Simulation of birefringence effects for high-energy neutrino detectors

• Main Author: Heyer, Nils
• Format: Bachelor Thesis
• Language: English
• Published: Uppsala universitet, Högenergifysik 2021
• Subjects: astroparticle physics; radio detection; high-energy neutrinos; birefringence; Subatomic Physics; Subatomär fysik; South Pole; South pole
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-459988

The detection of high-energy neutrinos in the E > O(PeV) range requires newdetection techniques in order to cope with the decreasing flux. The radio detectionmethod uses Askaryan emission to detect these neutrinos. The propagation of theradio pulses has to be modeled carefully in order to estimate the properties of theneutrinos from the detected radio pulse. This report introduces a model whichwas implemented to the NuRadioMC code to simulate birefringence effects in theice of the South Pole. To do that, a new ice model was created which combinesthe density and directional dependence on the refractive index. With this icemodel and an analytical ray tracer the time delay and polarization resulting frombirefringence was simulated for different geometries. A directional dependenceon the magnitude of the time delay and the change of the polarization along thepropagation path was found. To model the mixing of the polarization states dueto this change in polarization a pulse propagation model was introduced. Timedelay calculations resulting from this model were compared to simulations andmeasurements from the ARA experiment and have shown good agreement.