The Radar Echo Telescope for Cosmic Rays: Pathfinder Experiment for a Next-Generation Neutrino Observatory

TL;DR

The Radar Echo Telescope for Cosmic Rays (RET-CR) aims to detect ultra high energy neutrinos in polar ice by observing radar echoes from dense in-ice cascades caused by cosmic-ray air showers, serving as a pathfinder for future large-scale observatories.

Contribution

RET-CR introduces a novel radar echo detection method for in-ice cascades from cosmic rays, testing its feasibility as a next-generation neutrino observatory.

Findings

Expected about 1 radar echo event per day.

Simulations indicate the method's potential for neutrino detection.

RET-CR will validate radar echo detection in natural conditions.

Abstract

The Radar Echo Telescope for Cosmic Rays (RET-CR) is a recently initiated experiment designed to detect the englacial cascade of a cosmic-ray initiated air shower via in-ice radar, toward the goal of a full-scale, next-generation experiment to detect ultra high energy neutrinos in polar ice. For cosmic rays with a primary energy greater than 10 PeV, roughly 10% of an air-shower's energy reaches the surface of a high elevation ice-sheet ($\gtrsim$2 km) concentrated into a radius of roughly 10 cm. This penetrating shower core creates an in-ice cascade many orders of magnitude more dense than the preceding in-air cascade. This dense cascade can be detected via the radar echo technique, where transmitted radio is reflected from the ionization deposit left in the wake of the cascade. RET-CR will test the radar echo method in nature, with the in-ice cascade of a cosmic-ray initiated air-shower serving as a test beam. We present the projected event rate and sensitivity based upon a three part simulation using CORSIKA, GEANT4, and RadioScatter. RET-CR expects $\sim$1 radar echo event per day.