LOPES 3D -- studies on the benefits of EAS-radio measurements with vertically aligned antennas

TL;DR

This study evaluates the advantages of using vertically aligned antennas in radio detection of air showers, demonstrating improved efficiency for inclined showers and enhanced polarization analysis with the LOPES 3D setup.

Contribution

It introduces a novel 3D antenna configuration in radio air shower detection and analyzes its benefits over previous setups, including noise polarization and directional reconstruction improvements.

Findings

Radio detection efficiency increases for inclined showers with vertical antennas.

Vertical component measurement becomes more significant for inclined shower analysis.

Polarization-dependent noise characteristics are identified and analyzed.

Abstract

The LOPES experiment was a radio interferometer built at the existing air shower array KASCADE-Grande in Karlsruhe, Germany. The last configuration of LOPES was called LOPES 3D and consisted of ten tripole antennas. Each of these antennas consisted of three crossed dipoles east-west, north-south, and vertically aligned. With this, LOPES 3D had the unique possibility to study the benefits of measurements with vertically aligned antennas in the environment of the well understood and calibrated particle detector array KASCADE-Grande. The measurements with three spatially coincident antennas allows a redundant reconstruction of the electric field vector. Several methods to exploit the redundancy were developed and tested. Furthermore, for the first time in LOPES, the background noise could be studied polarization- and direction dependent. With LOPES 3D it could be demonstrated that radio detection reaches a higher efficiency for inclined showers when including measurements with vertically aligned antennas and that the vertical component gets more important for the measurement of inclined showers. In this contribution we discuss a weighting scheme for the best combination of three redundant reconstructed electric field vectors. Furthermore, we discuss the influence of these weighting schemes on the ability to reconstruct air showers using the radio method. We show an estimate of the radio efficiency for inclined showers with focus on the benefits of measurements with vertically aligned antennas and we present the direction dependent noise in the different polarizations.