Pursuing elusive cosmic particles utilizing radio antennas within Greenland's icy terrain
The Radio Neutrino Observatory Greenland (RNO-G) has begun its operations on the Greenland ice sheet, marking a significant step forward in the study of cosmic neutrinos. This pioneering project, a collaboration between more than a dozen international partners including the University of Chicago, Vrije Universiteit Brussel, Penn State University, the University of Wisconsin-Madison, and DESY, will remain operational for at least five years.
DESY, one of the world's leading particle accelerator centres, is investigating the structure and function of matter. They are playing a crucial role in RNO-G, contributing their expertise in the development and deployment of the observatory's radio antennas.
The advantage of using radio waves for this research is that ice is fairly transparent to them, allowing for detection over distances of several kilometres. This property enables the detection of very high-energy cosmic neutrinos, which are created in vast quantities in space, especially during high-energy processes.
The greater the range, the larger the volume of ice that can be monitored, and the greater the chances of detecting one of the rare neutrino collisions. RNO-G will be the first large-scale radio neutrino detector, setting a new standard for neutrino research.
The first antenna stations for RNO-G have been installed at the Summit Station research facility in Greenland. Each station operates autonomously, powered by solar panels, and is connected with its neighbours via a wireless network. The scientists plan to install 35 antenna stations, each 1.25 kilometres apart, around Summit Station.
The method relies on radio antennas to detect cosmic neutrinos. Neutrinos are extremely elusive, ultralight elementary particles that are difficult to detect due to their lack of electric charge and very weak interactions with other matter. However, when a neutrino interacts with an atomic nucleus in the ice, it creates a shockwave that can be detected by the radio antennas.
IceCube's optical detectors, which register neutrinos with energies up to about a quadrillion electron volts, complement the radio antennas for RNO-G, which will be sensitive to energies from about ten quadrillion to a hundred quintillion electron volts. Together, these two systems provide a comprehensive approach to detecting different energy ranges of neutrinos.
The installation of the equipment for RNO-G has faced logistical challenges due to the pandemic. Teams have had to spend several weeks quarantined at various locations before arriving at Summit Station to avoid introducing the coronavirus. Despite these challenges, the first stage of installing the equipment is due to continue until mid-August.
The physicist Ilse Plaisier works as part of the installation team at the Niels Bohr Institute in Greenland. She and her colleagues are already thinking ahead to the next step, which includes a planned radio neutrino observatory at the South Pole. This ambitious project will further expand our understanding of cosmic neutrinos and their role in the universe.
