Tunka-Rex: the Cost-Effective Radio Extension of the Tunka Air-Shower Observatory

TL;DR

Tunka-Rex is a cost-effective radio array extension of the Tunka observatory that demonstrates competitive precision in reconstructing cosmic-ray air-shower parameters using simple antennas and shared infrastructure.

Contribution

It introduces a low-cost, robust radio detection method integrated with existing observatory infrastructure for cosmic-ray air-shower measurements.

Findings

Radio measurements can match air-Cherenkov precision in energy reconstruction.

Tunka-Rex successfully operates with shared infrastructure and simple antennas.

First results show promising accuracy in determining shower parameters.

Abstract

Tunka-Rex is the radio extension of the Tunka cosmic-ray observatory in Siberia close to Lake Baikal. Since October 2012 Tunka-Rex measures the radio signal of air-showers in coincidence with the non-imaging air-Cherenkov array Tunka-133. Furthermore, this year additional antennas will go into operation triggered by the new scintillator array Tunka-Grande measuring the secondary electrons and muons of air showers. Tunka-Rex is a demonstrator for how economic an antenna array can be without losing significant performance: we have decided for simple and robust SALLA antennas, and we share the existing DAQ running in slave mode with the PMT detectors and the scintillators, respectively. This means that Tunka-Rex is triggered externally, and does not need its own infrastructure and DAQ for hybrid measurements. By this, the performance and the added value of the supplementary radio measurements can be studied, in particular, the precision for the reconstructed energy and the shower maximum in the energy range of approximately $10^{17}-10^{18}\,$eV. Here we show first results on the energy reconstruction indicating that radio measurements can compete with air-Cherenkov measurements in precision. Moreover, we discuss future plans for Tunka-Rex.