Reconstruction of air-shower parameters for large-scale radio detectors using the lateral distribution

TL;DR

This paper develops a simplified method to reconstruct cosmic ray air-shower parameters from radio signals, achieving high accuracy even with sparse antenna arrays by parameterizing and reducing the lateral distribution function.

Contribution

It introduces a new parameterization of the radio lateral distribution function that simplifies analysis and enables accurate reconstruction of air-shower parameters with minimal antenna data.

Findings

Reconstruction accuracy for energy better than 15%.

Reconstruction accuracy for shower maximum better than 30 g/cm².

Method effective with as few as three antennas.

Abstract

We investigate features of the lateral distribution function (LDF) of the radio signal emitted by cosmic ray air-showers with primary energies $> 0.1$~EeV and its connection to air-shower parameters such as energy and shower maximum using CoREAS simulations made for the configuration of the Tunka-Rex antenna array. Taking into account all significant contributions to the total radio emission, such as by the geomagnetic effect, the charge excess, and the atmospheric refraction we parameterize the radio LDF. This parameterization is two-dimensional and has several free parameters. The large number of free parameters is not suitable for experiments of sparse arrays operating at low SNR (signal-to-noise ratios). Thus, exploiting symmetries, we decrease the number of free parameters and reduce the LDF to a simple one-dimensional function. The remaining parameters can be fit with a small number of points, i.e. as few as the signal from three antennas above detection threshold. Finally, we present a method for the reconstruction of air-shower parameters, in particular, energy and $X_{\mathrm{max}}$ (shower maximum), which can be reached with a theoretical accuracy of better than 15\% and 30~g/cm$^2$, respectively.