* Astronomy

Title: Tunka-Rex: energy reconstruction with a single antenna station (ARENA 2016)
Author: R. Hiller, P. A. Bezyazeekov, N. M. Budnev Fedorov, O. A. Gress, A. Haungs, T. Huege, Y. Kazarina, M. Kleifges, E. E. Korosteleva, D. Kostunin, O. Krömer, V. Kungel, L. A. Kuzmichev, N. Lubsandorzhiev, R. R. Mirgazov, R. Monkhoev, E. A. Osipova, A. Pakhorukov, L. Pankov, V. V. Prosin, G. I. Rubtsov, F. G. Schröder, R. Wischnewski, A. Zagorodnikov

The Tunka-Radio extension (Tunka-Rex) is a radio detector for air showers in Siberia. From 2012 to 2014 on, Tunka-Rex operated exclusively together with its host experiment, the air-Cherenkov array Tunka-133, which provided trigger, data acquisition, and an independent air-shower reconstruction. It was shown that the air-shower energy can be reconstructed by Tunka-Rex with a precision of 15% for events with signal in at least 3 antennas, using the radio amplitude at a distance of 120m from the shower axis as an energy estimator. Using the reconstruction from the host experiment Tunka-133 for the air-shower geometry (shower core and direction), the energy estimator can in principle already be obtained with measurements from a single antenna, close to the reference distance. We present a method for event selection and energy reconstruction, requiring only one antenna, and achieving a precision of about 20%. This method enables energy reconstruction with Tunka-Rex for three times more events than the standard reconstruction. The effective detector area is tripled for high-energy events, vertical events are already observed at lower energies, and the energy threshold decreases to by about 40%.

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HiSCORE-EA is the first detector phase of this project. It will consist of an array of HiSCORE stations distributed over an area of up to 1 km². The components of HiSCORE-EA will be as close as possible to the final HiSCORE components.
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Title: Tunka-Rex: a Radio Antenna Array for the Tunka Experiment (ARENA 2012)
Authors: F.G. Schröder, D. Besson, N.M. Budnev, O.A. Gress, A. Haungs, R. Hiller, Y. Kazarina, M. Kleifges, A. Konstantinov, E.E. Korosteleva, D. Kostunin, O. Krömer, L.A. Kuzmichev, R.R. Mirgazov, A. Pankov, V.V. Prosin, G.I. Rubtsov, C. Rühle, V. Savinov, J. Stockham, M. Stockham, E. Svetnitsky, R. Wischnewski, A. Zagorodnikov

Tunka-Rex, the Tunka radio extension, is an array of 20 antennas at the Tunka experiment close to Lake Baikal in Siberia. It started operation on 08 October 2012. The antennas are connected directly to the data acquisition of the Tunka main detector, a 1 square-km large array of 133 non-imaging photomultipliers observing the Cherenkov light of air showers in dark and clear nights. This allows to cross-calibrate the radio signal with the air-Cherenkov signal of the same air showers - in particular with respect to the energy and the atmospheric depth of the shower maximum, Xmax. Consequently, we can test whether in rural regions with low radio background the practically achievable radio precision comes close to the precision of the established fluorescence and air-Cherenkov techniques. At a mid-term perspective, due to its higher duty-cycle, Tunka-Rex can enhance the effective observing time of Tunka by an order of magnitude, at least in the interesting energy range above 100 PeV. Moreover, Tunka-Rex is very cost-effective, e.g., by using economic Short Aperiodic Loaded Loop Antennas (SALLAs). Thus, the results of Tunka-Rex and the comparison to other sophisticated radio arrays will provide crucial input for future large-scale cosmic-ray observatories, for which measurement precision as well as costs per area have to be optimised. In this paper we shortly describe the Tunka-Rex setup and discuss the technical and scientific goals of Tunka-Rex.

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