Development of an in-situ calibration device of firn properties for Askaryan neutrino detectors

• Main Authors: Beise, J, Glaser, C, Anker, A, Baldi, P, Barwick, SW, Bernhoff, H, Besson, DZ, Bingefors, N, Cataldo, M, Chen, P, Fernández, DG, Gaswint, G, Hallgren, A, Hallmann, S, Hanson, JC, Klein, SR, Kleinfelder, SA, Lahmann, R, Liu, J, Magnuson, M, McAleer, S, Meyers, Z, Nam, J, Nelles, A, Novikov, A, Paul, MP, Persichilli, C, Plaisier, I, Pyras, L, Rice-Smith, R, Tatar, J, Wang, SH, Welling, C, Zhao, L
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2022
• Subjects: Ross Ice Shelf; Antarc*; Antarctica; Ice Shelf
• Online Access: https://escholarship.org/uc/item/33f1w9n4

High energy neutrinos (E >1017 eV) are detected cost-efficiently via the Askaryan effect in ice, where a particle cascade induced by the neutrino interaction produces coherent radio emission that can be picked up by antennas installed below the surface. A good knowledge of the near surface ice (aka firn) properties is required to reconstruct the neutrino properties. In particular, a continuous monitoring of the snow accumulation (which changes the depth of the antennas) and the index-of-refraction profile are crucial for an accurate determination of the neutrino’s direction and energy. We present an in-situ calibration system that extends the radio detector station with a radio emitter to continuously monitor the firn properties by measuring time differences of direct and reflected (off the surface) signals (D’n’R). We optimized the station layout in a simulation study and quantified the achievable precision. We present 14 months of data of the ARIANNA detector on the Ross Ice Shelf, Antarctica, where a prototype of this calibration system was successfully used to monitor the snow accumulation with unprecedented precision of 1 mm. We explore and test several algorithms to extract the D’n’R time difference from noisy data (including deep learning). This constitutes an in-situ test of the neutrino vertex distance reconstruction using the D’n’R technique which is needed to determine the neutrino energy.