ALmaty RAdio Cluster


    Almarac (Almaty Radio Cluster) - a cluster of antennas for the detection of cosmic rays and neutrinos of ultrahigh energies located at the high-altitude cosmic ray station on the Tien Shan (43 ° 15` N, 76 ° 57` E, 3340 m above sea level). The Tien Shan Mountain Cosmic Ray Station is designed for EAS detection in the range of the primary cosmic ray energies of 10^14 - 10^17 eV by direct detecting of charged shower particles at the station level
    is a convenient place for the development of the radio method for detecting of the same high energy cosmic rays. The inclusion of an antenna cluster for recording the EAS radio emission in the Tien Shan Mountain Cosmic Ray Station makes it possible to calibrate EAS research methods and allows you to set the accuracy limits for determining EAS parameters based on their simultaneous operation. In the future, with the development of experimental technology and the expansion of the detector system, the study of EASs with primary energy up to 10^19 eV should be possible. This opens up the possibility of studying many still unclear problems, such as the primary composition, the anisotropy of the sources of cosmic-ray particles of ultrahigh energies.

    As a detecting element, 2 loop antennas of the SALLA type (Short Aperiodic Loaded Loop Antenna), oriented to the northwest and northeast direction, are used. This type of antenna, developed by German engineer Oliver Kroemer, has two main advantages: firstly, these antennas are inexpensive and easy to manufacture, and secondly, their directivity pattern does not depend much on the underlying surface. Each antenna station is located 30 m from the registration point in the north, south, west, east direction and has two perpendicular antennas, which allows you to restore the polarization of the electromagnetic wave. The antennas in the lower part are shorted to the load, and in the upper part they are connected via a matching impedance transformer to the broadband LNA preamplifier (Low Noise Amplifier - amplifier with a transmission coefficient of 24 dB, developed on the basis of the MGA-62563 chip). The filter amplifier has the following characteristics: a filter passband of 30-80 MHz, a gain of 32 dB, a suppression of side frequencies of 46 over 90 dB.

    The experiment has been working since the beginning of 2019.