IceCube

ICECUBE

South Pole Neutrino ObservatoryIan Brandeberry

The Goal

IceCube was designed with the goal of looking at several sources of neutrinos: Solar neutrinos and neutrino oscillations – can detect different

flavors of neutrinos because of the size of the array Gamma ray bursts Supernovae Weakly interacting massive particles (WIMPs) from dark matter –

as of yet, still undetected, but IceCube has improved the limits from the cross sections of these particles [4]

These extremely high energy neutrinos will occasionally interact with the nuclei in the ice and produce muons and other secondary electromagnetic and hadronic particle showers These charged particles radiate Cherenkov light The ice has an effective absorption length of 100m or more,

depending on the depth of the particle in the ice

Digital Optical Module (DOM)

Digital Optical Module

Roughly the size of a basketball Equipped with LEDs to measure the optical

properties of the surrounding ice [3] Muons from muon-neutrinos have ranges from

kilometers at TeV energy to tens of kilometers at EeV energy – they generate showers along their path via pair production, bremsstrahlung, and photonuclear interactions [4]

Each DOM is autonomous from the other and receives power and calibration signals from the surface [4]

DOM Hardware

Timing resolution of less than 5 ns Capable of working in temperatures of -55

C Draws less than 5W of power – fuel must be

flown in, so energy requirements are quite stringent

Uses field-programmable gate array (FPGA) Common triggering setup – selects for the

event when 8 DOMs (that are near each other) fire within 5 µs [4]

DOM

Diagram of the circuitry within a DOM [4]

Detectors

Layers of Observation IceTop - detects

particles in cosmic showers, such as the muon

IceCube Array – forms the bulk of the IceCube observatory

DeepCore – designed to detect lower energy neutrinos and used as an additional veto moduleSource: http://icecube.wisc.edu/

IceTop

Consists of ice-filled tanks with DOMs – located above the Antarctic ice

Used to detect cosmic ray showers – upper limit of about 300 TeV [4]

Used as a coincidence module – can be used to veto high energy events in IceCube, or rule out low energy events and screen for muon-free showers from PeV photons [4]

IceCube Array

5,160 DOMs in place on 86 strings Forms the bulk of the IceCube

detector Lowest detectable energy is roughly

100 GeV Combined with the IceCube Deep

Core, the IceCube array can detect energy ranges of [4]

The Deep Core

Designed to detect lower energy neutrinos, potentially as low as 10 GeV [4]

Has a greater sensitivity to weakly interacting massive particles (WIMPs) [1]

Has a higher density of DOMs and takes advantage of the purer ice at depths of 2100m and lower [1]

The DOMs used in the Deep Core are more sensitive than the DOMs in the rest of IceCube

Functions as an additional veto module for cosmic showers

Two Downgoing Events

Source: http://icecube.wisc.edu/

Extremely high energy downgoing event

Source: http://icecube.wisc.edu/

High energy event passing through the bottom

Source: http://icecube.wisc.edu/

Sources

[1] Abbasi R., et al., “The design and performance of IceCube DeepCore,” Astroparticle Physics, Volume 35, Issue 10, May 2012, Pages 615-624.

[2] “Science.” IceCube South Pole Neutrino Observatory. University of Wisconsin-Madison, 2012. Web. 05 May 2012.

[3] Abbasi, R., et al., “Calibration and characterization of the IceCube photomultiplier tube,” Nuclear Instruments and Methods in Physics Research A , Volume A618, Issues 1-3, Pages 139-152, June 2012.

[4] Halzen, F. and Klein, S., “IceCube: An instrument for neutrino astronomy,” Rev. SCi. Instrum,. Volume 81, Issue 8, Article 081101, August 2010.