceiling.

The NOvA detector is operated by the University of Minnesota under a cooperative agreement with the U.S. Department of Energy’s Office of Science. In addition to Marshak, U of M faculty researchers from the School of Physics and Astronomy involved are Kenneth Heller, Dan Cronin-Hennessy, Gregory Pawloski and School of Physics and Astronomy HeadRonald Poling. Nathaniel Pearson is the supervisor for the Module Lab in Minneapolis. William Miller is the supervisor for the university’s Ash River laboratory.