IceCube Neutrino Observatory gets a major upgrade beneath the ice
The project ensures that UW–Madison’s efforts at IceCube remain at the forefront of neutrino astronomy for years to come.
After three successful field seasons at the South Pole, the IceCube Neutrino Observatory has received its first major upgrade since it came online 15 years ago, a project that significantly boosts the observatory’s scientific capabilities.
Located at the U.S. National Science Foundation’s Amundsen-Scott South Pole Station, IceCube uses one cubic kilometer of Antarctic ice to detect ghostly particles called neutrinos that travel through outer space. The international scientific endeavor is led by scientists at University of Wisconsin–Madison with NSF providing its main source of support.
Because neutrinos rarely interact with matter, the nearly massless particles can provide a lens into otherwise obscure extreme cosmic environments, carrying valuable information about their sources. IceCube has already discovered astrophysical neutrinos, identified two galaxies as neutrino sources and observed neutrinos from our own Milky Way galaxy.
Now, the upgrade will allow more precise measurements of neutrino properties, becoming the world’s premier neutrino experiment for understanding certain characteristics of the particles.
“The successful deployment of the IceCube Upgrade project is a feat of U.S. engineering that demonstrates significant logistical capabilities in Antarctica,” says Marion Dierickx, NSF program director for IceCube. “This upgrade will secure the nation’s continued leadership in neutrino physics for years to come, paving the way for new cosmic discoveries.”
IceCube uses more than 5,000 light sensors to capture the faint light produced by neutrino interactions in the ice. The pristine quality of the Antarctic ice makes it an ideal medium for detecting this light. The IceCube Collaboration, with over 450 scientists from around the world, then takes these light patterns to reconstruct the energy and direction of each detected neutrino to determine its origin.
Using the enhanced devices newly deployed in the ice, scientists will be able to better characterize the surrounding ice, leading to improved reconstruction of neutrinos and a reanalysis of 15 years of archived data. The upgrade will also improve scientists’ ability to determine cosmic ray composition and measure neutrinos from galactic supernovae.
A three-year international effort
Years of preparation and international coordination for the upgrade led up to three consecutive 10-week field seasons, with the upgrade completed in the most recent season. The equipment used to drill holes a mile and a half deep into the Antarctic ice was fabricated at UW–Madison’s Physical Sciences Laboratory and shipped to the South Pole. Scientists and engineers spent the first two field seasons refurbishing, testing and winterizing the systems and equipment and setting up the drill camp.
A team of IceCube engineers and scientists and additional engineers from the U.S., Sweden, Thailand, New Zealand, Taiwan, Germany, Australia and Japan, in coordination with the Antarctic Support Contract, overcame numerous challenges and harsh working conditions to complete the upgrade. During the third and final field season, they used a 5-megawatt hot water drill system, the largest such system in the world, to drill six holes for the upgrade. The drill team worked around the clock, with each hole taking about three days to complete.
“Seeing the refurbished drill come back to life again 15 years after IceCube’s original completion is truly remarkable,” says Albrecht Karle, principal investigator of the IceCube upgrade and a UW–Madison professor of physics. “The team’s around-the-clock effort to deploy the upgrade is an extraordinary accomplishment. By placing new optical sensors into the clearest ice on Earth, we will measure neutrino properties and observe transient astronomy with a level of precision not previously possible.”
As soon as each hole was drilled, the installation team went to work deploying the upgrade’s higher performing light sensors. Two new types of light sensors boast two to three times more sensitivity than the sensors that make up the original detector. Teams from around the world contributed to the development and deployment of the new sensors, along with prototypes for a possible future expansion of IceCube.
“Designing, assembling and testing the diverse set of photosensors and calibration devices across many institutions and countries is a testament to the collective expertise and commitment that make IceCube successful,” says Erin O’Sullivan, a professor of physics at Uppsala University and IceCube spokesperson.
Other science opportunities
The upgrade also presented an opportunity to support other scientific endeavors along the way. In collaboration with the U.S. Geological Survey, the crew installed two seismometers beneath the Antarctic ice. These seismometers are the deepest in the world and will help scientists monitor earthquakes with unprecedented clarity. The team also collected water samples for microbiologists in the U.S. who are looking for signs of life in the deep ice.
Now that the upgrade is finished, commissioning will continue to be a top priority to verify functionality of the newly deployed devices. The upgrade, a stepping-stone to a proposed expansion known as IceCube-Gen2, will ensure that IceCube remains at the forefront of neutrino astronomy for years to come.
“The successful completion of the IceCube Upgrade relied on the critical support of the South Pole station and Antarctic service contractors,” says Vivian O’Dell, the upgrade’s project director. “Their essential contributions allowed us to complete the entire installation in one drilling season despite extreme weather conditions and logistical constraints, for which I am deeply grateful.”
The IceCube Neutrino Observatory was funded and is operated primarily through an award from the U.S. National Science Foundation to the University of Wisconsin–Madison. The IceCube Collaboration, with over 450 scientists in 58 institutions from around the world, runs an extensive scientific program that has established the foundations of neutrino astronomy.
IceCube’s research efforts, including critical contributions to the detector operation, are funded by agencies in Australia, Belgium, Canada, Denmark, Germany, Italy, Japan, New Zealand, Republic of Korea, Sweden, Switzerland, Taiwan, the United Kingdom, and the United States including NSF. IceCube construction was also funded with significant contributions from the National Fund for Scientific Research (FNRS & FWO) in Belgium; Federal Ministry of Research, Technology and Space (BMFTR), Helmholtz Association of German Research Centers and the German Research Foundation (DFG) in Germany; National Research Foundation of Korea, in Korea; Japan Society for the Promotion of Science (JSPS), and the Ministry of Education, Culture, Sports, Science and Technology (MEXT) in Japan; the Knut and Alice Wallenberg Foundation, the Swedish Polar Research Secretariat, and the Swedish Research Council in Sweden; Michigan State University and the University of Wisconsin–Madison in the U.S.
The U.S. National Science Foundation (NSF) is an independent federal agency that promotes the progress of science by investing in research to expand knowledge in science, engineering and education across all 50 states and territories. NSF supports nearly 2,000 colleges, universities and other institutions through competitive grants aimed at advancing science with broad impacts across the nation and its people. Learn more at nsf.gov.
