Radio detection of the PeV - EeV cosmic-neutrino flux

ended

With the detection of the high-energy cosmic-neutrino flux by the IceCube neutrino observatory at the South-Pole, IceCube opened the field of neutrino astronomy. Nevertheless, due to the steeply falling energy spectrum, IceCube runs low in statistics at energies above a few PeV. To probe this flux at the highest energies (>PeV), therefore asks for an even larger detection volume than the cubic-kilometer currently instrumented by IceCube. Due to its long attenuation length the radio signal is an ideal probe to cover such a large volume. When a high-energy cosmic neutrino interacts in a dense medium like ice, a relativistic particle cascade is induced. In 1962 Askaryan already predicted that due to the net charge build-up inside the cascade, coherent radio emission is expected. However, this signal is only detectable for initial neutrino energies in access of a few EeV. Therefore, currently there is a sensitivity gap to probe the high-energy cosmic neutrino flux in the PeV – EeV energy range. This project aims to fill this sensitivity gap by the development of a novel radio detection technique to measure high-energy particle cascades in dense media, the radar detection technique. By directly probing the ionization plasma which is left behind after the neutrino induced particle cascade propagates through the medium, the radio detection energy threshold is lowered to a few PeV. The feasibility of the radar detection technique, was shown in a recent experiment. To determine the radar scattering efficiency more accurately, a new beam-test at the SLAC facility is planned as part of this proposal. Once the scattering parameters have been determined accurately, a detailed modeling and sensitivity study will be performed to achieve the main goal of this research proposal: The construction of an in-nature experiment at the South-Pole with the sensitivity to observe 1-10 cosmic neutrino events per year in the PeV – EeV energy range.