We present an improved method for the precise reconstruction of cosmic-ray air showers above 1017 eV with sparse radio arrays. The method is based on the comparison of measured pulses to predictions ...for radio pulse shapes by CoREAS simulations. We applied our method to the data of Tunka-Rex, a 1 km2 radio array in Siberia operating in the frequency band of 30–80 MHz. Tunka-Rex is triggered by the air-Cherenkov detector Tunka-133 and by scintillators (Tunka-Grande). The instrument collects air-shower data since 2012. The present paper describes an updated data analysis of Tunka-Rex and details of the new method applied. After quality cuts, when Tunka-Rex reaches its full efficiency, the energy resolution of about 10% given by the new method has reached the limit of systematic uncertainties due to the calibration uncertainty and shower-to-shower fluctuations. At the same time the shower maximum reconstruction has improved compared to the previous method based on the slope of the lateral distribution and reaches a precision of better than 35 g/cm2. We also define conditions of the measurements at which the shower maximum resolution of Tunka-Rex reaches a value of 25 g/cm2 and becomes competitive to optical detectors. To check and validate our reconstruction and efficiency cuts we compare individual events to the reconstruction of Tunka-133. Furthermore, we compare the mean of the shower maximum as a function of primary energy to the measurements of other experiments.
The radio technique is a promising method for detection of cosmic-ray air showers of energies around 100PeV and higher with an array of radio antennas. Since the amplitude of the radio signal can be ...measured absolutely and increases with the shower energy, radio measurements can be used to determine the air-shower energy on an absolute scale. We show that calibrated measurements of radio detectors operated in coincidence with host experiments measuring air showers based on other techniques can be used for comparing the energy scales of these host experiments. Using two approaches, first via direct amplitude measurements, and second via comparison of measurements with air shower simulations, we compare the energy scales of the air-shower experiments Tunka-133 and KASCADE-Grande, using their radio extensions, Tunka-Rex and LOPES, respectively. Due to the consistent amplitude calibration for Tunka-Rex and LOPES achieved by using the same reference source, this comparison reaches an accuracy of approximately 10% – limited by some shortcomings of LOPES, which was a prototype experiment for the digital radio technique for air showers. In particular we show that the energy scales of cosmic-ray measurements by the independently calibrated experiments KASCADE-Grande and Tunka-133 are consistent with each other on this level.
The Tunka-Grande experiment Monkhoev, R.D.; Budnev, N.M.; Chiavassa, A. ...
Journal of instrumentation,
06/2017, Letnik:
12, Številka:
6
Journal Article
Recenzirano
The investigation of energy spectrum and mass composition of primary cosmic rays in the energy range 1016–1018 eV and the search for diffuse cosmic gamma rays are of the great interest for ...understanding mechanisms and nature of high-energy particle sources, the problem of great importance in modern astrophysics. Tunka-Grande scintillator array is a part of the experimental complex TAIGA (Tunka Advanced Instrument for Cosmic Ray and Gamma Astronomy) which is located in the Tunka Valley, about 50 km from Lake Baikal. The purpose of this array is the study of diffuse gamma rays and cosmic rays of ultra-high energies by detecting extensive air showers. We describe the design, specifications of the read-out, data acquisition (DAQ) and control systems of the array.
We reconstructed the energy and the position of the shower maximum of air showers with energies E ∼> 100 PeV applying a method using radio measurements performed with Tunka-Rex. An event-to-event ...comparison to air-Cherenkov measurements of the same air showers with the Tunka-133 photomultiplier array confirms that the radio reconstruction works reliably. The Tunka-Rex reconstruction methods and absolute scales have been tuned on CoREAS simulations and yield energy and X{sub max} values consistent with the Tunka-133 measurements. The results of two independent measurement seasons agree within statistical uncertainties, which gives additional confidence in the radio reconstruction. The energy precision of Tunka-Rex is comparable to the Tunka-133 precision of 15%, and exhibits a 20% uncertainty on the absolute scale dominated by the amplitude calibration of the antennas. For X{sub max}, this is the first direct experimental correlation of radio measurements with a different, established method. At the moment, the X{sub max} resolution of Tunka-Rex is approximately 40 g/cm{sup 2}. This resolution can probably be improved by deploying additional antennas and by further development of the reconstruction methods, since the present analysis does not yet reveal any principle limitations.
The Tunka Radio Extension (Tunka-Rex) is a digital antenna array, which measures radio emission of the cosmic-ray air-showers in the frequency band of 30-80 MHz. Tunka-Rex is co-located with the ...TAIGA experiment in Siberia and consists of 63 antennas, 57 of them are in a densely instrumented area of about 1 km
2
. In the present workwe discuss the improvements of the signal reconstruction applied for Tunka-Rex. At the first stage we implemented matched filtering using averaged signals as template. The simulation study has shown that matched filtering allows one to decrease the threshold of signal detection and increase its purity. However, the maximum performanceof matched filtering is achievable only in case of white noise, while in reality the noise is not fully random due to different reasons. To recognize hidden features of the noise and treat them, we decided to use convolutional neural network with autoencoder architecture. Taking the recorded trace as an input, the autoencoder returns denoised traces, i.e. removes all signal-unrelated amplitudes. We present the comparison between the standard method of signal reconstruction, matched filtering and the autoencoder, and discuss the prospects of application of neural networks for lowering the threshold of digital antenna arrays for cosmic-ray detection.
The Cherenkov light array for the registration of extensive air showers (EAS) Tunka-133 collected data during 5 winter seasons from 2009 to 2014. The differential energy spectrum of all particles and ...the dependence of the average maximum depth on the energy in the range of 6 ⋅ 1015–1018 eV measured for 1540 hours of observation are presented.
Tunka-Rex is a radio detector for cosmic-ray air showers in Siberia, triggered by Tunka-133, a co-located air-Cherenkov detector. The main goal of Tunka-Rex is the cross-calibration of the two ...detectors by measuring the air-Cherenkov light and the radio signal emitted by the same air showers. This way we can explore the precision of the radio-detection technique, especially for the reconstruction of the primary energy and the depth of the shower maximum. The latter is sensitive to the mass of the primary cosmic-ray particles. In this paper we describe the detector setup and explain how electronics and antennas have been calibrated. The analysis of data of the first season proves the detection of cosmic-ray air showers and therefore, the functionality of the detector. We confirm the expected dependence of the detection threshold on the geomagnetic angle and the correlation between the energy of the primary cosmic-ray particle and the radio amplitude. Furthermore, we compare reconstructed amplitudes of radio pulses with predictions from CoREAS simulations, finding agreement within the uncertainties.
The Tunka Radio Extension (Tunka-Rex) is an antenna array spread over an area of about 1 km2. The array is placed at the Tunka Advanced Instrument for cosmic rays and Gamma Astronomy (TAIGA) and ...detects the radio emission of air showers in the band of 30 to 80 MHz. During the last years it was shown that a sparse array such as Tunka-Rex is capable of reconstructing the parameters of the primary particle as accurate as the modern instruments. Based on these results we continue developing our data analysis. Our next goal is the reconstruction of cosmic-ray energy spectrum observed only by a radio instrument. Taking a step towards it, we develop a model of aperture of our instrument and test it against hybrid TAIGA observations and Monte-Carlo simulations. In the present work we give an overview of the current status and results for the last five years of operation of Tunka-Rex and discuss prospects of the cosmic-ray energy estimation with sparse radio arrays.
Status of the Baikal-GVD project Avrorin, A.V.; Aynutdinov, V.M.; Bannasch, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2012, Letnik:
692
Journal Article
Recenzirano
Odprti dostop
The construction of a km3-scale neutrino telescope – the Gigaton Volume Detector (GVD) in Lake Baikal – is the central goal of the Baikal collaboration. During the R&D phase of the GVD project in ...2008–2010 years the basic elements of GVD – new optical modules, FADC readout units, underwater communications and trigger systems – have been developed, produced and tested in situ by long-term operating prototype strings in Lake Baikal. The prototyping phase of the GVD project has been started in April 2011 with the installation of a three string array (prototype cluster) which comprises all basic elements and systems of the GVD-telescope in Lake Baikal. We describe configuration and technical design of the GVD, present selected results obtained during 2008–2010 with prototype strings, and describe configuration and design of the 2011 prototype cluster.
The Tunka Radio Extension (Tunka-Rex) is a digital antenna array for the detection of radio emission from cosmic-ray air showers in the frequency band of 30 to 80 MHz and for primary energies above ...100 PeV. The standard analysis of Tunka-Rex includes events with zenith angle of up to 50?. This cut is determined by the efficiency of the external trigger. However, due to the air-shower footprint increasing with zenith angle and due to the more efficient generation of radio emission (the magnetic field in the Tunka valley is almost vertical), there are a number of ultra-high-energy inclined events detected by Tunka-Rex. In this work we present a first analysis of a subset of inclined events detected by Tunka-Rex. We estimate the energies of the selected events and test the efficiency of Tunka-Rex antennas for detection of inclined air showers.
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