Simulation of Cascades for the IceCube Neutrino Telescope

Abstract

Neutrino telescopes open a new observational window on the universe. Neutrino interactions in these detectors can give rise to a combination of electromagnetic cascades, hadronic cascades and long range muons. Cerenkov radiation from these products is detected by the neutrino telescope. In this thesis the observational signatures associated with various neutrino-nucleon interaction products are investigated. Cerenkov radiation is emitted at a distinctive angle, about 40o in ice. The maximum number of optical photons that can be produced per unit charged tracklength is calculated to be 562 photons cm−1. The simulation programs Pythia and GEANT are used to study neutrino interactions using ice as the medium. The production of tau from the tau neutrino interaction is considered and it is found that the Cerenkov angle from tau is not distinctive at low energies, due to its lifetime tau decays before travelling an observable distance. The energy required for a tau neutrino to produce a sharp tau Cerenkov signal is on the order of 1 PeV. In a high energy electron neutrino interaction the resulting hadronic cascade contains high energy pions and kaons. These particles decay, often producing muons that are also high energy and therefore long range. Due to the muons travelling faster than the local speed of light in ice, their signal may be received by the detector earlier than the signal resulting from the event that created the muon. This can complicate the reconstruction of electron neutrino events.