A Search for Ultra-High Energy Neutrinos and Cosmic Rays with ANITA-3

• Main Author: Strutt, BAF
• Other Authors: Nichol, RJ
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: UCL (University College London) 2017
• Subjects: ANITA; ultra-high energy neutrino; ultra-high energy cosmic ray; Antarctic; Austral; The Antarctic; Antarc*; Antarctica
• Online Access: https://discovery.ucl.ac.uk/id/eprint/1537263/1/strutt_phd_thesis_corrected.pdf; https://discovery.ucl.ac.uk/id/eprint/1537263/

The Antarctic Impulsive Transient Antenna (ANITA) is a balloon borne radio inter- ferometer, designed to detect the impulsive Askaryan radiation created by ultra-high energy neutrinos interacting in the ice sheets of Antarctica. Previous flights of the experiment have demonstrated an unexpected sensitivity to cosmic rays, detecting the radio emission from geo-magnetically induced transverse currents in extended air showers. The third flight of ANITA (ANITA-3) took place during the austral summer of 2014-15. In this thesis I present two contributions to the ANITA-3 experiment, the tim- ing calibration of the digitizer electronics, and my implementation of a real-time interferometric event prioritizer using a GPU flown with the experiment. Finally, I present a search for neutrinos and cosmic rays in the ANITA-3 data set. No evidence of neutrino interactions is observed, with zero candidate events discovered on a background of 0.11 ± 0.07 leading to the world’s best limit on the ultra-high energy neutrino flux in the energy range 10^19 eV to 10^21 eV. Four isolated, predominantly horizontally polarised events are found in the data. Further work is required to confirm these events have all the properties consistent with radio emission induced by cosmic ray air showers