MADISON, Wis. (WMTV/UW COMMUNICATIONS) IceCube, the Antarctic neutrino detector that in July of 2018 helped unravel one of the oldest riddles in physics and astronomy — the origin of high-energy neutrinos and cosmic rays — is getting an upgrade.
The National Science Foundation (NSF) approved $23 million in funding to expand the detector and its scientific capabilities. Seven new strings of optical modules will be added to the 86 existing strings, adding more than 700 new, enhanced optical modules to the 5,160 sensors already embedded in the ice beneath the geographic South Pole, according to the University of Wisconsin-Madison in a statement Tuesday.
The upgrade, to be installed during the 2022-23 polar season, will receive additional support from international partners in Japan and Germany as well as from Michigan State University and the UW. Total new investment in the detector will be about $37 million.
The principal goal of the upgrade, explains Kael Hanson, director of the Wisconsin IceCube Particle Astrophysics Center and a UW-Madison professor of physics, is to expand the cubic-kilometer detector in a way that permits more precise studies of the oscillation properties of neutrinos.
These neutrinos interact with other particles and transit space can change or oscillate from one type of neutrino to another, according to the statement from the university.
A second goal is to better characterize the ice around IceCube sensors and thereby obtain better performance with the existing detector, thus yielding more definitive reconstructions of high-energy neutrinos.
In addition, a better understanding of the ice that surrounds the neutrino detector will help bring the neutrino sky into crisper focus, providing opportunities to discover additional sources of high-energy neutrinos and improving scientists' ability to gather more insight into those sources.
The new strings will be deployed below the center of the existing detector, a mile deep in the Antarctic ice. The deep ice in and around the detector is known to be some of the world's clearest, which makes it a nearly ideal medium in which to study the properties of neutrinos, sometimes called "ghost particles" for their ability to breeze through planets and entire galaxies without missing a beat.
When neutrinos interact with other particles in or near the detector, they transform into secondary particles such as muons, which give off light that can be sensed by the detector to trace the trajectories of the parent neutrino.