Air Shower Measurements with the LOPES Radio Antenna Array

TL;DR

LOPES is a digital radio interferometer at Karlsruhe that detects radio pulses from extensive air showers, enabling studies of distant and inclined cosmic ray events through radio wave measurements.

Contribution

This paper presents the analysis of radio signals from the LOPES array, demonstrating the potential of radio detection for cosmic ray air showers and calibration with simulations.

Findings

Correlations in radio signals were identified.

Radio detection complements existing air shower measurements.

Calibration of electric field strength was achieved.

Abstract

LOPES is set up at the location of the KASCADE-Grande extensive air shower experiment in Karlsruhe, Germany and aims to measure and investigate radio pulses from Extensive Air Showers. Since radio waves suffer very little attenuation, radio measurements allow the detection of very distant or highly inclined showers. These waves can be recorded day and night, and provide a bolometric measure of the leptonic shower component. LOPES is designed as a digital radio interferometer using high bandwidths and fast data processing and profits from the reconstructed air shower observables of KASCADE-Grande. The LOPES antennas are absolutely amplitude calibrated allowing to reconstruct the electric field strength which can be compared with predictions from detailed Monte Carlo simulations. We report about the analysis of correlations present in the radio signals measured by the LOPES 30 antenna array. Additionally, LOPES operates antennas of a different type (LOPES-STAR) which are optimized for an application at the Pierre Auger Observatory. Status, recent results of the data analysis and further perspectives of LOPES and the possible large scale application of this new detection technique are discussed.