The lunar Askaryan technique: a technical roadmap

Abstract

The lunar Askaryan technique, which involves searching for Askaryan radio pulses from particle cascades in the outer layers of the Moon, is a method for using the lunar surface as an extremely large detector of ultra-high-energy particles. The high time resolution required to detect these pulses, which have a duration of around a nanosecond, puts this technique in a regime quite different from other forms of radio astronomy, with a unique set of associated technical challenges which have been addressed in a series of experiments by various groups. Implementing the methods and techniques developed by these groups for detecting lunar Askaryan pulses will be important for a future experiment with the Square Kilometre Array (SKA), which is expected to have sufficient sensitivity to allow the first positive detection using this technique. Key issues include correction for ionospheric dispersion, beamforming, efficient triggering, and the exclusion of spurious events from radio-frequency interference. We review the progress in each of these areas, and consider the further progress expected for future application with the SKA.

Overview of lunar detection of ultra-high energy particles and new plans for the SKA

“…Once a trigger is generated that passes the veto, both the array beams, and the buffered station beams, will be stored offline for further analysis. Further details of the proposed implementation of these components is given in [33].…”

Sensitivity of lunar particle-detection experiments

“…A proposed experiment with a phased-array feed on the Parkes radio telescope [26], or on a similar large single dish, could potentially achieve the first detection of cosmic rays with this technique. A proposed experiment (not shown here) with the low-frequency component of the Square Kilometre Array [21,27] would have a substantially greater sensitivity to both neutrinos and cosmic rays, but is a more distant prospect, as this telescope is planned for construction in 2018-2023.…”

Neutrino Connection with Cosmic Ray Origin

“…Future detectors such as JEM-EUSO will further explore the highest energy range [60]. Radio telescope arrays that view the Moon, where radio Cherenkov signals are generated by neutrino interactions in the lunar regolith, have been used to set limits on the cosmogenic neutrino flux, and plans are underway for future observations [61][62][63][64]. The RICE and ARA experiments use radio Cherenkov signals in ice to constrain the cosmogenic neutrino flux [65,66].…”