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The Askaryan Radio Array Experiment located near the South Pole works to pinpoint specific instances of neutrinos from outside the solar system interacting with nucleons inside the Antarctic ice. Neutrinos are a subatomic particle that has nearly no mass and a net neutral charge. As they are, neutrinos tend not to interact with anything as they travel through space which means they can provide us with information about events occurring far from Earth that might not be easily attained through other methods. Neutrinos are known to be emitted from a myriad of sources, including the Sun, the interaction between cosmic rays and the Earth’s atmosphere, supernovae and as cosmic neutrino background believed to be a result of the Big Bang. As the neutrinos pass through and interact with the ice, their collisions with nucleons will emit energy in the form of radio waves.
ARA detectors measure these radio waves to determine the neutrino flux: how many neutrinos pass through a given area over a given time. Specifically, the ARA experiment aims to measure ultra-high energy (UHE) neutrinos with energies above 10^15 electron volts. These UHE neutrinos are predicted to directly originate from cosmological sources. The measurement of this flux would be useful as evidence proving/disproving existing physics theories that expect certain flux values. If the measured flux deviates considerably from theorized values, it could also stand as an indication of physical phenomena that are not currently known.
Due to the bending of radio waves propagating close to the surface of the ice, a phenomenon occurring due to the dependence of the index of refraction on depth, radio waves are not able to propagate from certain regions of space to the receiving ARA stations, according to classical linear optics. It has been observed at ARA, however, that the classical picture is violated in practice. Although a shadow zone does exist, it is smaller than what theory predicts.
In this UCARE project, I worked on mapping the shadow zones found in the Antarctic ice experimentally, using calibration data generated by a radio transmitter inside a hole made for the SpiceCore project, which was recorded by the ARA stations.