Status, Calibration, and Cosmic Ray Detection of ARIANNA-HCR Station
2019 July 22
The ARIANNA Horizontal Cosmic Ray (HCR) station is an antenna array in Antarctica for detecting radio impulses emitted from inclined extensive air showers (EAS) above about 300 PeV generated by cosmic rays and ultra-high energy Earth-skimming tau neutrinos coming out from nearby mountains. The station has 8 log-periodic dipole antennas above the ice, pointing horizontally toward the mountain ridges, with bandwidth of 110-500 MHz and improved performance after upgrade from its prototype in November 2017, and has been continuously operating over almost the entire austral summer. The timing and angular resolution, which are crucial for discriminating between cosmic ray and neutrino events, are calibrated with ground-based transmitters both nearby the station and on the mountain. We will discuss the interference from reﬂected signal from the ice, which becomes apparent for signals from lower elevation angles (< 25◦), complicating the event reconstruction but also providing additional angular information. We will summarize its instrumentation and operation in the 2017-2018 season, and report the result of the search of cosmic-ray EAS candidates and their angular distribution.