Catching cosmic messengers

In nature, they can be found in rocks, bananas, the sun and even in gamma-ray bursts, which are energetic explosions in distant galaxies. They also can be found in man-made nuclear plants and about every second, approximately 65 billion of themneutrinospass through your thumbnail.

Neutrinos are high-intensity subatomic particles that pass through everything and interact with nothing. Despite occurring by the trillions, they are difficult to detect, yet physicists and astronomers regard these tiny travelers as a perfect source to study the universe because neutrinos are known to emerge from the cosmos.

While they carry no charge and only weakly interact with whats around them, these cosmic messengers travel through the universe in a straight line, with speed-of-light swiftness. They dont change direction or velocity, so once detected, neutrinos can point the way back to their origins.

Since 2010, scientists at the IceCube South Pole Neutrino Observatory have studied high-energy neutrinos with an extraordinary telescope embedded in the Antarctic ice. The telescope is equipped with over 5,000 sensors suspended on 86 cables nearly two-thirds of a mile deep in the ice. The sophisticated sensors, known as Digital Optical Modules (DOMs), detect and record the burst of blue light created the moment neutrinos strike other particles in the ice.

It doesnt happen oftenonly about 100 high-energy neutrinos have been detected in the last 10 yearsbut depending on the direction and intensity of the flair, scientists can infer whether the neutrino traveled from outside our solar system.

Nearly 30 students from five area high schools got a taste of the groundbreaking research in the field of neutrino astronomy during the IceCube Masterclass held on the University of Delawares Newark campus, Wednesday, April 11. Now in its fifth year, the project is a joint effort of the University of Wisconsin, UD and several other national and global research institutions.

Participants in the IceCube Masterclass heard from postdoctoral researcher Dennis Soldin, who coordinated the event, physicist Jamie Holder, electronics instrument specialist James Roth and several UD students about ongoing UD research at IceCube and life at the South Pole. Hands-on activities included analyzing actual IceCube data and identifying the trajectory of neutrinos that have been detected as they passed through the ice in a computer simulation.

Kathryn Certesio, a senior at Delaware Military Academy (DMA), was astonished by how many neutrinos actually exist, the precision with which scientists are able to measure them and how the research actually takes place.

The fact that scientists can find these big events in all of that data is surprising, Certesio said. Other students, including fellow DMA senior Elise Buonopane, were excited about the opportunity to ask questions you cant get answers to by reading a textbook or searching the Internet.

During a discussion on cosmic rays, physicist Jamie Holder demonstrated how scientists detect particles known as muons, which occur in particle showers and produce light when struck by other materials in the atmosphere. This light can be detected by photomultiplier tubes (PMTs) like those in the IceCube DOMs and recorded as an electric signal that scientists can use to understand cosmic rays.

The IceCube observatory detects over 250 million muons every day in its quest for elusive neutrinos, but muons occur in everyday places like Delaware, too, Holder said. The students watched as he showed the electrical signal created when muons passed through two rudimentary boxes containing the photomultiplier tubes, then how the same signals could be recorded as the muons traveled through the boxes and other solid objects, such as DMA senior Chris Trenthams head.

Tim Myers, a teacher at Perryville High School in Perryville, Maryland, said he purposely brought sophomore students this year who havent yet made decisions about what college to attend.

I wanted to expose them to the University of Delawares Physics Department and the complex research thats available to individuals who study science, Myers said. It helps them look into the future to see life beyond high school.

Rory Walsh, a senior from Newark High, said he had no idea about the conditions at the South Pole before hearing James Roth speak. Roth, senior supervisor of the electronics shop for the Universitys Department of Physics and Astronomy, has been to the South Pole 14 times over the last 16 years, working alongside researchers from institutions worldwide on the IceCube project, which is supported through the National Science Foundation and coordinated by the University of Wisconsin. 

Roth shared how UD researchers and engineers had a hand in developing and constructing the massive telescopes surface array of detectors, known as IceTop, that cap the IceCube observatory in Antarctica. He also described the difficulties of even getting to, and working in, remote locations in the polar regions. It takes more than 30 hours to travel the 12,000 or so miles from Delaware to the outpost, he said, not to mention the harsh environmental conditions and the challenges of living long stretches of time confined in close quarters with 150 researchers, engineering and IT folk.

Collecting the data, Roth continued, is easyits making sense of the data that is hard. Only four percent of our universe is made up of regular matter like atoms and molecules. The other 96 percent is stuff that even highly educated scientists barely understand, such as dark matter and dark energy. Neutrinos, though, are an important piece of the puzzle, one scientists hope will help unlock new clues about the universe and what lies beyond.

Until that happens, however, helping high school students learn about the far-flung research they might pursue in physics, astronomy or other scientific fields remains central to the IceCube Masterclass mission. Its also a key reason that high school teachers give up valuable class time to bring students to UD and other campuses.

Making that connection for students that have an interest is important, said Jamy Haughey, a physics teacher at Sanford School.

Students participants at the UD MasterClass represented the following high schools in DelawareNewark High, Sanford School, Caravel Academy and Delaware Military Academyand Perryville High School in Maryland. An additional 17 institutions hosted similar Masterclass events in March in Belgium, Denmark, Germany, Switzerland and several U.S. locations in Alabama, Florida, Michigan, New York, Ohio, South Dakota and Wisconsin.

Article by Karen Roberts; photos of master class by Kathy F. Atkinson; IceCube photo by Erik Beiser, National Science Foundation