The Design and Performance of IceCube DeepCore

TL;DR

DeepCore is a new, densely instrumented subarray of IceCube designed to detect lower-energy neutrinos around 10 GeV, enhancing the observatory's sensitivity to various astrophysical and particle physics phenomena.

Contribution

This paper presents the design, implementation, and initial performance results of DeepCore, a denser and more efficient subarray within IceCube for low-energy neutrino detection.

Findings

DeepCore lowers the neutrino energy threshold to about 10 GeV.

It has a module density five times higher than the standard IceCube array.

DeepCore's design improves sensitivity to dark matter, oscillations, supernovae, and point sources.

Abstract

The IceCube neutrino observatory in operation at the South Pole, Antarctica, comprises three distinct components: a large buried array for ultrahigh energy neutrino detection, a surface air shower array, and a new buried component called DeepCore. DeepCore was designed to lower the IceCube neutrino energy threshold by over an order of magnitude, to energies as low as about 10 GeV. DeepCore is situated primarily 2100 m below the surface of the icecap at the South Pole, at the bottom center of the existing IceCube array, and began taking physics data in May 2010. Its location takes advantage of the exceptionally clear ice at those depths and allows it to use the surrounding IceCube detector as a highly efficient active veto against the principal background of downward-going muons produced in cosmic-ray air showers. DeepCore has a module density roughly five times higher than that of the standard IceCube array, and uses photomultiplier tubes with a new photocathode featuring a quantum efficiency about 35% higher than standard IceCube PMTs. Taken together, these features of DeepCore will increase IceCube's sensitivity to neutrinos from WIMP dark matter annihilations, atmospheric neutrino oscillations, galactic supernova neutrinos, and point sources of neutrinos in the northern and southern skies. In this paper we describe the design and initial performance of DeepCore.