Radio pulses detected coming from ice in Antarctica

Summary

Once detected and traced to their source, these particles can reveal more about cosmic events than even the most high-powered telescopes, Wissel added, as the particles can travel undisturbed and almost as fast as the speed of light, giving clues about cosmic events that happened lightyears away. Wissel and teams of researchers around the world have been working to design and build special detectors to capture sensitive neutrino signals, even in relatively small amounts. Even one small signal from a neutrino holds a treasure trove of information, so all data has significance, she said. “We use radio detectors to try to build really, really large neutrino telescopes so that we can go after a pretty low expected event rate,” said Wissel, who has designed experiments to spot neutrinos in Antarctica and South America. ANITA is one of these detectors, and it was placed in Antarctica because there is little chance of interference from other signals. To capture the emission signals, the balloon-borne radio detector is sent to fly over stretches of ice, capturing what are called ice showers. “We have these radio antennas on a balloon that flies 40 kilometers above the ice in Antarctica,” Wissel said. “We point our antennas down at the ice and look for neutrinos that interact in the ice, producing radio emissions that we can then sense on our detectors.” These special ice-interacting neutrinos, called tau neutrinos, produce a secondary particle called a tau lepton that is released out of the ice and decays, the physics term referring to how the particle loses energy as it travels over space and breaks down into its constituents. This produces emissions known as air showers. If they were visible to the naked eye, air showers might look like a sparkler waved in one direction, with sparks trailing it, Wissel explained. The researchers can distinguish between the two signals — ice and air showers — to determine attributes about the particle that created the signal. These signals...