Speaker
Description
The Askaryan Radio Array (ARA) is an ultrahigh energy (UHE) neutrino experiment at the South Pole that aims to detect radio emissions from neutrino-induced particle showers using in-ice antennas buried up to 200m in depth. The depth-dependent refractive index profile in ice affects calibration efforts and neutrino sensitivity predictions of ARA as well as other UHE neutrino experiments at both South Pole and Summit Station, Greenland. We present an in-ice refractive index profile based on previous ice density data and constrained by radio signals received by ARA antennas. A pulser lowered into a borehole near ARA in the 2018-2019 summer season provides useful data in determining the refractive index profile of polar ice by comparing direct and refracted travel times at various pulser depths. Data from the 2018-2019 campaign strongly favors a glaciology motivated three-phase refractive index model over the single exponential scale height model which has been traditionally used.
