Astroparticle glaciology - How the extraordinary optics of glacial ice enables the IceCube Neutrino Observatory
After having discovered a flux of astrophysical neutrinos, the IceCube Neutrino Observatory is now gradually identifying the contributing sources. To detect the Cherenkov light emitted by charged relativistic particles resulting from neutrino interactions, the experiment instruments one cubic kilometer of deep, glacial ice at the geographic South Pole using 5160 photomultipliers. The inference of particle type, direction and energy from the recorded light patterns requires a detailed understanding of the optical properties of the instrumented ice. Thus, properties ranging from the impurity deposition over 100’000 years of climate history to the flow dynamics of ice over the underlying bedrock topography need to be accounted for.
In this talk I will introduce this somewhat exotic topic and discuss how optical properties can me measured in situ using pulsed light from co-deployed calibration LEDs.