University of Wisconsin-Madison

Beyond IceCube

IceCube is a highly successful detector. The only cubic-kilometer detector constructed to date, using natural ice as a Cherenkov medium, proved it was possible to build such a large scientific facility at the South Pole. Its operation has resulted in an even more optimized and efficient design for the next-generation detector.

Science has followed the detector’s performance. The recent discovery of astrophysical neutrinos has revealed the potential of high-energy neutrinos to explore our universe at energies at the PeV scale and above, where most of the universe is opaque to high-energy photons.

Artistic view of the Antarctic surface around the South Pole station, showing the position of the 86 strings of sensors in IceCube and the possible grid of the next-generation detector.
Artistic view of the Antarctic surface around the South Pole station, showing the position of the 86 strings of sensors in IceCube and the possible grid of the next-generation detector.

An in-depth exploration of the neutrino universe requires a next-generation IceCube detector. Named IceCube-Gen2 and based upon the robust design of the current detector, the goal for the new observatory is to deliver statistically significant samples of very high energy astrophysical neutrinos, in the PeV to EeV range, and yield hundreds of neutrinos across all flavors at energies above 100 TeV. This will enable detailed spectral studies, significant point source detections, and new discoveries.

Members of the recently formed IceCube-Gen2 Collaboration are working to develop a detailed proposal that will also include the PINGU sub-array. PINGU, the Precision IceCube Next Generation Upgrade, targets precision measurements of the atmospheric oscillation parameters and the determination of the neutrino mass hierarchy as well as the search for dark matter.

The facility’s reach will be further enhanced by exploiting the air-shower measurement and vetoing capabilities of an extended surface array. A radio array, the proposed Askaryan Radio Array (ARA) experiment, will also help achieve improved sensitivity to neutrinos in the 1016-1019 eV energy range, including cosmogenic neutrinos.

Neutrino astronomy will be only one topic in the rich science program of a next-generation neutrino observatory. Besides studying the properties of cosmic rays and searching for signatures of beyond-the-standard-model neutrino physics, this world-class, multipurpose detector will remain a discovery instrument for unanticipated physics and astrophysics. The observation of a supernova in our galactic neighborhood in coincidence with astronomical and gravitational wave instruments would be the astronomical event of the century.


IceCube-Gen2, a ten-cubic-kilometer detector

The unique properties of the Antarctic glacier, revealed by the construction and operation of IceCube, allow the spacing between light sensors to exceed 250 meters, instead of the current 125 meters in IceCube. The deployment of sensors in strings with larger spacings will enable the IceCube-Gen2 instrumented volume to rapidly grow at modest costs.

A possible IceCube-Gen2 configuration. IceCube, in red, and the infill subdetector DeepCore, in green, show the current configuration. The blue volume shows the full instrumented next-generation detector, with PINGU displayed in grey as a denser infill extension within DeepCore.
A possible IceCube-Gen2 configuration. IceCube, in red, and the infill subdetector DeepCore, in green, show the current configuration. The blue volume shows the full instrumented next-generation detector, with PINGU displayed in grey as a denser infill extension within DeepCore.

IceCube-Gen2 will benefit from the successful designs of the hot water drill systems and the digital optical modules in the original IceCube project. Minimal modifications will target improvements focused on modernization, efficiency, and cost savings. Because of its digital architecture, the next generation facility can be operated without a significant increase in costs.

By roughly doubling the instrumentation already deployed, the telescope will achieve a tenfold increase in volume to about 10 cubic kilometers, aiming at an order of magnitude increase in neutrino detection rates. The instrument will provide an unprecedented view of the high-energy universe, taking neutrino astronomy to new levels of discovery.


PINGU, a unique detector for high-energy neutrino oscillations

PINGU will deploy 40 new strings at the center of IceCube.
PINGU will deploy 40 new strings at the center of IceCube.

PINGU, proposed as a low-energy infill extension to the IceCube observatory, will feature the world’s largest effective volume for neutrinos at an energy threshold of a few GeV, enabling it to reach its chief goal of determining the neutrino mass hierarchy (NMH) quickly and at modest cost.

PINGU will be able to distinguish between the normal and inverted NMH at 3σ significance with an estimated 3.5 years of data. PINGU can also extend the search for solar WIMP dark matter into the region currently favored by some direct dark matter experiments. At the lower end of the energy range, PINGU can use neutrino tomography to perform the first-ever direct measurement of the composition of the Earth’s core.

Read IceCube-Gen2: A Vision for the Future of Neutrino Astronomy in Antarctica on arXiv.

Visit the website of the “Neutrinos Beyond IceCube” workshop, held on April 24, 2014.