Reconstruction of the energy and depth of maximum of cosmic-ray air-showers from LOPES radio measurements

TL;DR

This paper introduces a slope-based radio measurement method to reconstruct the energy and depth of maximum of cosmic-ray air showers, demonstrating its effectiveness on simulations and real LOPES data despite environmental noise.

Contribution

It presents a novel slope method for reconstructing cosmic-ray properties from radio data, validated through simulations and applied to actual measurements.

Findings

Reconstruction uncertainties of 13% for energy and 50 g/cm^2 for Xmax in simulations.

Achieved energy and Xmax estimates with 20-25% and 95 g/cm^2 precision on real data.

Method remains effective despite high noise levels at the measurement site.

Abstract

LOPES is a digital radio interferometer located at Karlsruhe Institute of Technology (KIT), Germany, which measures radio emission from extensive air showers at MHz frequencies in coincidence with KASCADE-Grande. In this article, we explore a method (slope method) which leverages the slope of the measured radio lateral distribution to reconstruct crucial attributes of primary cosmic rays. First, we present an investigation of the method on the basis of pure simulations. Second, we directly apply the slope method to LOPES measurements. Applying the slope method to simulations, we obtain uncertainties on the reconstruction of energy and depth of shower maximum Xmax of 13% and 50 g/cm^2, respectively. Applying it to LOPES measurements, we are able to reconstruct energy and Xmax of individual events with upper limits on the precision of 20-25% for the primary energy and 95 g/cm^2 for Xmax, despite strong human-made noise at the LOPES site.