https://doi.org/10.1140/epjc/s10052-021-08912-4
Regular Article – Experimental Physics
Final results of the LOPES radio interferometer for cosmic-ray air showers
1
Institute for Astroparticle Physics (IAP) [formerly, Institute for Nuclear Physics (IKP)], Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
2
Instituto de Física y Matemáticas, Universidad Michoacana, Morelia, Michoacán, Mexico
3
ASTRON, Dwingeloo, The Netherlands
4
Dipartimento di Fisica, Università degli Studi di Torino, Turin, Italy
5
Max-Planck-Institut für Radioastronomie, Bonn, Germany
6
Institute for Experimental Particle Physics (ETP), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
7
National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania
8
Osservatorio Astrofisico di Torino, INAF Torino, Turin, Italy
9
Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brasil
10
Department of Astrophysics, Radboud University Nijmegen, AJ Nijmegen, The Netherlands
11
Department of Physics, Bergische Universität Wuppertal, Wuppertal, Germany
12
Institut für Prozessdatenverarbeitung und Elektronik, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
13
Faculty of Natural Sciences and Engineering, Universität Siegen, Siegen, Germany
14
Institute of Space Science, Bucharest-Magurele, Romania
15
Department of Astrophysics, National Centre for Nuclear Research, Łódź, Poland
16
Studsvik Scandpower GmbH, Hamburg, Germany
17
Department of Physics and Astronomy, Bartol Research Institute, University of Delaware, Newark, DE, USA
18
Department of Physics, University of Bucharest, Bucharest, Romania
19
European Commission, Joint Research Centre (JRC), Karlsruhe, Germany
Received:
10
June
2020
Accepted:
25
January
2021
Published online:
22
February
2021
LOPES, the LOFAR prototype station, was an antenna array for cosmic-ray air showers operating from 2003 to 2013 within the KASCADE-Grande experiment. Meanwhile, the analysis is finished and the data of air-shower events measured by LOPES are available with open access in the KASCADE Cosmic Ray Data Center (KCDC). This article intends to provide a summary of the achievements, results, and lessons learned from LOPES. By digital, interferometric beamforming the detection of air showers became possible in the radio-loud environment of the Karlsruhe Institute of Technology (KIT). As a prototype experiment, LOPES tested several antenna types, array configurations and calibration techniques, and pioneered analysis methods for the reconstruction of the most important shower parameters, i.e., the arrival direction, the energy, and mass-dependent observables such as the position of the shower maximum. In addition to a review and update of previously published results, we also present new results based on end-to-end simulations including all known instrumental properties. For this, we applied the detector response to radio signals simulated with the CoREAS extension of CORSIKA, and analyzed them in the same way as measured data. Thus, we were able to study the detector performance more accurately than before, including some previously inaccessible features such as the impact of noise on the interferometric cross-correlation beam. These results led to several improvements, which are documented in this paper and can provide useful input for the design of future cosmic-ray experiments based on the digital radio-detection technique.
© The Author(s) 2021
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Funded by SCOAP3
